Guide
Zinc picolinate vs. zinc bisglycinate: what's actually different
Zinc picolinate and zinc bisglycinate are both chelated forms marketed on absorption, but no study has tested them head-to-head. This page covers the elemental-percentage difference and what the separate trials on each form found.
Zinc picolinate (about 21% elemental zinc by weight) and zinc bisglycinate (about 31%) are both chelated forms marketed on absorption claims, but no trial has tested them against each other directly. Each has separately outperformed zinc gluconate in its own small human study — picolinate in a 1987 trial, bisglycinate in a 2007 one — which is the closest the evidence gets to comparing them.
Elemental zinc, side by side
| Compound | ~% elemental zinc |
|---|---|
| Zinc picolinate | ~21% |
| Zinc bisglycinate (chelate) | ~31% |
Bisglycinate delivers more elemental zinc per milligram of compound than picolinate does — a smaller pill, or fewer fillers, for the same elemental dose. That's a label-arithmetic fact (21 CFR 101.9 requires the elemental figure on the panel), separate from the absorption question below.
What the separate trials found
A 2007 randomized crossover trial gave 12 healthy women a single 15 mg dose of zinc bisglycinate or zinc gluconate and measured serum zinc over time. Bisglycinate's bioavailability came out 43.4% higher than gluconate's.
A 1987 double-blind crossover trial gave 15 healthy adults zinc picolinate, zinc citrate, zinc gluconate (50 mg elemental/day each) or placebo for four weeks and measured zinc in hair, urine, erythrocytes and serum. Only picolinate produced significant rises in hair, urine and erythrocyte zinc; gluconate and citrate didn't differ from placebo.
Both forms, in other words, beat gluconate in their own trial — but nobody has put picolinate and bisglycinate in the same study, so there's no direct answer to "which is better absorbed, picolinate or bisglycinate." A 2024 narrative review of the clinical literature (funded by a supplement manufacturer) concluded that zinc glycinate — closely related to bisglycinate — and zinc gluconate absorbed better than the other forms it reviewed, which doesn't line up cleanly with the 1987 trial's result for picolinate either. The honest answer is that the two forms haven't been compared, not that one has been shown to beat the other.
What this means for choosing between them
Both are marketed as "gentler" or "better absorbed" chelated alternatives to plain mineral salts, and both have some trial evidence behind that positioning relative to gluconate specifically. Neither has a large, modern trial establishing an advantage over the other, so a choice between picolinate and bisglycinate today comes down to elemental content, price and personal tolerance rather than a documented winner. See how to choose a good zinc for the full label-reading checklist that applies regardless of which chelate you're considering.
Questions people ask
Which is better, zinc picolinate or zinc bisglycinate?
No trial has compared them directly. Each has outperformed zinc gluconate in its own separate study — picolinate by a significant rise in status markers in 1987, bisglycinate by 43.4% higher bioavailability in 2007 — but that's an indirect comparison, not a head-to-head one.
Is zinc bisglycinate the same as zinc glycinate?
They're closely related chelated forms and are often used interchangeably in marketing; bisglycinate specifically refers to zinc bound to two glycine molecules. Both are distinct from zinc picolinate, which is bound to picolinic acid instead.
Does zinc bisglycinate cause less stomach upset?
No trial identified for this page directly compared GI tolerability between bisglycinate and picolinate. General nausea and stomach-upset patterns for zinc at typical doses are covered in zinc side effects.
Related reading: what is zinc, zinc picolinate vs. gluconate, how to choose a good zinc, and how much zinc should you take a day.
Sources
- Comparative absorption of zinc picolinate, zinc citrate and zinc gluconate in humans A small 1987 crossover trial found zinc picolinate raised hair, urine and red-blood-cell zinc levels in 15 adults after four weeks at 50 mg/day, while zinc citrate and zinc gluconate at the same dose did not, though the study was small and its serum-zinc results were not statistically significant.
- 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.