Which supplement is used for sleep and circadian rhythm regulation and has hormone-like properties?

• A. Garlic
• B. St. John's Wort
• C. Melatonin
• D. Black cohosh

Answer: (C)

Melatonin acts as a hormone that helps regulate the sleep-wake cycle and circadian rhythms. The pineal gland normally releases melatonin in the dark, signaling that it’s time to sleep. As a supplement, it can mimic that natural signal and help align the internal clock, making it useful for sleep issues, jet lag, or shift-work-related circadian disruption. That hormone-like signaling is what makes it the best fit for sleep regulation.

Garlic is mainly discussed for cardiovascular or immune health, not sleep. St. John’s Wort is used for mood regulation and has indirect effects on sleep through mood, but it isn’t a circadian regulator. Black cohosh is used for menopausal symptoms and does not primarily target sleep-wake cycles.