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Supplement

Beta Carotene

The supplement that taught the field that a nutrient's food record does not transfer to a pill.

Beta carotene is the orange pigment in carrots and sweet potatoes and a precursor the body converts to vitamin A as needed. We grade Beta Carotene D on evidence and D for worth-it at about $6-10 per month.

D

Evidence

D

Worth it

Typical cost: $6-10/month

What it does

Beta carotene is the orange pigment in carrots and sweet potatoes and a precursor the body converts to vitamin A as needed. As a supplement it was marketed for decades as antioxidant insurance for cancer and heart disease, and it remains in multivitamins and eye formulas that have not caught up with the evidence. This record grades the supplement, not the vegetable.

What the research says

  • Increased lung cancer and mortality in smokers in two landmark trials

    Evidence: strong. ATBC (1994; 29,133 male smokers, 20 mg/day): lung cancer up 18 percent and total mortality up 8 percent on beta carotene. CARET (1996; 18,314 smokers and asbestos-exposed workers): stopped early, lung cancer up 28 percent, mortality up 17 percent. These are among the most consequential supplement trial results ever published, and they are why this record exists in this form.

  • No benefit for cancer or cardiovascular prevention in non-smokers either

    Evidence: strong. The Physicians' Health Study (22,071 physicians, 12 years) found no benefit and no clear harm in a mostly non-smoking population. The US Preventive Services Task Force (2022) recommends against beta carotene supplementation for cardiovascular or cancer prevention, a Grade D recommendation, for everyone.

  • Displaced from eye formulas by its own risk profile

    Evidence: moderate. Beta carotene was in the original AREDS eye formula. AREDS2 replaced it with lutein and zeaxanthin, and the 10-year follow-up found roughly double the lung cancer risk in the beta carotene group (concentrated in former smokers) with no such signal for the replacement pair. Both successor records are graded in this library.

Beta carotene is the canonical lesson in why this library exists. The observational data said people who eat carotenoid-rich diets fare better; the trials then showed that isolating the molecule into a pill harmed the highest-risk group and helped no one. Two large randomized trials with increased cancer and mortality, a null in non-smokers, and a Grade D recommendation from the USPSTF settle the supplement question. D is not a close call here.

The week's longevity and biohacking news.

This grade for Beta Carotene rests on the record above. When a new result changes that record, the grade changes with it, and the Thursday email is where the change lands first: the week's longevity and biohacking news, in plain English, linked back to the reasoning on this page.

The week's longevity and biohacking news. Every story graded against the evidence. Free. Unsubscribe anytime.

Every grade follows a published rubric, and sponsors never change one. When the evidence moves a grade, Thursday is where you hear it first, before you renew a stack that stopped earning its cost.

Is it worth it?

D

The derived value at any price is D, and cheapness does not soften a harm-direction record. About $8 a month at common doses. Derived from the October 2026 worth-it model.

Typical cost

$6-10/month

Common form, not a brand recommendation

Dosage context established

The harm trials used 20 to 30 mg/day, doses common in supplements of their era and still sold today. Food intake of beta carotene runs 2 to 6 mg/day in typical diets (carrots, sweet potatoes, leafy greens) and has never carried this risk profile. There is no established supplemental dose, because there is no established supplemental use.

Worth-it leaderboard

Beta Carotene sits outside the worth-it top 20.

Beta Carotene sits outside the current top 20 on the gated leaderboard. The leaders below clear an evidence floor of B- before price counts at all, so cheap alone never earns a rank.

  1. 1ACreatine evidence A-~$5-10/mo
  2. 2ACaffeine evidence B+~$5-10/mo
  3. 3AVitamin D evidence B~$5-8/mo

See the full worth-it leaderboard →

When the evidence moves a grade, this ranking moves with it. Thursday is where you hear it first.

Safety notes

If you smoke, have ever smoked heavily, or were exposed to asbestos, do not take beta carotene supplements: that is the population in which the trials found increased lung cancer and death, and regulators and the USPSTF advise against it. At dietary (food) levels none of this applies. High supplemental intakes turn skin orange (harmless and reversible) and, as a vitamin A precursor, beta carotene does not cause vitamin A toxicity, because conversion is regulated; preformed vitamin A is a different record with its own cautions.

Longevity Lab Report

Beta Carotene news. Graded when it happens.

The grade on this page stays free. The email carries the news on beta carotene: expert moves, dose changes, and what is working, in plain English every Thursday.

Changelog

Last updated 2026-10-23

  • 2026-10-23|Graded from the ATBC and CARET trials, the Physicians' Health Study, the USPSTF Grade D recommendation, and the AREDS2 follow-up. Dietary beta carotene from food is not what this grade covers; the record states that distinction explicitly, because the food-versus-supplement divergence is the central fact of this ingredient's history.
  • 2026-10-23|Not listed under any goal: no graded benefit maps to the library's ten goals, and the eye-health use has been superseded by the lutein and zeaxanthin records.