Evidence-based·Last reviewed May 30, 2026·How we grade evidence

Vitamin A

VitaminBest with a meal

Useful mainly for people with confirmed deficiency, especially in low-income settings where deficiency is prevalent.

Quick decision guide

May help most

People with confirmed deficiency, especially in low-income settings where deficiency is prevalent

Common dosing range

700-900 mcg RAE/day (RDA); never exceed 3000 mcg RAE/day of preformed vitamin A

When to expect effects

Weeks for deficiency correction

Watch out for

Preformed vitamin A is teratogenic in high doses - pregnant women must not exceed 3000 mcg RAE/day

What is it

Vitamin A is a fat-soluble vitamin essential for vision, immune function, and cell growth. It exists as preformed vitamin A (retinol, retinyl esters) from animal foods and as provitamin A carotenoids (mainly beta-carotene) from plant foods.

Is it worth it for you?

Use this as a quick fit check, not a diagnosis.

Worth considering if…

You have confirmed vitamin A deficiency (night blindness, Bitot spots)
You are in a population with widespread deficiency and limited food diversity
You have measles (high-dose per WHO protocol reduces complications)

Probably skip if…

You eat a varied diet with orange/yellow vegetables, leafy greens, eggs, or dairy
You are pregnant - never self-supplement above RDA with preformed vitamin A
You smoke - high-dose beta-carotene supplements increase lung cancer risk in smokers
You are taking retinoid medications (isotretinoin, tretinoin)

Evidence at a glance

vitamin A deficiency correction

Strong Evidence
Effect
Definitive; corrects all deficiency manifestations
Best fit
People with confirmed deficiency: night blindness, dry eyes (xerophthalmia), immune compromise from malnutrition
Time
Days to weeks

childhood mortality in vitamin A-deficient populations

Strong Evidence
Effect
Approximately 24% reduction in all-cause child mortality in deficient populations
Best fit
Children 6 months to 5 years in low-income, high-deficiency settings
Time
Months (population-level mortality reduction)

measles complication reduction

Strong Evidence
Effect
Significant reduction in measles mortality and severity
Best fit
Children with measles, particularly those with vitamin A deficiency
Time
Days (acute treatment)

age-related macular degeneration slowing

Good Evidence
Effect
Approximately 25% reduction in progression to advanced AMD (as part of AREDS formula)
Best fit
People with intermediate AMD or advanced AMD in one eye - as part of full AREDS/AREDS2 formula
Time
Years

Evidence for 4 uses

AI-assisted evidence assessment — talk to your doctor before relying on any single supplement.

vitamin A deficiency correction

Corrects deficiency
Strong Evidence

Vitamin A is essential for retinal (the visual pigment precursor), epithelial integrity, and immune function. Deficiency causes night blindness, then corneal damage (xerophthalmia) and potential irreversible blindness. It is the leading preventable cause of childhood blindness globally. Supplementation at therapeutic doses reverses all reversible manifestations rapidly and definitively.

Effect size
Definitive; corrects all deficiency manifestations
Time to effect
Days to weeks
Best fit
People with confirmed deficiency: night blindness, dry eyes (xerophthalmia), immune compromise from malnutrition

Bottom line: Vitamin A supplementation definitively corrects deficiency; this is one of the highest-impact nutritional interventions in deficient populations.

SourceGannon et al., 2025 — PMC

childhood mortality in vitamin A-deficient populations

Supplement benefit
Strong Evidence

Cochrane meta-analyses of over 190,000 children in multiple large RCTs consistently find that vitamin A supplementation reduces all-cause mortality by approximately 24% and diarrhea mortality by approximately 28% in populations where deficiency is prevalent. This is mediated through restored immune function. In high-income settings where deficiency is rare, supplementation beyond the RDA offers no mortality benefit and carries toxicity risk.

Effect size
Approximately 24% reduction in all-cause child mortality in deficient populations
Time to effect
Months (population-level mortality reduction)
Best fit
Children 6 months to 5 years in low-income, high-deficiency settings
Less likely
Children in high-income settings where deficiency is rare

Bottom line: One of the most robustly evidenced public health interventions for reducing child mortality in deficiency-prevalent regions.

SourceFawzi et al., 1993 — PubMed

measles complication reduction

Disease adjunct
Strong Evidence

Multiple RCTs confirm that high-dose vitamin A (100,000-200,000 IU for 2 days) given to children with measles significantly reduces mortality and pneumonia complications. The WHO recommends this for all children with measles in regions where deficiency is common. The mechanism involves restoration of deficiency-related immune suppression caused by the measles virus.

Effect size
Significant reduction in measles mortality and severity
Time to effect
Days (acute treatment)
Best fit
Children with measles, particularly those with vitamin A deficiency

Bottom line: High-dose vitamin A reduces measles mortality and complications; this is WHO standard of care in relevant populations.

SourceHuiming et al., 2005 — PMCSudfeld et al., 2010 — PMC

age-related macular degeneration slowing

Disease adjunct
Good Evidence

The AREDS trial showed that a specific antioxidant combination (vitamins C, E, beta-carotene, and zinc) reduced risk of advanced AMD progression by approximately 25% in people with intermediate or advanced AMD. Beta-carotene (a provitamin A precursor) was one component. The updated AREDS2 formula replaced beta-carotene with lutein/zeaxanthin, which performed equally well without the lung cancer risk in smokers. This benefit applies only to the full formula, not vitamin A alone.

Effect size
Approximately 25% reduction in progression to advanced AMD (as part of AREDS formula)
Time to effect
Years
Best fit
People with intermediate AMD or advanced AMD in one eye - as part of full AREDS/AREDS2 formula
Less likely
People with no or early AMD; beta-carotene component is inappropriate for smokers

Bottom line: Beta-carotene as part of the AREDS formula slows AMD progression; lutein/zeaxanthin-based AREDS2 is preferred and avoids lung cancer risk in smokers.

SourceAge-Related et al., 2001 — PMCChew et al., 2013 — PMC

How it works

Preformed vitamin A from animal sources is absorbed and stored in the liver as retinyl esters. When needed, it is released into the blood as retinol, then converted in cells to retinal (for vision) or retinoic acid (for gene regulation). Retinoic acid binds to nuclear receptors that control hundreds of genes involved in cell differentiation, immune function, and tissue development. Provitamin A carotenoids like beta-carotene are absorbed and converted to retinol in the intestinal wall, but conversion is regulated by the body — high intake does not cause vitamin A toxicity because conversion slows as needs are met. This is why vegetable sources are much safer than animal sources or supplements at high intakes.

How to take it

1. Typical dose
700-900 mcg RAE/day (women/men respectively)
2. Timing
With a fat-containing meal (fat-soluble)
3. With food
With food containing fat for optimal absorption
4. How long to try
Daily as part of dietary adequacy; short therapeutic courses for deficiency states

What to track

Night vision (early symptom of deficiency)
Skin and mucosal integrity
Signs of excess: headache, bone pain, hair loss, dry skin, nausea
Total vitamin A from all sources including multivitamins and fortified foods

3 commercial forms

Compare the main delivery options and what they’re best suited for.

Retinol / retinyl palmitate (preformed)

Direct form found in animal foods and supplements. Easily toxic at high doses long-term. Most multivitamins contain modest amounts (around the RDA).

highly bioavailable, stored in liver

Beta-carotene (provitamin A)

Plant-based precursor converted to retinol as needed. Does not cause vitamin A toxicity. Smokers should avoid high-dose beta-carotene supplements.

regulated conversion, much safer

Cod liver oil

A traditional source providing both vitamins A and D. Watch total intake — modern cod liver oil products can deliver substantial vitamin A.

traditional source, also provides vitamin D

Safety

Know the common side effects, key cautions, and who should avoid it.

Common side effects

GI upset at high dosesHeadacheDryness of skin and mucous membranes at excess doses

Serious risks

Who should avoid it

Pregnancy & breastfeeding

Critical caution: preformed vitamin A above 3000 mcg RAE/day is teratogenic and causes severe birth defects. Pregnant women should not exceed the RDA (770 mcg RAE) without medical supervision. Provitamin A carotenoids (beta-carotene from food) are safe.

SourceNIH Office of Dietary Supplements — Vitamin A — NIH ODS

Interactions

retinoid medications (isotretinoin, tretinoin, acitretin)Major

Additive vitamin A toxicity; never combine vitamin A supplements with retinoid medications

SourceNIH Office of Dietary Supplements — Vitamin A — NIH ODS
orlistatModerate

Reduces fat-soluble vitamin A absorption; separate doses by at least 2 hours

SourceNIH Office of Dietary Supplements — Vitamin A — NIH ODS
alcoholModerate

Increases risk of liver toxicity from vitamin A excess

SourceNIH Office of Dietary Supplements — Vitamin A — NIH ODS
mineral oil / cholestyramineMinor

Reduces vitamin A absorption by binding fat-soluble vitamins

SourceNIH Office of Dietary Supplements — Vitamin A — NIH ODS

Documented interactions

Evidence-graded pair pages with sources, dosing notes, and timing guidance — a complement to the narrative section above.

Warnings (2)

+ alcohol

high

Alcohol depletes the liver's vitamin A by inducing cytochrome P450 enzymes (notably CYP2E1) that break retinol down into toxic byproducts. Adding high-dose vitamin A or beta-carotene supplements on top of regular drinking can worsen liver injury rather than correct the deficiency, so repletion in drinkers is not as simple as taking a pill.

+ vitamin d

low

Vitamins A and D share the RXR receptor partner, but the best human evidence shows high-dose preformed vitamin A can blunt vitamin D's effect on calcium and bone — the relationship is competitive, not a proven beneficial synergy. At ordinary dietary or multivitamin levels there is no meaningful problem.

Beneficial pairs (3)

+ zinc

synergy

Zinc is required for the liver to synthesize retinol-binding protein, the carrier that moves vitamin A from liver stores into the bloodstream. When zinc is low, circulating vitamin A can stay low even though liver stores are adequate, and in deficient populations supplementing the two together corrects vitamin A status more reliably than vitamin A alone.

+ vitamin d3

synergy

Vitamin D and vitamin A act through partnered nuclear receptors. Vitamin D's active form binds the vitamin D receptor (VDR), which pairs with the retinoid X receptor (RXR) — whose ligand comes from vitamin A — to switch on genes for immunity, epithelial health, and bone. Adequate levels of both support this signaling, but at extreme doses they can work against each other for calcium and bone endpoints, where a controlled human study showed high preformed vitamin A blunting vitamin D's calcium response.

+ iron

synergy

Vitamin A and beta-carotene appear to improve absorption of non-heme iron from plant foods by forming soluble complexes with iron that keep it from binding to phytates and polyphenols in the gut. In controlled human absorption studies, adding vitamin A to a grain-based meal increased the amount of iron absorbed.

See all 5 Vitamin A interactions →

Protocols featuring Vitamin A

Evidence-backed routines where Vitamin A plays a role.

Psoriasis Support

skin conditions

Psoriasis is a chronic, immune-mediated inflammatory disease affecting 2-3% of adults. The hallmark is accelerated keratinocyte turnover — skin cells replicating every 3-5 days instead of the normal 28-30 — driven by a Th17/IL-23 immune axis. Clinically that shows up as well-demarcated red plaques with silvery scale, classically on the elbows, knees, scalp, and lower back. Psoriasis is not just a skin disease: it carries substantial comorbid risk. Roughly 30% of patients develop psoriatic arthritis, and the cohort as a whole runs higher cardiovascular disease, metabolic syndrome, and depression rates than the general population. Treatment is genuinely multi-modal — topical corticosteroids and vitamin D analogs (calcipotriol) for limited disease, phototherapy for wider involvement, and systemic biologics targeting IL-17 (secukinumab/Cosentyx), IL-23 (risankizumab/Skyrizi, guselkumab/Tremfya, ustekinumab/Stelara), or TNF-alpha (adalimumab/Humira) for moderate-to-severe disease. If you have moderate-to-severe psoriasis — significant body surface area, scalp/genital/palmar-plantar involvement, joint symptoms, or quality-of-life impact — see a dermatologist. The biologics era has been transformative; PASI 90 (90% lesion clearance) is now a realistic goal for most patients, not the exception. Supplements occupy a supportive role: they can blunt systemic inflammation, correct deficiencies that worsen disease activity, and address the cardiometabolic comorbidity burden. They don't replace appropriate dermatologic care for anything beyond mild localized disease.

Food sources

Beef liver, 3 oz cooked

Amount
6,582 mcg RAE
%DV
731%

Sweet potato (baked, with skin)

Amount
1,403 mcg RAE
%DV
156%

Spinach (boiled), 1/2 cup

Amount
573 mcg RAE
%DV
64%

Carrots (raw), 1/2 cup

Amount
459 mcg RAE
%DV
51%

Cantaloupe, 1/2 cup

Amount
135 mcg RAE
%DV
15%

Red bell pepper, 1/2 cup raw

Amount
117 mcg RAE
%DV
13%

Mango, 1 fruit

Amount
112 mcg RAE
%DV
12%

Egg, 1 hard-boiled

Amount
75 mcg RAE
%DV
8%

Cheddar cheese, 1 oz

Amount
75 mcg RAE
%DV
8%

Choosing a product

What to look for on the label — and what to be skeptical of.

Look for…

Dose stated in mcg RAE (retinol activity equivalents) or IU with clear conversion
Form clearly stated: retinol/retinyl ester vs. beta-carotene vs. mixed carotenoids
For smokers: ensure product uses beta-carotene from food sources only or choose alternative without beta-carotene

Be skeptical of…

Prevents cancer (beta-carotene increases lung cancer risk in smokers)
Safe in any amount (preformed vitamin A has a clear toxicity threshold)
Substitutes for a varied diet in well-nourished populations

Frequently asked questions

Is vitamin A safe in pregnancy?⌄

Yes at the RDA (770 mcg RAE), but high-dose preformed vitamin A (retinol) is teratogenic and can cause birth defects. Avoid supplements above the RDA and avoid liver-rich meals during pregnancy.

Should I take vitamin A or beta-carotene?⌄

Beta-carotene from food is safer because conversion is regulated. Supplemental beta-carotene at high doses should be avoided by smokers. Most multivitamins use a mix.

What are signs of vitamin A toxicity?⌄

Headache, hair loss, dry skin, bone pain, liver problems, and visual disturbances. Stop the source and consult a doctor.

Can I get enough vitamin A from a vegan diet?⌄

Through beta-carotene conversion, yes. Eat orange and dark green vegetables regularly. Cooking and pairing with fat improves absorption.

Is cod liver oil too high in vitamin A?⌄

It depends on the brand. Some traditional cod liver oils provide thousands of micrograms RAE per dose. Read labels and avoid stacking with multivitamins.

References by claim

vitamin A deficiency correction

Gannon et al., 2025 — PMC (2025) link

childhood mortality in vitamin A-deficient populations

Fawzi et al., 1993 — PubMed (1993) link

measles complication reduction

Huiming et al., 2005 — PMC (2005) link

Sudfeld et al., 2010 — PMC (2010) link

age-related macular degeneration slowing

Age-Related et al., 2001 — PMC (2001) link

Chew et al., 2013 — PMC (2013) link

Safety

NIH Office of Dietary Supplements — Vitamin A — NIH ODS link

Track Vitamin A with Pilora

Set up dose reminders, check interactions, and join the community in the Pilora iPhone app.

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Evidence-based·Last reviewed May 30, 2026·Evidence current as of May 30, 2026·How we grade evidence

Disclaimer: These statements have not been evaluated by the FDA. This page is educational, not a substitute for personalized medical advice. Evidence grades are AI-assisted assessments — talk to your doctor before starting any new supplement, especially if you’re pregnant, breastfeeding, on medications, or managing a chronic condition.