Daidzein
INCI: genistein (sister isoflavone)
Reviewed by Kate · Last updated 18 Aug 2026
Also known as: genistein (sister isoflavone)
A type of antioxidant known as an isoflavone found in soybeans Pronounced ability to help skin better withstand environmental exposure
EWG Safety Score
What Is Daidzein?
Daidzein is one of the primary isoflavone antioxidants found naturally in soy, although lesser amounts occur in other foods such as nuts, grapes, and cabbage. Research on human skin has shown it helps mitigate the cascade of oxidative and other damage triggered by exposure to UVB light. Indeed, one study showed daidzein reduced this damage by 71%! This also makes it a good soothing ingredient since it helps offset the multi-layer irritation UV light causes.
This soy isoflavone has been shown to have protective benefits for skin’s underlying support, helping to maintain the look and feel of youthful firmness instead of leaving age-related deterioration unchecked.
Daidzein is absorbed well, but research has shown its “sister” isoflavone genistein has better absorption; however, studies have also shown that combining daidzein and genistein offers greater benefits due to their natural affinity for skin and the distinctive benefits each provides. Research has also shown daidzein is more effective topically when formulated in a skin-friendly delivery system such as complex sugars known as cyclodextrins.
Daidzein is considered safe and non-irritating as used in skin care, where amounts range from 0.02%–0.5% when used in pure form (rather than what naturally occurs in soy extracts).
Clinical Evidence & References
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Daidzein is a variant of Genistein, the form you will most often see on an ingredients list.
Belongs to a set of compounds known as isoflavones, which are sources of phytoestrogens Commonly derived from soy
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Genistein
Belongs to a set of compounds known as isoflavones, which are sources of phytoestrogens Commonly derived from soy
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