IngredientsDunaliella salina (Dunal) Teodoresco, 1905, belongs to the kingdom Plantae, phylum Chlorophyta, class Chlorophyceae, order Volvocales (also listed under Chlamydomonadales in some classifications), and family Dunaliellaceae. The original name of the organism was Protococcus salinus Dunal, 1837, with synonyms including Haematococcus salinus Dunal, 1837, and Diselmis dunalii Dujardin, 1841.
Dunaliella salina is a single-cell organism in the family Chlorophyceae. It lacks a true cell wall but is wrapped in a glycoprotein and has two flagella that can swim freely in liquid environments. D. salina has somewhat larger cells than its congeners, and under suitable conditions it synthesizes massive amounts of carotenoid pigments, coloring the cells brightly red.
So far, 28 species of Dunaliella have been identified; 5 of them are from freshwater and 23 of them are from marine and saline environments. The family Dunaliellaceae comprises four sections as described by Massjuk (1973): section Tertiolectae, which are oligo-euhaline and do not accumulate carotenes; section Dunaliella, which are halophilic species that accumulate carotenes; section Virides, which are hyperhaline and always green; and section Peirceinae, which are hyperhaline, always green, but bilaterally symmetrical. Within section Dunaliella, three accepted species are recognized: D. salina, D. parva, and D. pseudosalina, as well as D. bardawil.
Dunaliella salina stands out for its remarkable ability to thrive in environments with extremely high salt concentrations, even in fully saturated saline water. It can grow normally at concentrations of NaCl ranging from 0.05 M to saturated, and regulates the osmotic pressure inside and outside the cell by regulating glycerol metabolism. The unicellular green alga is responsible for most of the primary production in hypersaline environments worldwide.
Dunaliella salina, a halotolerant chlorophyte, is one of the richest sources of natural carotenoids, and accumulates up to 10% of the dry biomass as β-carotene under conditions that are sub-optimal for growth — i.e., high light intensity, sub-optimal temperatures, nutrient limitation, and high salt concentrations. Among the culture conditions, the parameters such as ambient salinity, temperature, and intensity of illumination are the most effective ones for carotenoid production.
From a first pilot plant established in the USSR in 1966, commercial cultivation of D. salina for the production of β-carotene throughout the world is now one of the success stories of halophile biotechnology. Different technologies are used, from low-tech extensive cultivation in lagoons to intensive cultivation at high cell densities under carefully controlled conditions. Commercial production of this alga as a source of β-carotene has occurred since the 1980s, and currently there are large D. salina production plants in Australia and Israel. The two Australian plants are the largest commercial microalgae production plants in the world, with a total pond area of more than 900 hectares.
These plants produce "natural" β-carotene in the form of suspensions in oil, beadlets, and water-soluble powder for pharmaceutical and nutraceutical applications. Natural β-carotene is marketed in various forms: β-carotene extracts, Dunaliella powder for human use, and dried Dunaliella for feed coloration. Additional commercial formats include softgel capsules containing oil-based extracts, spray-dried dispersible powders for use in beverages, and topical cosmetic preparations made via supercritical CO₂ extraction. A natural supercritical CO₂ extract of Dunaliella salina rich in the colorless carotenoids phytoene and phytofluene has also been developed specifically for dermatological applications.
The first description of a unicellular biflagellate red-colored alga living in concentrated brines was made in 1838 by Dunal, who reported the occurrence of the organism we know today as D. salina in the salterns of Montpellier, on the Mediterranean coast of France. He initially named the organism Haematococcus salinus and Protococcus.
Descriptions of Dunaliella as a new genus were presented in 1905 by Teodoresco from Bucharest using Romanian salt lake samples and by Clara Hamburger from Heidelberg using samples from Cagliari, Sardinia. Teodoresco was the first to publish his work, so he is generally given credit for this categorization. A formal description of the genus Dunaliella, named in honor of Dunal, and of the first two species within the genus, D. salina and D. viridis, was published in 1906.
Notable early studies include Cavara's article in 1906 expanding on the Cagliari saltern study by Hamburger, Peirce's article in 1914 on Dunaliella in the Salton Sea, California, Labbé's various ecological studies of the algae in salterns of Le Croisic, France, as well as in-depth taxonomic studies by Hamel and Lerche.
Dunaliella salina was first proposed as a commercial source of β-carotene by Massyuk (1966) and later as a source of glycerol (Ben-Amotz et al., 1982).
Dunaliella salina as a formally identified and intentionally exploited organism has no documented traditional ethnobotanical history predating 20th-century science. The alga was not knowingly consumed, prepared, or administered as a remedy in any identified historical medical tradition — it was only observed, described, and taxonomically defined beginning in the 19th century by European natural scientists. Its deliberate use as a nutritional supplement is entirely a product of biotechnology research beginning in the second half of the 20th century, following its commercial cultivation starting in the 1980s. Its applications range from functional food and dietary supplements to additives for animal feed that can improve productivity and health.
β-Carotene is produced by D. salina, making up 10 to 14% of its dry matter. The organism contains many active substances, including β-carotene, glycerol, proteins, and vitamins.
A defining feature of D. salina-derived β-carotene is its distinctive isomeric profile. β-Carotene is composed of two major stable geometric isomers: all-trans β-carotene, the common natural form of this pigment, and 9-cis β-carotene. Thylakoid β-carotene consists principally of all-trans β-carotene, while the accumulated β-carotene, found in globules of lipid in the inter-thylakoid spaces of the chloroplast, appears at high concentration in both cis/trans configurations at a ratio of approximately 1:1. The 9-cis to all-trans β-carotene ratio in oil preparations has been reported as constant at approximately 60:40 (g/g).
Synthetic β-carotene is predominantly composed of all-trans compounds and is of questionable benefit, whereas intake of food supplements enriched with natural β-carotene containing both cis- and trans-stereoisomers is linked with mitigation of a range of diseases including atherosclerosis, diabetes, psoriasis, and ophthalmologic diseases. Several experimental studies have suggested that 9-cis β-carotene has a higher antioxidant and anti-cancer potency than that of the all-trans isomers.
Natural carotenoids extensively synthesized in D. salina microalgae include β-carotene, astaxanthin, zeaxanthin, and lutein. In the cells, β-carotene is usually accompanied by other carotenoids (astaxanthin and canthaxanthin), which are all accumulated in 'oily' globules in the chloroplast.
A natural supercritical COâ‚‚ extract of Dunaliella salina is also rich in the colorless carotenoids phytoene and phytofluene. Phytoene and phytofluene are the biosynthetic precursors for all colored carotenoids and, due to their shorter conjugated C=C double-bond chromophores, absorb light in the UV range and not in the visible range. The colorless carotenoids have been shown to have antioxidative, anti-inflammatory, and DNA protection activities.
The halophilic species of Dunaliella also accumulate very high concentrations of glycerol. Glycerol functions as a compatible solute, allowing the alga to regulate osmotic pressure in its hypersaline environment. Attempts have been made to exploit the high concentrations of glycerol accumulated by D. salina as the basis for commercial glycerol production; although technically feasible, economic viability has been low and no sustained biotechnological operation has emerged specifically for this purpose.
The D. salina cell contains a variety of nutrients, including minerals, vitamins, lipids, protein, pigments, and antioxidants. Its amino acid content includes all essential amino acids in addition to nonessential ones. It is also considered one of the most important species for commercial production due to the presence of β-carotene and other active compounds such as lutein, zeaxanthin, chlorophyll, and polyunsaturated fatty acids. D. salina may also be a source of vitamin B12.
In D. salina, beta-carotene biosynthesis does not proceed via the classical acetate/mevalonate pathway, but via the novel glyceraldehyde 3-phosphate/pyruvate pathway. This favors the yield of C₅ isoprenoid units for synthesis of isopentenyl diphosphate, the precursor in the biosynthesis of C₂₀ compounds, including geranylgeranyl diphosphate. Consequently, this pathway promotes carotenogenesis and the biosynthesis of C₄₀ β-carotene in D. salina.
These lipophilic compounds comprise a range of carotenes and xanthophylls, and their health benefits generally derive from their ability to quench oxygen radicals and absorb potentially damaging visible light. β-Carotene can play the role of a powerful antioxidant compound because of its efficient ability to mitigate free radicals, with important effects on the suppression of superoxide ions.
The occurrence of high concentrations of 9-cis β-carotene in D. salina is of great pharmaceutical interest. 9-cis β-carotene has a higher antioxidant activity than all-trans β-carotene, and may also be more efficient than all-trans β-carotene in vivo.
Beta-carotene is a vital precursor for the synthesis of vitamin A in humans and animals, and is also an antioxidant. Unlike preformed vitamin A (retinol), beta-carotene conversion is controlled by the body's needs, making toxicity virtually impossible from dietary sources. 9-cis β-carotene is also one of the most potent precursors of retinoids.
In ex vivo testing, a D. salina supercritical CO₂ extract showed antiglycation and anti-inflammatory activities, demonstrating strongly reduced formation of N-ε-carboxy-methyl-lysine with exposure to methylglyoxal, reduced AGE receptor levels, and significantly reduced interleukins 6 and 8.
Glycation, and the resulting buildup of advanced glycation end products (AGEs), is recognized as a key driver of cumulative skin damage and skin aging. The phytoene- and phytofluene-rich extract of D. salina has demonstrated capacity to interfere with AGE formation, reduce AGE receptor expression, and modulate downstream inflammatory signaling pathways in ex vivo experimental models.
Carotenoids are used in the animal body to improve the immune system, inhibit and prevent cancer, delay aging, improve liver damage, and act as nutritional antioxidants that promote communication between cellular junctions, which can effectively inhibit the occurrence of some chronic diseases.
Dunaliella salina is a rich source of 9-cis β-carotene, which has been identified as an important biomolecule in the treatment of retinal dystrophies and other diseases.
Clinical Evidence: A randomized, double-masked, placebo-controlled crossover clinical trial was conducted at a university tertiary medical facility. Thirty-four patients with retinitis pigmentosa (RP) who were at least 18 years of age were enrolled, and 29 completed the study. Patients were treated daily for 90 days with capsules containing 300 mg of 9-cis β-carotene-rich alga Dunaliella bardawil (approximately 20 mg β-carotene) or placebo (starch). Following a 90-day washout period, they were treated for 90 days with the other capsules. Oral treatment with the 9-cis-β-carotene-rich Dunaliella bardawil algae powder significantly improved visual and retinal functions in patients with retinitis pigmentosa and fundus albipunctatus.
9-cis β-carotene has been proposed in treatments for retinal dystrophies, chronic plaque psoriasis, and atherosclerosis, and as an anti-aging therapy. A further randomized crossover double-masked study — "Treatment With 9-cis Beta-Carotene-Rich Extract of Dunaliella Alga in Retinitis Pigmentosa Patients" (NCT07509229, Sheba Medical Center) — was in pre-recruitment phase as of early 2026, with an estimated start date of May 2026 and completion by April 2029.
Evidence Assessment: Human clinical evidence for this indication is promising but limited by the small sample sizes and the specialized patient populations studied (hereditary retinal dystrophies with known genetic defects in the retinoid cycle). Independent replication is needed before definitive conclusions can be drawn.
Clinical Evidence: In a randomized, double-blind, placebo-controlled clinical trial, 34 patients were recruited, of whom 22 subjects were treated with Dunaliella capsules and 12 subjects were treated with placebo. Twenty-eight patients completed the study: 17 in the treatment arm and 11 in the placebo arm. The trial reported reduction in the severity of chronic plaque psoriasis. A 9-cis β-carotene-enriched diet, provided as Dunaliella powder, has been shown to have a beneficial effect on lipid profiles and psoriasis in human trials.
Evidence Assessment: Preliminary positive evidence from small randomized controlled trials; sample sizes are insufficient to establish clinical efficacy definitively. The proposed mechanism centers on the retinoid-receptor activity of 9-cis β-carotene and its anti-inflammatory properties.
Studies have demonstrated that diets enriched with Dunaliella salina improve blood lipid profiles by reducing cholesterol synthesis and absorption in the digestive system, leading to lower levels of triglycerides, cholesterol, and low-density lipoprotein.
Clinical Evidence: A clinical trial with 9-cis β-carotene-rich powder of the alga Dunaliella bardawil in fibrate-treated patients found increases in plasma HDL-cholesterol (Atherosclerosis, 189:215–221, 2006). The effect of 9-cis anti-peroxidants in comparison with all-trans forms (both crucial isomers of beta-carotene) has been described as much greater in counteracting severe cardiovascular disease.
Animal Evidence: A 9-cis beta-carotene-enriched diet has been shown to inhibit atherogenesis and fatty liver formation in LDL receptor knockout mice, and to prevent atherosclerosis progression in apoE-deficient mice.
Evidence Assessment: The evidence for cardiovascular benefits is largely based on animal models and small human studies focused on lipid parameters. Large, high-quality randomized trials linking oral Dunaliella to reductions in cardiovascular events are not yet available. Extrapolation from general carotenoid research provides plausibility, but does not demonstrate disease modification.
Dunaliella salina is a halophile microalga adapted to intense solar radiation through the production of carotenoids. Its carotenoids provide a measure of protection against UV and oxidative damage leading to premature aging and other disorders.
Clinical Evidence (Topical): A supercritical COâ‚‚ extract of Dunaliella salina rich in phytoene and phytofluene exhibited antiglycation and anti-inflammatory activities in ex vivo testing. In a placebo-controlled clinical study under intense solar exposure, the extract significantly reduced the skin's glycation scores and its sensitivity to histamine; key skin aging parameters were also significantly improved versus placebo, including wrinkle counts and spots.
Oral Evidence: A clinical study by Heinrich using a daily dose of 50 mg of mixed carotenoids sourced from D. salina algae for 6 weeks found that oral ingestion of high doses of carotenoids provides a preventive measure in skin protection from sun exposure (in addition to, not as a replacement for, topical creams and sensible exposure). Early human data suggest topical Dunaliella extract can improve markers of photoaging; oral evidence for specific outcomes remains limited.
Evidence Assessment: Topical preparations have the strongest human evidence for photoprotection and anti-aging outcomes, supported by at least one placebo-controlled clinical trial. Oral photoprotective evidence is preliminary.
Clinically demonstrated benefits attributed to beta-carotene include systemic skin photoprotection (increasing minimal erythema dose) and immune system enhancement. The broader body of carotenoid research supports the role of Dunaliella-derived carotenoids in augmenting systemic antioxidant defenses, particularly in conditions of oxidative stress.
Animal Evidence: Dunaliella salina and its isolated zeaxanthin were investigated for effects on age-related hepatic steatosis, which was induced in rats by intraperitoneal injection of D-galactose (200 mg/kg/day) for eight consecutive weeks. D. salina biomass (450 mg/kg), its polar fraction (30 mg/kg), carotenoid fraction (30 mg/kg), and isolated zeaxanthin heneicosylate (250 μg/kg) were orally administered to treated rats for two weeks. Oral treatment ameliorated serum hepatic function parameters as well as serum levels of adiponectin, apolipoprotein B-100, and insulin. D. salina also decreased hepatic lipid contents, redox status biomarkers, and inflammatory cytokines, and showed antiapoptotic properties. The study concluded that D. salina carotenoids have a beneficial effect on age-related hepatic steatosis in senescence rats through regulation of redox status, inflammatory indices, and apoptotic biomarkers.
Evidence Assessment: This area of research is entirely preclinical (animal model). No human clinical evidence is available.
D. salina's biochemical makeup and extensive biological advantages have demonstrated favorable impacts on immunity, growth, fertility, gut health, and disease resistance in animal studies. Human immunological data are largely indirect, derived from the well-established immunomodulatory properties of carotenoids as a class. Evidence specific to Dunaliella-derived preparations in humans is limited.
Beta-carotene is recognized by the FDA as a treatment for erythropoietic protoporphyria. This clinical application is attributed to beta-carotene as a pharmacological entity rather than specifically to Dunaliella-derived preparations; the exact source (natural vs. synthetic) used in the trials underlying this recognition is not specified by the available sources.
Many studies have shown that carotene extracted from marine microalgae — including beta-carotene, lutein, alpha-carotene, zeaxanthin, fucoxanthin, lycopene, and neoxanthin — can have an immediate effect on the non-proliferation of cancer cells (in vitro studies). However, results of intervention studies undertaken so far are disappointing and do not indicate a preventive potential for beta-carotene in cancer prevention. No clinical trials specifically using Dunaliella-derived products as cancer treatments in humans have produced confirmatory evidence.
Natural β-carotene is marketed in various forms: β-carotene extracts, Dunaliella powder for human use, and dried Dunaliella for feed coloration. Commercial preparations include suspensions in oil, beadlets, and water-soluble powder for pharmaceutical and nutraceutical applications.
The following dosages are drawn directly from sources; they represent what was used in specific research contexts and are not therapeutic recommendations:
The most consequential safety signal associated with beta-carotene supplementation — and by direct relevance, with Dunaliella-derived supplements — comes from two large-scale randomized controlled trials. In Finland, the Alpha-Tocopherol Beta-Carotene (ATBC) cancer prevention trial evaluated the effects of 20 mg/day of β-carotene and/or 50 mg/day of α-tocopherol in more than 29,000 male smokers. In the United States, the β-Carotene And Retinol Efficacy Trial (CARET) evaluated the effects of a combination of 30 mg/day of β-carotene and 25,000 IU/day of retinol (preformed vitamin A) in 18,314 men and women who were smokers, former smokers, or had a history of occupational asbestos exposure.
The ATBC and CARET studies reported a statistically significant increase in the incidence of lung cancer among subjects who received beta-carotene. A meta-analysis based on data from 109,394 subjects conclusively demonstrated a 24% increase in the risk of lung cancer among smokers who received high-dose beta-carotene supplements.
Supplementation above 20 mg/day significantly increases lung cancer and cardiovascular mortality risk in smokers and asbestos-exposed individuals. These trials used synthetic all-trans beta-carotene; whether mixed-isomer natural Dunaliella preparations carry the same magnitude of risk at equivalent doses has not been definitively established in trials of equivalent scale. Both the ATBC Study and the CARET Study did not show any benefit and indicated potential harm in some individuals.
The increased risk of lung cancer was noted in heavy smokers taking high doses (5 to 10 times the dose of 2–4 mg/d regarded as sufficient for antioxidant protection) of β-carotene for long periods.
The most common adverse effect of excessive beta-carotene intake from any source, including Dunaliella, is carotenodermia — a harmless yellowing or orange discoloration of the skin, particularly the palms and soles, reversible upon dose reduction.
Current or former smokers and asbestos-exposed individuals should avoid beta-carotene supplements. Over a 10-year follow-up, researchers found that beta-carotene supplementation was linked with a higher risk of lung cancer in participants with a prior history of smoking.
Medications including cholestyramine (Questran), colestipol (Colestid), and orlistat (Xenical, Alli) interact with beta-carotene by reducing its absorption. Fat-soluble absorption of carotenoids from Dunaliella preparations, like all dietary carotenoids, depends on co-consumption with dietary fat; very low-fat meals reduce bioavailability.
Unlike synthetic beta-carotene, Dunaliella's carotenoids naturally occur as a mix of isomers that may be better tolerated. This distinction — the presence of both 9-cis and all-trans forms rather than exclusively all-trans — is frequently cited in the scientific literature as potentially relevant to both efficacy and safety profiles, but direct comparative evidence in controlled human trials is not yet available at large scale.
There is no established tolerable upper intake level (UL) for beta-carotene itself. The absence of a formal UL does not indicate unlimited safety; it reflects the difficulty of establishing one given the complex population-specific risk profile.
Genetic studies have revealed that up to 45% of the population carries BCO1 gene variants affecting the efficiency with which beta-carotene is converted to vitamin A. This variability means that individual responses to supplementation with Dunaliella-derived beta-carotene — both in terms of vitamin A yield and plasma carotenoid levels — can differ substantially across individuals.
Health conditions that Dunaliella may help support.
Body systems that Dunaliella may help support.
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