As
Astaxanthin
AstaxanthinAntioxidant
A red-orange antioxidant from algae. Pills raised skin moisture in trials; evidence for putting it on skin is thin.
What it does
It’s a red-orange pigment made by algae, sold as an antioxidant. For skin use there are only two small studies with no comparison group, one of which also used pills, and they suggested a slight benefit.
The evidence, graded
strongZhou et al. (2021) found nine randomized controlled trials of oral astaxanthin and two open-label studies of topical or oral-plus-topical use. Oral supplements significantly restored moisture and improved elasticity but did not significantly decrease wrinkle depth. The open-label studies suggested slightly protective effects. In one, by Fuji Chemical authors, 30 women combined 6 mg a day by mouth with daily application to the skin for 8 weeks, with no control group.Zhou 2021 · Nutrients ↗
Graded per the methodology: strong · moderate · emerging · expert consensus. A weak source on a strong claim gets the weaker label.
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