Vitamin A

Vitamin A supplementation · Retinol · Retinyl palmitate · Retinyl acetate

Snapshot

Indications	Contraindications
Vitamin A deficiency¹ Night blindness¹ Xerophthalmia¹ Measles incidence in at-risk children¹ Anemia with low retinol² Deficiency in cystic fibrosis¹ Preterm infant deficiency¹	High-dose use in pregnancy¹ Beta-carotene in smokers^{1, 3}

Vitamin A is a group of fat-soluble retinoids, mainly retinol and retinyl esters, that support vision through rhodopsin and regulate cell growth and differentiation¹. Supplementation is used to correct or prevent deficiency, whose first sign is night blindness¹. In children at risk of deficiency it is also used to lower new measles cases¹. Other uses are anemia with low retinol and immune function. Typical patients have fat malabsorption from cirrhosis, bariatric surgery, or pancreatic insufficiency⁴, or are preterm infants¹.

The evidence is strongest where deficiency is present, though supplementation did not reduce measles deaths¹. A 2026 review concluded that vitamin A for retinitis pigmentosa is no longer supported by current evidence⁵. In a 2026 systematic review of case reports and series, not trials, excess intake produced hepatic stellate cell enlargement that progressed in some patients to fibrosis and cirrhosis⁶. Supplements are sold as retinyl acetate, retinyl palmitate, beta-carotene, or combinations, and roughly 200,000 products list vitamin A; see Form comparison¹.

The key caution is teratogenicity: intakes of preformed vitamin A above the upper limit can cause birth defects, and the fact sheet states experts advise pregnant or lactating women against high-dose supplements¹. Per product labeling, orlistat users are told to take a multivitamin containing vitamin A, since absorption falls¹.

Last updated October 16, 2026. Read how we make monographs.

In the full monograph

89 sources, 74 studies

When to useThe situations practitioners use it for, each with the reason and the study behind it.
SafetyWho should avoid it, who needs extra care, and the side effects reported in studies.
InteractionsThe medicines and supplements it interacts with, the effect of each, and what labeling says to watch.
Protocol notesThe doses used in studies, how and when they were taken, and how the forms on the market compare.
How it worksWhat it is and how it works in the body, in plain terms.
Published studiesThe studies behind each use, popular claims checked against them, and trials still under way.
Word of mouthWhat patients and practitioners report online, kept separate from the clinical evidence.
Clinical perspectiveA closing read of where the evidence is solid, where it is thin, and what has not been studied.

Snapshot

In the full monograph

Sources