Why we chose 0.9 mg of melatonin for Yu Sleep

By Ethan Techwell · Published September 15, 2026 · Updated September 25, 2026 · 7 min read

Disclosure: Three Whole Health owns the FemiCore and Yu Sleep brands mentioned in this article. This content is educational and is not medical advice. See our editorial policy.

If you have shopped for a sleep supplement recently, you have probably noticed that melatonin doses keep climbing: 5 mg, 10 mg, even 20 mg gummies are common. Yu Sleep contains 0.9 mg. This article explains why we went the other way.

What melatonin actually does

Melatonin is a hormone your pineal gland releases when it gets dark. It does not sedate you the way a sleeping pill does. Instead it tells your body clock that night has started, which nudges the processes that make you drowsy. Night-time blood levels in healthy adults are modest, and the amount the body produces over a whole night is well under 1 mg.

What the dose research shows

Several lines of evidence point toward lower doses being sufficient for many people:

• Work from the Massachusetts Institute of Technology in the 1990s and 2000s found that doses of about 0.3 mg raised blood melatonin to typical night-time levels and improved sleep in older adults, while higher doses produced levels far above normal and were more likely to cause daytime drowsiness or a "hangover" feeling.
• The NCCIH notes that melatonin appears to help with certain sleep-timing problems and may modestly reduce the time it takes to fall asleep, and that side effects such as headache, dizziness, nausea and daytime drowsiness are reported, particularly at higher doses.
• Analyses of commercial melatonin products in North America have found that actual content can differ substantially from the label, which is one more reason to be cautious with very high doses.

None of this means a higher dose never helps. It means the assumption that more melatonin equals more sleep is not well supported, and that the cost of a high dose is often the grogginess people complain about the next morning.

Why 0.9 mg specifically

We wanted a dose that sits within the range studied for physiological replacement (roughly 0.3 to 1 mg) while leaving room for people to adjust. Because Yu Sleep is a sublingual liquid, a full 2 mL serving delivers 0.9 mg, but a single dropper delivers about half that. Someone who is sensitive can start at one dropper; someone who needs the full serving can take two. That flexibility is much harder to get from a fixed-dose gummy.

Melatonin is not doing the job alone

The other reason we could keep melatonin low is that Yu Sleep is not a single-ingredient product. The formula addresses several reasons people struggle to sleep:

Each of these ingredients has its own evidence base of varying strength, and we are candid about that: the human data on melatonin and magnesium is stronger than the data on GABA or apigenin. Together, though, they let us support sleep from more than one direction without pushing melatonin to pharmacological levels.

Who should be cautious

• Anyone pregnant or nursing.
• People taking antidepressants or other serotonergic medication, because 5-HTP may interact.
• People on sedatives, blood-pressure medication or anticoagulants.
• Anyone with a diagnosed sleep disorder such as sleep apnea, which needs medical treatment rather than a supplement.

Melatonin can cause drowsiness, so do not drive after taking it. If sleep problems persist for more than a few weeks, see a clinician; ongoing insomnia has causes a supplement cannot fix.

How to tell if a lower dose is right for you

1. If you currently use a 5 mg or higher product and wake up foggy, that is the clearest sign to try less.
2. Start with one dropper of Yu Sleep (about 0.45 mg melatonin) for three nights.
3. Move to the full serving only if you need it.
4. Keep the rest of your routine consistent: same bedtime, dim lights, no screens for the last half hour.

Sources

1. National Center for Complementary and Integrative Health. Melatonin: What You Need To Know. nccih.nih.gov
2. Zhdanova IV, Wurtman RJ, et al. Melatonin treatment for age-related insomnia. Journal of Clinical Endocrinology & Metabolism, 2001;86(10):4727-4730.
3. Erland LA, 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.
4. National Institutes of Health, Office of Dietary Supplements. Magnesium: Fact Sheet for Health Professionals. ods.od.nih.gov

† These statements have not been evaluated by the Food and Drug Administration. Our products are not intended to diagnose, treat, cure, or prevent any disease.