Dunaliella Salina

• Antioxidant protection
• Immune support
• Cellular defense
• Anti-inflammatory

• Eye health
• Skin protection
• Cardiovascular support
• Cognitive function
• Respiratory health

Dunaliella salina exerts its biological effects primarily through its exceptionally high content of natural beta-carotene, which can constitute up to 14% of the microalgae’s dry weight under optimal growth conditions. This halophilic (salt-loving) microalgae produces beta-carotene as a protective mechanism against intense light and oxidative stress in its natural high-salinity environments. Unlike synthetic beta-carotene, D. salina provides a complex mixture of carotenoid isomers, with approximately 40-60% occurring in the 9-cis configuration, which has distinct biological activities compared to the all-trans form predominant in synthetic sources.

The antioxidant properties of D. salina are central to its health benefits. Beta-carotene functions as a powerful scavenger of reactive oxygen species (ROS) and singlet oxygen, neutralizing these harmful molecules before they can damage cellular components like lipids, proteins, and DNA. This antioxidant activity is complemented by other carotenoids present in D.

salina, including alpha-carotene, lutein, zeaxanthin, and cryptoxanthin, which provide protection across different cellular compartments and against various types of oxidative stress. Beyond direct antioxidant activity, D. salina’s carotenoids modulate cellular signaling pathways involved in oxidative stress response. They activate nuclear factor erythroid 2-related factor 2 (Nrf2), a master regulator of antioxidant defense, which increases the expression of endogenous antioxidant enzymes like superoxide dismutase (SOD), catalase, and glutathione peroxidase.

This indirect enhancement of the body’s antioxidant network provides more comprehensive and sustained protection than direct ROS scavenging alone. The immune-modulating effects of D. salina involve multiple mechanisms. Beta-carotene and other carotenoids influence immune cell function, enhancing natural killer (NK) cell activity, macrophage phagocytosis, and T-cell proliferation.

These compounds also modulate cytokine production, generally promoting anti-inflammatory profiles while suppressing excessive pro-inflammatory responses. Additionally, D. salina contains unique polysaccharides and glycoproteins that may stimulate immune function through interaction with pattern recognition receptors on immune cells. The anti-inflammatory properties of D.

salina stem from its ability to inhibit nuclear factor-kappa B (NF-κB) signaling, a key pathway in inflammatory responses. This inhibition reduces the production of pro-inflammatory cytokines like tumor necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β), and interleukin-6 (IL-6). The 9-cis beta-carotene isomers found abundantly in D. salina appear particularly effective at modulating inflammatory pathways compared to all-trans isomers.

For eye health, the beta-carotene in D. salina serves as a precursor to vitamin A (retinol), which is essential for proper retinal function and visual adaptation to darkness. Other carotenoids present in smaller amounts, particularly zeaxanthin and lutein, accumulate in the macula of the eye where they filter harmful blue light and protect retinal cells from photo-oxidative damage. The skin-protective effects of D.

salina involve both systemic antioxidant activity and the accumulation of carotenoids in the skin, where they provide a first line of defense against UV-induced oxidative damage. Beta-carotene has been shown to reduce UV-induced erythema (redness) and may help maintain skin elasticity and hydration through protection of structural proteins like collagen and elastin. Beyond carotenoids, D. salina contains significant amounts of essential fatty acids, including omega-3 and omega-6 polyunsaturated fatty acids, which support cell membrane integrity and function.

These fatty acids serve as precursors to eicosanoids, which regulate inflammatory processes, immune function, and vascular responses. The microalgae also provides a range of vitamins (including vitamin E, several B vitamins, and vitamin C) and minerals (including iron, magnesium, and zinc) that support numerous enzymatic reactions and physiological functions throughout the body.

The optimal dosage of Dunaliella salina varies based on the concentration of beta-carotene in the specific product and the intended health benefit. Typical supplementation ranges from 50-300 mg of D. salina extract daily, providing approximately 5-30 mg of natural mixed carotenoids. For whole algae powder, typical doses range from 250-1000 mg daily.

Most clinical studies have used doses providing 8-25 mg of natural beta-carotene daily, which is generally considered the effective range for most health benefits.

The bioavailability of carotenoids from Dunaliella salina varies significantly based on formulation and individual factors. Natural beta-carotene from D. salina typically has better bioavailability than synthetic beta-carotene, with absorption rates ranging from 10-30% depending on formulation. The 9-cis isomers abundant in D.

salina (40-60% of total beta-carotene) appear to have different absorption kinetics than all-trans isomers, with some studies suggesting preferential absorption of certain isomers. Oil-based extracts generally show 2-5 times higher bioavailability compared to powder forms due to the lipophilic nature of carotenoids. Individual factors including age, nutritional status, gut health, and genetic variations in carotenoid metabolism enzymes can cause significant variations in absorption efficiency between individuals.

Consuming with dietary fats (at least 3-5g) to stimulate bile release and micelle formation, essential for carotenoid absorption, Oil-based formulations significantly improve absorption compared to powder forms, Emulsified preparations that create pre-formed micelles enhance absorption by bypassing the need for digestive emulsification, Liposomal delivery systems that protect carotenoids from degradation in the digestive tract and enhance cellular uptake, Micronization to reduce particle size and increase surface area for improved dissolution and absorption, Consuming with avocado, nuts, or olive oil particularly effective for enhancing carotenoid absorption, Moderate heat treatment (cooking) of whole algae powder can break cell walls and increase carotenoid bioavailability, Avoiding simultaneous consumption with high-fiber foods, which can bind carotenoids and reduce absorption, Formulations with phospholipids to enhance micelle formation and cellular uptake, Consuming with vitamin E, which may protect carotenoids from oxidation during digestion

For optimal absorption, Dunaliella salina supplements should be taken with a meal containing some fat (at least 3-5g). The largest meal of the day typically provides the best absorption environment due to longer digestive time and higher fat content. Morning or midday administration is generally preferred over evening, as some individuals report mild stimulatory effects from beta-carotene supplements that could potentially affect sleep if taken late in the day. Consistent timing of supplementation helps maintain stable blood levels of carotenoids, which is important as these compounds accumulate in tissues over time.

For skin photoprotection benefits, consistent daily supplementation for at least 8-10 weeks before sun exposure is recommended to allow sufficient accumulation in the skin. Dividing larger doses between two meals may improve overall absorption compared to a single large dose, as carotenoid absorption can become saturated at higher concentrations. If taking multiple fat-soluble supplements (vitamin D, vitamin E, omega-3s, etc.), taking them together with D. salina can enhance absorption of all components through shared digestive mechanisms.

For individuals with compromised digestion or fat malabsorption conditions, specialized emulsified or liposomal formulations taken with meals may provide better absorption.

• Carotenodermia (harmless, reversible yellowing/orange discoloration of the skin) with high doses over extended periods
• Mild digestive discomfort (nausea, bloating) in some individuals, particularly with higher doses
• Potential for loose stools with very high doses
• Mild allergic reactions in rare cases (more common in individuals with seafood or algae allergies)
• Temporary increase in liver enzymes in some individuals (generally not clinically significant)
• Potential for burping with fishy taste in some formulations
• Mild headache reported by some users (rare)

• Current or former smokers should avoid high-dose beta-carotene supplements (>20 mg/day) due to potential increased risk of lung cancer based on studies with synthetic beta-carotene
• Individuals with known allergy or hypersensitivity to algae products
• Caution advised for individuals with severe liver disease due to carotenoid metabolism occurring primarily in the liver
• Individuals with hypervitaminosis A or at risk for vitamin A toxicity (rare genetic conditions)
• Caution advised during pregnancy and breastfeeding due to limited safety data
• Individuals with malabsorption syndromes may experience unpredictable absorption
• Those with pending surgery (discontinue 2 weeks before due to theoretical concerns about antioxidant effects on wound healing)

• Cholesterol-lowering medications (statins): Potential enhanced absorption of carotenoids, generally beneficial but monitor for side effects
• Orlistat and other fat-blocking medications: May reduce absorption of carotenoids
• Mineral oil laxatives: May reduce carotenoid absorption if taken simultaneously
• Anticoagulants/blood thinners: Theoretical concern due to vitamin K content in whole algae (minimal in extracts)
• Alcohol: May enhance beta-carotene metabolism, potentially reducing effectiveness
• Retinoid medications (isotretinoin, acitretin): Avoid combining with high-dose beta-carotene due to potential additive effects
• Certain chemotherapy drugs: Consult oncologist before use due to theoretical antioxidant interference
• Hormone replacement therapy: May affect carotenoid metabolism (clinical significance unclear)

No official toxic upper limit has been established specifically for Dunaliella salina. For beta-carotene from all sources, the European Food Safety Authority (EFSA) has suggested that supplemental intake of up to 15 mg/day (in addition to dietary intake) is not associated with adverse effects in the general population, except for current and former smokers. The Institute of Medicine has not set a Tolerable Upper Intake Level (UL) for beta-carotene due to lack of evidence for adverse effects from food sources, but cautions against high-dose supplementation for smokers. Practical upper limits based on clinical experience suggest that doses providing up to 30 mg of natural beta-carotene daily (approximately 300 mg of D.

salina extract) are well-tolerated by most non-smoking individuals. The most common limiting factor is carotenodermia (skin yellowing), which is harmless and reversible but may be cosmetically undesirable. This typically occurs at doses above 20-30 mg of beta-carotene daily for extended periods.

Dunaliella salina is generally recognized as safe (GRAS) in the United States when used as a food ingredient or dietary supplement. The FDA granted GRAS status to D. salina as a source of beta-carotene in 1995 (GRN No. 351).

It is regulated as a dietary supplement under the Dietary Supplement Health and Education Act (DSHEA) of 1994. Manufacturers are not permitted to make specific disease treatment claims but can make structure/function claims (e.g., ‘supports immune health’ or ‘provides antioxidant protection’) with appropriate disclaimers. D. salina is also approved as a natural color additive (21 CFR 73.95) for use in foods, drugs, and cosmetics, listed as ‘beta-carotene’ derived from D.

salina.

Eu: In the European Union, Dunaliella salina is approved as a food additive (E160a(iv)) for use as a color in various food categories. As a food supplement ingredient, it falls under the general food law and novel food regulations. The European Food Safety Authority (EFSA) has evaluated the safety of D. salina and found no safety concerns at typical consumption levels. Health claims are strictly regulated under Regulation (EC) No 1924/2006, and while no specific authorized health claims exist for D. salina itself, generic claims related to beta-carotene and vitamin A may apply to products with sufficient beta-carotene content.

Canada: Health Canada has approved Dunaliella salina as a Natural Health Product (NHP) ingredient. It is listed in the Natural Health Products Ingredients Database with approved uses as a source of antioxidants and provitamin A. Products containing D. salina must have a Natural Product Number (NPN) to be legally sold in Canada. D. salina is also permitted as a food coloring agent.

Australia: The Therapeutic Goods Administration (TGA) regulates D. salina products as listed complementary medicines. D. salina is included in the Permissible Ingredients Determination and can be used in listed medicines. Australia has a particular interest in D. salina regulation as it is a major producer of this microalgae. Food Standards Australia New Zealand (FSANZ) permits D. salina as a natural food coloring.

Japan: Japan’s Ministry of Health, Labour and Welfare recognizes D. salina as a food ingredient and natural colorant. It may be used in Foods with Health Claims when meeting specific regulatory requirements.

China: The National Medical Products Administration (NMPA) of China permits D. salina in health food products and as a natural food colorant. China has become a significant producer of D. salina in recent years.

Israel: The Israeli Ministry of Health permits D. salina in dietary supplements and as a food colorant. Israel is one of the pioneering countries in D. salina cultivation and research.

Brazil: Brazil’s National Health Surveillance Agency (ANVISA) permits D. salina in food supplements and as a natural food colorant under specific regulations for microalgae products.

Medium to high compared to synthetic beta-carotene supplements, but moderate compared to other specialized microalgae products

Typical retail pricing for Dunaliella salina supplements ranges from $0.50 to $2.00 per effective daily dose (providing 10-15 mg of natural beta-carotene). Oil-based extracts and specialized delivery systems (liposomal, emulsified) tend to be at the higher end of this range, while powder forms and basic softgels are generally more affordable. Whole algae powder typically costs $0.40 to $1.00 per gram, with effective doses ranging from 250-1000 mg daily. Products standardized for higher 9-cis beta-carotene content command premium prices, often 30-50% higher than basic D.

salina supplements.

Dunaliella salina represents moderate to good value as a carotenoid supplement, particularly when compared to synthetic beta-carotene. While significantly more expensive than synthetic beta-carotene (which can cost as little as $0.10-0.20 per dose), the unique isomer profile and additional nutrients in D. salina may justify the premium for many consumers. The price premium is justified for individuals who: 1) Prefer natural sources of nutrients over synthetic alternatives; 2) Are specifically seeking the 9-cis beta-carotene isomers abundant in D.

salina, which have distinct biological activities; 3) Value the additional minor carotenoids, essential fatty acids, vitamins, and minerals present in whole algae products; 4) Have concerns about the safety profile of synthetic beta-carotene, particularly based on studies showing potential risks for smokers. For maximum cost efficiency, consumers should compare products based on standardized beta-carotene content rather than total weight, as potency can vary significantly between products. Oil-based extracts typically offer better bioavailability than powder forms, potentially providing better value despite higher upfront costs. When evaluating D.

salina against other natural carotenoid sources, it offers competitive pricing compared to astaxanthin from Haematococcus pluvialis but is generally more expensive than lutein from marigold flowers or lycopene from tomatoes. For those primarily seeking general antioxidant benefits rather than the specific properties of beta-carotene, more affordable alternatives like vitamin C, vitamin E, or plant-based antioxidant complexes may offer better value. However, for targeted benefits related to beta-carotene’s unique properties, particularly skin photoprotection and certain aspects of immune function, D. salina remains a cost-effective natural option.

Consumers should also consider the environmental sustainability of production methods, as some D. salina cultivation systems have significantly lower environmental impacts than others, potentially offering better long-term value despite similar pricing.

Properly stored Dunaliella salina products typically have a shelf life of 18-24 months from date of manufacture for oil extracts and 12-18 months for powder forms. However, carotenoid content begins to degrade earlier, especially if exposed to adverse conditions. For maximum potency, use within 6-12 months of opening the container. The 9-cis beta-carotene isomers, which are particularly valuable in D.

salina, tend to be more susceptible to degradation than all-trans isomers, making proper storage especially important for maintaining the unique isomer profile of natural D. salina products.

Store in a cool, dry place away from direct sunlight, preferably below 70°F (21°C). Refrigeration is recommended for oil-based extracts after opening and can extend shelf life for all formulations. Freezing is generally not recommended for liquid formulations as it can disrupt emulsions and lead to precipitation of active compounds. Once opened, ensure the container is tightly sealed after each use to prevent oxygen exposure.

For powders, use a dry spoon to remove product to avoid introducing moisture. The carotenoids in D. salina are highly susceptible to oxidation, so minimizing air exposure is critical for maintaining potency. Some manufacturers include oxygen absorber packets in their products to extend shelf life; these should be kept in the container but not consumed.

If purchasing in bulk quantities, consider transferring a portion to a smaller container for regular use while keeping the remainder sealed until needed. For softgel and oil formulations, storing the container upright helps prevent leakage and maintains capsule integrity.

Light: Direct sunlight and even bright indoor lighting can rapidly degrade carotenoids through photo-oxidation, Oxygen: Exposure to air causes oxidation of carotenoids, particularly the 9-cis isomers abundant in D. salina, Heat: Temperatures above 85°F (30°C) accelerate carotenoid degradation; prolonged exposure even to moderate heat (75-85°F) can significantly reduce potency, Moisture: Promotes microbial growth and accelerates chemical degradation reactions, particularly in powder forms, Transition metals: Iron and copper ions can catalyze oxidation reactions, accelerating carotenoid degradation, pH extremes: Significant changes in pH can affect the stability of carotenoids and other compounds, Enzymes: Some formulations may contain residual enzymes that can degrade carotenoids over time if not properly deactivated during processing, Oxidizing agents: Contact with peroxides, ozone, or other strong oxidizers rapidly degrades carotenoids, Freeze-thaw cycles: Can disrupt emulsions and microencapsulation structures, exposing carotenoids to oxidation, Radiation: Exposure to ionizing radiation (X-rays, gamma rays) can degrade carotenoids and should be avoided

Synthesis Methods

Natural Sources

Quality Considerations

Dunaliella salina has a relatively recent history of human use compared to many traditional medicinal plants and herbs. This halophilic (salt-loving) microalgae was first scientifically described in 1838 by Michel Felix Dunal, who observed its distinctive red coloration in salt evaporation ponds in southern France. However, its commercial cultivation and use as a nutritional supplement began only in the latter half of the 20th century. Indigenous populations living near salt lakes and high-salinity coastal areas where D.

salina naturally grows, such as certain Aboriginal communities in Australia near pink salt lakes, may have had traditional knowledge of its presence, though documented medicinal or nutritional use is limited. The modern interest in D. salina began in the 1960s and 1970s when researchers identified it as the source of the distinctive red coloration in certain salt lakes and recognized its exceptional ability to produce and accumulate beta-carotene. The first commercial cultivation of D.

salina specifically for beta-carotene production began in the 1980s in Australia, with operations established at Hutt Lagoon and Dunaliella Lake – both natural habitats where the microalgae thrived in high-salinity conditions. The development of D. salina as a commercial source of natural beta-carotene was driven by growing consumer demand for natural alternatives to synthetic beta-carotene, which had dominated the market since its development in the 1950s. Research in the 1980s and 1990s revealed that D.

salina’s beta-carotene had a different isomer profile than synthetic versions, with a significant proportion of 9-cis beta-carotene rather than the all-trans form predominant in synthetic sources. This discovery heightened interest in D. salina as potentially offering unique health benefits beyond those of synthetic beta-carotene. The Chernobyl nuclear disaster in 1986 indirectly contributed to increased interest in D.

salina, as researchers investigated natural beta-carotene’s potential protective effects against radiation-induced oxidative damage. A notable clinical study conducted in the 1990s examined the effects of D. salina supplementation in children exposed to radiation from the Chernobyl accident, finding beneficial effects on oxidative stress markers. The market for D.

salina expanded significantly in the 1990s and 2000s as research into carotenoids and their health benefits intensified. The publication of studies suggesting potential risks of synthetic beta-carotene supplementation for certain populations (particularly smokers) further increased interest in natural sources like D. salina, which were hypothesized to have a different risk profile due to their complex mixture of carotenoid isomers and accompanying nutrients. In recent decades, cultivation technology has advanced significantly, with both open pond systems and closed photobioreactors being optimized for D.

salina production. These technological developments have increased yield, consistency, and purity while reducing production costs, making D. salina supplements more widely available. Today, D.

salina is recognized as one of the richest natural sources of beta-carotene and is cultivated commercially in multiple countries including Australia, Israel, China, and the United States. It is used not only as a nutritional supplement but also as a natural food colorant, an ingredient in cosmetics, and as a research tool for studying carotenoid biosynthesis and algal adaptation to extreme environments.

No comprehensive meta-analyses specifically focused on Dunaliella salina have been published to date., D. salina has been included in broader meta-analyses of carotenoids and antioxidants: Kopcke W, Krutmann J. Protection from sunburn with beta-carotene–a meta-analysis. Photochemistry and Photobiology. 2008;84(2):284-288., Systematic reviews of microalgae in human nutrition have included D. salina: Wells ML, et al. Algae as nutritional and functional food sources: revisiting our understanding. Journal of Applied Phycology. 2017;29(2):949-982.

Natural Carotenoids from Dunaliella salina for Skin Photoprotection (CAROSKIN-2023), Effects of Dunaliella salina Supplementation on Oxidative Stress Markers in Athletes (ALGASPORT-2022), Comparative Bioavailability of Different Microalgae Carotenoid Sources (ALGABIO-2023), Dunaliella salina Extract for Age-Related Macular Degeneration: A Pilot Study (MACULA-PROTECT-2022)