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Bt2.0
Beta-Carotene Research
Mostly mechanism / observational
5 peer-reviewed studies
What the evidence says
Mostly mechanism / observational
Most Beta-Carotene studies are mechanism or observational rather than RCTs that measure a clinical effect — keep findings provisional.
Most evidence is from high-quality meta-analyses and randomised trials published 1994–2026 with a typical study size of 29,133 participants.
Based on 5 studies · 1 meta-analysis · 2 RCTs · 47,447 total participants
Confidence
Moderate confidence
By outcome
Therapeutic & clinical
Too few graded studies2 studies
Heart & blood pressure
Too few graded studies1 study
Cholesterol & lipids
Too few graded studies1 study
Men's vitality
Too few graded studies1 study
Safety profile
Too few graded studies1 study
Active research area
2 studies in the last 5 years · Latest meta-analysis: 2012
199420102026
1RCTn=29,133 · very large study1994
In plain English: Among 29,133 male smokers, beta-carotene supplementation unexpectedly increased lung cancer incidence by 18% and total mortality by 8%.
Alpha-Tocopherol, Beta Carotene Cancer Prevention Study Group · N Engl J Med (1994)
Lung cancer incidence with beta-carotene: +18% (95% CI 3% to 36%) compared with those not receiving it — an unexpected harm
Total mortality was 8% higher (95% CI 1% to 16%) with beta-carotene, primarily from lung cancer and ischaemic heart disease
Alpha-tocopherol showed no reduction in lung cancer (-2%, 95% CI -14% to 12%) and more deaths from haemorrhagic stroke, though fewer prostate cancers
In plain English: The Beta-Carotene and Retinol Efficacy Trial was stopped 21 months early after beta-carotene plus retinol raised lung cancer risk by 28% in smokers, former smokers and asbestos-exposed workers.
Omenn GS, Goodman GE, Thornquist MD, Balmes J, Cullen MR, Glass A, Keogh JP, Meyskens FL, Valanis B, Williams JH, Barnhart S, Hammar S · N Engl J Med (1996)
Lung cancer relative risk in the active-treatment group: 1.28 (95% CI 1.04-1.57, P=0.02) versus placebo
Relative risk of death from any cause 1.17 (95% CI 1.03-1.33); from lung cancer 1.46 (1.07-2.00); from cardiovascular disease 1.26 (0.99-1.61)
The trial was stopped 21 months earlier than planned because of these findings
In plain English: We found no evidence to support antioxidant supplements for primary or secondary prevention. Beta-carotene and vitamin E seem to increase mortality.
In plain English: Sunless tanning agents offer UV-free alternatives for cosmetic pigmentation but are not without risk.
Resnick G, Khajeh-Afzaly M, Yousefian F, Raza A, Issa NT · J Clin Aesthet Dermatol (2026)
Reviewed the mechanisms, uses and adverse effects of self-tanning agents including DHA, melanotan and carotenoids
Carotenoids taken orally accumulate in skin and subcutaneous fat, creating a yellow-orange hue
Groups carotenoids as an alternative pigmentation pathway rather than an equivalent to melanin
5Review2024
In plain English: In carotenodermia associated with high β-carotene intake the discoloration tends to be widespread, mainly in thick areas of the skin (e.g., the palm of the hand), and can last from 14 days to 4.5 years.
Kapsetaki ME · Int J Dermatol (2024)
Reviewed roughly 100 published human cases of carotenodermia from high beta-carotene intake
Discolouration is widespread and concentrated in thick skin such as the palms
Duration ranged from 14 days to 4.5 years after intake stopped