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Vitamins

Vitamin A

Vision, immune defence, and cell differentiation — the original essential vitamin

Evidence Grade: A — Strong clinical evidence Vitamins
A
Evidence Grade A: Strong clinical evidence Based on the volume and quality of published human clinical trials.

Vitamin A encompasses retinol (preformed, animal sources) and provitamin A carotenoids (beta-carotene, plant sources). Retinol is the form active in the body — essential for rhodopsin (night vision), epithelial cell integrity, immune function, and embryonic development. Beta-carotene conversion to retinol is inefficient and variable. Fat-soluble and stored in the liver — both deficiency and excess are clinically significant.

Key Benefits

  • Night vision maintenance
  • Immune function
  • Skin and acne management
  • Mucous membrane integrity
  • Bone remodelling
  • Reproductive health

Best Form

Preformed retinol (palmitate or acetate) for people who don't convert beta-carotene well. Beta-carotene is safe (no toxicity risk) but relies on conversion.

Dosage

700–3,000 IU preformed retinol/day (lower is safer for supplementation)

⚠ Safety Notes

Fat-soluble — TOXICITY IS REAL. Chronic intake >10,000 IU preformed retinol/day causes liver damage, bone loss, birth defects. Beta-carotene does NOT cause toxicity. Smokers should avoid high-dose beta-carotene supplements (increased lung cancer risk in trials).

This page is for educational purposes only. Consult a healthcare professional before starting any supplement.