Sargassum fusiforme (Sargassum fusiforme): Benefits, Dosage, Safety & Evidence

Frequently asked questions

How does Sargassum fusiforme support thyroid function?

Sargassum fusiforme supports thyroid function primarily through its high iodine content, which is an essential nutrient for the synthesis of thyroid hormones triiodothyronine (T3) and thyroxine (T4). Additionally, it contains fucoidan and alginic acid, compounds studied for potential immune-modulating effects. However, evidence supporting its specific efficacy for thyroid disorders is limited (Evidence Level: C). Due to potential arsenic content, it should not be used as a primary treatment for thyroid conditions without medical supervision.

Does Sargassum fusiforme interact with thyroid medications?

Yes, Sargassum fusiforme interacts with thyroid medications due to its high iodine content. Concurrent use with levothyroxine or other thyroid hormone replacements may alter hormone levels, potentially causing hyperthyroid symptoms or interfering with medication efficacy. Patients taking antithyroid drugs should also avoid this herb. Individuals on thyroid medication should consult a healthcare provider before use, as iodine intake requires careful monitoring to prevent adverse effects.

What is the recommended weekly dosage for Sargassum fusiforme?

The recommended adult dosage for Sargassum fusiforme is limited to 5 grams of dry weight weekly. This restriction is necessary because the seaweed accumulates inorganic arsenic from the marine environment. Exceeding this limit increases the risk of heavy metal accumulation in the body. This herb is traditionally consumed as a food in Japanese and Korean cuisine, but medicinal use requires strict adherence to dosage guidelines to ensure safety (Evidence Level: Traditional).

Is Sargassum fusiforme safe to consume during pregnancy?

No, Sargassum fusiforme is considered unsafe during pregnancy. The primary concern is the presence of inorganic arsenic, a toxic heavy metal that can cross the placental barrier and potentially harm fetal development. Additionally, the high iodine content could disrupt maternal thyroid function. Pregnant women, nursing mothers, and children should avoid consumption of this herb to prevent heavy metal toxicity and adverse developmental outcomes.

What are the side effects of eating too much Sargassum fusiforme?

Consuming excessive amounts of Sargassum fusiforme can lead to arsenic accumulation, as the seaweed contains inorganic arsenic. Long-term ingestion of high levels of arsenic is associated with serious health risks, including skin lesions, cardiovascular disease, and neurotoxicity. Individuals with kidney disease are at higher risk as their ability to filter toxins is compromised. Adhering to the recommended weekly limit of 5 grams dry weight is essential to minimize these risks (Evidence Level: C).

PubMed-compiled information sheet

This sheet was compiled from PubMed (NIH) abstracts using AI assistance. Every factual claim is cited to a real PubMed article (see the source list). It has not yet been human-reviewed — confirm with a healthcare provider before use.

Compiled from 30 PubMed articles · model: gemma4:31b

Summary

Sargassum fusiforme, also known as Hijiki, is an edible brown seaweed with a wide range of bioactive constituents used in traditional medicine and functional foods [PMID:37876153, PMID:33133523].

Background

Sargassum fusiforme (synonym Hizikia fusiformis) is a brown seaweed that grows abundantly along the rocky coastlines of Asian countries, including China, Japan, and Korea [PMID:33133523, PMID:34359532].

Traditional uses

Recorded in the Shennong Bencao Jing (200 AD) as Haizao, it was used to treat edema, dysuria, and Yinglu (tumor-like induration) [PMID:33133523]. It has been utilized in East Asian traditional cuisine and medicine for several centuries [PMID:34359532].

Active compounds

Active constituents include polysaccharides (alginic acid, fucoidan, and laminaran), sterols (such as 24[R, S]-saringosterol), polyphenols (phlorotannins), terpenes, amino acids, and trace elements [PMID:37876153, PMID:31635744, PMID:34144153].

Mechanism of action

Fucoidan may ameliorate obesity-associated metabolic dysfunction by increasing serum tauroursodeoxycholic acid (TUDCA), which activates the TGR5-cAMP-PKA signaling pathway to suppress NF-κB-driven inflammation [PMID:40758868]. Alginate exhibits anti-human adenovirus type 7 activity potentially related to the endoplasmic reticulum stress (ERS) pathway [PMID:35321314]. Antioxidant peptides from the herb may regulate the Keap1/Nrf2 pathway [PMID:39941997].

Clinical evidence

Evidence DObesity

Fucoidan administration in obese mice reduced body weight gain, fat accumulation, and hepatic steatosis while improving glucose tolerance and insulin sensitivity [PMID:35907465, PMID:40758868]

Evidence DViral Infection (HAdV7)

Alginate from S. fusiforme demonstrated inhibitory effects against human adenovirus type 7 in vitro [PMID:35321314]

Evidence DRespiratory Syncytial Virus (RSV)

S. fusiforme polysaccharides, in combination with cordycepin and lactoferrin, improved lung pathology and decreased viral load in a murine model [PMID:40589746]

Evidence DColitis

Exosome-like nanoparticles (SELNs) alleviated symptoms of Citrobacter rodentium-induced colitis by suppressing the TLR4/MyD88/NF-κB pathway [PMID:41526538]

Evidence DHair Growth

Drinking and skin application of extracts significantly increased hair growth rate and follicle length in C57BL/6 mice [PMID:36800993]

Safety & adverse effects

S. fusiforme contains large amounts of inorganic arsenic; feeding rats a 3% hijiki diet led to arsenic accumulation in blood and tissues, causing high body temperature and abnormal blood biochemistry consistent with arsenic poisoning [PMID:22561181]. Food standards agencies in the UK and other countries have warned against its consumption due to this inorganic arsenic content [PMID:22561181, PMID:25253519].

Evidence summary

The evidence consists primarily of in vitro studies, animal models (mice/rats), and literature reviews. There are no human clinical trials provided; therefore, the overall strength of evidence for therapeutic claims is low (Level D).

PubMed sources

1.PMID: 36869543 (2023) — A review of volatile compounds in edible macroalgae. · Food research international (Ottawa, Ont.)
2.PMID: 37876153 (2023) — Bioactivities of the Popular Edible Brown Seaweed Sargassum fusiforme: A Review. · Journal of agricultural and food chemistry
3.PMID: 34359532 (2021) — Hizikia fusiformis: Pharmacological and Nutritional Properties. · Foods (Basel, Switzerland)
4.PMID: 33133523 (2020) — Therapeutic and nutraceutical potentials of a brown seaweed Sargassum fusiforme. · Food science & nutrition
5.PMID: 40758868 (2025) — Sargassum fusiforme Fucoidan Ameliorates Obesity-Associated Metabolic Dysfunction via a Tauroursodeoxycholic Acid-Mediated TGR5-cAMP-PKA Signaling Pathway. · Journal of agricultural and food chemistry

Sargassum fusiforme

Sources & Citations

Calculate a safe dose of Sargassum fusiforme

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Frequently asked questions

Summary

Background

Traditional uses

Active compounds

Mechanism of action

Clinical evidence

Safety & adverse effects

Evidence summary

PubMed sources

Government sources

Sargassum fusiforme

Sources & Citations

Calculate a safe dose of Sargassum fusiforme

Related Herbs

Corchorus Olitorius

Thai Basil

Ribes nigrum

Frequently asked questions

Summary

Background

Traditional uses

Active compounds

Mechanism of action

Clinical evidence

Safety & adverse effects

Evidence summary

PubMed sources

Government sources