diff --git a/conf/pulsar_tools_env.sh b/conf/pulsar_tools_env.sh
index f16bbca7365b5..a356dbb9a28df 100755
--- a/conf/pulsar_tools_env.sh
+++ b/conf/pulsar_tools_env.sh
@@ -42,10 +42,10 @@
 # PULSAR_GLOBAL_ZK_CONF=
 
 # Extra options to be passed to the jvm
-PULSAR_MEM="-Xmx128m -XX:MaxDirectMemorySize=128m"
+PULSAR_MEM=${PULSAR_MEM:-"-Xmx128m -XX:MaxDirectMemorySize=128m"}
 
 # Garbage collection options
-PULSAR_GC=" -client "
+PULSAR_GC=${PULSAR_GC:-" -client "}
 
 # Extra options to be passed to the jvm
 PULSAR_EXTRA_OPTS="${PULSAR_MEM} ${PULSAR_GC} ${PULSAR_GC_LOG} -Dio.netty.leakDetectionLevel=disabled ${PULSAR_EXTRA_OPTS}"