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Sleep Supplements Compared: How Much Melatonin, Magnesium, Valerian and Others Actually Help

For most adults, sleep supplements help a little at best. Melatonin has the most trials: in adults and children, people fell asleep about 7 minutes sooner and slept about 8 minutes longer (grade B). Ashwagandha and L-theanine improved sleep scores slightly (grade B), while valerian did not speed sleep onset (grade B). Cognitive behavioral therapy for insomnia (CBT-I) cut about 19 minutes and is the guideline first choice. Melatonin labels are often wrong about the amount inside.

Published How we grade evidenceEditorial policy

The short version

  • Melatonin: 7.06 minutes faster to fall asleep and 8.25 minutes more sleep, in a meta-analysis of 19 trials in adults and children. Grade B (Ferracioli-Oda 2013).
  • Ashwagandha and L-theanine: small gains in sleep scores. Grade B (Cheah 2021; Bulman 2025).
  • Valerian: no faster sleep onset than placebo across 18 trials. Grade B (Fernández-San-Martín 2010).
  • Magnesium: small, inconsistent results in low-quality trials. Grade C (Lopresti 2026).
  • CBD on its own: no clear effect. Grade C (da Silva 2025).
  • CBT-I (a talking therapy, not a pill): 19.03 minutes faster to fall asleep and 26.00 fewer minutes awake at night. Grade A (Trauer 2015).

This guide is for adults. For a child, ask a clinician; it gives no amounts for children. If you are pregnant or breastfeeding, ask your doctor or midwife before taking any sleep supplement.

What is the best supplement for sleep?

Melatonin, by a small margin, and its effect is small (grade B). The table puts each option's effect side by side. Minutes are the extra speed or sleep compared with placebo; a "standardized difference" is a unit-free effect size, where bigger numbers mean bigger effects.

SupplementWhat trials foundSize of effectGrade
Melatonin19 trials, 1,683 adults and childrenAsleep 7.06 minutes sooner, 8.25 minutes more sleep (Ferracioli-Oda 2013)B
Ashwagandha5 trials, 400 adultsSmall: standardized difference 0.59 for overall sleep (Cheah 2021)B
L-theanine19 trials, 897 people, many mixed with other ingredientsSmall: 0.15 for time to fall asleep (10 trials), 0.43 for sleep quality (12 trials) (Bulman 2025)B
Lavender oil by mouthTrials in people with anxietyBetter sleep scores, almost all through less anxiety (Seifritz 2019)B
Valerian18 trials0.70 minutes, no real difference either way (Fernández-San-Martín 2010)B
Magnesium3 small trials in older adults; 12 trials overall, inconsistentAsleep 17.36 minutes sooner in older adults (2 trials, 55 people), low quality (Mah 2021)C
GlycineSmall studies from one research teamLess next-day tiredness after short sleep (Bannai 2012)C
Chamomile10 studies, 772 peopleSleep-quality score 1.88 points better in 5 pooled studies (Kazemi 2024)C
Tart cherryTiny positive trials, larger negative onesUp to 84 minutes more sleep in 8 people; nothing in 34 or 44 (Losso 2018; Tucker 2024; Hillman 2026)C
Tryptophan4 pooled studiesLess time awake at night; nothing else changed (Sutanto 2022)C
CBD alonePooled cannabinoid trialsNo clear effect (0.13) (da Silva 2025)C
5-HTP1 trial, 30 older adultsBetter sleep scores in poor sleepers only (Sutanto 2024)D
CBT-I (therapy)20 trials, 1,162 adultsAsleep 19.03 minutes sooner, 26.00 fewer minutes awake (Trauer 2015)A

Does melatonin work for sleep?

Grade B. Yes, a little. In a meta-analysis of 19 trials (1,683 adults and children), melatonin cut the time to fall asleep by 7.06 minutes and added 8.25 minutes of sleep, and the effect did not wear off with continued use (Ferracioli-Oda 2013). In adults with diagnosed insomnia, prolonged-release tablets sped sleep onset by 5.05 to 6.30 minutes (Maruani 2023), and a review of 24 trials found no significant effect in adults with chronic insomnia (Choi 2022). Our database page grades melatonin B too.

Dose and timing: the benefit rose with dose up to a peak at 4 mg a day, and the authors suggest taking it about 3 hours before bedtime rather than the usual 2 mg half an hour before (Cruz-Sanabria 2024).

Labels are a problem. When 31 products were tested, their melatonin ranged from 83% under the label to 478% over it, and serotonin turned up in 8 of them (Erland 2017). In 110 US products sold for children, content ranged from 0% to 667% of the label (Pawar 2025).

Is it safe to take melatonin every night?

Short-term use appears safe for most people, but long-term safety hasn't been studied well (NCCIH). In trials of 10 mg or more, serious harms didn't rise against placebo, but drowsiness, headache and dizziness did (Menczel Schrire 2022). In 2025, a conference abstract linked a year or more of melatonin use with heart failure. It has not been peer reviewed (Savvidis 2026), and in a national US health survey, melatonin use was not linked with heart failure; neither result proves harm or safety (Khan 2026).

Does magnesium help you sleep?

Grade C. Maybe slightly, and the trials are weak. In a review of 3 small trials (151 older adults), the two that measured it (55 people) found magnesium cut the time to fall asleep by 17.36 minutes, but the evidence quality was low (Mah 2021). A 2026 review of 12 trials found results that varied from study to study and did not support magnesium as a routine insomnia treatment (Lopresti 2026). Trials have used, for example, 500 mg of magnesium a day for 8 weeks in 46 older adults (Abbasi 2012) and 250 mg a day in 155 adults, where insomnia scores improved by a small amount (Schuster 2025). Upper limit for adults: 350 mg a day from supplements; take more only with blood tests or your clinician's advice (NIH ODS; upper-limit calculator). We found no trial that compared forms of magnesium head to head for sleep.

Does valerian help you sleep?

Grade B that it does not speed sleep. In a meta-analysis of 18 trials, the time to fall asleep on valerian differed from placebo by 0.70 minutes (95% confidence interval -3.44 to 4.83 minutes, so no real difference either way), and measured sleep quality didn't differ; only a yes-or-no "did you sleep better?" question favored it (Fernández-San-Martín 2010). A 2024 review of 8 reviews found no evidence that it works for insomnia (Valente 2024). The American Academy of Sleep Medicine suggests doctors not use it (Sateia 2017). Our myth checker covers this claim.

Do glycine or L-theanine help sleep?

Grade C for glycine. In healthy volunteers whose sleep was cut short for 3 nights, 3 g of glycine before bed eased next-day tiredness (Bannai 2012). The same research team reported better self-rated sleep in people prone to insomnia (Bannai 2012). We found few trials from other groups.

Grade B for L-theanine, an amino acid from tea. In a review of 19 trials (897 people), it improved self-rated time to fall asleep a little (0.15, pooled from 10 trials) and overall sleep quality more (0.43, from 12 trials), but few trials used theanine alone (Bulman 2025). Trials of theanine alone used 50 to 900 mg a day, and 200 to 450 mg a day looked helpful (Cotter 2026).

Do chamomile or lavender help you sleep?

Grade C for chamomile. In 10 studies (772 people), a sleep-quality questionnaire score improved by 1.88 points in the 5 that could be pooled, but sleep length and daytime function didn't change; the abstract doesn't say whether people drank tea or took extract (Kazemi 2024). In 34 adults with long-term insomnia, an extract taken twice a day for 4 weeks made no clear difference (Zick 2011).

Grade B for lavender oil by mouth, in people with anxiety. In 212 people with anxiety, 80 mg a day of an oral lavender oil preparation for 10 weeks improved sleep scores against placebo, but 98.4% of that came from easing anxiety, not from sedation (Seifritz 2019; Seifritz 2022). Breathing in lavender oil is a different product, not covered here.

Does tart cherry juice help you sleep?

Grade C. Small early trials were positive: in 8 adults over 50 with insomnia, juice twice a day for 2 weeks added 84 minutes of sleep (Losso 2018), and in 20 healthy adults, a week of juice concentrate lengthened sleep (Howatson 2012). Two larger trials then found nothing: capsules in 34 adults for 14 days (Tucker 2024) and juice or capsules in 44 adults for 30 days (Hillman 2026).

Does ashwagandha help sleep?

Grade B. A little. Pooling 5 trials (400 adults), ashwagandha extract improved sleep by a small amount (0.59). Gains were larger in people with diagnosed insomnia, with 600 mg daily or higher, and in courses of 8 weeks or longer (Cheah 2021). Our ashwagandha guide covers its safety in detail.

Do tryptophan or 5-HTP help sleep?

Grade C for tryptophan. In 4 pooled studies, it cut time awake during the night, more at 1 g a day or above, but nothing else changed (Sutanto 2022). The sleep-medicine academy suggests doctors not use it (Sateia 2017).

Grade D for 5-HTP. In one small 12-week trial of 30 older adults, with no placebo, 100 mg a day improved sleep scores in poor sleepers only (Sutanto 2024).

Does CBD help you sleep?

Grade C. CBD by itself showed no clear effect: in a 2025 review of cannabinoid trials, the CBD-only subgroup scored 0.13, too small to tell from placebo, while products with other cannabinoids did better (da Silva 2025). Cannabinoid products as a group caused more side effects, mostly dizziness and dry mouth (Asim 2026), and many contain THC, the intoxicating part of cannabis. This guide gives no CBD amounts.

What works better than sleep supplements?

Grade A for CBT-I, a short course of therapy that retrains sleep habits and worries. In a meta-analysis of 20 trials (1,162 adults), it cut the time to fall asleep by 19.03 minutes and time awake at night by 26.00 minutes (Trauer 2015). The American Academy of Sleep Medicine strongly recommends it for chronic insomnia (Edinger 2021), and suggests doctors not use melatonin, valerian or tryptophan for it (Sateia 2017).

What we'd skip

Safety and interactions

  • Melatonin: if you have epilepsy or take a blood thinner, use it only under medical supervision. In older people it can linger and cause daytime drowsiness (NCCIH).
  • Magnesium: it interacts with osteoporosis pills (bisphosphonates) and tetracycline and quinolone antibiotics; space them apart (NIH ODS). With kidney disease, ask first. See magnesium with blood pressure medicine and iron, calcium or magnesium with levothyroxine.
  • Valerian: headache, stomach upset and vivid dreams; don't combine it with alcohol or sedatives; very rare liver injury (NCCIH).
  • Chamomile: allergy is more likely if you react to ragweed or daisies, and interactions with warfarin have been reported (NCCIH).
  • Lavender by mouth: diarrhea, headache, nausea or burping; it may add to sedatives (NCCIH).
  • Ashwagandha: rare liver injury, with jaundice 2 to 12 weeks after starting (Björnsson 2020).
  • Tryptophan and 5-HTP: tryptophan supplements were pulled in 1989 after a contaminated batch caused eosinophilia-myalgia syndrome, a rare, serious illness (Das 2004). 5-HTP raises serotonin, so serotonin syndrome is the main concern (Turner 2006); combining serotonin-raising products, such as SSRI antidepressants, can be life-threatening (Mikkelsen 2023). Ask your prescriber or pharmacist first. See 5-HTP with SSRIs.
  • CBD: linked with liver injury and drug interactions (NCCIH).
  • No interaction studies were found for glycine or L-theanine. Don't stack several sedating products.

When to see a doctor

  • Insomnia that has gone on for months: ask about CBT-I (Edinger 2021).
  • Loud snoring, gasping at night or heavy daytime sleepiness: signs of sleep apnea, which supplements don't address.
  • Restless, crawling feelings in your legs at night, or low mood, worry or pain keeping you awake.
  • Agitation, fever, shaking or a racing heart after combining 5-HTP or tryptophan with an antidepressant: get help right away (Mikkelsen 2023).
  • Yellow skin or eyes on ashwagandha or valerian (Björnsson 2020; NCCIH).

Don't stop a prescribed medicine on your own; ask the prescriber or pharmacist. For a child, ask a clinician. If you are pregnant or breastfeeding, ask your doctor or midwife.

FAQ

What is the best supplement for sleep? Melatonin has the most evidence (grade B): in trials of adults and children, people fell asleep about 7 minutes sooner and slept about 8 minutes longer. CBT-I, a talking therapy, does more (grade A).

Is magnesium or melatonin better for sleep? Melatonin has more and better trials (grade B). Magnesium's trials are small and inconsistent (grade C).

What can I take for sleep instead of melatonin? Ashwagandha and L-theanine have the best evidence after melatonin, both with small gains in sleep scores (grade B). Lavender oil by mouth helped sleep in people with anxiety (grade B).

Does valerian work for sleep? Not for falling asleep: in a meta-analysis of 18 trials it differed from placebo by under a minute (grade B). Only a yes-or-no "slept better" question favored it.

Is it safe to take melatonin every night? Short-term use appears safe for most people, but long-term safety hasn't been studied well. A heart-failure signal came from a conference abstract that has not been peer reviewed.

Sources

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