Dunaliella salina

BotanicalBest with a meal

What is it

Dunaliella salina is a halotolerant green microalga that produces high concentrations of beta-carotene and other carotenoids when exposed to high salinity and intense light. It is used as a natural beta-carotene source in supplements.

Evidence for 2 uses

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

Vitamin A precursor and antioxidant intake

Strong Evidence

Beta-carotene is an established source of vitamin A, with antioxidant activity in vivo.

Skin protection from UV (limited)

Limited Evidence

Some studies suggest beta-carotene at higher doses provides modest protection against UV-induced erythema; effect is small and not a substitute for sunscreen.

How it works

Dunaliella salina produces 9-cis and all-trans beta-carotene, the precursor the body uses to make vitamin A as needed. Unlike high-dose isolated synthetic beta-carotene (which raised lung cancer risk in smokers in the ATBC and CARET trials), natural Dunaliella beta-carotene delivers a more diverse carotenoid mix and is generally consumed at lower doses. Beta-carotene supports antioxidant defense and visual function via vitamin A.

Dosage

Supplements provide 2-15 mg of natural mixed carotenoids (often labeled as beta-carotene) per dose. The vitamin A RDA is 700-900 mcg RAE for adults.

When and how to take it

Taken with a meal containing fat to improve absorption.

1 commercial form

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Natural Dunaliella salina extract (mixed carotenoids)

Most common natural beta-carotene supplement source.

Fat-soluble; absorbed with fat-containing meals.

Safety

Generally well tolerated. High doses can cause carotenodermia (yellow-orange skin tint), which is harmless and reversible. High-dose isolated beta-carotene raised lung cancer risk in smokers; natural Dunaliella at supplement doses has not shown this signal, but smokers should still be cautious with high-dose beta-carotene products.

Who should be cautious

Smokers and people with significant asbestos exposure should avoid high-dose isolated beta-carotene. Pregnancy: beta-carotene (provitamin A) is preferred over preformed vitamin A.

Interactions

Beta-carotene absorption can be affected by orlistat and bile acid sequestrants. May interact with statins in some studies.

Food sources

Carrots, sweet potato, leafy greens (other beta-carotene sources)

Amount
varies
%DV
—

Frequently asked questions

Is natural Dunaliella beta-carotene safer than synthetic?⌄

It provides a mix of natural carotenoid isomers rather than pure all-trans synthetic beta-carotene. The concerning lung cancer signal from high-dose synthetic beta-carotene in smokers has not been seen with natural sources at typical doses, but smokers should be cautious.

Will beta-carotene supplements give me too much vitamin A?⌄

Unlike preformed vitamin A (retinol), beta-carotene is converted to vitamin A as needed and does not typically cause vitamin A toxicity at supplement doses.

References

Dunaliella salina on Wikidata — Wikidata link

Dunaliella salina on NIH DSLD (US supplement label database) — NIH Dietary Supplement Label Database link

Research on Dunaliella salina (PubMed search) — PubMed link

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Evidence-based·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.