antioxidant · for blurry vision
Astaxanthin
Builds up in the central part of your retina and shields it from light damage.
Say that in clinical terms
Accumulates in macular tissue as carotenoid, reduces eye fatigue, protects retinal cells from photooxidative damage.
How strong is the research?
1 paper read, 1 supporting.
Tested as: Haematococcus pluvialis-derived esterified astaxanthin, 9 mg/day in a 180 mg soft capsule (BGG Japan Co., Ltd., Tokyo, Japan); one capsule daily during or after breakfast for 6 weeks; placebo capsule contained safflower
Who was studied: Studied for focusing and eye strain in screen workers. Blurry vision on its own was not the outcome.
How much to take
daily
6–12 mg
Take with meals containing fat. Effects accumulate over weeks.
Before you take it
- No NIH ODS Tolerable Upper Intake Level (UL) has been established for supplemental astaxanthin. The EFSA/JECFA acceptable daily intake (ADI) for natural astaxanthin is 0.2 mg/kg body weight per day (~14 mg/day for a 70 kg adult) per 2018 EFSA assessment. Most human supplement studies use 4–12 mg/day.
- Warfarin/anticoagulant drug interaction: one published case report documents INR elevation from 1.4 to 10.38 with probable causality (PMID 31073352); proposed mechanism includes enhanced protein C and antithrombin III activity. Concurrent use with anticoagulants warrants intensive INR monitoring.
- Avoid during pregnancy and lactation: no adequate human safety studies exist in these populations; most practitioners recommend avoiding as a precaution.
- Blood pressure lowering: small reductions in diastolic blood pressure have been observed in some studies; caution warranted with concurrent antihypertensive medications due to possible additive hypotensive effect.
- FDA GRAS (Generally Recognized as Safe) status applies to natural astaxanthin from Haematococcus pluvialis at supplemental doses up to 12 mg/day; a safety review of 87 human studies found no safety concerns at doses up to 40 mg/day. Synthetic astaxanthin (petrochemical-derived; used in aquaculture) is a structurally related but distinct product not typically used in dietary supplements.
What we make of it
We claimed it builds up in the macula. It does not.
The detail
This contained a factual error. Lutein and zeaxanthin are the two carotenoids that form the pigment in the macula; astaxanthin has not been shown to deposit there in humans. The mechanism as written was wrong.