If you’ve ever stood in front of a supplement aisle at 4pm running on five hours of sleep, you know the problem: everything promises rest, and nothing tells you what the research actually says. So we did the reading. Here are the seven sleep supplements with the most credible evidence behind them — what they do, who they tend to suit, and what to know before trying one.
A quick note before the list: supplements support sleep; they don’t replace the basics. If caffeine after 2pm, screens in bed, or an erratic schedule are in the picture, fix those first — everything below works better on a decent foundation.
1. Magnesium glycinate
If we could stock only one thing in the cabinet for sleep, it would be this. Magnesium is involved in hundreds of processes in the body, including regulating GABA — the neurotransmitter that helps your nervous system downshift. Many adults don’t get enough from food, and research suggests supplementing may support both falling asleep and sleep quality, particularly in people with low magnesium levels.
Why glycinate specifically? It’s bound to glycine — itself a calming amino acid — and it’s gentle on the stomach, unlike citrate or oxide forms which are better known for their laxative effect. (We compare the forms properly in our magnesium glycinate vs citrate guide.)
200–400mg, 1–2 hours before bed.
From iHerb: [AFFILIATE LINK — Doctor’s Best Magnesium Glycinate] · [AFFILIATE LINK — KAL Magnesium Glycinate]
2. L-theanine
An amino acid found naturally in green tea, L-theanine is the option for people whose problem isn’t being tired — it’s a brain that won’t stop talking. Research suggests it may promote relaxation without sedation by influencing alpha brain-wave activity, which is why it’s popular with people who want calm focus in the evening rather than a knockout effect.
100–200mg in the evening; some people pair it with magnesium.
From iHerb: [AFFILIATE LINK — NOW Foods L-Theanine 200mg]
3. Ashwagandha
An adaptogenic herb with a long history in Ayurvedic practice, ashwagandha is best known today for stress support: several small clinical trials suggest it may help lower perceived stress and cortisol levels, and better evenings often follow better-managed days. If your sleep problem is really a stress problem, this is the one to read up on.
300–600mg of a root extract (KSM-66 and Sensoril are the most-studied forms), taken with dinner.
From iHerb: [AFFILIATE LINK — Jarrow Formulas Ashwagandha KSM-66]
4. Glycine
The quiet achiever. Glycine is a simple amino acid that, taken before bed, may support falling asleep faster and feeling more refreshed — possibly by slightly lowering core body temperature, one of the body’s natural sleep cues. It’s inexpensive, has a mildly sweet taste, and stacks well with magnesium.
3g before bed (powder stirs into water easily).
From iHerb: [AFFILIATE LINK — NOW Foods Glycine Powder]
5. Melatonin (used correctly)
Melatonin is the most famous name here and the most misused. It’s a timing signal, not a sedative — research supports it most clearly for shift work, jet lag, and resetting a delayed body clock, less so for ordinary insomnia. Less is often more: studies frequently use doses far below what’s sold on shelves.
One regional note: in Australia melatonin is regulated differently than in the US and is typically pharmacist- or prescription-supplied, so this entry is most relevant to our US readers.
0.5–3mg, 30–60 minutes before your target bedtime — timing matters more than dose.
From iHerb: [AFFILIATE LINK — Natrol Melatonin 1mg]
6. Chamomile
The oldest entry on the list, and not just folklore: chamomile contains apigenin, a compound that binds to some of the same calming receptors targeted by anti-anxiety medications, though far more gently. Evidence is modest but consistent for mild relaxation, and there’s real value in the ritual itself — a warm cup at the same time each night is a powerful cue to your brain that the day is done.
Tea 30–45 minutes before bed, or a standardised extract.
From iHerb: [AFFILIATE LINK — Traditional Medicinals Chamomile Tea]
7. Lavender (oral or aromatherapy)
Lavender is more than a nice smell. An oral lavender oil preparation (silexan) has clinical research suggesting it may help with restlessness and anxious tension, and even simple aromatherapy studies show small improvements in sleep quality. A pillow spray won’t fix insomnia, but as part of a wind-down routine it earns its place.
80mg oral lavender oil capsules, or diffused/pillow spray at bedtime.
From iHerb: [AFFILIATE LINK — lavender oil capsules] · [AFFILIATE LINK — lavender essential oil]
How to choose (without buying all seven)
Start by matching the supplement to your actual problem:
- Can’t switch your mind off: L-theanine, or glycine.
- Stressful days bleeding into nights: ashwagandha.
- Wake unrefreshed, restless legs, or low dietary magnesium: magnesium glycinate.
- Body clock out of sync (travel, shifts, night-owl drift): melatonin, correctly timed.
- Want a gentle ritual, not a pill: chamomile + lavender.
Pick one, use it consistently for two to three weeks alongside a regular wind-down routine, and judge it on how you feel in the morning — not on the first night.