Supplement
Vitamin A
Essential, and toxic in excess.
Vitamin A (retinol) is essential for vision and immunity. We grade Vitamin A C+ on evidence and C+ for worth-it at about $5-8 per month.
Evidence
Worth it
Typical cost: $5-8/month
What it does
Vitamin A (retinol) is essential for vision and immunity. Deficiency is rare in well-fed populations, and excess is toxic, which is why more is not better here.
What the research says
Corrects deficiency
Evidence: strong. Deficiency correction is well established; deficiency itself is uncommon in the target audience.
DRAFT: essential nutrient, but supplementation rarely helps non-deficient people.
Is it worth it?
DRAFT: cheap, but most buyers do not need it.
Typical cost
$5-8/month
Common form, not a brand recommendation
Dosage contextestablished
RDA is the ceiling for most people, not the floor.
Safety notes
Liver toxicity at high chronic doses. Teratogenic in excess during pregnancy. Do not megadose. Talk to your doctor. This page is information, not medical advice.
Longevity Lab Report
Vitamin A news, graded when it happens.
New studies, dose debates, and expert shifts on vitamin a, in one email a week. Free.
Changelog
Last updated 2026-10-15
- 2026-10-15|Batch 3 entry, DRAFT. Grades provisional; expert positions unsourced unless noted.