Vitamin A
Retinol (Vitamin A, preformed) / Beta-Carotene (provitamin A)
Fat-soluble vitamin essential for retinal photoreceptor function, immune cell differentiation (especially T-cells and NK cells), epithelial tissue maintenance, and gene transcription regulation via RAR/RXR nuclear receptors
Typical longevity dose: 3000-7500 mcg RAE (10,000-25,000 IU)/day
Price Comparison
| Product | Vendor | Price | Per Serving | Trust | |
|---|---|---|---|---|---|
NOW Foods Vitamin A 25000 IU 250 Softgels 7500mg · softgel · 250 servings | iHerb | $13.46 | $0.05 | 8 | Buy |
NOW Foods Vitamin A 25000 IU 100 Softgels 7500mg · softgel · 100 servings | iHerb | $6.72 | $0.07 | 8 | Buy |
Add to cart: /cart?items=vitamina-now-25000iu-250ct
Key Research
Vitamin A is critical for maintaining innate and adaptive immune function; deficiency increases susceptibility to infections
Huang Z et al. (2018). Journal of Clinical Medicine
Vitamin A supplementation reduced child mortality by 23-34% in regions with deficiency
Sommer A, Vyas KS (2012). Proceedings of the National Academy of Sciences
Interaction Warnings
Retinoids (isotretinoin, tretinoin)
Combining supplemental vitamin A with retinoid medications risks hypervitaminosis A toxicity
Blood thinners (warfarin)
Very high-dose vitamin A may enhance anticoagulant effects
Alcohol
Chronic alcohol use combined with high-dose vitamin A increases hepatotoxicity risk
Synergies
Vitamin D
Vitamins A and D share nuclear receptor partnerships (RXR); balanced intake optimizes immune and bone health
Zinc
Zinc is required for retinol-binding protein synthesis; deficiency impairs vitamin A transport and utilization
Iron
Vitamin A improves iron mobilization from stores and supports erythropoiesis
Disclaimer: This information is for educational purposes only and is not medical advice. Research citations are provided for reference — consult your healthcare provider before starting any supplement regimen. Prices are estimates and may not reflect current retail pricing.