Micro Ingredients Glycine Powder Review

The Supplement Facts panel prints a serving size of 1 scoop (1 g) and Glycine (Free-Form) 1,000 mg per serving, with 1,000 servings per container. The studied sleep dose is 3 g (Yamadera 2007; Bannai 2012, PMID 22529837), so you need three scoops. The back label suggests one scoop daily at bedtime, which is a third of the studied dose. The Amazon title says 1000mg per serving, and that is accurate: it is the label serving, not the sleep dose.

The panel says 1 scoop (1 g), and a gallery tile says the scoop measures 1/8 teaspoon. We could not confirm that a level scoop of that volume holds 1 g of this powder. Weigh the first few scoops on a kitchen scale, then count scoops from there. Counting three small scoops each night is the main practical cost of this product against a 3 g scoop.

The panel lists one ingredient, Glycine (Free-Form), and prints Other Ingredients: None. The back label also says free of soy, dairy and gluten, and a Non-GMO seal is printed on the pack. That is the plain free-form glycine the sleep studies used, so it passes the purity test this list applies.

The pack prints a Third Party Lab Tested seal, and the brand FAQ says its products are third-party lab tested for heavy metals and micro-organisms. No lab is named and we found no certificate of analysis on the site. We checked the NSF Certified for Sport listing on October 18, 2026 and found no Micro Ingredients product. We could not read the USP or Informed Choice listings, so those are unchecked. The claim is plausible, but we could not verify it at a certifier.

On cost, yes. The Amazon offer we checked on October 18, 2026 was $29.99 for 1,000 servings of 1 g, which is about 3 cents a scoop and about 9 cents for a 3 g dose. The trade is the scoop count: three scoops a night where Nutricost's scoop is the whole dose. If you want the tub with the 3 g scoop, Nutricost is the easier nightly routine.

1. [1] Bannai 2012 PMID 22529837 — The effects of glycine on subjective daytime performance in partially sleep-restricted healthy volunteers. In healthy volunteers whose sleep was restricted for three nights, 3 g of glycine before bed significantly reduced subjective daytime fatigue and sleepiness and improved reaction-time performance versus placebo. The best-replicated glycine sleep finding — but a small study, and the authors are affiliated with a glycine manufacturer (noted for transparency).
2. [2] Kawai 2015 PMID 25533534 — The sleep-promoting and hypothermic effects of glycine are mediated by NMDA receptors in the suprachiasmatic nucleus. Mechanistic study in rats: oral glycine promoted sleep and lowered core body temperature by acting on NMDA receptors in the suprachiasmatic nucleus (the master circadian clock), increasing skin blood flow and heat loss. Provides the leading biological explanation for glycine's sleep effect — but it is an animal study, so extrapolation to humans is indirect.
3. [3] Yamadera 2007 — Glycine ingestion improves subjective sleep quality in human volunteers, correlating with polysomnographic changes. In volunteers with unsatisfactory sleep, 3 g of glycine before bed improved subjective sleep quality and, on polysomnography, shortened latency to sleep onset and to slow-wave sleep. The canonical human glycine-sleep study and the source of the 3 g dose — but small (~11 subjects) and published in a journal PubMed does not index, so no PMID exists. Cited honestly without a fabricated identifier.