Zinc forms compared for absorption in people
What it found
In people, zinc glycinate and zinc gluconate were taken up better than some other forms of zinc.
The evidence comes from small studies, and results for zinc gluconate were mixed.
What they found
Studies in people
Zinc glycinate
Three studies found zinc glycinate was taken up better than zinc gluconate, zinc picolinate and zinc oxide. In a 6-week trial, 30 women taking 60 mg of zinc a day as zinc glycinate had higher blood zinc levels than those taking zinc gluconate or a placebo.
Zinc gluconate
Results for zinc gluconate were mixed. Three studies found it was taken up better than zinc oxide, but two found no change in blood zinc levels with zinc gluconate, and three found it was taken up less well than zinc glycinate.
Zinc oxide vs sulfate
Four studies in fortified foods found no difference in how much zinc was absorbed from zinc oxide compared with zinc sulfate. One study in pregnant adolescents found higher blood zinc levels in those taking zinc sulfate than zinc oxide.
Other zinc forms
Single studies suggested zinc citrate, zinc picolinate, zinc-enriched yeast and zinc-histidine complexes may be taken up better than certain other forms. These findings come from one study each.
Other findings
Study limits
Most studies were small, with about 10 to 15 people per group, and most measured zinc in blood, which has known limits. Most studies included only one sex.
What the authors conclude
“The clinical evidence reviewed here suggests that zinc glycinate and zinc gluconate are better absorbed than other forms of zinc.”
Also in their conclusions
- They conclude that the clinical evidence reviewed here suggests that zinc glycinate and zinc gluconate are better absorbed than other forms of zinc.
- They advise that these results should be interpreted with caution due to the small number of studies per zinc form and differences in how zinc levels were assessed.
How it was done
Little information compares how well the different chemical forms of zinc in supplements are absorbed. No earlier review the authors knew of had compared the absorption of different zinc forms in people.
The authors searched for human studies that compared how well two or more forms of zinc were taken up by the body. They found five longer-term studies and nine single-dose studies, with 6 to 90 people each, plus reviews on related topics.
What it can’t tell you
- Most studies were small and measured zinc in blood, which can fluctuate for many reasons. They cannot show how much of a difference these forms make to health over time.
- The studies used different doses, foods and ways of measuring zinc, so the forms cannot be ranked with certainty.
Who paid
- Funding
- Funded by Pharmavite, LLC (from the PubMed record).
- Conflicts
- P.P.D., R.W.G., and S.H.M. are employees of Pharmavite, LLC. Q.M. was an intern at Pharmavite, LLC. when the work was completed.
The paper
- Title
- Comparative Absorption and Bioavailability of Various Chemical Forms of Zinc in Humans: A Narrative Review
- Type
- ReviewThe authors read earlier studies and describe what they found. It isn’t a new study.
- Evidence
- Studies in people
- Summarised from
- Full text
- Cite
- Devarshi PP, Mao Q, Grant RW, Hazels Mitmesser S (2024). Comparative Absorption and Bioavailability of Various Chemical Forms of Zinc in Humans: A Narrative Review. Nutrients. doi:10.3390/nu16244269Free full textPubMed 39770891DOI
Summary written 26 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error