The short version
Most sleep supplements are built from the same short list of ingredients. What separates them is whether the dose on the label matches the dose in the research.
| Ingredient | Studied dose | What the trial showed |
|---|---|---|
| Glycine | 3 g, 1 hour before bed | Faster sleep onset, faster to slow-wave sleep, better subjective quality, less next-day sleepiness |
| L-Theanine | 200 mg daily, 4 weeks | Improved sleep quality scores, specifically sleep latency and disturbance |
| Tart cherry | Juice concentrate, 7 days | Raised melatonin, longer total sleep time, better sleep efficiency |
| Magnesium | 250 mg elemental, 4 weeks | Modest improvement in insomnia severity, larger in people with low dietary intake |
| Honey | Varies | Improved sleep quality in poor sleepers, compared favourably with melatonin |
Use that table as a checklist. If a product lists an ingredient without a dose, or at a fraction of the studied amount, the research behind it does not transfer.
How to judge a sleep ingredient
Three questions settle most of it.
Is the dose disclosed per serving? Proprietary blends exist to avoid this question.
Does the dose match the research? This is where most products fall down. Sprinkling 50 mg of an ingredient studied at 3 g lets a brand print the name on the label without paying for the actual dose.
Can you take it every night? The L-theanine trial ran four weeks. The tart cherry trial ran seven days. Nothing here works on a one-off basis, so palatability and format matter as much as the formula.
Glycine
Dose that works: 3 g, about an hour before bed.
Glycine is an amino acid that lowers core body temperature, one of the signals the body uses to start sleep.
In a crossover trial, adults with ongoing poor sleep took 3 g of glycine or a flavoured placebo an hour before bed, with polysomnography recording the night. Time to fall asleep and time to reach slow-wave sleep both shortened, subjective quality improved, and next-day sleepiness was lower. Sleep architecture itself was undisturbed, meaning this supports your own sleep rather than sedating you (Yamadera et al., Sleep and Biological Rhythms, 2007).
For athletes, the undisturbed architecture is the important part. Slow-wave sleep is when most physical recovery happens, and you do not want an ingredient that buys you hours at the cost of quality.
L-Theanine
Dose that works: 200 mg daily.
L-theanine is the amino acid in tea leaves associated with calm without drowsiness.
Thirty healthy adults took 200 mg daily or placebo for four weeks in a randomised, double-blind crossover trial. Pittsburgh Sleep Quality Index scores improved against placebo, with specific gains in sleep latency and sleep disturbance (Hidese et al., Nutrients, 2019).
Note that this was four weeks of daily use. L-theanine appears to work by lowering the baseline, so it rewards consistency more than most.
Tart cherry
Studied as: juice concentrate, twice daily for seven days.
Montmorency tart cherries are one of the few foods containing meaningful melatonin, alongside anthocyanins associated with recovery from hard training.
In 20 healthy volunteers, tart cherry supplementation raised total melatonin and increased time in bed, total sleep time and sleep efficiency (Howatson et al., European Journal of Nutrition, 2012).
Worth knowing: that trial used juice concentrate. Freeze-dried cherry powder is the same fruit in a different presentation, which is a reasonable way to get it into a product that is not a drink.
Magnesium
Studied dose: 250 mg elemental magnesium, four weeks.
Magnesium takes part in hundreds of enzymatic processes, including those regulating the nervous system, and athletes lose it through sweat.
A randomised placebo-controlled trial of 155 adults with poor sleep found magnesium bisglycinate improved Insomnia Severity Index scores more than placebo, with a small effect size overall. The improvement was notably larger in participants whose dietary magnesium intake was low to begin with.
The practical read: magnesium is supportive rather than transformative, and it does the most for people who were short of it. The glycinate form is chelated to glycine, which makes it gentle on the stomach and pairs naturally with glycine itself.
One label trap. Check whether the number refers to elemental magnesium or to the whole compound. They are very different figures, and the research doses are given in elemental magnesium.
Honey
Honey works through a mechanism physiologists have understood for decades. Carbohydrate raises insulin, insulin clears the amino acids that compete with tryptophan for transport into the brain, and tryptophan is what your body builds serotonin and then melatonin from.
It also has direct research behind it. A crossover study of poor sleepers run out of the University of Saskatchewan found honey safe and effective for improving sleep quality, performing favourably alongside melatonin, with no adverse effects. The follow-up randomised double-blind trial in 110 adults is registered as NCT04207281.
For athletes there is a second argument. Hard evening training draws down glycogen, and overnight is the longest window your body has to replace it. Honey covers the sleep pathway and the fuel at the same time.
It is also the most pleasant thing on this list to take every night, which is not a trivial point when consistency is what decides the outcome.
Melatonin, and why many athletes choose to avoid it
Melatonin deserves a fair hearing. It is genuinely effective for circadian problems: jet lag, shift work, and any situation where your body clock is in the wrong time zone. If that is your problem, melatonin is the right tool.
Two things make it a poor fit for nightly use.
Next-day grogginess. Common supplement doses run far above what the body produces, and feeling flat the next morning is the usual complaint. For anyone training the following day, that cost lands directly on performance.
The label is often wrong. In an analysis of 31 commercial melatonin products from 16 brands, more than 71% failed to come within 10% of their label claim. Actual content ranged from 83% below to 478% above what was printed. Lot-to-lot variation within a single product reached 465%. Serotonin, which is a controlled substance, turned up in roughly a quarter of the products tested (Erland and Saxena, Journal of Clinical Sleep Medicine, 2017).
You cannot dose something accurately when the bottle does not know what is in it. This is the honest case for melatonin-free formulas, and it is about quality control rather than any claim that melatonin does not work.
Putting it together
The ingredients above are complementary rather than competing. Glycine and L-theanine act on different parts of winding down. Tart cherry contributes melatonin from food. Magnesium supports the nervous system. Carbohydrate opens the tryptophan pathway and refills what training emptied.
A sensible stack covers several of those at studied doses, in something you will take every night. Pair it with protein before sleep if you train hard, since around 40 g of casein raises overnight muscle protein synthesis and carbohydrate does not substitute for that.
Where Hibernation Honey sits
One sachet:
| Per serving | Amount |
|---|---|
| Calories | 60 |
| Total carbohydrate | 16 g |
| Glycine | 3,000 mg |
| L-Theanine | 200 mg |
| Magnesium glycinate | 400 mg |
| Organic freeze-dried tart cherry | 2.5 g |
Other ingredients: organic domestic wildflower honey, purified water, mineral sea salt. Twenty sachets per pouch. No added melatonin. Third-party tested.
Glycine at 3,000 mg and L-theanine at 200 mg are exactly the doses used in the trials above. The tart cherry is freeze-dried rather than concentrate. The base is raw wildflower honey, which carries the carbohydrate side and makes the whole thing something you look forward to rather than something you remember to do.
Related reading: Honey Before Bed: What It Does for Sleep and Recovery and Carbs Before Bed for Recovery.
Who should skip it
Do not feed honey to infants 12 months or under. If you are pregnant, nursing, taking medication, or have a medical condition, talk to your doctor before use.
References
- Yamadera W, Inagawa K, Chiba S, Bannai M, Takahashi M, Nakayama K. Glycine ingestion improves subjective sleep quality in human volunteers, correlating with polysomnographic changes. Sleep and Biological Rhythms. 2007;5(2):126-131.
- Hidese S, Ogawa S, Ota M, et al. Effects of L-theanine administration on stress-related symptoms and cognitive functions in healthy adults: a randomized controlled trial. Nutrients. 2019;11(10):2362.
- Howatson G, Bell PG, Tallent J, Middleton B, McHugh MP, Ellis J. Effect of tart cherry juice (Prunus cerasus) on melatonin levels and enhanced sleep quality. European Journal of Nutrition. 2012;51(8):909-916.
- Erland LAE, Saxena PK. Melatonin natural health products and supplements: presence of serotonin and significant variability of melatonin content. Journal of Clinical Sleep Medicine. 2017;13(2):275-281.
- Magnesium bisglycinate supplementation in healthy adults reporting poor sleep: a randomized, placebo-controlled trial. 2025.
- Honey to Improve Sleep Quality. University of Saskatchewan. ClinicalTrials.gov NCT04207281.
- Trommelen J, van Loon LJC. Pre-sleep protein ingestion to improve the skeletal muscle adaptive response to exercise training. Nutrients. 2016;8(12):763.
These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.