Vitamin A
Supplements · Vitamins · Supplement, Typed Supps
One of the few vitamins you can genuinely take too much of.
Stage by stage
- Intake (Softgel): Fat-soluble, needing dietary fat to absorb well, like vitamin D.
- Small intestine (Micelle transport): Bile forms micelles that carry it across the intestinal wall.
- Liver (Stored for later): The liver stores most of your body’s vitamin A, releasing it as needed.
- Tissues (Vision, immunity, skin): Supports vision, immune function, and skin cell turnover.
What the evidence supports
- Preventing deficiency-related blindness in at-risk populations — strong evidence. One of the highest-impact public health interventions there is, in populations where deficiency is endemic.
- Correcting a documented deficiency — strong evidence. Clear.
- Evidence that it causes preventing cancer via high-dose beta-carotene — insufficient evidence. Worth stating as a negative: two large trials found high-dose beta-carotene increased lung cancer incidence in smokers, and both were stopped early.
Typical dose
700–900 mcg RAE daily; often supplied as beta-carotene instead
Upper limit: 3,000 mcg daily of preformed vitamin A (retinol) — beta-carotene from food is not capped
Timing
Take with a meal containing fat.
Time to effect
- Weeks: Skin/immune support builds gradually.
Medication interactions
- Isotretinoin, acitretin, and other retinoids: Additive vitamin A toxicity — a genuine hazard, not a theoretical one. (high)
- Orlistat and other fat-absorption blockers: Reduce absorption of vitamin A along with dietary fat. (moderate)
- Anticoagulants: High doses may increase bleeding risk. (moderate)
Common myth
“More vitamin A is always better for skin.” In reality: Excess accumulates in the liver and can become toxic — one of the easier vitamins to overdose.
Food sources
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