Form Comparison

Zinc Bisglycinate vs Zinc Oxide

How zinc bisglycinate and zinc oxide differ in elemental content, absorption, tolerance, and cost.

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Quick verdict. Bisglycinate is the better choice for targeted zinc: it does not depend on stomach acid, is less affected by phytates, and is gentle on an empty stomach. Oxide's 80% zinc content makes compact multivitamin tablets, but its fractional absorption is lower and falls further on acid suppression. Choose oxide only when it comes inside a multivitamin or AREDS formula you already take.

Side by Side

Zinc Bisglycinate Zinc Oxide
Elemental content Varies by product 80% elemental zinc
Absorption High Moderate
How it is absorbed Zinc chelated to glycine. Small human studies suggest absorption at least comparable to gluconate, with less sensitivity to phytate. Insoluble at neutral pH; requires gastric acid to dissolve. Lower fractional absorption than citrate or gluconate in Wegmuller 2014, and further reduced with acid suppression.
Typical dose 15-30 mg elemental zinc daily Found in multivitamins at 8-15 mg elemental zinc
Common uses general supplementation, GI sensitivity multivitamins, food fortification, AREDS formula (with copper)
Side effects Often better tolerated on an empty stomach than salts. Fewer taste complaints; GI effects at high doses.
Cost Moderate Low
Also called zinc glycinate, zinc bisglycinate chelate None
Labels in index 199 190

When to Choose Zinc Bisglycinate

Choose zinc bisglycinate when zinc salts cause nausea. Elemental content varies by manufacturer; use the panel value.

Zinc Bisglycinate

Choose zinc bisglycinate when zinc salts cause nausea.

What to look for: Zinc Bisglycinate named on the Supplement Facts panel, with the amount per serving stated.

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When to Choose Zinc Oxide

Choose zinc oxide when it comes in a multivitamin. For targeted supplementation a soluble salt absorbs better. Common in multivitamins because it is compact and cheap. The AREDS trial used 80 mg zinc as oxide plus 2 mg copper.

Zinc Oxide

Choose zinc oxide when it comes in a multivitamin. For targeted supplementation a soluble salt absorbs better.

What to look for: Zinc Oxide named on the Supplement Facts panel, with the amount per serving stated.

Find on iHerb Affiliate link

Products on Titrate

In Titrate's index of NIH label data, 199 labels named as zinc products list zinc bisglycinate and 190 list zinc oxide.

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Zinc does not have its own search category yet. Each product above links to its full label in the NIH database.

Related

References

NIH Office of Dietary Supplements. Zinc: Fact Sheet for Health Professionals.

Barrie SA, et al. Comparative absorption of zinc picolinate, zinc citrate and zinc gluconate in humans. Agents Actions. 1987;21(1-2):223-228.

Age-Related Eye Disease Study Research Group. A randomized, placebo-controlled, clinical trial of high-dose supplementation with vitamins C and E, beta carotene, and zinc for age-related macular degeneration and vision loss: AREDS report no. 8. Arch Ophthalmol. 2001;119(10):1417-1436.

Willis MS, et al. Zinc-induced copper deficiency: a report of three cases initially recognized on bone marrow examination. Am J Clin Pathol. 2005;123(1):125-131.

Nations SP, et al. Denture cream: an unusual source of excess zinc, leading to hypocupremia and neurologic disease. Neurology. 2008;71(9):639-643.

Wegmüller R, et al. Zinc absorption by young adults from supplemental zinc citrate is comparable with that from zinc gluconate and higher than from zinc oxide. J Nutr. 2014;144(2):132-136.

Hemilä H. Zinc lozenges and the common cold: a meta-analysis comparing zinc acetate and zinc gluconate, and the role of zinc dosage. JRSM Open. 2017;8(5):2054270417694291.