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Vitamin A

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Vitamin A is a fat-soluble essential nutrient crucial for vision, immune function, and skin health. It exists in two forms: retinol (preformed vitamin A from animal sources) and provitamin A carotenoids (beta-carotene from plants). Adequate intake supports cellular differentiation, antioxidant defence, and reproductive health.

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Benefits

Supports healthy vision and prevents night blindness
Enhances immune system function and disease resistance
Promotes skin health and reduces acne
Supports bone health and calcium absorption
Protects against age-related macular degeneration

Dosage

Typical Dose

700–900 mcg RAE daily (adults)

Upper Limit

3,000 mcg RAE daily from supplements

Timing

With food containing fat for optimal absorption

Forms & Bioavailability

Retinyl Palmitate

Highly bioavailable preformed retinol; rapid absorption but risk of accumulation with excess intake

Beta-Carotene

Provitamin A carotenoid; converted to retinol as needed; safer at high doses due to self-regulating conversion

Retinyl Acetate

Stable, bioavailable form; commonly used in supplements and fortified foods

Side Effects

Hypervitaminosis A (toxicity) at excessive doses: nausea, headaches, dizziness, skin peeling
Birth defects if excessive intake during pregnancy
Joint pain and bone fragility with chronic overdose
Carotenemia (yellowing of skin) from excess beta-carotene

Interactions

Fat-soluble vitamin absorption affected by dietary fat intake and bile salt availability
May increase anticoagulant effects when combined with warfarin
Zinc deficiency impairs vitamin A absorption and metabolism
Retinoid medications (isotretinoin, tretinoin) increase toxicity risk when combined

Research Summary

Extensive evidence supports vitamin A's essential role in vision and immune function; deficiency causes serious impairment in developing countries. Research confirms benefits for skin health and potential protection against certain cancers and age-related diseases. However, high-dose supplementation in smokers and high-risk populations has shown increased mortality risk, particularly with beta-carotene, suggesting dietary sources or moderate supplementation is preferable for most.

The Bottom Line on Vitamin A

Vitamin A is well-researched with strong evidence supporting its primary benefits.It is most commonly used for supports healthy vision and prevents night blindness and enhances immune system function and disease resistance. As with any supplement, individual results vary. Start with the lower end of the dosage range and assess for 4-8 weeks before adjusting.

About Our Research

This profile is compiled from peer-reviewed research published on PubMed, the NIH Office of Dietary Supplements, and established nutritional science databases. Dosages reflect clinically-studied amounts from human trials where available. We update profiles as new research emerges. This is not medical advice — consult a healthcare professional before supplementing.

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Disclaimer: This information is for educational purposes only and is not medical advice. Always consult a healthcare professional before starting any supplement, especially if you have existing health conditions or take medication.

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