Astaxanthin reduces sneezing, IgE, and histamine in mouse models of allergic rhinitis. A major review concedes the doses used are not achievable in humans and no clinical trials have been reported.
Two randomized trials in adults aged 65 to 82 found real strength and endurance gains. The supplement was a three-ingredient formula, every gain required exercise, and the effects differed by sex.
A 132-patient randomized trial tested 16 mg and 40 mg of astaxanthin against placebo in functional dyspepsia. The primary outcome was null. One reflux measure moved, at a dose no consumer product sells.
Two human trials are cited for astaxanthin and sleep. One found nothing until it split the data after the fact. The other gave participants zinc at the same time, and the zinc-only group also improved.
Three randomized trials report more retrieved eggs and better embryo grades with astaxanthin before IVF. A 2025 network meta-analysis rates the certainty as very low, and no trial has reported a live birth.
Several of the most-cited astaxanthin trials tested multi-ingredient formulas. One supplied 100 micrograms per capsule. Here is how to check whether a cited study actually tested the ingredient on the label.
Astaxanthin has a coherent mechanism for protecting bone and a supportive preclinical literature. It has no human trial with a bone density or fracture endpoint. A different carotenoid does.
A meta-analysis found nine randomized trials of oral astaxanthin and only two open-label studies of topical. The evidence is lopsided, and the wrinkle result is not what you would expect.
One crossover trial reports improved recovery from mental fatigue, but it tested a combination product and was industry funded. Here is what that does and does not establish.
Astaxanthin degrades measurably above 60 degrees C and under prolonged UV. Here is what the stability research shows and how it translates to the bottle on your counter.
Natural astaxanthin is mostly esterified, synthetic is mostly free. Research shows stability and absorption pull in opposite directions, and labels rarely tell you which you are buying.
Two randomized trials in women with PCOS report real metabolic and inflammatory changes at 12 mg per day. Both come from one research group, and neither measured fertility outcomes.