Astaxanthin supplementation does not augment fat use or improve endurance performance
Participants
n=32 young, well-trained male cyclists/triathletes (age 25 ± 1 yr, 73 ± 1 kg, VO2peak 60 ± 1 mL/kg/min, Wmax 395 ± 7 W; mean ± SEM)
Protocol
20 mg/day astaxanthin or placebo, 4 weeks
Test before and after: 60 min submaximal at 50% Wmax → TT of approximately 1 h
Key Results
| Metric | Result |
|---|---|
| Plasma astaxanthin | non-detectable → 187 ± 19 μg/kg (p<0.05) |
| Antioxidant capacity | no difference (p=0.90) |
| MDA (oxidative stress) | no difference (p=0.63) |
| Fat oxidation (submaximal) | no group difference, no change over time (PLA 0.71 → 0.68, ASTA 0.66 → 0.61 g/min; p=0.73) |
| TT performance | no improvement in either group (PLA 236 → 239 W, ASTA 238 → 244 W; p=0.63) |
Findings
Despite a significant plasma astaxanthin increase, 20 mg/day for 4 weeks does NOT improve antioxidant capacity, fat oxidation, or TT performance in trained cyclists.
Critical Finding for Practice
Most robust of the base's three astaxanthin studies (n=32, well-trained, VO2peak 60). Inference across REF-211 and REF-212, not tested here: the positive findings come from recreationally trained cyclists (Brown, REF-211, n=12) or a trial with heavy dropout (Earnest, REF-212, 7 per group). For a trained cyclist: effect unlikely.
Practical Application
In 32 young well-trained male cyclists/triathletes (VO2peak 60 mL/kg/min), 20 mg/day astaxanthin for 4 weeks raised plasma astaxanthin to 187 ± 19 μg/kg but did not change antioxidant capacity (P = 0.90), whole-body fat oxidation during 60 min at 50% Wmax (P = 0.73) or time-trial power over approximately 1 h (PLA 236 → 239 W, ASTA 238 → 244 W; P = 0.63) (double-blind parallel RCT) — do not use astaxanthin as a fat-oxidation or endurance aid in trained athletes.
Inference, not tested here: other doses, longer durations or less-trained populations were not studied.
Limitations
From the design as the abstract reports it: a single double-blind parallel trial, n=32 young well-trained men (two groups).
One dose (20 mg/day) and one duration (4 weeks).
Performance was one time trial of approximately 1 h after 60 min at 50% Wmax; other exercise durations were not tested.
How this entry was checked and changed
Why this level
regraded 2026-09-27 from A−: single parallel RCT, n=32 (rubric: parallel RCT 20-39)
Content correction 2026-09-27
Level A− -> B+: a single parallel RCT with n=32 is B+ under the rubric (A− needs ≥40).
Added the abstract's per-group fat-oxidation and TT power values; the cross-study interpretation is now labelled as inference.
2026-09-28: added Limitations and Practical Application from the abstract (Europe PMC/PubMed PMID 23274592).