Red Tart Cherry Juice Concentrate in Yu Sleep

Yu Sleep's Supplement Facts panel lists "Red Tart Cherry Juice Concentrate" first among the seven ingredients in its undisclosed 637 mg "Proprietary Blend," ahead of magnesium glycinate, apigenin, lemon balm extract, 5-HTP, L-theanine and GABA. The brand's own sales copy and its Amazon listing call the same ingredient "Red Tart Cherry Extract" instead, but the label wording is the one we use here. This page checks what that first-listed spot actually gets a buyer, and it is our Yu Sleep review that goes through what the other nine ingredients are and do. Under 21 CFR 101.36(c)(2), blend ingredients must be listed in descending order of weight, so tart cherry, named first, would be the largest of the seven if Yu Sleep's label complies with that rule. Only three of Yu Sleep's ten ingredients, melatonin and the two B vitamins, carry a stated milligram amount; the other seven, tart cherry included, sit inside the blend total with no individual figure attached.

What tart cherry does for sleep

Tart cherry is a food ingredient studied in a handful of small human trials for sleep, and the leading theory behind any effect is its antioxidant and anthocyanin content, not one confirmed mechanism. Yu Sleep's sales letter goes further, claiming the ingredient "contains high levels of tryptophan, the amino acid your body uses to create serotonin and, later, melatonin." That claim does not hold up against the research it is built on: Losso and colleagues, whose own trial produced the "84 minutes" figure Yu Sleep cites elsewhere, measured only 9 mg of tryptophan per 100 g of cherries and wrote that such a small amount could not be presumed to affect insomnia on its own. Cherry-derived melatonin is similarly small: Howatson's tart cherry concentrate added about 85 micrograms of melatonin a day, a fraction of even a low supplement dose, and roughly ten times less than the 0.9 mg of melatonin Yu Sleep adds separately and synthetically. No trial has identified a confirmed mechanism for tart cherry's effect on sleep, and none of the five human trials in the evidence base below was designed to test one. That leaves the tryptophan and melatonin explanations as candidates the researchers themselves have not confirmed, not settled findings. For the fuller mechanism discussion and every study behind it, see our full look at the tart cherry sleep research.

The evidence for tart cherry

Ingredient-evidence.md rates tart cherry's evidence for sleep "weak": a few small trials found a benefit, and two more recent ones found none at all. The table below condenses the four trials that matter most for dose comparison.

A 2025 systematic review by Barforoush and colleagues, covering seven studies of tart cherry and sleep, found only three positive and called the overall evidence "limited and heterogeneous." The pattern across the four trials above is consistent: the two smallest, shortest studies produced the positive results, while the trial that used the smallest dose (Tucker's 500 mg capsule) and the one that ran the longest (Hillman's 30 days) both found nothing. Our full breakdown of the tart cherry studies covers the study-by-study detail, including a fifth trial and the timing and form questions this page does not repeat.

The dose in Yu Sleep vs the study doses

The amount of tart cherry in Yu Sleep is not disclosed, and the entire 2 mL serving is far smaller than the volumes the positive trials used. Even in the best case for the brand, where the blend is listed by weight as US rules require and tart cherry (named first) takes up most of the 637 mg, the whole serving a buyer drinks is 2 mL. The trials that found a sleep benefit used far more:

• Yu Sleep's entire serving: 2 mL, shared among ten ingredients.
• Howatson's positive trial: 60 mL of concentrate a day (30 mL, twice daily).
• Losso's positive trial: 480 mL of juice a day (240 mL, twice daily).
• Tucker's null trial: 500 mg of tart cherry powder in capsule form, and it found no effect at all.

No trial has tested a dose anywhere near 2 mL and found a sleep benefit, and matching Losso's 480 mL-a-day volume with juice alone would mean drinking close to a pint and a half a day, an amount no Yu Sleep serving comes close to providing. For the dose picture on Yu Sleep's other nine ingredients, see Yu Sleep's full ingredient list.

Safety and interactions

In the clinical trials, tart cherry juice and concentrate were used as food, and none reported an adverse event or a drug interaction. Across Howatson, Pigeon, Losso, Tucker and Hillman's trials, researchers found no safety signal worth flagging, so the main real-world caution comes from outside the trial data: an allergy to cherries. One Yu Sleep buyer reported on the Better Business Bureau that they discovered a cherry allergy "during that month" of taking the product, which contains cherries. That is a Yu Sleep buyer's own report, not a trial finding, and of the 14 readable Yu Sleep buyer reports we analyzed, 21% (3 of 14) describe worse sleep or a bad reaction, including that allergy case. The following groups should be careful with tart cherry:

• Anyone allergic to cherries.
• Anyone who wants an exact dose before trying it, since the amount in Yu Sleep is not disclosed.
• Anyone pregnant, breastfeeding or considering giving it to a child, since no trial studied any of those groups.
• Anyone combining it with a sleep medication, since no trial tested a combination.

For the full safety picture across all ten Yu Sleep ingredients, see Yu Sleep's side effects.

Tart cherry juice alone vs tart cherry inside Yu Sleep

Drinking tart cherry juice or concentrate alone lets a buyer match the volumes the trials actually used, while tart cherry inside Yu Sleep comes at an undisclosed amount bundled with six other undisclosed ingredients. Tart cherry, magnesium glycinate, apigenin, lemon balm, 5-HTP, L-theanine and GABA are the seven blend ingredients with no stated amount; only melatonin (0.9 mg), vitamin B6 (0.5 mg) and vitamin B2 (0.5 mg) carry a disclosed dose on the label. A plain tart cherry product lets a buyer replicate the 60 mL of concentrate or 480 mL of juice a day that the positive trials used, something Yu Sleep's fixed 2 mL serving cannot do. See our Yu Sleep vs tart cherry juice comparison for the full side-by-side on price, guarantee and evidence.

Bottom line

On its own, tart cherry has a real but weak research record, and only at volumes far larger than Yu Sleep's 2 mL serving. The ad's own tart cherry claim, the "84 minutes" figure (Yu Sleep's sales letter, paragraph 521), is partly supported: it comes from a real result in Losso's trial, but that trial had just 8 completers, and two later, larger-style trials (Tucker 2024, Hillman 2022) found no effect. Buyer reports do not settle the question either: of the 14 readable Yu Sleep buyer reports we analyzed, 64% report no noticeable effect and 14% report improved sleep, too small a sample and too undifferentiated by ingredient to credit or blame tart cherry specifically. Nothing in that sample separates a buyer who noticed a change from the nine other ingredients in the blend, so it cannot answer whether tart cherry itself did anything. Whether an undisclosed amount of tart cherry inside a ten-ingredient blend does anything for sleep is the question our full Yu Sleep review answers for the product as a whole.