Yu Sleep Ingredients: Every One of the 10 Ingredients, the Evidence and the Doses

Yu Sleep supplement facts label

In August 2026 the manufacturer published an updated label that disclosed the melatonin amount for the first time. This is the current panel. Inactive ingredients are purified water, vegetable glycerin, natural flavor and citric acid.

† Daily Value not established. Ingredients in a proprietary blend are listed in descending order by weight, so tart cherry concentrate is the largest component and GABA the smallest.

Why the proprietary blend matters

A 637 mg blend across seven ingredients averages about 90 mg each, but the real distribution is uneven. Tart cherry concentrate, listed first, probably accounts for a large share. That leaves less room for magnesium glycinate, which is bulky (glycinate is only about 14% elemental magnesium). A clinically studied 200 mg dose of L-theanine plus 100–300 mg of GABA plus a meaningful magnesium dose would exceed 637 mg on their own.

The practical conclusion: Yu Sleep almost certainly provides lower doses of some ingredients than the studies below used. That does not mean it does not work. Ingredients that act on the same calming pathways can add up, and the sublingual route improves absorption of small doses. But it does mean you should judge the product on how it works for you, not on ingredient studies alone.

Ingredient-by-ingredient breakdown

1. Melatonin (0.9 mg)

What it does: Melatonin is the hormone your pineal gland releases when it gets dark. It does not sedate you; it tells your brain that night has started and shifts your circadian clock.

Evidence: A widely cited MIT study led by Richard Wurtman found that 0.3 mg restored normal sleep in older adults, while higher doses raised blood levels far above physiologic range and were linked to next-day hangover. Meta-analyses show melatonin shortens time to fall asleep by about 7 minutes and increases total sleep by around 8 minutes on average, with larger effects for circadian problems like jet lag and delayed sleep phase.

Why 0.9 mg: It sits between the 0.3 mg physiologic dose and the 1–3 mg range that most clinical trials use, and well below the 5–10 mg in typical gummies. This is the main reason Yu Sleep users report less grogginess. We compare doses in Yu Sleep vs melatonin.

2. Magnesium glycinate

What it does: Magnesium regulates GABA receptors, lowers cortisol and relaxes muscle. Glycine, the amino acid it is bound to, has sleep benefits of its own: 3 g of glycine before bed improved sleep quality and reduced daytime fatigue in Japanese trials.

Evidence: A randomized trial in older adults with insomnia found that 500 mg of magnesium daily for eight weeks improved sleep time, sleep efficiency and time to fall asleep, and lowered cortisol. About half of Americans do not get enough magnesium from food, which is why it appears in almost every serious sleep formula.

Dose note: The trial dose (500 mg of magnesium oxide, roughly 300 mg elemental) is far more than could fit in Yu Sleep's blend. Expect a modest contribution, not a full magnesium supplement. If you are deficient, a separate magnesium product may still be worthwhile.

3. GABA (gamma-aminobutyric acid)

What it does: GABA is the brain's main inhibitory neurotransmitter. Benzodiazepines and Z-drugs work by boosting GABA signaling. Oral GABA cannot cross the blood-brain barrier easily, so its effect may work through the gut-brain axis instead.

Evidence: A 2016 Japanese trial found 100 mg of oral GABA reduced time to fall asleep by about 5 minutes and increased early-night deep sleep compared with placebo. A 2019 study combining GABA with L-theanine found the pair worked better together than either alone in animal models.

4. L-theanine

What it does: L-theanine, the amino acid that makes green tea calming despite its caffeine, raises alpha brain-wave activity associated with relaxed alertness and increases GABA, serotonin and dopamine in the brain.

Evidence: A 2019 randomized trial in healthy adults found 200 mg daily for four weeks reduced stress scores and improved sleep quality ratings. In children with ADHD, 400 mg improved sleep efficiency on actigraphy. L-theanine does not cause drowsiness, which makes it a good fit for a formula that promises no grogginess.

5. 5-HTP (5-hydroxytryptophan)

What it does: 5-HTP is one step away from serotonin in the tryptophan pathway. Serotonin is then converted to melatonin at night. Raising 5-HTP can therefore support both mood and the body's own melatonin production.

Evidence: Small studies show 5-HTP increases REM sleep and, combined with GABA, shortens time to fall asleep. Doses in trials range from 50 to 300 mg. Yu Sleep's amount is not disclosed but is likely at the lower end given the blend size.

Warning: 5-HTP should not be combined with SSRIs, SNRIs, MAOIs, tramadol, triptans or St. John's wort without medical advice because of the risk of serotonin syndrome. We cover this in does 5-HTP help you sleep? and in the side effects guide.

6. Apigenin

What it does: Apigenin is the flavonoid responsible for chamomile's calming reputation. It binds to benzodiazepine sites on GABA-A receptors, producing mild anxiolytic effects without the sedation or dependence of drugs that act on the same receptor.

Evidence: A 2017 trial of chamomile extract in adults with generalized anxiety found meaningful symptom reduction over eight weeks. Research on isolated apigenin at 50 mg is mostly preclinical but popular in biohacking "sleep stacks."

7. Lemon balm extract

What it does: Lemon balm (Melissa officinalis) inhibits the enzyme that breaks down GABA, so GABA stays active longer. It has been used for nervous tension since the Middle Ages.

Evidence: A 2011 pilot study found 600 mg of lemon balm extract reduced anxiety symptoms by 18% and insomnia by 42% in stressed volunteers. Combined with valerian it improved sleep quality in a randomized trial of menopausal women.

8. Red tart cherry juice concentrate

What it does: Montmorency tart cherries are one of the few foods that naturally contain melatonin, plus anthocyanins that reduce inflammation and tryptophan-degrading enzymes.

Evidence: A 2012 crossover trial found tart cherry juice raised urinary melatonin, increased total sleep time by 25 minutes and improved sleep efficiency. A 2018 pilot in older adults with insomnia showed 84 more minutes of sleep on polysomnography. Tart cherry is the largest component of Yu Sleep's blend.

9. Vitamin B6 (0.5 mg)

What it does: B6 is the cofactor that converts 5-HTP to serotonin and glutamate to GABA. It is included to make the other ingredients work, not for its own sleep effect. There is also some evidence that B6 increases dream recall.

10. Vitamin B2 (0.5 mg)

What it does: Riboflavin supports energy metabolism and tryptophan conversion. At 0.5 mg it is a supporting player. Do not expect it to change your sleep on its own.

Evidence quality summary

What Yu Sleep does not contain

Yu Sleep is free of valerian, diphenhydramine (the antihistamine in ZzzQuil and Tylenol PM), doxylamine, CBD, kava and any prescription-only compound. It contains no gluten, dairy, soy or artificial colors according to the manufacturer. It is not certified organic or third-party tested by NSF or USP, which we note as a transparency gap.

How Yu Sleep compares to other sleep formulas

The ingredient profile is close to what sleep researchers and biohackers often recommend as a "sleep stack": magnesium glycinate, L-theanine, apigenin and low-dose melatonin. What Yu Sleep adds is GABA, 5-HTP, lemon balm and tart cherry, plus a liquid delivery. Compared with a typical melatonin gummy, it has one-tenth the melatonin and nine more actives. Compared with a "PM" antihistamine product, it works through calming pathways rather than blocking histamine, which is why it does not cause the dry mouth and hangover those products are known for.

Frequently asked questions