Vitamin A
Research Reliability -
A critical fat-soluble vitamin supporting vision, immune barriers, skin health, and healthy cell development.
Appetite
Mood
Sleep
Vitamin A
Description
Vitamin A plays essential roles in maintaining the integrity of epithelial tissues, which form the body's first line of immune defense, including the skin, lungs, and gut lining. It is vital for night vision and overall eye health, proper immune cell maturation, and embryonic development. As a fat-soluble vitamin, it is stored in the liver and should be taken at appropriate doses. This formula delivers preformed retinol for direct bioavailability, without the conversion variability of beta-carotene.
Effects
First 2 weeks
no obvious change
Weeks 2–4
Ongoing
How It Feels
Vitamin A is a quiet worker; you will not feel a dose. Benefits to skin and vision accrue slowly. Because it is fat-soluble and stores in the body, more is not better, so respect the ceiling.
Evidence
Evidence Strength
Strong (human RCTs / meta-analyses)
Caveats
Strongest evidence is for deficiency states; excess preformed vitamin A carries its own toxicity risk (do not exceed labeled dose).
Usage
Commonly Referenced Starting Amount
1,500 mcg RAE (about 5,000 IU) as preformed retinol
Commonly Referenced Amount
700–3,000 mcg RAE covers the RDA through commonly studied repletion doses
Referenced Upper Limit
3,000 mcg RAE/day (10,000 IU) is the upper limit for preformed retinol, set by liver toxicity and, critically, teratogenicity in pregnancy — beta-carotene forms carry no such limit
Onset
2–4 weeks
Biomarkers to Track
Subjective
(Daily)
Skin dryness and texture changes
Night vision quality
Frequency of infections
Objective
(Quarterly)
Serum retinol level
Liver enzymes (ALT/AST at high dose)
CBC (immune cell counts)
Real toxicity risk here. As a fat-soluble vitamin, chronic high doses can damage the liver and bones and cause birth defects.
Pregnant women must not exceed limits since retinol is teratogenic, and anyone with liver disease.
Stacking multiple vitamin A sources without adding them up, and taking high-dose retinol during pregnancy.
Disclaimer
This information is for educational purposes only and is not medical advice. It is not intended to diagnose, treat, cure, or prevent any disease. Consult a qualified healthcare provider before starting any new supplement, especially if you are pregnant, nursing, taking medication, or managing a health condition.
Imdad A et al. (2017). Cochrane Database of Systematic Reviews. Meta-analysis (childhood mortality/deficiency). PMID: 28282701.
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