Melatonin

What it is

Melatonin is a tryptophan-derived hormone secreted by the pineal gland in response to darkness. It regulates sleep onset and entrains circadian rhythms; it is also a direct antioxidant and modulator of mitochondrial function.

Why it’s of interest beyond sleep

• Endogenous melatonin production declines with age.
• Mitochondrial melatonin synthesis is high; melatonin is a potent scavenger of reactive species inside mitochondria.
• Effects on glucose handling, blood pressure, and inflammation in older adults.
• Possible role in immune function and oncology supportive care.

Practical use

• For sleep onset / jet lag: 0.3–1 mg taken ~30 minutes before desired sleep is well-tolerated; high OTC doses (3–10 mg) are commonly oversold and may cause next-day grogginess.
• For older-adult sleep maintenance: extended-release formulations (e.g. Circadin 2 mg) are approved in many countries.
• Doses up to 5–20 mg are used in oncology and longevity-medicine practice, often before bed; mechanism vs sleep effect are separate.

Safety

Generally well tolerated. Common short-term effects: vivid dreams, morning grogginess at high doses. Long-term safety at supraphysiologic doses is less established. Caution in pregnancy and with immunosuppressants.

Related entries

Sleep optimization, Mitochondrial dysfunction, Circadian rhythm.