Vitamin A (retinol, carotenoids) C
There are no sports data; excess is dangerous — chronic overdose is toxic
Citable fact
«Vitamin A (retinol, carotenoids)» — evidence level C. Dosage: The adult requirement is 700–900 µg RAE per day. In supplements, intake is justified only in confirmed deficiency. The upper safe level for retinol is 3000 µg RAE per day; in pregnancy the threshold is substantially lower. Beta-carotene from food has no such restrictions. Source: PMID 40901583, permanent link to the source in the list below.
How it works
Retinoic acid regulates gene expression through the nuclear receptors RAR and RXR: vision, epithelial differentiation, immune response. No direct involvement in sports performance has been shown.
Dosage and intake
The adult requirement is 700–900 µg RAE per day. In supplements, intake is justified only in confirmed deficiency. The upper safe level for retinol is 3000 µg RAE per day; in pregnancy the threshold is substantially lower. Beta-carotene from food has no such restrictions.
With fatty food: the vitamin is fat-soluble. In deficiency — at the dose and according to the regimen prescribed by a doctor.
Forms
Retinyl palmitate and retinyl acetate (retinol), as well as beta-carotene, have been studied. High doses of synthetic retinol and retinoids are prescription products, only as prescribed by a doctor.
What is confirmed
- Correction of deficiency: night vision, epithelial condition, immune response
- Needed for normal growth and reproductive function
Adverse effects and limitations
- Chronic excess: headache, dry skin, liver damage, reduced bone density
- Acute excess: nausea, intracranial hypertension — reported at doses from 100,000 IU
- Retinoids are teratogenic: high doses in pregnancy increase the risk of birth defects
- Isotretinoin and acitretin are prescription products, only as prescribed by a doctor
Interactions
- Taking them together with isotretinoin or acitretin increases toxicity
- Orlistat and other agents that impair fat absorption reduce uptake
Who must not use it
- Under 18 years: Dietary intake is usually sufficient; retinol supplements in children — only as prescribed by a doctor.
- Pregnancy and lactation: Retinol supplements above 3000 µg RAE are not recommended: excess increases the risk of birth defects.
- liver disease
- pronounced hyperlipidemia
- pregnancy and pregnancy planning
- retinoid use
Sources
- Vitamin A toxicity and hepatic pathology: A comprehensive review · Pestalardo ML, Bevilacqua CS, Amante MF · World journal of hepatology, 2025 · PMID 40901583
- Micronutrients and athletic performance: A review · Beck KL, von Hurst PR, O'Brien WJ · Food and chemical toxicology : an international journal published for the British Industrial Biological Research Association, 2021 · PMID 34662692
See also
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