IngredientsLessonia is a genus of large brown seaweeds (macroalgae) belonging to the order Laminariales (kelps). It is the type genus for the family Lessoniaceae. Restricted to the temperate southern hemisphere, species of Lessonia form dense forests from the low intertidal to 25 m depth at wave-exposed sites. There are currently records of 11 species of the genus Lessonia that are taxonomically accepted, distributed along the coasts of South America, New Zealand, Tasmania, and Sub-Antarctic islands.
Full taxonomic classification places Lessonia within the Phylum Ochrophyta, Class Phaeophyceae (brown algae), and Order Laminariales. The type species (holotype) of the genus Lessonia is Lessonia flavicans Bory.
The genus encompasses several ecologically and commercially prominent species:
An important taxonomic note: the Lessonia nigrescens complex has been under taxonomic review; populations from northern and central-austral Chile were identified as different cryptic species and reclassified as L. berteroana and L. spicata, respectively. Representative specimens of Lessonia nigrescens were not found during new visits to its type locality in Cape Horn and along Chile, and future studies should verify the status of this species. In dietary supplement labeling and commerce, the name L. nigrescens continues to appear widely, though it may now refer taxonomically to either L. berteroana or L. spicata.
Species of Lessonia are very difficult to identify based on morphological characteristics, as the kelp are very plastic. The blades may be flat and elongated, broad, or narrow, with a smooth, rugose, or wavy surface and can have smooth or jagged edges. A major factor in the morphology is wave exposure, as Lessonia is found across a variety of habitats. Lessonia trabeculata can grow to a length of 2.5 m; it is distinguished from all other members of the genus by the presence of trabeculae (cross struts) in the hollow centres of the blades and stipes, and by the massive, irregular holdfast by which it is attached to rocks.
Lessonia trabeculata occurs in the southeastern Pacific Ocean, in the subtidal zone off the coasts of Peru and northern and central Chile; its range extends from Antofagasta to Puerto Montt and its depth range is between 0.5 and 20 m. Lessonia trabeculata is the most abundant kelp species along the south-east coast of South America, between 18° and 42°S, and constitutes one of the most important components of shallow subtidal ecosystems.
Lessonia spp. are among the most harvested kelps globally due to their importance in providing raw materials for food, cosmetics, bioactive, and biomedical industries. In commerce, Lessonia appears in the following forms:
Chile is the world's largest producer of wild-harvested algae, with Lessonia from Chile making up 29% of global exports. Chile produces over 300,000 dry tons of seaweed per year, with more than 11,000 people employed in the industry, and almost all of it is Lessonia.
Lessonia was used as fuel in the Atacama Desert c. 3050 BC, demonstrating a human relationship with this kelp that extends at least five millennia. Archaeological, ethnohistoric, and ethnographic evidence from the broader Andean coastal region documents a long history of kelp use by indigenous peoples.
Compiled information from archaeological, ethnohistoric, and ethnographic sources indicates that six areas along the South American Pacific coast, each with different geomorphological, ecological, and cultural backgrounds, show a coexistence of traditional and modern exploitation modes driven by local and transnational demand, as well as a persistence throughout the region of large-scale distribution systems of seaweed reaching the western slope of the Andes. At least two clearly differentiated modes of seaweed exploitation exist: one on coastal northern Peru and another on coastal south-central Chile, with different gathering practices, uses, economic drivers, and indigenous knowledge systems.
Until 2002, the Chilean brown seaweed fishery was mainly sustained by natural mortality, where plants cast ashore were collected by artisanal fishermen. The use of drifted, beached kelp as a nutritional and medicinal resource thus predates the modern industrial fishery by centuries.
Coastal communities of Chile and Peru traditionally incorporated Lessonia into their diets and local healing practices. It held an esteemed place in indigenous and local communities for its medicinal and nutritional value; for centuries, coastal populations have harvested Lessonia species for their rich mineral content, especially iodine, potassium, magnesium, and a spectrum of vitamins, which contributed to its historical use as a remedy for thyroid-related issues such as goiter, and as a general fortifier during periods of nutritional deficiency.
In folk medicine, mucilaginous extracts of Lessonia nigrescens were employed as soothing agents for digestive ailments, including gastritis and ulcers, due to their demulcent properties. Folk healers also utilized its bioactive compounds to promote wound healing, reduce inflammation, and support recovery from skin conditions, leveraging the seaweed's natural antibacterial and antioxidant activities. Its high fiber content made it a valuable adjunct in promoting digestive health and gentle detoxification.
Lessonia species are brown macroalgae and share the broad phytochemical profile characteristic of the class Phaeophyceae. Research has increasingly focused on brown algae due to their rich content of bioactive compounds exhibiting antimicrobial, anticancer, antioxidant, anti-inflammatory, antidiabetic, and antiparasitic properties. Key constituents, including phlorotannins, fucoxanthin, alginic acid, fucoidan, and laminarin, have been widely studied for their chemical composition and functional bioactivities.
Brown seaweeds contain a broad spectrum of bioactive components, including polysaccharides (alginate, fucoidan), proteins and bioactive peptides, polyphenols (notably phlorotannins), carotenoids (including fucoxanthin), phytosterols (such as fucosterol), and n-3 long-chain polyunsaturated fatty acids (like eicosapentaenoic acid). These bioactive molecules underpin their increasing relevance in pharmaceutical, nutraceutical, and cosmeceutical applications.
The crude protein (13.5 ± 1.0%), total lipids (0.9 ± 0.2%), crude fiber (16.3 ± 1.6%), ash (30.1 ± 1.5%), and nitrogen-free extract (39.2 ± 2.0%) contents of L. berteroana were within reference values for Laminariales species. In terms of mineral content, seaweeds boast elevated levels of calcium, zinc, potassium, copper, and iron, surpassing even meat and spinach in iron and copper content. Iodine is also prominent; this essential micronutrient is required for the synthesis of thyroid hormones and the prevention of iodine deficiency-related conditions.
Animal and in vitro evidence (no human clinical trials identified):
The antidiabetic activity of Lessonia nigrescens ethanolic extract (LNE) was investigated in streptozotocin-induced type 2 diabetic mice fed with a high-sucrose/high-fat diet. UHPLC coupled with photo-DAD and ESI-MS was employed to analyze major compounds in LNE. Intestinal microflora components were analyzed by high-throughput 16S rRNA gene sequencing. Fasting blood glucose levels in diabetic mice were significantly decreased after LNE administration, and histology revealed that LNE could protect the cellular architecture of liver and kidney. LNE treatment significantly increased Bacteroidetes and decreased Firmicutes populations in intestinal microflora; specifically, it selectively enriched the amounts of beneficial bacteria, Barnesiella, while reducing abundances of Clostridium and Alistipes.
In a separate rodent study specifically examining L. trabeculata fucoidan: the objective was to evaluate a nutritional strategy based on the consumption of fucoidan extract from Lessonia trabeculata to control oxidative stress in experimental alloxan-induced insulin-dependent diabetes mellitus rats. Over 30 days, 75, 100, and 125 mg/kg of body weight of fucoidan doses were administered, with positive and negative controls (n = 5 per group). Measures included lipid peroxidation, superoxide dismutase and catalase activity, and antioxidant activity; results showed an increase in the activity of antioxidant enzymes while reducing oxidative damage (lipid peroxidation index) in serum (p ≤ 0.05) and tissues (p ≤ 0.05). A significant protective effect against oxidative stress caused by alloxan-induced diabetes was found in this model, suggesting that fucoidan extracted from Lessonia trabeculata could be considered a good functional compound for the control of oxidative stress in diabetic patients.
Evidence strength: Preclinical only (animal models). No controlled human clinical trials have been published on Lessonia-derived extracts for blood glucose management. Results are preliminary and cannot be extrapolated to clinical recommendations.
Several laboratory studies have demonstrated that extracts from Lessonia nigrescens exhibit significant antioxidant and free radical scavenging activities, attributed largely to its polyphenol and fucoidan content. Crude polysaccharide extracts from brown algae have been reported to exhibit stronger antioxidant activity and higher sulfate and polyphenol content than those from green or red seaweeds.
Evidence strength: In vitro and some animal-model studies only. No human interventional trials specifically using Lessonia spp. as the primary antioxidant intervention have been identified in the peer-reviewed literature.
The most investigated anticancer avenue for Lessonia concerns fucoidan derived from L. trabeculata, studied in cell-line and spheroid models of breast cancer.
Experiments conducted on triple-negative breast cancer (TNBC) have shown that fucoidan from Lessonia trabeculata (FLt) exhibits cytotoxic and antitumor properties; however, further research is necessary to gain a complete understanding of its bioactivity and level of cytotoxicity. This in vitro study demonstrated that FLt has high cytotoxicity and selectivity and induces apoptosis through activation of caspase 3/7 and transcriptional expression of proapoptotic genes (caspase 8 and caspase 9) in TNBC 4T1 cells. Fucoidan inhibited the expression of antiapoptotic transcripts (Bcl-2 and XIAP). Transcriptional expression of AIF could induce apoptosis by the intrinsic caspase-independent pathway.
Fucoidan, a polysaccharide extracted from brown seaweed, stands out among marine-derived compounds with scientific evidence supporting anticancer and immunomodulatory properties. Its composition varies and includes fucose, sulphate, uronic acid, galactose, xylose, mannose, rhamnose, glucose, and arabinose. It has been shown to be non-toxic and is currently marketed as a functional supplement in several countries.
Fucoidan from Lessonia trabeculata (FuLt) has demonstrated cytotoxic activity against TNBC 4T1 cells in both monolayer and three-dimensional cultures, whilst reducing cytotoxicity against VERO cells. Furthermore, FuLt has been shown to be non-toxic to both RAW264.7 cells and human peripheral blood mononuclear cells.
Previous research has also determined the immunomodulatory effect of FLt on human peripheral blood mononuclear cells, as well as its cytotoxic and apoptotic activity on human squamous cell carcinoma type 2 (Hep-2), cervical adenocarcinoma (HeLa), and human promonocytic leukemia (U937) cell lines.
The therapeutic benefits of brown algae fucoidan in the treatment of breast cancer have attracted considerable interest in recent years; however, research using spheroids — which provide relevant results in trials for antitumor and immunomodulatory products because they adequately simulate the tumor microenvironment — is limited.
Evidence strength: Preclinical only — in vitro cell-line and tumor spheroid studies. Experiments on triple-negative breast cancer have shown that fucoidan from Lessonia trabeculata exhibits cytotoxic and antitumor properties; however, further research is necessary to gain a complete understanding of its bioactivity and level of cytotoxicity. No human clinical trials exist for Lessonia or its isolated compounds in oncology.
The same animal study referenced under antidiabetic activity also examined microbiome composition. LNE treatment significantly increased Bacteroidetes and decreased Firmicutes populations in intestinal microflora; it could selectively enrich beneficial bacteria, Barnesiella, while reducing the abundances of Clostridium and Alistipes. These findings are from diabetic mouse models and require human validation.
UV treatment induces the production of phlorotannins in L. nigrescens, and the seaweed contains the phytosterol saringosterol, which shows an inhibitory effect on Mycobacterium tuberculosis growth. This finding derives from chemical characterization studies and is preliminary. No clinical antimicrobial trials have been conducted.
In terms of mineral content, seaweeds boast elevated levels of calcium, zinc, potassium, copper, and iron. Iodine is prominent in seaweed; this essential micronutrient is required for the synthesis of thyroid hormones and the prevention of iodine deficiency-related conditions. The historical use of Lessonia as a goiter remedy relates to its iodine content. No specific human interventional trials with Lessonia for thyroid function have been identified; however, the iodine content of kelp is well-established across the broader literature.
Alginate has been reported as being able to form edible films; due to its excellent stabilizing and thickening properties, it is commonly used in food products and medicine. Seaweeds contain soluble fiber such as carrageenan and alginic acid, compounds associated with beneficial effects on digestive health. In the food industry, alginate extracted from Lessonia is used as a viscosity modifier, gelling agent, and stabilizer. Clinical evidence for digestive health outcomes specific to Lessonia-sourced alginate in humans is limited and mostly indirect, drawn from research on alginates as a class.
Dosages reported in the peer-reviewed scientific literature are exclusively from preclinical (animal) studies. No human clinical trials defining dosage for Lessonia or its isolated compounds have been identified.
In commercial supplement products, whole-thallus Lessonia powders are typically included in capsule or tablet formulations as part of proprietary blends, with no standardized therapeutic dose established by any regulatory body.
Kelp supplements can cause decreased thyroid function (hypothyroidism) in some people due to the high iodine content. High doses of iodine can cause thyroid dysfunction and have other negative effects; the FDA states that a kelp supplement should not provide more than 225 mcg of iodine per daily serving.
A published case report documented thyroid dysfunction following ingestion of a kelp-containing marketed diet: a case of thyroid dysfunction was reported following the ingestion of a kelp-containing marketed diet in a 45-year-old woman with no previous thyroid disease; signs of hyperthyroidism occurred shortly after starting the kelp-containing diet, lasted 2 months, and were followed by overt hypothyroidism. This clinical history is compatible with a case of iodine-induced thyrotoxicosis followed by prolonged block of the sodium–iodide symporter activity as a consequence of excessive iodine consumption from kelp.
Some types of seaweed have a high concentration of arsenic and other heavy metals like lead, mercury, and aluminum. Iodine and mercury can have a synergistic effect, affecting thyroid function and reducing the thyroid hormone T3. Heavy metal concentrations in seaweeds are generally below levels that are toxic for humans; however, the bioaccumulation of arsenic is a concern with continuous seaweed consumption.
In Lessonia trabeculata specifically, a study measuring concentrations of essential and non-essential metals — including Fe, Cr, Cu, Zn, Mn, Pb, Cd, Ni, and Al — was conducted in different thallus parts (blade, stipe, holdfast) of Lessonia trabeculata. Seaweeds are well known to concentrate metals from seawater and have been employed as monitors of metal pollution in coastal waters and estuaries; research has shown that various intrinsic and extrinsic factors can influence metal accumulation, raising doubts about the basis for using seaweeds in biomonitoring programs. Cadmium and arsenic consistently reach levels of regulatory concern in kelp, and dried seaweeds could harbor higher concentrations compared to raw products.
Fucoidan has anticoagulant, anti-inflammatory, antiviral, antioxidant, antitumor, and immunomodulatory effects. The anticoagulant activity of fucoidan is documented across in vitro studies; theoretically, products rich in fucoidan could interact with anticoagulant medications (e.g., warfarin), though clinical evidence specific to Lessonia-sourced fucoidan in humans is lacking.
Eating 5 g a day or more of dried seaweed can create a situation where sodium intake becomes excessively high. Given that sodium alginate is the predominant commercial form of alginate, and Lessonia is a major alginate source, sodium content is a consideration for individuals on sodium-restricted diets.
Testing of six popular kelp supplements revealed that half contained approximately twice the amount of iodine listed on their labels, and one of these products was also contaminated with arsenic, a toxic heavy metal. While this testing was not specific to Lessonia products, the finding is relevant to all kelp-derived supplements due to variability in wild-harvest conditions and processing.
The geographical origin of harvested Lessonia matters for contaminant load. Near industrially polluted areas in Chile, high heavy metal concentrations in seawater and marine sediments have been recorded, exceeding international permissible limits; unexpectedly high concentrations of copper and arsenic were also registered at sites often considered unpolluted. Consumers of Lessonia-based supplements should be aware that heavy metal content may vary significantly by harvest location and season.
Lessonia species and their derived ingredients (including alginate) are used commercially in food and supplement markets. Sodium alginate derived from brown seaweeds including Lessonia has Generally Recognized as Safe (GRAS) status for specific food uses in the United States. Purified fucoidan and phlorotannin fractions from Lessonia do not have established regulatory status as drug substances in major jurisdictions and are marketed as dietary supplements or novel food ingredients, subject to jurisdiction-specific frameworks. No EMA, ESCOP, or WHO monograph specific to the genus Lessonia has been identified.
The body of scientific literature on Lessonia as a dietary supplement ingredient is largely preclinical. In vitro and animal-model studies provide proof-of-concept data for antidiabetic, antioxidant, antitumor, antimicrobial, and gut microbiome-modulating activities, attributable primarily to its fucoidan, phlorotannin, and alginate fractions. Lessonia nigrescens continues to be included in nutritional products due to its rich nutrient profile and potential functional benefits; its contributions to dietary diversity, particularly as a source of dietary fiber and essential minerals, are well recognized. Human clinical trials specific to Lessonia spp. extracts as therapeutic or nutraceutical interventions have not been published in the peer-reviewed literature as of the current date. Claims made for Lessonia-based supplements beyond its established nutritional contributions (iodine, dietary fiber, minerals) are not supported by clinical evidence.
Health conditions that Lessonia may help support.
Body systems that Lessonia may help support.
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