Sleep Supplements Ranked: What Works, What Doesn't
The sleep supplement market is worth billions. Most of it is placebo. Here's an honest look at what the clinical evidence actually supports, ranked by strength of evidence and effect size.
Before you supplement: Supplements should be the last thing you optimize, not the first. If your evening lighting is wrong, your room is too warm, or your schedule is inconsistent, no supplement will overcome those fundamentals. Fix your environment first.
Tier 1: Good Evidence
Magnesium (Glycinate or Threonate)
Verdict: Worth trying. Magnesium glycinate (200–400mg elemental) taken 30–60 minutes before bed has decent evidence for improving sleep quality, particularly in people who are deficient — and most people are. A 2012 study in the Journal of Research in Medical Sciences found it improved subjective sleep quality, sleep time, and melatonin levels in elderly insomniacs.
Magnesium threonate (Magtein) may have additional benefits for cognitive function. The bioavailability is better than magnesium oxide (which is basically a laxative at supplement doses).
Downsides: Can cause GI issues at higher doses. Effect is subtle, not dramatic.
Melatonin (Low Dose)
Verdict: Useful for timing, not sedation. Most people take too much. The evidence supports 0.3–0.5mg, taken 2–3 hours before target bedtime. At this dose, melatonin works as a circadian signal, not a sedative. It tells your brain "it's evening" — the same thing proper lighting does.
Higher doses (3–10mg) don't work better and may cause next-day grogginess, vivid dreams, and circadian disruption.
The real question: If your evening lighting is right, your body produces melatonin naturally. Supplementing melatonin while sitting under blue-spiking LEDs is treating the symptom while ignoring the cause.
Tier 2: Moderate Evidence
Glycine
Verdict: Promising. 3g of glycine before bed lowered core body temperature and improved subjective sleep quality in a small but well-designed Japanese study. The mechanism (peripheral vasodilation → core temp drop) makes physiological sense. Cheap and low-risk.
L-Theanine
Verdict: Good for anxiety-driven insomnia. 200–400mg promotes alpha brain waves and reduces anxiety without sedation. If your sleep problem is a racing mind rather than a timing issue, L-theanine is reasonable. Often found in combination with magnesium.
Tier 3: Weak or Mixed Evidence
Apigenin (Chamomile Extract)
Verdict: Probably mild. Popularized by Andrew Huberman. Apigenin is a flavonoid that acts on GABA receptors. The evidence is mostly from chamomile tea studies, which don't isolate apigenin well. Probably mildly calming. Unlikely to be transformative.
Tart Cherry Juice
Verdict: Contains small amounts of melatonin. Some studies show modest improvements in sleep. The amount of melatonin is tiny compared to even a low-dose supplement. Probably not worth the sugar and calories unless you enjoy the taste.
Valerian Root
Verdict: Mixed results. Studies are inconsistent. Some show small improvements in subjective sleep quality after 2–4 weeks. Others show nothing. The effect, if real, is modest.
Tier 4: Don't Bother
CBD
The evidence for CBD and sleep is extremely weak. Most positive studies use very high doses (150–300mg) that are expensive and impractical. Lower doses may actually increase wakefulness. The hype far exceeds the data.
Ashwagandha (for sleep specifically)
Ashwagandha has some evidence for reducing cortisol and anxiety, which can indirectly help sleep. But as a sleep supplement specifically, the evidence is thin. If anxiety is your primary issue, it might help. For garden-variety sleep optimization, there are better options.
"Sleep blend" proprietary formulas
Most contain underdosed amounts of several ingredients in a "proprietary blend" that doesn't disclose amounts. You're paying premium prices for subtherapeutic doses. Buy individual ingredients at effective doses instead.
The Hierarchy
Before spending money on supplements, make sure you've addressed:
- Evening lighting — the biggest lever for natural melatonin production
- Temperature — 65–68°F bedroom
- Schedule consistency — same wake time daily
- Morning light — 10 min bright light after waking
- Evening routine — 90-minute wind-down
If you've done all of that and still want supplemental help: magnesium glycinate (400mg) + low-dose melatonin (0.3mg) is the evidence-based starting point. Add glycine or L-theanine if needed.
The unsexy truth
The most effective "sleep supplement" is fixing your light environment. Your body makes its own melatonin — it just needs the right signal. A $130 set of circadian bulbs replaces a lifetime of melatonin purchases and works better.