The full moon can have some subtle effects on humans, particularly related to mental health, sleep, and physiological functions, but many popular beliefs about its influence are not strongly supported by scientific evidence.

Effects on Mental Health and Mood

• The lunar cycle may impact mood and mental health, especially in people with bipolar disorder. Studies have found that some individuals with bipolar disorder experience rapid mood swings synchronized with the lunar cycle, possibly due to disruptions in their circadian rhythm and sleep-wake cycles

• For the general population, scientific evidence does not support a significant effect of the full moon on mood, aggression, violence, or psychiatric hospital admissions

• Anxiety and depression may be influenced indirectly by environmental factors, but the moon itself is unlikely to be a direct cause

Effects on Sleep

• The brightness of a full moon can affect melatonin production, a hormone that regulates sleep, potentially making it harder to fall asleep or reducing deep sleep

• Some studies suggest that full moons may delay entry into REM sleep and reduce total sleep time, with possible differences between males and females in sleep patterns during full moons

Physical and Cardiovascular Effects

• The moon’s gravitational pull affects Earth's tides, and some research suggests it might slightly influence human physiology, such as lowering blood pressure and heart rate during full and new moons

• However, findings are mixed, and other studies have found no significant impact on athletic performance or cardiovascular health related to lunar phases

Effects on Reproductive Cycles

• Despite common beliefs, menstrual cycles are not synchronized with lunar phases. Large studies have found no association between the full moon and the timing of menstrual cycles or fertility

Summary

While the full moon has a well-documented effect on natural phenomena like tides, its influence on human behavior and health is generally weak or unproven. Exceptions may exist for individuals with bipolar disorder, who might experience mood changes linked to lunar cycles. The full moon can also subtly affect sleep patterns due to increased nighttime brightness. Overall, the full moon's impact on humans is less powerful than folklore suggests

The effect of this heavenly body on your body is less powerful than once believed - Healthline summary