Melatonin impairs morning cognition in healthy young adults (2023)
New research suggesting that nighttime melatonin impairs morning cognition in healthy young adults has prompted scrutiny of how the hormone is used as an over-the-counter sleep aid. Commenters highlight that many studies — and most U.S. supplements — use doses far above the roughly 0.3 mg the body naturally produces, which may explain reports of morning grogginess and headaches. Others note that for people with insomnia or jet lag, some cognitive dulling may be an acceptable tradeoff for better sleep, and they point to lower doses, alternative supplements, and non-pill sleep hygiene strategies as potentially safer approaches.
Study Design and Dosage Concerns
- Commenters note the abstract omits key details; a related thesis indicates 2 mg and 5 mg doses, with no separate analysis by dose.
- Many argue these doses are much higher than what some sleep experts and self‑experimenters recommend (~0.1–0.3 mg).
- Several say conclusions about “melatonin” are misleading without testing low-dose groups or clearly reporting doses.
Morning Grogginess and Cognitive Effects
- Numerous anecdotes report morning fog, headaches, or feeling “hit like a truck,” especially at ≥1–3 mg.
- Others report minimal grogginess or find the tradeoff worth it compared to severe insomnia or jet lag.
- A few say even 100–200 µg causes noticeable brain fog; others claim 2–4 mg or even 10+ mg is needed to feel any effect.
- Some point out that lack of usual morning caffeine could itself impair cognition in trials.
Individual Variability and Use Cases
- Strong variation in response is emphasized: some get great sleep with no impairment; others get no benefit or paradoxical effects.
- Several stress that the study is limited to “healthy young adults,” whereas many real-world users have insomnia, delayed sleep phase, or jet lag; they question generalizing beyond this cohort.
- Some argue that for insomniacs, “melatonin + mild grogginess” can be better than chronic sleep deprivation.
Supplement Quality and Regulation
- Multiple comments highlight that melatonin content in supplements often diverges from labels, especially in unregulated markets.
- Wide dosage ranges are compared to other supplements (vitamin D, B12), reinforcing concerns about reliability.
Timing, Circadian Rhythm, and Best Practices
- Several suggest taking small doses (≈0.1–0.3 mg) 1–3 hours before bed to shift circadian phase, not as a direct sedative.
- There is concern that high or extended‑release doses may blur the melatonin “signal” and disrupt circadian rhythms long term.
Alternatives, “Sleep Stacks,” and Lifestyle
- Alternatives mentioned: magnesium (various forms), glycine, GABA, L‑theanine, valerian, tart cherry, herbal teas, antihistamine sleep aids, prescription hypnotics, antidepressants, breathing techniques, and CBT‑I.
- Some criticize reliance on “sleep stacks” and gadgets instead of basic sleep hygiene: limiting screens/blue light, managing caffeine, regular schedules, and environmental control.
- Long exchanges discuss night-owl vs early-bird biology, school/work timing, and the difficulty of aligning personal rhythms with social expectations.