Form Comparison

Zinc Oxide vs Zinc Sulfate

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

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Quick verdict. Sulfate is soluble and absorbs well without depending on stomach acid; oxide needs acid to dissolve and absorbs less. Sulfate is the form used to treat clinical deficiency, while oxide sits in multivitamins and the AREDS formula because it is compact. Choose sulfate for treating deficiency under a clinician, and do not count on oxide if you take acid-suppressing drugs.

Side by Side

Zinc Oxide Zinc Sulfate
Elemental content 80% elemental zinc 23% elemental zinc
Absorption Moderate High
How it is absorbed 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. Soluble inorganic salt releasing ionic zinc.
Typical dose Found in multivitamins at 8-15 mg elemental zinc 220 mg compound (about 50 mg elemental zinc) in prescription use
Common uses multivitamins, food fortification, AREDS formula (with copper) clinical zinc deficiency, WHO oral zinc for childhood diarrhea
Side effects Fewer taste complaints; GI effects at high doses. More nausea and metallic taste than organic salts.
Cost Low Low
Also called None None
Labels in index 190 141

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.

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When to Choose Zinc Sulfate

Choose zinc sulfate when a clinician prescribes it for documented deficiency. The form used in much of the clinical deficiency literature.

Zinc Sulfate

Choose zinc sulfate when a clinician prescribes it for documented deficiency.

What to look for: Zinc Sulfate 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, 190 labels named as zinc products list zinc oxide and 141 list zinc sulfate.

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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.