Astaxanthin
Haematococcus pluvialis (algal source)
Marine carotenoid for skin elasticity and UV defense
Evidence tier
Preliminary
Research weight
Citations
20 verified / 20
Classification
Joint & Skin
❝
What the evidence says. Early or small human trials; promising but not yet conclusive.
What is Astaxanthin?
Astaxanthin (Haematococcus pluvialis (algal source)) is a joint and skin supplement used for may improve elasticity & moisture. NutriDex grades the human evidence as Preliminary. Astaxanthin is a red xanthophyll carotenoid, usually from the microalga Haematococcus pluvialis, valued as a potent lipid-soluble antioxidant. Small RCTs suggest oral supplementation can modestly improve skin moisture and elasticity and may reduce crow's-feet wrinkles; a 2021 meta-analysis found significant pooled effects for moisture and elasticity but not wrinkle depth. A placebo-controlled trial also reported reduced UV-induced moisture loss and a higher minimal erythema dose. Its proposed mechanism is quenching of reactive oxygen and singlet oxygen. Evidence is weak: trials are small, often enroll mostly Japanese women, and several carry industry funding.
Purported Benefits
✓May improve elasticity & moisture
✓Reduces appearance of fine lines
✓Supports photoprotection
✓Potent ROS-quenching antioxidant
Evidence by outcome
The same supplement can be well-proven for one use and unproven for another — here is the human evidence graded outcome by outcome.
| Outcome | Evidence | Effect | Studies |
|---|---|---|---|
| Improved skin moisture & elasticityA 2021 meta-analysis is significant, but a 2025 review judged evidence insufficient; small, often industry-funded. | Preliminary | ↑ benefit · small | 2 |
| Reduced wrinkle depthPooled meta-analysis found no significant reduction in wrinkle depth. | Mixed | — no effect · negligible | 1 |
| UV photoprotection (erythema/moisture)Single FUJIFILM-sponsored RCT raised minimal erythema dose; needs replication. | Preliminary | ↑ benefit · small | 1 |
| Improved lipid profile (HDL/triglycerides)Some meta-analyses raise HDL and lower TG; others show LDL rise or no effect. | Mixed | ↔ mixed · small | 3 |
| Lower fasting glucose/HbA1c in diabetesA 2026 meta-analysis reduced glucose/HbA1c, but earlier analyses found no glycemic effect. | Preliminary | ↔ mixed · small | 2 |
| Reduced oxidative stress/inflammation markersMultiple meta-analyses lower MDA and IL-6, though CRP/TNF-alpha effects inconsistent. | Moderate | ↑ benefit · moderate | 3 |
Dosing & Compounds
Typical Dose
4–12 mg/day (most trials used 4–6 mg/day).
Active Compounds
Safety & Cautions
Generally well tolerated at 4–12 mg/day. Mild GI upset and a harmless reddish skin tint possible at higher doses; may slightly lower blood pressure (caution with antihypertensives). Long-term data are limited and trials are often industry-funded; consult a clinician in pregnancy/lactation. Educational only — always check with your doctor or pharmacist before combining Astaxanthin with any medicine.
Key Studies ★ 20 studies
meta-analysis
Laurindo 2025 (meta-analysis)
✓ PubMed
Meta-analysis of 8 RCTs (moderate-to-high dose 6-24 mg/d) found astaxanthin significantly raised HDL-C (SMD 0.42; 95% CI 0.11 to 0.73) and lowered triglycerides (SMD -0.31; 95% CI -0.51 to -0.10), with no significant effect on LDL-C or total cholesterol.
systematic review/meta-analysis
Nikbaf-Shandiz 2024 (systematic review/meta-analysis)
✓ PubMed
Single-arm meta-analysis of 4 RCTs in women with PCOS found astaxanthin improved follicular-fluid total antioxidant capacity and modestly increased oocyte quality and high-quality embryos, but had inconsistent effects on malondialdehyde/SOD and no significant effect on fertilization or pregnancy rates.
meta-analysis
Liu 2024 (meta-analysis)
✓ PubMed
Meta-analysis of 11 RCTs (346 healthy adults) found astaxanthin plus training significantly enhanced fat oxidation (SMD 2.56) and physical performance (SMD 0.62), but only marginally improved cognitive accuracy (SMD 0.12; 95% CI -0.02 to 0.26) with no effect on reaction time.
meta-analysis
Molani-Gol 2026 (meta-analysis)
✓ Full text
Meta-analysis of 9 RCTs (403 patients with prediabetes/type 2 diabetes) found astaxanthin reduced fasting glucose (~16 mg/dL; p=0.014), HbA1c (-0.34%; p=0.011), triglycerides, total cholesterol and LDL-C, and raised HDL-C, but did not alter insulin or HOMA-IR.
Meta-analysis
Yang 2025 (Front Med)
✓ PubMed
Meta-analysis of 40 RCTs (n=2,119 healthy adults); astaxanthin assessed in 3 trials (n=102, 2-4 mg, 6-12 wk) and the authors concluded there is currently insufficient evidence to recommend astaxanthin for treating skin photoaging.
Systematic review
IJMS 2026 (MDPI)
✓ Full text
Systematic review of 15 human studies (2020-2025) reported astaxanthin consistently reduced pro-inflammatory cytokines (IL-6, TNF-alpha, TGF-beta1) and oxidative stress indices while increasing antioxidant capacity (SOD, TAC).
Meta-analysis
Wan et al. 2024 (Nutrients)
✓ PubMed
Meta-analysis of antioxidant lipid RCTs (search through May 2024): astaxanthin vs placebo significantly lowered LDL-C (-0.11 mmol/L), total cholesterol (-0.22 mmol/L), triglycerides (-0.46 mmol/L) and fasting insulin (-2.66 pmol/L), and raised HDL-C (+0.13 mmol/L).
Meta-analysis
Zhou 2021 (meta-analysis)
✓ Full text
Meta-analysis of 11 trials found oral astaxanthin significantly improved skin moisture (SMD 0.53) and elasticity (SMD 0.77); wrinkle depth not significant.
systematic review/meta-analysis
Leung 2022 (systematic review/meta-analysis)
✓ Full text
Meta-analysis of 7 RCTs (321 adults at risk of metabolic syndrome) found only marginal reductions in systolic blood pressure (p=0.05) and total cholesterol, no significant effect on fasting glucose or HDL-C, and an unexpected LDL-C increase.
meta-analysis
Mokhtari 2021 (meta-analysis)
✓ Full text
Meta-analysis of 10 RCTs (493 participants) found astaxanthin only marginally reduced diastolic blood pressure (mean difference -1.21 mmHg; 95% CI -2.51 to 0.09) with no significant effect on systolic blood pressure; effect stronger in non-healthy and Asian subgroups.
meta-analysis
Ma 2022 (systematic review/meta-analysis)
✓ PubMed
Meta-analysis of 12 RCTs (380 participants) found astaxanthin significantly lowered malondialdehyde (SMD -0.95; 95% CI -1.67 to -0.23) and reduced IL-6 in type 2 diabetics, but had no significant effect on CRP or TNF-alpha.
Meta-analysis
Zhou 2021 (Nutrients)
✓ Full text
Systematic review and meta-analysis found oral astaxanthin significantly restored skin moisture content (SMD=0.53; 95% CI 0.05-1.01; p=0.03) and improved elasticity (SMD=0.77; 95% CI 0.19-1.35; p=0.009) but did not significantly reduce wrinkle depth.
Meta-analysis
Xia et al. 2020 (Pharmacol Res)
✓ PubMed
Meta-analysis of 14 RCTs: astaxanthin increased HDL-C (WMD +1.47 mg/dL; 95% CI 0.32-2.63; P=.012) and lowered CRP only at longer duration (>=12 weeks: WMD -0.53 mg/L) and higher dose (>12 mg/day: WMD -0.39); no significant effect on fasting glucose, HbA1c, total/LDL cholesterol, triglycerides, BMI, weight, or blood pressure.
Systematic review
Leung et al. 2022 (Nutrients)
✓ PubMed
Systematic review/meta-analysis of 7 RCTs (n=321) in adults at risk of metabolic syndrome: astaxanthin produced a significant reduction in LDL cholesterol and marginal reductions in total cholesterol and systolic blood pressure; authors note further robust evidence is needed.
Meta-analysis
Zhou et al. 2021 (Nutrients)
✓ PubMed
Systematic review/meta-analysis of 11 human studies (9 RCTs): oral astaxanthin significantly improved skin elasticity (SMD 0.77; 95% CI 0.19-1.35; P=.009) and moisture content (SMD 0.53; P=.03) versus placebo, but did not significantly reduce wrinkle depth (SMD -0.26; P=.11).
RCT
Ciaraldi 2023 (RCT)
✓ PubMed
Double-blind RCT in 34 adults with prediabetes and dyslipidaemia (12 mg/day, 24 wk) significantly lowered LDL-C and total cholesterol and improved cardiovascular risk markers (fibrinogen, L-selectin, fetuin-A) with good tolerability.
RCT
Gowtham 2024 (J Maxillofac Oral Surg)
✓ Full text
Double-blind placebo-controlled RCT (n=68, 5 mg twice daily for 12 weeks) in oral submucous fibrosis found astaxanthin produced statistically significant improvement in mouth opening and reduction in burning sensation versus control.
RCT
Ito 2018 (RCT)
✓ PubMed
RCT in 23 healthy Japanese adults (4 mg/day, 10 wk) increased minimal erythema dose and reduced UV-induced moisture loss vs placebo. (FUJIFILM-sponsored.)
RCT
Ito 2018 (Nutrients)
✓ Full text
10-week double-blind placebo-controlled RCT (n=23 healthy adults, 4 mg/day) found the astaxanthin group had increased minimal erythema dose and reduced UV-induced loss of skin moisture in irradiated areas versus placebo.
RCT
Tominaga 2012 (RCT)
✓ PubMed
Double-blind trial in 36 men (6 mg/day + topical, 6 wk) plus open study in 30 women improved crow's-feet wrinkles, elasticity, and transepidermal water loss.