Vitamin A
Fat-soluble vitamin that contributes to the maintenance of normal vision and normal function of the immune system.
Also known as Retinol, Beta-Carotene, Vit A, Retinyl Palmitate
Common doses
3000-10000 IU
Best timing
Morning
Food
Take with food
Interactions
1 known
Vitamin A is a group of fat-soluble retinoids essential for vision, immune function, reproduction, and cellular communication. It exists in two dietary forms: preformed Vitamin A (retinol, from animal sources) and provitamin A carotenoids (beta-carotene, from plants), which the body converts to retinol as needed.
The conversion of beta-carotene to retinol is highly variable between individuals, depending on genetics, gut health, and dietary fat intake. Some people convert beta-carotene poorly, making preformed retinol or well-dosed retinyl palmitate more reliable for addressing deficiency.
Vitamin A toxicity is a real concern with preformed retinol. Unlike water-soluble vitamins, excess Vitamin A accumulates in the liver and can cause serious harm. Beta-carotene does not carry this risk because the body downregulates conversion when retinol levels are adequate.
Key benefits
Vision
Vitamin A contributes to the maintenance of normal vision. Retinal (a form of Vitamin A) is a component of rhodopsin, the protein in rod cells that enables low-light vision.
Immune function
Vitamin A contributes to the normal function of the immune system. It maintains the integrity of mucosal barriers and supports white blood cell function.
Skin health
Vitamin A contributes to the maintenance of normal skin and normal mucous membranes.
Cell differentiation
Vitamin A plays a role in the process of cell specialisation, regulating gene expression in developing cells.
Available forms
Retinyl Palmitate
Preformed Vitamin A ester. Well-absorbed. The most common supplement form. Must be dosed carefully to avoid excess.
Beta-Carotene
Provitamin A. Converted to retinol as needed. No toxicity risk. Conversion rate varies individually. Better as insurance than treatment.
Retinol
Pure preformed Vitamin A. Highly bioactive. Found in some specialty supplements and cod liver oil. Toxicity risk at high doses.
Food sources
- Liver (extremely rich)
- Sweet potato
- Carrots
- Spinach and kale
- Egg yolks
- Butter and cheese (especially grass-fed)
Signs of deficiency
- Night blindness
- Dry eyes
- Dry, rough skin
- Frequent infections
- Impaired wound healing
- Delayed growth in children
Upper intake limit
3,000 mcg RAE/day preformed Vitamin A (NIH). Pregnant women should not exceed 3,000 mcg RAE due to teratogenic risk. Beta-carotene does not count toward this limit.
Research summary
Strong evidence for vision and immune function support. Deficiency remains a major global health issue in developing countries. In developed countries, supplementation is mainly warranted for people with fat malabsorption, restricted diets, or documented deficiency. The beta-carotene vs retinol choice depends on individual conversion ability.
Known interactions (1)
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1 flagZinc and Iron compete for the same absorption pathway. Take at least 2 hours apart.
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This information is for educational purposes only. It is not medical advice and does not diagnose, treat, cure, or prevent any disease. Always consult a qualified healthcare professional.