Guide
Zinc and glycine: bisglycinate vs a separate glycine supplement
Zinc bisglycinate is zinc already chelated to glycine, not a pairing of two separate ingredients. This page covers reading a bisglycinate label and how that differs from taking zinc alongside a standalone glycine supplement.
"Zinc and glycine" usually means one of two different things: zinc bisglycinate, a chelated form of zinc where glycine is already bound to the mineral, or a separate zinc product taken alongside a standalone glycine supplement. They're not the same question, and the label math is different for each.
Zinc bisglycinate: glycine as part of the mineral
Zinc bisglycinate (also called zinc glycinate) is zinc chelated to two glycine molecules — glycine is part of the compound, not a separate ingredient. A 2007 crossover trial in 12 women found zinc bisglycinate's bioavailability was 43.4% higher than zinc gluconate's after a single dose, and a 2024 review of the clinical literature, written by a supplement manufacturer's science team, concluded zinc glycinate and zinc gluconate absorbed better than the other forms it reviewed. See zinc vs bisglycinate for the fuller comparison against other chelated forms.
A bisglycinate label typically shows two numbers: the total weight of "zinc bisglycinate" and the smaller "elemental zinc" figure, since glycine adds weight to the compound without adding zinc. A product listing "zinc bisglycinate 50 mg" isn't giving you 50 mg of zinc — check the elemental zinc line specifically, since that's the number to compare against the RDA (11 mg/day men, 8 mg/day women) and the 40 mg/day upper intake level.
Zinc plus a separate glycine supplement
Free-form glycine, sold as its own amino acid supplement, is a different product from zinc bisglycinate. No research identified for this page tested whether taking a separate glycine supplement changes zinc's absorption or effects, or the reverse — that's a distinct pairing question from the chelation question above, and glycine's own evidence base as a standalone supplement is outside what this zinc-focused page reviews.
Questions people ask
Is zinc bisglycinate the same as zinc plus glycine?
Chemically, yes — bisglycinate is zinc already bound to two glycine molecules in one compound. That's different from buying a zinc supplement and a separate glycine supplement and taking both.
Why does a zinc glycinate label show two different numbers?
The larger number is the weight of the whole compound (zinc plus the attached glycine); the smaller "elemental zinc" number is the actual zinc content, which is what matters for comparing to the RDA and upper intake level.
Does glycine improve zinc absorption?
As part of the bisglycinate compound, a 2007 crossover trial found higher bioavailability than zinc gluconate. Whether taking a separate, unbound glycine supplement alongside a different zinc form does the same thing hasn't been tested, as far as any research identified for this page shows.
Related reading: zinc vs bisglycinate, zinc forms compared, how much zinc should you take a day, and what is zinc.
Sources
- A bioavailability study comparing two oral formulations containing zinc (Zn bis-glycinate vs. Zn gluconate) after a single administration to twelve healthy female volunteers A 2007 crossover trial in 12 women found zinc bisglycinate's bioavailability was 43.4% higher than zinc gluconate's after a single dose.
- Comparative Absorption and Bioavailability of Various Chemical Forms of Zinc in Humans: A Narrative Review A 2024 review of the clinical literature, written by a supplement manufacturer's science team, concluded zinc glycinate and zinc gluconate absorbed better than the other forms it reviewed.
*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.