Supplement analysis backed by scientific evidence · PT · ES · DE · FR

← All supplements
Limited evidenceLongevity & antioxidants

Beta-Carotene

Beta-carotene supplements are one of the clearest cautionary tales in supplement science: two large RCTs found they increased lung cancer and mortality in smokers and asbestos-exposed workers. Get carotenoids from food; do not supplement isolated beta-carotene.

View on iHerb Ships to 180+ countries · welcome discount for new customers

What the science says

  • Increases lung cancer risk in smokers Strong evidence

    The ATBC trial (29,133 male smokers, 20 mg/day beta-carotene, median 6.1 years) found an 18% increase in lung cancer incidence and 8% higher total mortality in the beta-carotene arms. CARET (18,314 smokers and asbestos-exposed workers, 30 mg beta-carotene plus 25,000 IU retinol) was stopped early for a 28% increase in lung cancer and 17% increase in death. This is a consistent, replicated harm signal.

  • Prevents cancer or cardiovascular disease in general populations Limited evidence

    Beyond the smoker trials, beta-carotene supplementation has repeatedly failed to reduce cancer or cardiovascular disease incidence in RCTs despite strong observational associations for carotenoid-rich diets. The dissociation between food carotenoids and isolated supplements is the whole lesson here.

  • Slows age-related macular degeneration progression (as part of AREDS) Moderate evidence

    The original AREDS formulation containing 15 mg beta-carotene reduced progression to advanced AMD by about 25% over 5 years, but beta-carotene was replaced by lutein and zeaxanthin in AREDS2 precisely because of the smoker cancer risk. Any AMD benefit is attributable to the combination, and the modern formulation omits beta-carotene.

  • Prevents sunburn or acts as an 'internal sunscreen' Limited evidence

    Trials show only marginal increases in minimal erythema dose after weeks to months of high-dose supplementation, far below what a topical SPF provides. Prolonged high intake mainly produces carotenodermia — harmless orange skin discolouration.

Dosage & safety

Studied doseNo RDA exists; beta-carotene is a provitamin A source, with roughly 12 mcg dietary beta-carotene equivalent to 1 mcg retinol. Trials showing harm used 20-30 mg/day. There is no dose of isolated supplemental beta-carotene with an established favourable risk-benefit profile in adults. Dietary carotenoids from carrots, sweet potato, and leafy greens carry none of this risk.
SafetyContraindicated in current and former smokers and anyone with significant asbestos exposure — supplemental doses of 20-30 mg/day increased lung cancer and all-cause mortality in two large RCTs. Carotenodermia (yellow-orange palms and skin) is common above ~30 mg/day and is cosmetic only. Unlike preformed vitamin A, beta-carotene from food does not cause hypervitaminosis A because conversion is regulated, and it is not teratogenic. Multivitamins and older AMD formulas may contain it — check labels if you smoke.

How to take it

TimingTiming does not matter.
With food?With a meal containing fat, which several-fold increases absorption of any carotenoid.
Worth knowingIf you have ever smoked, read the label of your multivitamin and any eye formula — beta-carotene is still in many of them, and this is the one supplement with two large trials showing increased mortality.

Interactions

With medications

  • orlistat, cholestyramine and other bile acid sequestrants

    Fat malabsorption reduces carotenoid uptake substantially. separate by at least 4 hours

With other supplements

  • preformed vitamin A (retinol)

    Beta-carotene contributes to your total vitamin A activity, and combined high-dose products carry the lung cancer signal seen in smokers. do not stack them, and avoid both if you smoke or have smoked

  • lutein and other carotenoids

    High-dose supplemental beta-carotene competes with lutein for absorption and lowers its blood levels. avoid high-dose single-carotenoid supplements if eye health is the goal

Well-established interactions only — this is not a complete list. Always tell your doctor and pharmacist what you take.

Frequently asked questions

Is beta-carotene safe for smokers?

No — the evidence of harm is strong. In two large trials, 20–30 mg/day of beta-carotene raised lung cancer and death rates in smokers and asbestos-exposed workers, with ATBC finding 18% more lung cancer. Current and former smokers should avoid beta-carotene, including in multivitamins and older eye formulas.

Does beta-carotene prevent cancer or heart disease?

No — the evidence is limited and negative. Beta-carotene supplements have repeatedly failed to reduce cancer or cardiovascular disease in trials, even though carotenoid-rich diets look protective, so get carotenoids from food rather than a pill.

Is beta-carotene still used in eye vitamins for macular degeneration?

The original AREDS formula contained 15 mg of beta-carotene and slowed progression to advanced AMD, but AREDS2 replaced beta-carotene with lutein and zeaxanthin because of the smoker cancer risk. The modern AMD formula leaves beta-carotene out.

Does beta-carotene work as an internal sunscreen?

Not in any useful way — the evidence is limited. Beta-carotene trials show only marginal gains in sunburn resistance, far below a topical SPF, and high intake mostly turns your skin harmlessly orange.

Scientific references

Where to buy

Swanson Vitamins, Beta Carotene, 10,000 IU (3,000 mcg RAE), 100 Softgels

View on iHerb

Ships to 180+ countries · welcome discount for new customers

Referral link — this site may earn a commission on purchases.

Related in Longevity & antioxidants