Vitamins
Vitamin A (Retinol / Beta-Carotene)
Also known as: Retinol · Beta-carotene · Retinoic acid · Retinyl palmitate
Fat-soluble vitamin essential for vision, immune function, and cellular differentiation. Toxicity risk is real with preformed retinol — beta-carotene is the safer plant-based precursor.
Effective Dose
700–3000mcg RAE / day
per clinical evidence
Evidence Level
Strong
Vitamins
Mechanism
Nuclear receptor activation (RAR/RXR), visual cycle (retinal), immune gene regulation
primary action
Best For
Immune health
Vision, Skin health, Bone development
This profile is for informational purposes only and does not constitute medical advice. Consult a qualified healthcare professional before starting any supplementation, especially if you have pre-existing conditions or take medications.
What Is Vitamin A (Retinol / Beta-Carotene)?
Vitamin A encompasses preformed retinoids (retinol, retinal, retinoic acid — from animal foods) and provitamin A carotenoids (beta-carotene — from plants). Retinoids directly activate retinoic acid receptors (RAR/RXR); beta-carotene is cleaved to retinal in the gut. Deficiency causes night blindness and increased infection susceptibility.
How It Works: The Science
Retinoic acid binds RAR-RXR heterodimers, acting as a transcription factor for genes controlling immune cell differentiation (T-reg cells, IgA secretion), epithelial maintenance, and bone remodelling. Retinal is the chromophore in rhodopsin — the visual pigment in rod cells essential for low-light vision.
Primary Mechanism
Nuclear receptor activation (RAR/RXR), visual cycle (retinal), immune gene regulation
Evidence-Based Benefits
Dosage Guide
Effective Dose
700–3000mcg RAE / day
700mcg RAE (women) / 900mcg RAE (men) daily from diet. Supplemental retinol: do not exceed 3000mcg RAE/day. Beta-carotene has no established toxicity (only carotenodermia — harmless skin yellowing at high doses). Avoid high-dose retinol during pregnancy.
Safety Profile & Side Effects
Preformed retinol is toxic above 10,000 IU/day chronically — causes headache, liver damage, hair loss, bone fractures. Teratogenic at high doses. Beta-carotene is safe even at high supplemental doses in non-smokers (smokers: associated with increased lung cancer risk at pharmacological doses).
Who Should (and Shouldn't) Take It
Supplementation needed only when dietary intake is insufficient. Most at risk: vegans eating few carotenoid-rich vegetables, those with fat malabsorption, and those in developing countries. Avoid preformed retinol supplementation in pregnancy beyond the RDA.
Frequently Asked Questions
Related Ingredients
Medical Disclaimer
Ingredient profiles are for informational purposes only and do not constitute medical advice. Consult a qualified healthcare professional before starting any supplementation, especially if you have pre-existing conditions or take medications. Full disclaimer →