Evidence-based·Last reviewed May 31, 2026·How we grade evidence

Vitamin A (retinol)

VitaminAll-trans-retinolBest with a meal

Essential fat-soluble vitamin for vision, immunity, reproduction, and skin. Deficiency is rare in high-income countries but devastating where it occurs. Excess intake is genuinely dangerous — preformed retinol is teratogenic in pregnancy and chronically toxic to the liver.

Quick decision guide

May help most

People with documented vitamin A deficiency or malabsorption (cystic fibrosis, IBD, post-bariatric, very-low-fat diets); children in regions with endemic deficiency.

Common dosing range

RDA 900 µg RAE/day (men), 700 µg RAE/day (women). UL 3,000 µg/day preformed retinol.

When to expect effects

Days for night-vision recovery in deficiency; weeks for serum retinol normalization.

Watch out for

Pregnancy: do NOT exceed 3,000 µg RAE/day of preformed retinol — it causes birth defects. Smokers should avoid high-dose beta-carotene (lung cancer risk).

Evidence snapshot

Deficiency correction (xerophthalmia, night blindness)Strong
Child mortality in high-deficiency regionsStrong
Adjunct in measles for deficient childrenStrong
AMD (AREDS2 mixed-nutrient formula)Moderate
Immune support in well-nourished adultsLow
Cancer preventionLow / harmful in smokers

What is it

Retinol is the alcohol form of preformed vitamin A found in animal foods and used in many supplements. The body converts it to retinal for vision and retinoic acid for gene regulation.

Is it worth it for you?

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

Worth considering if…

You have a malabsorption condition (cystic fibrosis, IBD, celiac, post-bariatric surgery)
You eat a very-low-fat diet or have chronic alcohol use (impaired vitamin A status)
You're on an ophthalmologist-prescribed AREDS2 regimen for intermediate/advanced AMD
Your child is in a region with endemic vitamin A deficiency under a WHO/UNICEF program
Blood tests show low serum retinol and a clinician recommends targeted supplementation

Probably skip if…

You're pregnant or might become pregnant — daily intake >3,000 µg RAE preformed retinol causes birth defects
You smoke or recently quit — high-dose beta-carotene/retinol increases lung cancer risk
You eat a typical Western omnivorous diet (deficiency is rare; most people exceed the RDA from food)
You're hoping to 'boost immunity' or prevent cancer without a deficiency — evidence doesn't support it
You're taking isotretinoin, acitretin, or another retinoid medication (additive toxicity)

Evidence at a glance

Vitamin A deficiency correction (xerophthalmia, night blindness)

Strong Evidence
Effect
WHO protocol: 200,000 IU on day 1, day 2, and day 14 reverses xerophthalmia in most cases; serum retinol normalizes within 2–4 weeks.
Best fit
Children and adults in low-income countries with endemic deficiency; severe fat malabsorption (cystic fibrosis, post-bariatric, IBD, chronic cholestasis); chronic alcohol use
Time
Days (night vision) to weeks (serum retinol)

Child mortality reduction in high-deficiency regions

Strong Evidence
Effect
All-cause mortality ↓ 12% (RR 0.88, 95% CI 0.83–0.93); diarrhea mortality ↓ ~12%; measles mortality reduced markedly
Best fit
Children 6–59 months in regions where vitamin A deficiency is endemic
Time
Months (population-level outcomes)

Adjunct treatment for measles in vitamin-A-deficient children

Strong Evidence
Effect
Two-dose regimen: overall mortality ↓ 82% in <2 yr olds (RR 0.18, 95% CI 0.03–0.61)
Best fit
Children with measles in regions with endemic vitamin A deficiency, or any severely-malnourished child with measles
Time
Days (acute treatment)

Age-related macular degeneration (AREDS2 formula)

Good Evidence
Effect
AREDS formula: ~25% relative risk reduction for AMD progression over 5 years in eligible patients; AREDS2 lutein/zeaxanthin formula equivalent
Best fit
Adults with intermediate or unilateral advanced age-related macular degeneration, prescribed by an ophthalmologist
Time
Years

Skin (topical retinoids vs oral retinol)

Limited Evidence
Effect
Oral vitamin A supplementation does not reproduce topical retinoid skin effects
Best fit
No one — for skin, topical retinoids and prescription isotretinoin are the evidence-based options
Time
Not applicable

General immune function in well-nourished adults

Mixed Evidence
Effect
No reliable clinical-endpoint benefit in non-deficient adults
Best fit
Adults with low baseline vitamin A status (whose 'immune support' is really deficiency correction)
Time
Not established

Evidence for 6 uses

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

Vitamin A deficiency correction (xerophthalmia, night blindness)

Corrects deficiency
Strong Evidence

Preformed retinol corrects vitamin A deficiency reliably and is the WHO-recommended treatment for xerophthalmia. Night blindness, the earliest functional sign, reverses within days of repletion. Untreated deficiency progresses to corneal scarring and irreversible blindness, especially in young children and pregnant women in low-resource settings.

Effect size
WHO protocol: 200,000 IU on day 1, day 2, and day 14 reverses xerophthalmia in most cases; serum retinol normalizes within 2–4 weeks.
Time to effect
Days (night vision) to weeks (serum retinol)
Best fit
Children and adults in low-income countries with endemic deficiency; severe fat malabsorption (cystic fibrosis, post-bariatric, IBD, chronic cholestasis); chronic alcohol use
Less likely
Adults in high-income countries eating a varied omnivorous diet

Bottom line: Curative when there's a true deficiency. When there isn't, supplementing is more risk than benefit.

SourceNIH Office of Dietary Supplements — Vitamin A and Carotenoids — Health Professional Fact SheetImdad et al., 2022 — Cochrane Database of Systematic Reviews

Child mortality reduction in high-deficiency regions

Disease adjunct
Strong Evidence

A 2022 Cochrane review of 47 trials (1.2 million children) found vitamin A supplementation reduces all-cause mortality in children 6–59 months by about 12% in low- and middle-income countries with high vitamin A deficiency prevalence, primarily by reducing diarrhea and measles mortality. This is the basis for WHO/UNICEF semi-annual mass dosing in deficient regions.

Effect size
All-cause mortality ↓ 12% (RR 0.88, 95% CI 0.83–0.93); diarrhea mortality ↓ ~12%; measles mortality reduced markedly
Time to effect
Months (population-level outcomes)
Best fit
Children 6–59 months in regions where vitamin A deficiency is endemic
Less likely
Children in well-nourished populations — no demonstrated mortality benefit

Bottom line: A public-health intervention for at-risk populations — not a wellness supplement for well-fed children.

SourceImdad et al., 2022 — Cochrane Database of Systematic Reviews

Adjunct treatment for measles in vitamin-A-deficient children

Disease adjunct
Strong Evidence

WHO recommends two consecutive doses of vitamin A (200,000 IU/day for children >12 months) for all children with measles in regions where deficiency is common. A Cochrane review found two doses cut overall measles mortality by 82% in children under 2 years and pneumonia-specific mortality by 67%. A single dose was less effective.

Effect size
Two-dose regimen: overall mortality ↓ 82% in <2 yr olds (RR 0.18, 95% CI 0.03–0.61)
Time to effect
Days (acute treatment)
Best fit
Children with measles in regions with endemic vitamin A deficiency, or any severely-malnourished child with measles
Less likely
Routine use in well-nourished children with measles (still recommended by WHO/AAP, but the absolute benefit is smaller)

Bottom line: Established WHO/AAP recommendation. Two doses, 24 hours apart, with severity-stratified dosing.

SourceHuiming et al., 2005 — Cochrane Database of Systematic Reviews

Age-related macular degeneration (AREDS2 formula)

Disease adjunct
Good Evidence

The original AREDS formula (1992 trial published 2001) contained 15 mg beta-carotene plus zinc, copper, vitamin C, and vitamin E and slowed progression to advanced AMD by ≈25% in people with intermediate or unilateral advanced disease. AREDS2 (2013) REMOVED beta-carotene after the CARET trial showed it caused lung cancer in smokers; lutein/zeaxanthin substituted with equivalent eye outcomes. The modern AREDS2 formula no longer contains vitamin A — it's a multi-nutrient eye-health combination.

Effect size
AREDS formula: ~25% relative risk reduction for AMD progression over 5 years in eligible patients; AREDS2 lutein/zeaxanthin formula equivalent
Time to effect
Years
Best fit
Adults with intermediate or unilateral advanced age-related macular degeneration, prescribed by an ophthalmologist
Less likely
Adults without AMD, or with only early/mild AMD — no benefit shown for prevention

Bottom line: Use the AREDS2 (no beta-carotene) formula and only under an ophthalmologist's guidance.

Evidence is mixed

The current AREDS2 formula intentionally avoids beta-carotene because of the CARET trial (Omenn 1996) showing increased lung cancer in smokers from beta-carotene + retinol. Don't take 'AMD vitamins' containing beta-carotene if you've ever smoked.

SourceOmenn et al., 1996 (CARET trial) — NEJM· conflictingAREDS2 Research Group, 2013 — JAMA· conflicting
SourceAREDS2 Research Group, 2013 — JAMA

Skin (topical retinoids vs oral retinol)

Mechanism only
Limited Evidence

Topical retinoids (tretinoin, adapalene, retinol) have strong evidence for photoaging and acne — but that's a TOPICAL skin treatment, not oral vitamin A supplementation. Oral retinol does not reproduce the skin benefits of topical retinoids, and oral isotretinoin (Accutane) for severe acne is a prescription drug at doses far above the supplemental range, with mandatory pregnancy prevention. Don't take oral vitamin A 'for your skin.'

Effect size
Oral vitamin A supplementation does not reproduce topical retinoid skin effects
Time to effect
Not applicable
Best fit
No one — for skin, topical retinoids and prescription isotretinoin are the evidence-based options
Less likely
Anyone hoping to substitute oral vitamin A for topical retinoids

Bottom line: Topical retinoids for skin. Oral vitamin A is for deficiency, not cosmetics.

SourceNIH Office of Dietary Supplements — Vitamin A and Carotenoids — Health Professional Fact Sheet

General immune function in well-nourished adults

Mechanism only
Mixed Evidence

Vitamin A is essential for normal immune cell function and mucosal barrier integrity, but in well-nourished adults without deficiency, supplementing has not been shown to reduce infection frequency or severity. The cases where supplemental vitamin A clearly helps (measles, severe diarrhea) all involve pre-existing deficiency.

Effect size
No reliable clinical-endpoint benefit in non-deficient adults
Time to effect
Not established
Best fit
Adults with low baseline vitamin A status (whose 'immune support' is really deficiency correction)
Less likely
Adults with adequate vitamin A from food

Bottom line: Don't take daily vitamin A for 'immunity' — well-nourished people get no demonstrated benefit and the toxicity ceiling is low.

SourceNIH Office of Dietary Supplements — Vitamin A and Carotenoids — Health Professional Fact Sheet

How it works

Retinol is absorbed in the small intestine bound to retinol-binding protein and stored in the liver as retinyl esters. When tissues need vitamin A, the liver releases retinol back into circulation. Cells convert it to retinal — required for the visual cycle in the retina — or to retinoic acid, which binds nuclear receptors and regulates hundreds of genes involved in cell differentiation, immune function, and skin and tissue health. Retinol is the form most easily able to cause toxicity because it bypasses the regulated conversion step that limits vitamin A from plant carotenoids. Chronic high intake accumulates in the liver and exceeds the body's ability to use or excrete it safely.

How to take it

1. Typical dose
• RDA: 900 µg RAE/day (men), 700 µg RAE/day (women) • Pregnancy RDA: 770 µg RAE/day; Lactation: 1,300 µg RAE/day • UL (preformed retinol): 3,000 µg RAE/day for adults — do not exceed without medical supervision • Most adults already meet the RDA from food; supplementation is only indicated for documented deficiency or malabsorption
2. Higher studied dose
Therapeutic dosing for documented deficiency (xerophthalmia, malabsorption) uses 50,000–200,000 IU (15,000–60,000 µg RAE) under medical supervision. WHO measles protocol: 200,000 IU on day 1, day 2, and day 14 for severe measles. NEVER self-administer these doses.
3. Timing
Vitamin A is fat-soluble — take with a meal containing dietary fat for absorption. A spread-out daily dose is gentler than a single weekly mega-dose for routine supplementation.
4. With food
With a fat-containing meal.
5. Split dosing
Single daily dose is fine at RDA-level intakes. Therapeutic mega-doses (50,000+ IU) should only be given on a clinician's protocol.
6. How long to try
For deficiency correction: until serum retinol normalizes and the deficiency cause is addressed. For chronic malabsorption: indefinite at clinician-monitored doses, typically 5,000–10,000 IU/day with periodic serum-retinol checks. Avoid casual long-term mega-dosing.

What to track

Serum retinol (deficiency confirmation and monitoring) — get a baseline if supplementing therapeutically
Signs of toxicity: headache, blurred vision, nausea, dry/peeling skin, hair loss, joint pain, bone pain
Liver function (ALT/AST) on long-term high-dose therapy
Pregnancy test before starting any dose >3,000 µg RAE/day if you could become pregnant

Bottom line: Match your dose to your need. RDA from food is enough for most people. If you supplement, stay at or below 3,000 µg RAE/day preformed retinol unless a clinician has you on a therapeutic protocol. Pregnancy or possible pregnancy: do not exceed the RDA.

5 commercial forms

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

Retinyl palmitate / retinyl acetate (preformed retinol esters)

Standard supplement

The dominant supplement form. Well absorbed when taken with dietary fat. Same teratogenic and hepatotoxic ceiling as retinol itself — count it against the 3,000 µg RAE/day UL.

Reliably absorbed; carries the full toxicity profile of preformed retinol.

Beta-carotene (provitamin A carotenoid)

Pregnancy-safe form

Plant pigment found in carrots, sweet potatoes, leafy greens. The body converts it to retinol in a tightly regulated way, so dietary beta-carotene cannot cause hypervitaminosis A and is NOT teratogenic. However, high-dose supplemental beta-carotene (≥20 mg/day) increases lung cancer risk in smokers.

12 µg dietary beta-carotene ≈ 1 µg RAE; absorption is variable and improves with cooking and dietary fat.

Mixed carotenoids (beta-carotene + alpha-carotene + cryptoxanthin)

Diverse plant pigments

Closer to what's in food. Same regulated conversion to retinol; lower lung-cancer concern than isolated high-dose beta-carotene alone.

Similar bioavailability rules as beta-carotene; closer match to dietary carotenoid exposure.

Cod liver oil

Concentrated retinol + vitamin D + omega-3

Traditional source. Vitamin A content is high and variable by brand — a single tablespoon can deliver 4,500–13,500 µg RAE preformed retinol. Risk of unintended over-dose, especially in pregnancy. Read the label and count it against your daily total.

Well absorbed but easy to exceed the UL — pregnant women in particular should avoid daily cod liver oil.

AREDS2 eye-health formula

Combination — not vitamin A alone

Lutein + zeaxanthin (not vitamin A), plus vitamin C, vitamin E, zinc, copper. Designed by the AREDS2 trial after the original AREDS formula's beta-carotene was found harmful in smokers. Only indicated for diagnosed intermediate or unilateral advanced AMD on ophthalmologist guidance.

Take with food; effects accrue over years, not weeks.

Safety

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

Common side effects

nauseaheadachedizzinessblurred visiondry skin

Serious risks

Who should avoid it

Pregnancy & breastfeeding

Pregnancy is the most important safety context for vitamin A. The RDA in pregnancy is 770 µg RAE/day; the UL of 3,000 µg RAE/day applies, and daily intakes ABOVE 3,000 µg RAE of preformed retinol are linked to major birth defects (craniofacial, cardiac, CNS). The risk is from preformed retinol — NOT from beta-carotene or other provitamin A carotenoids in fruits and vegetables, which the body converts in a regulated manner and which carry no teratogenic risk. Standard prenatal vitamins contain modest amounts of vitamin A (often as a mix of retinol and beta-carotene) and are safe. Do not add additional preformed retinol unless explicitly directed by your obstetrician for a documented deficiency. Also avoid retinoid acne medications (tretinoin, isotretinoin, adapalene) and high-dose cod liver oil during pregnancy.

SourceMotherToBaby Vitamin A Fact Sheet — OTIS / NCBI BookshelfRothman et al., 1995 — NEJMNIH Office of Dietary Supplements — Vitamin A and Carotenoids — Health Professional Fact Sheet

Bottom line: The toxicity ceiling for preformed vitamin A is genuinely low. Stay within the RDA from food + a standard multivitamin unless a clinician is treating a documented deficiency. Never exceed 3,000 µg RAE/day in pregnancy.

Interactions

oral retinoid medications (isotretinoin, acitretin, bexarotene, alitretinoin)Major

Additive vitamin A toxicity. These drugs are themselves retinoids; adding supplemental vitamin A risks hepatotoxicity, intracranial hypertension, and bone loss.

SourceNIH Office of Dietary Supplements — Vitamin A and Carotenoids — Health Professional Fact Sheet
orlistat (Xenical, Alli)Moderate

Orlistat blocks fat absorption and reduces absorption of fat-soluble vitamins including vitamin A. Take a multivitamin with fat-soluble vitamins at least 2 hours apart from orlistat.

SourceNIH Office of Dietary Supplements — Vitamin A and Carotenoids — Health Professional Fact Sheet
cholestyramine, colestipol, colesevelam (bile acid sequestrants)Moderate

Bile acid sequestrants interfere with fat-soluble vitamin absorption. Long-term use may require monitoring of vitamin A status.

SourceNIH Office of Dietary Supplements — Vitamin A and Carotenoids — Health Professional Fact Sheet
warfarinModerate

High-dose vitamin A may increase warfarin's anticoagulant effect and bleeding risk. Avoid mega-doses on warfarin; standard prenatal/multi doses are generally fine.

minocycline, tetracycline (high-dose long-term)Moderate

Both tetracyclines and vitamin A can independently cause intracranial hypertension (pseudotumor cerebri). Combined use raises the risk.

SourcePenniston & Tanumihardjo, 2006 — American Journal of Clinical Nutrition
hepatotoxic drugs and chronic alcoholModerate

Vitamin A is stored in the liver and is itself hepatotoxic at chronic high doses. Combining with hepatotoxic drugs or heavy alcohol use amplifies liver injury risk.

SourceNIH Office of Dietary Supplements — Vitamin A and Carotenoids — Health Professional Fact Sheet

Protocols featuring Vitamin A (retinol)

Evidence-backed routines where Vitamin A (retinol) 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, pan-fried

Amount
3 oz (6,582 µg RAE)
%DV
731%

Sweet potato, baked with skin

Amount
1 medium (1,403 µg RAE)
%DV
156%

Spinach, frozen, boiled

Amount
½ cup (573 µg RAE)
%DV
64%

Pumpkin pie

Amount
1 piece (488 µg RAE)
%DV
54%

Carrots, raw

Amount
½ cup (459 µg RAE)
%DV
51%

Cantaloupe

Amount
½ cup (135 µg RAE)
%DV
15%

Mango, raw

Amount
1 whole (112 µg RAE)
%DV
12%

Egg, hard boiled

Amount
1 large (75 µg RAE)
%DV
8%

Whole milk

Amount
1 cup (110 µg RAE)
%DV
12%

Cheddar cheese

Amount
1.5 oz (124 µg RAE)
%DV
14%

Salmon, sockeye, cooked

Amount
3 oz (59 µg RAE)
%DV
7%

Choosing a product

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

Look for…

Dose given in µg RAE (Retinol Activity Equivalents) — the modern unit. 1 µg RAE = 3.33 IU retinol or 12 µg dietary beta-carotene.
Vitamin A from a MIX of retinol (retinyl palmitate) AND beta-carotene is preferable to all-retinol — carotenoids carry no toxicity ceiling
Stay at or below 3,000 µg RAE/day from supplements (the UL for preformed retinol)
Third-party tested (USP, NSF, ConsumerLab) — fat-soluble vitamins can vary widely on label vs actual content
For AREDS2 eye formulas: confirm NO beta-carotene (substituted with lutein/zeaxanthin) if you've ever smoked

Be skeptical of…

'Mega-dose' products (10,000–50,000 IU per softgel) marketed for daily wellness use — this is the chronic-toxicity range
Cod liver oil marketed as a daily-multivitamin substitute — single tablespoons can deliver 4,500+ µg RAE retinol
'Boosts immunity' marketing on retinol — only true in deficient individuals
'Anti-aging skin' claims for oral retinol — topical retinoids are the evidence base, not oral
Pregnancy-targeted retinol supplements above 3,000 µg RAE/day — teratogenic; trust your prenatal
Beta-carotene supplements marketed to smokers as 'antioxidant lung protection' — actually increases lung cancer risk

Frequently asked questions

Is retinol safer than beta-carotene?⌄

No — the opposite. Retinol can cause vitamin A toxicity at chronic high doses. Beta-carotene conversion to vitamin A is regulated and does not cause toxicity.

How much retinol is safe?⌄

Up to 3,000 mcg RAE per day from all sources. Pregnant women should stay near the 770 mcg RAE RDA and avoid liver-rich meals.

Does oral retinol improve skin like topical retinol?⌄

Not in a comparable way. Topical retinol works locally on skin cells. Oral retinol affects the whole body and high doses are dangerous.

Can men take retinol freely?⌄

Up to the upper limit of 3,000 mcg RAE per day. Even men should track total intake to avoid liver effects.

References by claim

Vitamin A deficiency correction (xerophthalmia, night blindness)

NIH Office of Dietary Supplements — Vitamin A and Carotenoids — Health Professional Fact Sheet (2025) link

Imdad et al., 2022 — Cochrane Database of Systematic Reviews (2022) link

Adjunct treatment for measles in vitamin-A-deficient children

Huiming et al., 2005 — Cochrane Database of Systematic Reviews (2005) link

Age-related macular degeneration (AREDS2 formula)

AREDS2 Research Group, 2013 — JAMA (2013) link

Omenn et al., 1996 (CARET trial) — NEJM (1996) link

Safety

Penniston & Tanumihardjo, 2006 — American Journal of Clinical Nutrition (2006) link

MotherToBaby Vitamin A Fact Sheet — OTIS / NCBI Bookshelf (2024) link

Rothman et al., 1995 — NEJM (1995) link

Other references

Vitamin A (retinol) on Wikidata — Wikidata link

Vitamin A (retinol) on ChEBI — ChEBI link

Vitamin A on NIH DSLD — NIH Dietary Supplement Label Database link

Track Vitamin A (retinol) with Pilora

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Evidence-based·Last reviewed May 31, 2026·Evidence current as of May 31, 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.