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description: Melatonin improves sleep, & sleep is valuable
One of the problems with 'productivity' devices and methods is assessing their worth.
Many of them claim immeasurable gains^[[mindmaps](!Wikipedia "Mind map")], dubious gains^['image-streaming'], or clear gains which mayn't be worth the overhead^[schedulers, [personal organizers](!Wikipedia), _[Getting Things Done](!Wikipedia)_].
The benefits of others are perfectly measurable, like adding [keybindings](!Wikipedia) for repetitive tasks; just time the manual way versus the shortcut, and multiply it by the usage. But then the cost is hard to measure. How to assess the price of creating, learning, and rendering habitual a custom shortcut? There are scads of useful bindings in [Emacs](!Wikipedia) that I have tried to learn, only to forget them or remember them after I needed them.
My favorite 'productivity tool' is one that suffers from none of these problems, and has refreshingly clear-cut costs and benefits. Even though it eats up a third to a half of your life, sleep is neglected because people assume it is too hard to quantify or is too mysterious; but since it takes such a large chunk of time, even doubtful or unreliable improvements are well worth your while.
## Use
[Melatonin](!Wikipedia) is a [hormone](!Wikipedia) secreted by the [pineal gland](!Wikipedia). Its primary purpose is regulating the sleep cycle; its abatement permits waking. Odds are your local greengrocer carries it. It's often used by people suffering from insomnia or to combat conditions such as [jet lag](!Wikipedia).^[For which it has an excellent scientific track record; eg [Rikkert 2001](, [Zhadanova 2001](, or [Cardinali 2002](; this is the only use of melatonin Natural Standard gave an A rating, 'Strong scientific evidence for this use'.] It has other miscellaneous uses like combating other chronobiological issues and linked problems like depression[^depression]
[^depression]: Melatonin levels and chronobiological disturbances have been frequently correlated with various forms of depression; eg.
- [Mendlewicz et al 1979]( (review of existing research linking depression with abnormal melatonin secretion & low levels)
- [Nair et al 1984](
- [Brown et al 1985]( & [Frazer et al 1986]( (2 studies; in both, depressed had reduced melatonin secretion. Frazer's abstract notes that "These results are similar to those found recently by several other groups of investigators." Indeed.)
- [Kennedy et al 1989]( (controls vs eating disorder victims; only eating disorder plus depression correlated with lower melatonin)
- [Shafii et al 1996]( ("Post hoc analysis showed a significantly higher melatonin profile in depressed subjects without psychosis (n = 15) than in depressed subjects with psychosis (n = 7) or in the controls.")
- [Voderholzer et al 1997]( (a *negative* result - studying 9 young depressed former alcoholics, Voderholzer did not find any melatonin differences)
- [Crasson et al 2004]( (found delayed melatonin secretion eg. less in evening & more in morning, but still similar *total* secretions)
- [Dallaspezia & Benedetti 2011](
> Alteration of the sleep-wake cycle and of the sleep structure are core symptoms of a major depressive episode, and occur both in course of bipolar disorder and of major depressive disorder. Many other circadian rhythms, such as the daily profiles of body temperature, cortisol, thyrotropin, prolactin, growth hormone, melatonin and excretion of various metabolites in the urine, are disrupted in depressed patients, both unipolar and bipolar individuals. These disrupted rhythms seem to return to normality with patient recovery. Research on circadian rhythms and sleep have led to the definition of nonpharmacological therapies of mood disorder that can be used in everyday practice...
Improvement in the depressed:
- [Lewy et al 1998]( -(placebo-controlled trial of 5 patients)
- [Pacchierotti et al 2001]( (review of previous trials; concluded the relationship between melatonin & mood is unclear and the evidence was *not* solid enough to outright recommend it)
- [Dalton, et al 2000]( (sleep improvements in the depressed; depression improvement also occurred, but authors don't regard it as significant. No mention of worsening.)
- [Lewy et al 2006]( ([PDF](; 81 subjects; small improvements in depression, although not designed to test that. The results are very interesting inasmuch as it suggests SAD is made of two populations whose circadian rhythm are differently out of sync and who the theory predicts would benefit from melatonin supplementation at different times of day; the authors note that the subject whose depression got worse was also receiving melatonin at the 'wrong' time of day.)
- [Garzón et al 2009]( (sleep improvements in the elderly using melatonin; abstract mentions improvements in depression questionnaire scores but not whether any had actually been diagnosed depressed)
- Bright [light therapy](!Wikipedia), which affects melatonin, has been employed with various depressions:
- [SAD](!Wikipedia "Seasonal affective disorder"): [Pail et al 2011](
- [premenstrual dysphoric disorder](!Wikipedia): [Parry et al 2011](; see also [Bellipanni et al 2005]( ("At present we assert that the six-month treatment with MEL produced a remarkable and highly significant improvement of thyroid function, positive changes of gonadotropins towards more juvenile levels, and abrogation of menopause-related depression.")
Because of melatonin's weak anti-depressant effects, attempts have been made to customize it. The best covered seems to be [agomelatine](!Wikipedia) which binds to melatonin receptors and in the clinical trials, has the desired anti-depressant effects. [Hickie & Rogers 2011]( reviews "the associations between disrupted chronobiology and major depression" and regards agomelatine favorably, as does [Quera Salva et al 2011](; although [Howland 2011]( reviewed 13 placebo-controlled trials of agomelatine, concluding that the benefit may not be large (but neither mentions agomelatine being *pro*-depressant)
The one study I was able to find showing any negative effects was [Carman et al 1976]( ("Negative effects of melatonin on depression"), a double-blind study of 6 depressed patients. It does not seem to have been replicated. Lewy et al 2006 would seem to suggest that if there is anything to it, it may be caused by the specific timing of melatonin supplementation. If nothing else, melatonin may help with the depressed's sleep quality ([Dolberg et al 1998](, Dalton 2000, Garzón et al 2009).
But it's also useful for adults[^children] with perfectly normal sleep-cycles[^normal]. I am unsure whether its effect is to put one to sleep faster, or to do that and also deepen sleep, but melatonin does it well.
[^children]: Abnormal children benefit, although this may be as much due to the fact that children usually sleep very well to begin with and who would bother to study them? From the Natural Standard:
> "There are multiple trials investigating melatonin use in children with various neuro-psychiatric disorders, including mental retardation, autism, psychiatric disorders, visual impairment, or epilepsy. Studies have demonstrated reduced time to fall asleep (sleep latency) and increased sleep duration. Well-designed controlled trials in select patient populations are needed before a stronger or more specific recommendation can be made...Based on human study, melatonin may be beneficial in children with insomnia. More well-designed studies are needed before a conclusion can be made."
[^normal]: [Natural Standard]( 2011:
> "Multiple human studies have measured the effects of melatonin supplements on sleep in healthy individuals. A wide range of doses has been used often taken by mouth 30 to 60 minutes prior to sleep time. Most trials have been small, brief in duration, and have not been rigorously designed or reported. However, the weight of scientific evidence does suggest that melatonin decreases the time it takes to fall asleep ("sleep latency"), increases the feeling of "sleepiness," and may increase the duration of sleep. Better research is needed in this area."
## Safety
### Pro
Melatonin is apparently [safe](!Wikipedia "Melatonin#Side effects")^[As one would expect if the null hypothesis really is true, there are occasional cases where melatonin has *fewer* side-effects than placebo. [Lemoine et al 2012]( "Efficacy and safety of prolonged-release melatonin for insomnia in middle-aged and elderly patients with hypertension: a combined analysis of [4] controlled clinical trials") found that slow-release melatonin improved sleep quality & latency, but also that "The rate of adverse events normalized per 100 patient-weeks was lower for PRM [melatonin] (3.66) than for placebo (8.53)."]; from Wikipedia, a [meta-analysis](!Wikipedia), and a review (respectively) of melatonin studies:
> "Melatonin appears to cause very few side-effects in the short term, up to three months, when healthy people take it at low doses. A systematic review^[[63](]^ in 2006 looked specifically at efficacy and safety in two categories of melatonin usage: first, for sleep disturbances that are secondary to other diagnoses and, second, for sleep disorders such as jet lag and shift work that accompany sleep restriction.^[63]^ The study concluded that 'There is no evidence that melatonin is effective in treating secondary sleep disorders or sleep disorders accompanying sleep restriction, such as jet lag and shiftwork disorder. There is evidence that melatonin is safe with short term use.'^[63]^ A similar analysis^[[64](]^ by the same team a year earlier on the efficacy and safety of exogenous melatonin in the management of primary sleep disorders found that: 'There is evidence to suggest that melatonin is safe with short-term use (3 months or less).'"
> "The most commonly reported adverse effects of melatonin were nausea (incidence: ~ 1.5 percent), headache (incidence: ~ 7.8 percent), dizziness (incidence: 4.0 percent), and drowsiness (incidence: 20.33 percent); however, these effects were not significant compared to placebo. This result did not change by dose, the presence or absence of a sleep disorder, type of sleep disorder, duration of treatment, gender, age, formulation of melatonin, use of concurrent medication, study design, quality score, and allocation concealment score."^[["Melatonin for Treatment of Sleep Disorders: Summary"](; this meta-analysis also suggests that melatonin works on some metrics, but has little or no effect on other measurements, which is a contrast to my own generally sanguine belief.]
> "Based on available studies and clinical use, melatonin is generally regarded as safe in recommended doses (5 milligrams daily) for up to two years. Available trials report that overall adverse effects are not significantly more common with melatonin than placebo. However, case reports raise concerns about risks of blood clotting abnormalities (particularly in patients taking warfarin), increased risk of seizure, and disorientation with overdose."^[[Natural Standard]( 2011]
### Con
The FDA does not regulate melatonin, as a supplement, but it has declined to give it [GRAS](!Wikipedia)-status - the highest level of safety which allows it to be added to regular food; its warning letters are good sources if we are looking for evidence *against* melatonin's safety. One such [letter](, sent to the makers of the soda [Drank](!Wikipedia "Drank (soda)") which includes melatonin, cites 3 pieces of evidence:
1. increased cancer in female lab mice (but an increased lifespan! And human studies have not found any increased cancer[^cancer])
2. retinal damage in 2 lab mice variants (human clinical study found a *protective effect*[^retina])
3. a summary of a [Natural Standard](!Wikipedia) review monograph mentioning human research finding weak potential for decreased blood pressure[^blood], hyperglycemia[^sugar], and increased atherosclerotic plaque, and its general concern about the use of a hormone
[^cancer]: Natural Standard 2011:
> "There are several early-phase and controlled human trials of melatonin in patients with various advanced stage malignancies, including brain, breast, colorectal, gastric, liver, lung, pancreatic, and testicular cancer, as well as lymphoma, melanoma, renal cell carcinoma, and soft-tissue sarcoma. Currently, no clear conclusion can be drawn in this area. There is not enough definitive scientific evidence to discern if melatonin is beneficial against any type of cancer, whether it increases (or decreases) the effectiveness of other cancer therapies, or if it safely reduces chemotherapy side effects."
[^retina]: From the 2011 Natural Standard ['Bottom Line Monograph'](, ['Evidence' section](
> "Melatonin may exert antioxidant effects which may contribute to its beneficial effects on the eyes. According to clinical study, melatonin may play a role in protecting the retina to delay macular degeneration. Well-designed clinical trials are needed before a conclusion can be made....It has been theorized that high doses of melatonin may increase intraocular pressure and the risk of glaucoma, age-related maculopathy and myopia, or retinal damage. However, there is preliminary evidence that melatonin may actually decrease intraocular pressure in the eye and delay macular degeneration, and it has been suggested as a possible therapy for glaucoma. Additional study is necessary in this area. Patients with glaucoma taking melatonin should be monitored by a healthcare professional."
[^blood]: NS 2011:
> "Several controlled studies in patients with high blood pressure report small reductions blood pressure when taking melatonin by mouth (orally) or inhaled through the nose (intranasally). Specifically, nocturnal high blood pressure may improve with melatonin use. Better-designed research is necessary before a firm conclusion can be reached."
[^sugar]: [NS]( 2011:
> "Elevated blood sugar levels (hyperglycemia) have been reported in patients with type 1 diabetes (insulin-dependent diabetes), and low doses of melatonin have reduced glucose tolerance and insulin sensitivity. Caution is advised in patients with diabetes or hypoglycemia, and in those taking drugs, herbs, or supplements that affect blood sugar. Serum glucose levels may need to be monitored by a healthcare provider, and medication adjustments may be necessary."
## Benefits
### Health & performance
> `Luke`: "Is the dark side stronger?" \
> `Yoda`: "No, no, no! Quicker, easier, more seductive..."^[_The Empire Strikes Back_]
One might object that they do not wish to tamper with their natural sleep, even if melatonin is a normally-secreted hormone.
Sad to say, I would point out to such readers that they are *already* profoundly tampering with their natural sleep cycle, and indeed, all of Western civilization is tampering with it; most of my readers do not even sleep multiple times during the day, as 'Nature intends' and as humans have usually slept through history[^stampi], but rather in a single 7-9 hour long block. [Sleep debt](!Wikipedia) causes negative changes similar to [aging](, and [sleep deprivation](!Wikipedia), both acute [*and* chronic](, damage mental performance[^daylightsavings], and chronic does so [cumulatively]( over the deprivation period (conversely, sleep [improves performance](; worse, one may not be able to simply sleep in on the weekend, both because it's too short a time period to repay sleep debt ([William Dement 2005]( noting it may take a full month to repay the large sleep debt incurred by regular shortfalls; [jet lag](!Wikipedia) in well-rested mice can take [up to 28 days]( to mentally recover from) and because in practice one *doesn't* sleep in very much - the Zeo database of sleep records only [an extra 23 minutes a day]( on the weekend. Subjects in chronic sleep deprivation studies were subjectively [unable to notice their performance declines]( Finally, there are multiple lines of research suggesting chronic sleep deprivation is prevalent among [young adults]( (including historical comparisons^[See Webb WB, Agnew HW (1975), "Are we chronically sleep deprived?" _Bull. the Psychonomic_ Soc. 6:47-48.]^[["Never Enough Sleep: A Brief History of Sleep Recommendations for Children"](/docs/2012-matricciani.pdf) reviews literature from 2009 back to 1897, finding that sleep fell by around an hour on average (with very wide variation at both dates); they also find that sleep recommendations are regularly anchored towards recommending more sleep than children were actually getting - which the authors apparently take as evidence for the recommendations being false but I take as perfectly consistent with the picture I illustrate here of an ever more short-sleeping modern society and explicable by the fact that the *average* of the 1890s sleep recommendations - *10.8* hours - would be hysterically laughed at by modern parents (hence the average recommendation in the 2000s of closer to 9.8 hours).]). It is striking that unemployed adults sleep a full hour longer than the employed^["A coming study by Mr. Krueger, using historical data on time use between 1991 and 2006, finds that unemployed Americans tend to sleep an hour longer than the employed." ["Leisure Trumps Learning in Time-Use Survey: Americans Opt for TV in Spare Hours, Not Workouts or Classes, Poll Finds"](, 23 June 2011 _Wall Street Journal_], and that when normal adults are placed in settings without time indicators, they sleep longer than before - exactly as if they were sleep deprived.[^arctic] Additional sleep is linked with athletic[^ericssonnyt] and artistic success[^ericssonpdf], and so on and so on. One could well ask with [Alexander Pushkin](!Wikipedia), "Why am I to feel this pain?"[^pushkin]
[^stampi]: Biphasic sleep was universal until recently, especially in England; see A. Roger Ekirch's ["Sleep We Have Lost: Pre-industrial Slumber in the British Isles"]( and his 2005 _At Day’s Close: Night in Times Past_. Anthropology agrees; [biphasic]( sleep is positively pedestrian, and from [Claudio Stampi](!Wikipedia)'s book on [polyphasic sleep](!Wikipedia) ([_Why We Nap_]( pg 8-9):
> "It is worth mentioning that anthropological studies conducted in tribes active at night show that human sleep can be highly polyphasic in certain cultures. Although they have different cultures and ways of life, both the Temiars of Indonesia and the Ibans of Sarawak have similar polyphasic sleep-wake behaviors (Petre-Quadens, 1983). Their average nocturnal sleep episode duration ranges between 4 and 6 hr, and nighttime activities (fishing, cooking, watching over the fire, rituals) at any one time involve approximately 25% of the adult members. Daytime napping is very common in both tribes: at almost any time of day, about 10% of the adult members are asleep. Whatever the cause of these polyphasic sleep patterns,whether the expression of an inborn ultradian rest-activity tendency or other factors, such populations exhibit extremely flexible and fragmentary sleep-wake cycles. The minimal contact with modern civilization could be one of the reasons for the preservation of this possibly ancestral sleep pattern."
[^daylightsavings]: With potentially fatal effect. From Coren 1998:
> "In fact, our societal sleep debt is so great that simply losing one additional hour of sleep due to the spring shift to daylight savings time can increase traffic accident rates by 7% ([Coren, 1996b]( and death rates due to all accidents by 6.5% ([Coren, 1996c]("
[^arctic]: ["Sleep Deprivation, Psychosis and Mental Efficiency"](, Coren 1998, _Psychiatric Times_
> "Confirmation of these natural sleep durations comes from [Palinkas, Suedfeld and Steel (1995)]( These researchers spent a summer above the arctic circle where there is continuous light 24 hours a day. All watches, clocks and other timekeeping devices were removed, and only the station's computers tracked the times that the team went to sleep and awakened. Individual researchers did their work, and chose when to sleep or wake according to their "body time." At the end of the experiment, they found that their overall average sleep daily time was 10.3 hours. Every member of the team showed an increase in sleep time, with the shortest logging in at 8.8 hours a day, and the longest almost 12 hours a day. This study, like many others, seems to suggest that our biological need for sleep might be closer to the 10 hours per day that is typical of monkeys and apes living in the wild, than the 7 to 7.5 hours typical of humans in today's high-tech, clock-driven lifestyle."
[^ericssonnyt]: ["Peak Performance: Why Records Fall"](, Goleman 1994, _The New York Times_:
> '"When we train Olympic weight lifters, we find we often have to throttle back the total time they work out," said Dr. Mahoney. "Otherwise you find a tremendous drop in mood, and a jump in irritability, fatigue and apathy."
> Because their intense practice regimen puts them at risk for burnout or strain injuries, most elite competitors also make rest part of their training routine, sleeping a full eight hours and often napping a half-hour a day, Dr. Ericsson found.'
[^ericssonpdf]: ["The Role of Deliberate Practice in the Acquisition of Expert Performance"](/docs/1993-ericsson-deliberatepractice.pdf) 1993:
> "The high relevance of sleep for improving violin performance must be indirect and related to the need to recover from effortful activities such as practice. Consistent with the ratings, sleep is the least effortful of the activities and thus constitutes the purest form of rest. The weekly amount of sleep during the diary week did not differ for the two best groups and averaged 60.0 hr. This average was reliably longer than that for the music teachers, which was 54.6 hr, jF(l, 27) = 5.02, p < .05. Hence the two best groups, who practice more, also sleep reliably longer."
[^pushkin]: ["Verses, composed during a night of insomnia..."](
Indeed, aside from all the previous cited evidence that one's sleep is already being badly damaged by modern lifestyles (deprivation, monophasic block sleep, etc.), there's a specific argument to be made that the health of heavy electronics-users (such as myself and my readers) will *improve* through melatonin supplementation. Computer use correlates with less sleep and negative events [in teenagers]( Indoor lighting affects the [timing of circadian shifts]( "Intrinsic period and light intensity determine the phase relationship between melatonin and sleep in humans") and ordinary room lighting at night, before bedtime, has been shown to cut melatonin secretion in half[^light], and afternoon/evening artificial light damages subjective alertness & [dual n-back](DNB FAQ) performance compared to natural light[^DNB]. Blue light is the [main culprit](!Wikipedia "Melatonin#Light dependence")[^blue] (white is [still bad](/docs/2011-falchi.pdf), though); there are counter-measures to reduce one's exposure to blue light [like]( [light-filtering]( [glasses]([^shah] or programs such as [Redshift]([f.lux]( which lower the [color temperature](!Wikipedia) (reducing the blueness & redden) of one's monitor. They are a good idea^[Fellow programmers: you would particularly benefit from using Redshift/F.lux. If you don't believe me, read [some]( [testimonials](]. But they aren't perfect solutions and only reduce the damage; and if [Robin Hanson](!Wikipedia) is [right that]( future bright [LED lights](!Wikipedia) will be cheaper and more popular, we can expect that much more problems with melatonin deficiency. And what are those problems?
[^blue]: To quote extensively from ["In Eyes, a Clock Calibrated by Wavelengths of Light"](, _New York Times_:
> "So scientists at the University of Basel in Switzerland tried a simple experiment: They asked 13 men to sit before a computer each evening for two weeks before going to bed. During one week, for five hours every night, the volunteers sat before an old-style fluorescent monitor emitting light composed of several colors from the visible spectrum, though very little blue. Another week, the men sat at screens backlighted by light-emitting diodes, or LEDs. This screen was twice as blue.
> “To our surprise, we saw huge differences,” said Christian Cajochen, who heads the Center for Chronobiology at the University of Basel. Melatonin levels in volunteers watching the LED screens took longer to rise at night, compared with when the participants were watching the fluorescent screens, and the deficit persisted throughout the evening. The subjects also scored higher on tests of memory and cognition after exposure to blue light, Dr. Cajochen and his team reported in the May issue of The Journal of Applied Physiology. While men were able to recall pairs of words flashed across the fluorescent screen about half the time, some scores rose to almost 70 percent when they stared at the LED monitors.
> The finding adds to a series of others suggesting, though certainly not proving, that exposure to blue light may keep us more awake and alert, partly by suppressing production of melatonin. An LED screen bright enough and big enough “could be giving you an alert stimulus at a time that will frustrate your body's ability to go to sleep later,” said Dr. Brainard. “When you turn it off, it doesn't mean that instantly the alerting effects go away. There's an underlying biology that's stimulated.”
> ...Artificial light has been around for more than 120 years. But the light emitted by older sources, like incandescent bulbs, contains more red wavelengths. The problem now, Dr. Brainard and other researchers fear, is that our world is increasingly illuminated in blue. By one estimate, 1.6 billion new computers, televisions and cellphones were sold last year alone, and incandescent lights are being replaced by more energy-efficient, and often bluer, bulbs.
> In January in the journal PLoS One, the University of Basel team also compared the effects of incandescent bulbs to fluorescents modified to emit more blue light. Men exposed to the fluorescent lights produced 40 percent less melatonin than when they were exposed to incandescent bulbs, and they reported feeling more awake an hour after the lights went off. In addition, the quantity of light necessary to affect melatonin may be much smaller than once thought. In research published in March in The Journal of Clinical Endocrinology and Metabolism, a team at the Harvard Medical School reported that ordinary indoor lighting before bedtime suppressed melatonin in the brain, even delaying production of the hormone for 90 minutes after the lights were off, compared with people exposed to only dim light.
> What do these findings mean to everyday life? Some experts believe that any kind of light too late into the evening could have broad health effects, independent of any effect on sleep. For example, a report published last year in the journal PNAS found that mice exposed to light at night gained more weight than those housed in normal light, even though both groups consumed the same number of calories. Light at night has been examined as a contributor to breast cancer for two decades. While there is still no consensus, enough laboratory and epidemiological studies have supported the idea that in 2007, the World Health Organization declared shift work a probable carcinogen. Body clock disruptions “can alter sleep-activity patterns, suppress melatonin production and disregulate genes involved in tumor development,” the agency concluded."
See also a Navy-funded RPI sleep study, which found ["Only the higher level of blue light resulted in a reduction in melatonin levels relative to the other lighting conditions."](
[^shah]: A fellow [Zeo]() user, Sanjiv Shah has reportedly found significant benefits for himself from the orange glasses, although he seems to not have a webpage on it but [given talks](; from _Technology Review_, ["The Measured Life"](
> "Sanjiv Shah, a longtime insomniac who participates in the Boston group, believes that wearing orange-tinted glasses for several hours before bed makes it easier for him to fall asleep. (The theory is that the orange tint blocks blue light, which has been shown in both human and animal studies to influence circadian rhythms.) To quantify the effects, he used not only the Zeo but also a thumb-size device called the Fitbit, which incorporates an accelerometer that measures movement, and a camera trained on his bed to record his sleep for a month. His results: without the glasses, he took an average of 28 minutes to fall asleep, but with them he took only four."
[^DNB]: ["Effects of prior light exposure on early evening performance, subjective sleepiness, and hormonal secretion"](, Münch et al 2011 ([media coverage](
> "...We tested the impact of two realistic office lighting conditions during the afternoon on subjective sleepiness, hormonal secretion, and cognitive performance in the early evening hours. Twenty-nine young subjects came twice and spent 8 h (12:00-20:00) in our laboratory, where they were exposed for 6 h to either artificial light (AL) or to mainly daylight (DL). In the early evening, we assessed their salivary cortisol and melatonin secretion, subjective sleepiness, and cognitive performance (n-back test) under dim light conditions. Subjects felt significantly more alert at the beginning of the evening after the DL condition, and they became sleepier at the end of the evening after the AL condition. For cognitive performance we found a significant interaction between light conditions, mental load (2- or 3-back task) and the order of light administration. On their first evening, subjects performed with similar accuracy after both light conditions, but on their second evening, subjects performed significantly more accurately after the DL in both n-back versions and committed fewer false alarms in the 2-back task compared to the AL group. Lower sleepiness in the evening was significantly correlated with better cognitive performance (p < .05)..."
[Shift workers](!Wikipedia) have been linked to a great many health problems (such as [various]( [cancers]( or [mental delays](; see [shift work sleep disorder](!Wikipedia)), and the proposed causal mechanism is usually a melatonin deficiency (and melatonin supplementation one of the [treatments](!Wikipedia "Shift work sleep disorder#Melatonin treatment")). (They have also been linked to many accidents and [near-accidents](
[^light]: See ["Light Exposure May Cut Production of Melatonin: Study Shows Artificial Light Before Bedtime May Affect Quality of Sleep"](, _WebMD_; ["Melatonin production falls if the lights are on"](, _BBC News_; and an older study, ["The dark side of light at night: physiological, epidemiological, and ecological consequences"]( More recently, the [National Sleep Foundation](!Wikipedia) released its [2011 survey]( finding ever more electronics use before bed; relevant quote:
> ""Artificial light exposure between dusk and the time we go to bed at night suppresses release of the sleep-promoting hormone melatonin, enhances alertness and shifts circadian rhythms to a later hour--making it more difficult to fall asleep," says Charles Czeisler, Ph.D., MD, Harvard Medical School and Brigham and Women's Hospital. "This study reveals that light-emitting screens are in heavy use within the pivotal hour before sleep. Invasion of such alerting technologies into the bedroom may contribute to the high proportion of respondents who reported that they routinely get less sleep than they need." Computer or laptop use is also common. Roughly six in ten (61%) say they use their laptops or computers at least a few nights a week within the hour before bed. More than half of generation Z'ers (55%) and slightly less of generation Y'ers (47%) say they surf the Internet every night or almost every night within the hour before sleep."
### _Tempus Fugit_
My rule of thumb is melatonin subtracts an hour. (I originally guessed at this value, but my Zeo sleep recordings seem to suggest the value is [more like 50 minutes](Zeo#melatonin-analysis).) That is: if one slept for 7 hours, one awakes as refreshed as if one had slept for 8 hours etc. There are few to no side-effects to melatonin use in adults (there is uncertainty about the risks & benefits in children & adolescents[^adolescents]), and it is not addictive or habit-forming like caffeine is. The usual dose for a night is 1-3 mg and I take 1.5mg[^od]; this may be too high and be responsible for why some people try melatonin and report that it does nothing or hurts them, since in [one study]( "'Melatonin Treatment for Age-Related Insomnia', Zhdanova et al 2001"), the best dose for old people was 10x smaller (0.1mg or 0.3mg) and for one blind person, 0.5mg^[["Low, but not high, doses of melatonin entrained a free-running blind person with a long circadian period"](, Lewy et al 2002]^[["Entrainment of Free-Running Circadian Rhythms by Melatonin in Blind People"](, Sack et al 2000 found that 10mg succeeded in forcing circadian rhythms in the blind; they tapered the dose down to 0.5mg for a few subjects over 4 months, and the rhythms seemed to persist.]. A study of delayed-release melatonin found with their high dose of 4mg (but not 0.4mg) elevated melatonin levels 10 hours after bedtime ([Gooneratne et al 2011](/docs/2011-gooneratne.pdf "Melatonin pharmacokinetics following two different oral surge-sustained release doses in older adults")) - potentially interfering with waking time. Tested supplements have the claimed amounts of melatonin, but their recommended doses can be terrible ideas and definitely should be ignored if they advise more than 5mg![^] (Experimentation may be necessary; people can be very different.)
[^od]: If one overdoses and takes, say, 9 mg, the effect is that one will sleep for 10-12 hours, and as I can attest, then awake with a nasty headache that lasts for the rest of that day. You'll notice that one doesn't sleep 3 or 6 times the normal amount; this suggests that melatonin quickly loses effectiveness and soon becomes counterproductive; [Wikipedia summarizes](!Wikipedia "Melatonin#Use as a dietary supplement"):
> "Large doses of melatonin can even be counterproductive: Lewy et al[68] provide support to the 'idea that too much melatonin may spill over onto the wrong zone of the melatonin phase-response curve' (PRC). In one of their subjects, 0.5 mg of melatonin was effective while 20 mg was not."
My own dose of 1.5mg is not due to any real kind of experimentation; rather, I created a batch of about a thousand capsules using split 3mg pills, have not yet used them up, and have no real interest in throwing them out or otherwise changing them.
[^adolescents]: My own experience was positive, and teenagers are frequently sleep-deprived due to factors like their circadian rhythms wildly conflicting with school schedules (see my [rough notes](education-is-not-about-learning#school-hours) on the topic). However, children & adolescents have melatonin secretion rates [5-9 times greater]( than middle-aged or very old adults, and those very high rates combined with large supplements like 3mg *may* (and I use this word advisedly) be able to push melatonin concentration to high enough levels that some [negative chemistry]( may happen (extremely high doses have often been used in clinical trials with no noted side-effect eg. [40mg/day]( but these are almost all adults). In addition, there's general uncertainty about how melatonin interacts with puberty and why the concentration falls so much with age.
[^]: From [press release summary]( of [](!Wikipedia)'s [melatonin testing](
>' Can melatonin help you sleep? “Melatonin supplements may help some people get to sleep sooner, particularly those with chronic sleeping problems, but don’t just buy any supplement - they vary significantly in strength, dosage, and cost,” says President, Tod Cooperman, M.D. recently selected and tested nine different melatonin supplements. The testing showed that all contained their labeled amounts of melatonin, but the suggested daily dosage ranged from 1 mg to 50 mg [!]; and cost ranged from just 4 cents to $1.36 for an equivalent dose of melatonin. This means you may not be using the right dose for your needs and you could be paying as much as 33 times more than necessary. also found that one supplement failed to properly disclose all of its ingredients.'
So that's what it does: it lets one cut 1 hour of sleep. (There are other benefits, such as enforcing a bedtime - invaluable for young people - but their values are indeterminate.)
Let's work out the cost of regularly using melatonin. Conservatively, a bottle of melatonin pills will cost about 6 USD for 150 pills. Per milligram, the 3 mg pills are the least costly, and are easily convertible into lower dosages. Regardless, one will get a minimum of 150 doses per $6. $\frac{600}{150}$ = 4¢ per pill. 1 night requires 1 dose, so each night costs 4¢. We need to consider much we value the effort of remembering and taking the pill, though. Let us be conservative and price it as high as 10¢. So we spend 14¢ per night[^price]. The reward is that we gain an hour.
[^price]: I say very pessimistic because my actual price is ~1.4¢ per night. In 2009, Tommy Health sold 120 3mg pills for $2.49; I bought 6, with shipping, at $20.89. Remembering that I take half a pill, the price per night is $\frac{\frac{2000}{6 \times 120}}{2}$, or, 1.38¢
Now how do we value an hour of our time? One could make an intuitive guess, or consider one's current salary and things like that, but in economics 101, it's common to just set the value of an hour at [minimum wage](!Wikipedia). This will hopefully not be *too* erroneous, since over our lifetime, the days where that extra hour was really valuable will balance out the days where the hour was worthless.
More concretely, the minimum wage is the floor for one's [opportunity cost](!Wikipedia); even if the hour's opportunity you forgo by sleeping more wasn't worth a million dollars, you could still have worked a unskilled minimum wage job and gotten the minimum wage.^[Like all models, this is wrong. There are [many ways]( in which it could be wrong or misleading to value an hour of your time at minimum wage or higher. While all models are wrong, some are more useful than others and this is a useful model.]
The federal minimum wage as of 2008 is $6.55 an hour[^conservative]. So let's say that is the reward.
[^conservative]: Here's another place I am being overly conservative to guard against optimism on my part; the minimum wage was boosted to $7.25 in 2009, which obviously makes the gained hour that much more valuable and consequently all the figures will favor melatonin that much more.
### ROI
In other words, by investing 14¢, we realize a net of 655¢, for a profit of 641¢. This represents a return on our investment of approximately 4678% ($\frac{655}{14} \times 100$).
Suppose we use only half a pill a night? Then our number of doses doubles, our pill price per night halves (though our 10¢ of effort remains constant), and our return becomes 5458% ($\frac{655}{12} \times 100$).
My local store sometimes runs a 2-for-1 sale on melatonin. One could buy only at these sales - the low consumption rate (1 a night, or less) means you must buy less than annually. Thus, the pill price halves again to 1¢ per night, and now the return is 5959% ($\frac{655}{11} \times 100$).
### Absolute gains
Let's look at another perspective. Those are impressive percentages, but they're on a low base so perhaps it's not worthwhile even with 6000% returns. What are the absolute gains one would realize over the course of a year? Well, to calculate: ($(365 \times 6.55) - (365 \times 0.11)$), or to simplify: ($365 \times (6.55 - 0.11)$) = $2350.60. We would have to assume our calculations are 3 or 4 orders of magnitude before melatonin stops being a good deal.
One year of melatonin amply repays the original costs of learning about and experimenting with it. (And the long-run benefits are substantial.[^future])
[^future]: Applying the usual 'net [present value](!Wikipedia) of a future sum' formula, which goes $present = \frac{future}{(1-discount)^n}$, we find that 60 years from now, the $2000 is worth $92: $2000 \times (1-0.05)^60 = 92.1$. We can be pessimistic and value the annual return at $200, and sum the 60 years in Haskell with `sum (map (\x -> 200 * (1-0.05)^x) [0..60])`, or $38245.a
## Self-discipline
Speaking from personal experience, I know that one of the obstacles to sleeping well is going to sleep at all. Even though one knows that one ought to go to bed on time, and that not doing so will cause problems, it's hard to actually do it, One wants to finish the book, chat with friends, play a game, etc. It is even more difficult when one doesn't feel tired. For me, I had a chronic _[akrasia](!Wikipedia)_ problem with going to sleep; in college, it was bad enough that I would on occasion stay up to 4 AM for no reason at all!
This dilemma is far from unique. It is called [hyperbolic discounting](!Wikipedia); humans can make the rational decision when at a great distance from a choice, but the closer they come, the more warped their decisions are. Procrastination is often thanks to hyperbolic discounting - 'hard work pays off tomorrow but procrastination pays off now', and never mind that tomorrow always comes. Similarly, addicts want to be free of their addiction, but their want for a drink _right now_ overwhelms their lifetime desire to not have drinks. (For more on the topic, see ["Akrasia, hyperbolic discounting, and picoeconomics"]( and ["Applied Picoeconomics"](
How do we deal with this? The classic mechanism is avoiding the choice entirely. An addict can avoid bars or liquor stores, but no one can avoid sleep. Failing to avoid the choice entirely, one raises the cost of 'procrastination' - make the addict pay $100 for every drink they take. Even apparently trivial cost increases like [someone watching our computer desktop]( through [VNC](!Wikipedia "Virtual Network Computing"), or working at a coffee shop[^coffee] can make a real difference with procrastination. We need to raise the cost, then, and somehow change the incentives to make us want to sleep.
[^coffee]: Many people [swear]( [by]( working in public places like libraries or cafes. Neeti Gupta remarks in ["Grande Wi-Fi: Understanding What Wi-Fi Users Are Doing in Coffee-Shops"]( (2004) that:
> "...when we are alone in a public place, we have a fear of "having no purpose". If we are in a public place and it looks like that we have no business there, it may not seem socially appropriate. In coffee-shops it is okay to be there to drink coffee but loitering is definitely not allowed by coffee-shop owners, so coffee-shops patrons deploy different methods to look "busy". Being disengaged is our big social fear, especially in public spaces, and people try to cover their "being there" with an acceptable visible activity."
We *can* do this simply by waiting until the need to sleep is so strong we can no longer resist; and in practice, many (especially college students) do just this. But few of us have the luxury of the bizarre schedule this entails. We could try some sort of monetary fine for not going to bed by midnight, but enforcement is difficult and if you're a college student, you may not be able to afford a vow painful enough to deter you.
Melatonin allows us a different way of raising the cost, a _physiological_ & self-enforcing way. Half an hour before we plan to go to sleep, we take a pill. The procrastinating effect will not work - half an hour is so far away that our decision-making process & willpower are undistorted and can make the right decision (viz. following the schedule). When the half-hour is up, the melatonin has begun to make us sleepy. Staying awake ceases to be free, to be the default option; now it is costly to fight the melatonin and remain awake. The choice of sleep may now prevail over the hyperbolically-distorted choice of video games. The long time-lag and the extreme ease of taking the melatonin makes it harder to succumb to a kind of 'meta-_akrasia_'[^eby] where you come up with a good trick or solution to make yourself do whatever it is you need to do - and then you start procrastinating/suffering from _akrasia_ about the trick!
[^eby]: Professional coach P.J. Eby [remarks that]( "*Most Akrasia Techniques Are Subject To "Meta"-Akrasia*. If you procrastinate taking your pills or doing your exercises, your hygenic method is unstable: the more you delay, the more likely you are to delay some more. The same is true for maintaining your "trusted system" in Getting Things Done, breaking your tasks into Pomodoros, or whatever other focusing method you use. And of course, if you put off doing your motivation technique, it's not going to motivate you."
And going to sleep when you need to go to sleep is, in the long-run, a very valuable thing in its own right.
## Excuses, excuses...
Melatonin is a clear-cut Good Thing. The gains I have laid out are significant enough I consider it irrational for someone not to use it, unless:
1. You've never heard of it, or seen an analysis of the possible benefits.
- You, dear reader, are no longer allowed this excuse.
2. You are *so* poor that 6 dollars every 150 or 300 days is a crippling expense.
- But then how come you to have the free time to read this?
3. Melatonin supplements just doesn't work on you, period.
- Possible (I have read [multiple anecdotes]( that melatonin did nothing to help), but it's not *that* common. Melatonin isn't some mental trick - it's a fundamental fact of mammalian biology. I've run into more people who have tried melatonin and had it help than found it completely ineffective, and I wonder if some of the non-responders varied their doses to test the lower ranges like 0.1mg.
4. They work, but not well enough.
- This implies that melatonin save you only a few minutes or seconds, else the gain would be smaller but still be positive. (This too strikes me as unlikely.)
4. You value a simpler, less complicated life *that* much.
- Taking a pill at night, and buying some pills once every year or two stresses you out?
5. You value an hour at less than 11¢, so melatonin is not profitable.
- Please contact me. I would like to hire you at the princely rate of a quarter an hour to do drudge-work on Wikipedia.^[To clarify: In the hypothetical case, why would you be willing to pay one hour of your time (which could be spent doing anything, even high-quality work or experiences and perhaps *especially* high quality work, given all the research on good sleep and mental performance) to gain a few cents by not buying melatonin, but not willing to pay one hour of easy Wikipedia editing to gain many more cents?]
6. You are a child or adolescent (see the footnote previously)
- Legitimate; at the very least, the cost-benefit analysis becomes uncertain enough that there's no *obvious* right answer.
7. Melatonin is prescription-only or banned.
- You have my sympathies.
## Competition
A parting thought: millions of Americans regularly take [multivitamin](!Wikipedia) supplements. These supplements are unlikely to help a balanced diet, there is little evidence they do, and there are studies which have indicated actual harm from the consumption of multivitamins[^vitamins]. Multivitamins are noticeably more expensive than melatonin pills, and are certainly harder to swallow. And this is to say nothing of supplements which are actually dangerous, like [kava](!Wikipedia) or [ephedra](!Wikipedia). Do you take a multivitamin, but not melatonin? If so, how can you justify this?
[^vitamins]: See the multiple large studies cited in ["Vitamin Pills: A False Hope?"](; note that at least 3 studies showed increased disease & mortality rates associated with multivitamin usage, and [Wikipedia](!Wikipedia "Multivitamin#Evidence against") mentions a few downbeat reports & commissions.
Interestingly, [antioxidants](!Wikipedia "Antioxidant#Adverse effects") show [no]( [anti-cancer]( effects and [no mortality reduction]( in very large datasets and [Cochrane reviews]( (sometimes [increased mortality](, and only weak evidence in randomized trials measuring [elderly infection rates]( That's when they don't actually [cause]( [problems]( [with]( [cancer]( (eg. [negating chemotherapy]( and [destroying](!Wikipedia "Antioxidant#Physical exercise") [benefits]( [from]( [exercise](, see also the post ["Antioxidants and Exercise: More Harm Than Good?"]( or the review ["Antioxidants and Skeletal Muscle Performance: 'Common Knowledge' vs. Experimental Evidence"]( "Hernández et al 2012")). Multivitamins don't have much research backing, and a risk with multivitamins is that they are a [moral hazard](!Wikipedia) and an example of [risk homeostasis](!Wikipedia) - because people mistakenly expect benefits (large or small), they feel free to [act in unhealthy ways](
> "The study, [published online]( "A randomized experiment to examine unintended consequences of dietary supplement use among daily smokers: taking supplements reduces self-regulation of smoking") today in the journal _Addiction_, describes two experiments run by the authors. In the first experiment, run as a dummy health-food test, 74 daily smokers were given a placebo, but half were told they had taken a Vitamin C supplement. The smokers then took a one-hour unrelated survey during which they were allowed to smoke. Those who thought they had taken a vitamin pill smoked almost twice as much as those who knew they had taken a placebo (the control group) and reported greater feelings of invulnerability. The second experiment was an expanded version of the first, with 80 participants taken from a larger community and half told they were taking a multivitamin pill. The one-hour survey also contained questions about attitudes to multivitamins. The smokers who thought they had taken a multivitamin once again smoked more than the control group. But this time, researchers found that among the multivitamin group, smokers with more positive attitudes toward multivitamins experienced a higher boost in perceived invulnerability and smoked even more than their less enthusiastic counterparts. In other words, the amount of extra smoking rose if the smoker expressed a conscious belief that multivitamins increased health."
Of course, such contrarianism receives its own critics; [Phil Goetz]( "Even if you have a nail, not all hammers are the same") says that 3 of the major anti-vitamin studies have fatal statistical flaws.
# See also
- [Modafinil]() - if you want to go even further down the sleep-modification rabbit hole of trading money for time
# External links
- ["Case study: Melatonin"]( - an earlier version posted on [_LessWrong_](, with >=136 comments. LW experience reports:
1. <>
2. <>
3. <>
- [Erowid](!Wikipedia)'s [melatonin case reports]( -(both positive & negative)
- ["#34 2-Me-DMT"]( -(melatonin entry in the Shulgin's _[TiHKAL](!Wikipedia); skeptical)
- ["Taking Melatonin forever?"]( -(Reddit discussion of long-term risks & whether there is tolerance)
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