Astaxanthin: How much is too much? A safety review.

Astaxanthin (AX)-containing preparations are increasingly popular as health food supplements. Evaluating the maximum safe daily intake of AX is important when setting dose levels for these products and currently, there are discrepancies in recommendations by different regulatory authorities. We have therefore conducted a review of approved dose levels, clinical trials of natural AX, and toxicological studies with natural and synthetic AX. Recommended or approved doses varied in different countries and ranged between 2 and 24 mg. We reviewed 87 human studies, none of which found safety concerns with natural AX supplementation, 35 with doses ≥12 mg/day. An acceptable daily intake (ADI) of 2 mg as recently proposed by European Food Safety Authority was based on a toxicological study in rats using synthetic AX. However, synthetically produced AX is chemically different from natural AX, so results with synthetic AX should not be used in assessing natural AX safety. In addition, few safety studies have been conducted in either humans or animals with synthetic AX. We therefore recommend the ADI for natural AX to be based only on studies conducted with natural AX and further studies to be conducted with synthetic AX (including human clinical trials) to establish a separate ADI for synthetic AX.