Zinc

Which form of zinc is best?

Updated 10 Nov 2026

Short answer

For absorption, zinc citrate and zinc gluconate did equally well in a small trial, and zinc oxide did worse.[1] For colds, half of the trials in a 2024 Cochrane review used lozenges, most often of zinc gluconate.[2] For any form, the label gives the amount of elemental zinc.[3]

Forms on the market

Supplements contain zinc as zinc sulfate, zinc acetate, zinc gluconate and other compounds.[3] The Supplement Facts label lists elemental zinc, the amount of zinc itself, not the weight of the whole compound.[3] Zinc sulfate is 23% zinc by weight and zinc gluconate is 14.3%. So 50 mg of zinc gluconate gives about 7 mg of zinc.[4] Zinc is sold alone, combined with other ingredients and in many multivitamin and mineral products.[3]

Absorption

In a 2014 trial, 15 healthy adults took 10 mg of zinc without food as zinc citrate, zinc gluconate and zinc oxide, in random order. The share absorbed was:[1]

  • zinc citrate: 61.3%[1]
  • zinc gluconate: 60.9%[1]
  • zinc oxide: 49.9%, and 3 people absorbed little or none[1]

Zinc gluconate, sulfate and acetate dissolve in water. Zinc oxide does not. Zinc citrate has a high zinc content and tastes better in syrups.[1]

For colds

In a 2024 Cochrane review, half of the cold trials used lozenges of zinc gluconate, zinc acetate or zinc orotate. The others used capsules, tablets, powders, syrups or nasal sprays.[2] Lozenges and syrups stay in the mouth and throat for a while, which brings zinc into contact with the cold virus there.[3] A 2021 review of 28 trials in adults found it unclear which zinc forms and doses work best. In that review, mild side effects such as nausea and irritation of the mouth or nose were more common with zinc (risk ratio 1.41).[5]

For other uses

For diarrhea in children, trials used zinc acetate, zinc gluconate or zinc sulfate, most often 20 mg a day.[3] Prevention trials in children most often gave zinc sulfate as a syrup.[6] For blood sugar, a 2019 review found a larger fall in fasting glucose with inorganic zinc compounds.[7] Trials for period pain used zinc sulfate in 5 of 6 trials and zinc gluconate in 1.[4]

For the eyes

The AREDS trial used zinc oxide, 80 mg a day, with 2 mg of copper.[8]

With food and other minerals

From food, the body absorbs zinc better from meat and fish than from beans, nuts and whole grains, which contain phytate. Phytate is the storage form of phosphorus in plants, and it binds zinc in the gut.[3] Iron supplements of 25 mg or more taken at the same time lower zinc absorption, but the iron added to fortified foods does not.[3] In trials in children, zinc given together with iron had a smaller benefit than zinc alone for several outcomes.[6]

Sources (8)

  1. Zinc absorption by young adults from supplemental zinc citrate is comparable with that from zinc gluconate and higher than from zinc oxide. Wegmüller R, Tay F, Zeder C, Brnic M, Hurrell RF J Nutr, 2014. PMID 24259556
  2. Zinc for prevention and treatment of the common cold. Nault D, Machingo TA, Shipper AG, Antiporta DA, Hamel C, Nourouzpour S, et al. Cochrane Database Syst Rev, 2024. PMID 38719213
  3. Zinc: Fact Sheet for Health Professionals. NIH Office of Dietary Supplements. ods.od.nih.gov
  4. Efficacy of Zinc Supplementation in the Management of Primary Dysmenorrhea: A Systematic Review and Meta-Analysis. Hsu TJ, Hsieh RH, Huang CH, Chen CS, Lin WY, Huang YC, et al. Nutrients, 2024. PMID 39683510
  5. Zinc for the prevention or treatment of acute viral respiratory tract infections in adults: a rapid systematic review and meta-analysis of randomised controlled trials. Hunter J, Arentz S, Goldenberg J, Yang G, Beardsley J, Myers SP, et al. BMJ Open, 2021. PMID 34728441
  6. Zinc supplementation for preventing mortality, morbidity, and growth failure in children aged 6 months to 12 years. Imdad A, Rogner J, Sherwani RN, Sidhu J, Regan A, Haykal MR, et al. Cochrane Database Syst Rev, 2023. PMID 36994923
  7. Zinc supplementation improves glycemic control for diabetes prevention and management: a systematic review and meta-analysis of randomized controlled trials. Wang X, Wu W, Zheng W, Fang X, Chen L, Rink L, et al. Am J Clin Nutr, 2019. PMID 31161192
  8. 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. PMID 11594942

More about zinc

What is zinc?Which foods contain zinc?What is zinc used for?What are the signs of zinc deficiency?Is zinc safe?Do zinc lozenges help with colds?

For education; not medical advice. Talk to a doctor before you start, stop or change a supplement.