Dosage · Supplement
Vitamin A: dosage and how to take it
Liver, dairy, eggs, orange/green vegetables; supplement only within RDA.
- Overall grade
- Grade B
- Last revised
- 0
- graded outcomes
- 1
- reference listed
Assembled by the app from other entries in this library. It adds no evidence of its own — follow the links to the entries it draws on.
The evidence in words
How much to take
Food-first (liver, dairy, eggs, orange and dark-green vegetables). If supplementing, keep within the RDA range; pregnant women must avoid high preformed-retinol doses.
Timing & separation
There are no strict timing conflicts on record for Vitamin A; consistency matters more than the exact hour for most goals.
Why the dose is what it is
Retinal is the light-sensing chromophore in the retina; retinoic acid is a hormone-like regulator of gene transcription governing cell differentiation and immunity. Preformed A is fat-soluble and stored in the liver, so it accumulates — the reason chronic high intake is toxic.
Bottom line
A deficiency you fix, not a supplement you stack. Get it from food; avoid high-dose retinol in pregnancy and beta-carotene supplements if you smoke.
How it is used
As the entry records it, from the studies it summarises. Not a recommendation for you — doses that suit a trial population may not suit you.
- Food-first
- Liver, dairy, eggs, orange/green vegetables; supplement only within RDA.
Goes with
- Vitamin AFull Vitamin A monographEvidence grade B
Related reading
Entries that share this one's tags or conditions.
- Andrographis: dosage and how to take itStandardized andrographolide at onset.Evidence grade B
- Astragalus: dosage and how to take itStandardized extract; oncology use under care.Evidence grade C
- Beta-Glucans: dosage and how to take it3 g/day oat beta-glucan.Evidence grade B
- Chaga: dosage and how to take itAvoid high doses (oxalates).Evidence grade D
Sources
As this entry records them: title, journal and year. None carries a DOI or PubMed id, so none is linked as a verified paper. Each link searches PubMed for the title; check that what you find is what the entry describes.
- 1.Effect of beta-carotene and vitamin A on lung cancer (CARET) — N Engl J Med, 1996. Search PubMed (opens in a new tab)
Last revised . A grade is this entry's reading of the evidence, not medical advice.