Bladderwrack supplements are derived from a type of seaweed found in the North Atlantic Ocean. Bladderwrack (Fucus vesiculosus) gets its name from the bladder-like sacs found on its stems and branches. This seaweed has been used for centuries in traditional Chinese and European medicine for its purported health benefits.

Bladderwrack supplements are rich in iodine, which is a mineral that is essential for the proper functioning of the thyroid gland. Iodine deficiency can lead to goiter (enlargement of the thyroid gland) and other problems with the thyroid. Bladderwrack supplements are also a good source of other minerals, including calcium, magnesium, and potassium.

This article explores the potential health benefits of Bladderwrack supplements, dosage, and side effects.

Bladderwrack Benefits

Even though there are a lot of health claims associated with bladderwrack, there isn’t much evidence to support the use of bladderwrack for its benefits like weight reduction, arthritis, or joint pain. Here are some of its other potential benefits.

1. Bladderwrack for Weight Loss

Bladderwrack supplements are often marketed as a weight loss aid. This is because iodine boosts metabolism, which can help the body burn more calories.

Your thyroid gland plays a role in regulating your metabolism and keeping your weight healthy. Hypothyroidism is when the body does not generate enough thyroid hormone, leading to a slow metabolic rate and potentially altered appetite.

Bladderwrack’s iodine content may be helpful for this condition. However, its efficacy may vary depending on the underlying reason for your hypothyroidism. As it might also induce hypothyroidism, you should discuss it with your doctor before starting treatment.

2. Bladderwrack for Thyroid Health

Low levels of T3 and T4 might develop when the body lacks iodine. Low iodine may lead to the development of goiter and hypothyroidism, which are characterized by weight gain, weariness, dry skin, and increased cold sensitivity.

Bladderwrack contains iodine, a trace element that aids in the production of the thyroid hormones triiodothyronine (T3) and thyroxine (T4). These hormones are important in maintaining a healthy metabolic rate and promoting normal growth and brain function. [1]

However, if bladderwrack has enough iodine to promote weight loss, it likely contains enough iodine to produce a hyperthyroid state. Therefore, while bladderwrack may have beneficial health effects, it’s advisable to check with your doctor first.

3. Bladderwrack Benefits for Eyes

Bladderwrack also contains beta-carotene, making it a fantastic choice for anyone looking to enhance their eyesight. In addition, fucoxanthin and fucoidan, two nutrients found in abundance in bladderwrack, are being hailed by Chinese researchers as the “eye nutrition of the future.”

Fucoxanthin is the main component of the seaweed’s light-absorbing mechanism, responsible for its brown or olive-green hue. The blue light given out by many electronic gadgets, including computers, smartphones, and tablets, is considered harmful to the eyes.

Fucoxanthin is a xanthophyll, a carotenoid that helps preserve eyesight by absorbing blue-green to yellow-green wavelengths of visible light.

Also, a preliminary study suggests that fucoidan may be useful in treating age-related macular degeneration by inhibiting the growth of new blood vessels in areas where cells are not getting enough oxygen. Similar to the effects of fucoxanthin, fucoidan has been shown to slow down the aging and death of cells. [2]

4. Bladderwrack Skin Benefits

Bladderwrack is effective as a topical therapy for various skin conditions, including cellulite, skin aging, and burns. It is also used in skin care products to relieve skin discomfort. Bladderwrack also has high B-complex vitamins, calcium, iodine, iron, magnesium, potassium, sodium, sulfur, and silicon content. [3]

Additional antioxidant vitamins A, C, and E and the minerals carotene and selenium provide bladderwrack its special anti-aging and healing abilities. Preliminary studies suggest that bladderwrack’s antioxidants, including fucoidan, encourage collagen production in the skin, which may reduce the appearance of cellulite, speed up skin healing, and slow the aging process. [4]

Its hydrating ingredients are especially beneficial for dry, older skin and make it appear fuller and younger-looking. [5]

5. Bladderwrack for Inflammation

Fucoidans, a kind of sulfated polysaccharides, are among the potent nutrients in bladderwrack seaweed that have anti-inflammatory properties. Researchers have looked into these compounds’ antioxidant, anticancer, immune-modulating, and anti-inflammatory effects. [6, 7]

Bladderwrack may also help protect the stomach lining from acid and reduces inflammation. As a result, it may help alleviate stomach issues by acting as a barrier between your stomach’s delicate lining and irritating substances like stomach acid. Inflammation is also reduced, which may help with gastrointestinal problems.

Moreover, preliminary research in cells and animals suggests that bladderwrack and other brown algae may help slow tumor development, lower blood sugar, and lessen the likelihood of developing heart disease. Its anti-inflammatory qualities have led to its usage as a topical therapy for bug bites and burns and an alternate treatment for arthritis. [8]

6. Bladderwrack for Heart Health

Some research suggests that bladderwrack might benefit heart health. In platelet testing, the fucoidans in bladderwrack exhibited potent antithrombin and anticoagulant action. It may also boost “good” (HDL) cholesterol, which removes excess cholesterol from the blood and transports it to the liver to be metabolized. [9]

Bladderwrack Side Effects 

Bladderwrack is typically harmless. However, it can cause thyroid dysfunction and heavy metal poisoning. In addition, some people find that consuming iodine from sea vegetables like bladderwrack or any other source worsens their acne.

Similarly to other types of seaweed, bladderwrack is okay to eat in moderation. However, it has significant concentrations of iodine, salt, and heavy metals, which are potentially harmful.

External use of bladderwrack is likely risk-free. But don’t put it on any cuts or wounds that aren’t completely healed, and stop using it if you develop a rash or other response.

Furthermore, pregnant women or nursing may also be at risk of consuming bladderwrack due to its potential teratogenic effects. Before using bladderwrack, you should always check with a physician or other qualified healthcare professional.

Bladderwrack Dosage

You may purchase bladderwrack in dry, powdered, or encapsulated form online or in selected health food stores. There’s a tea version of it, too.

Bladderwrack is safe for most people. However, the proper dosage may vary according to individual factors such as weight and health. Supplements containing bladderwrack typically come in 500-mg quantities. Nonetheless, 4-6 g/day of crude dry seaweed, providing approximately 400-500 g of iodine, is within the acceptable dosage range for this herb.

Please speak with your doctor about the right quantity of iodine and dose for bladderwrack before taking it to treat a thyroid issue or help you reduce weight.

Bottomline: Bladderwrack Supplement Benefits and Side Effects

Bladderwrack is an edible brown seaweed used for generations as a natural remedy. It is now available as a dietary supplement in various forms.

Numerous health benefits are attributed to bladderwrack. However, just a small amount of evidence supports its use as a possible therapy for any condition. People with thyroid conditions or using certain drugs should also stay away from bladderwrack because of its high iodine concentration.

Talk to your doctor before beginning treatment to determine whether bladderwrack is safe and effective for you. Pregnant or nursing women should avoid it since there is little information on its safety.

Disclaimer: This article is only a guide. It does not substitute the advice given by your own healthcare professional. Before making any health-related decision, consult your healthcare professional.

Editorial References and Fact Checking

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  • Thring TS, Hili P, Naughton DP. Anti-collagenase, anti-elastase and anti-oxidant activities of extracts from 21 plants. BMC Complement Altern Med. 2009 Aug 4;9:27. doi: 10.1186/1472-6882-9-27. PMID: 19653897; PMCID: PMC2728709.
  • Atashrazm F, Lowenthal RM, Woods GM, Holloway AF, Dickinson JL. Fucoidan and cancer: a multifunctional molecule with anti-tumor potential. Mar Drugs. 2015 Apr 14;13(4):2327-46. doi: 10.3390/md13042327. PMID: 25874926; PMCID: PMC4413214.
  • Sanjeewa KKA, Lee JS, Kim WS, Jeon YJ. The potential of brown-algae polysaccharides for the development of anticancer agents: An update on anticancer effects reported for fucoidan and laminaran. Carbohydr Polym. 2017 Dec 1;177:451-459. doi: 10.1016/j.carbpol.2017.09.005. Epub 2017 Sep 5. PMID: 28962791.
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  • Haiyan Liu and Liwei Gu. Phlorotannins from Brown Algae (Fucus vesiculosus) Inhibited the Formation of Advanced Glycation Endproducts by Scavenging Reactive Carbonyls. Journal of Agricultural and Food Chemistry. 2012 60 (5), 1326-1334. DOI: 10.1021/jf204112f.


  • Shaira Urbano, Licensed Pharmacist

    Shaira is a licensed pharmacist (Bachelor of Pharmacy) and an experienced content writer. She enjoys inspiring and informing her readers through research-backed, comprehensive health content. Shaira draws from her personal experience working with real-life patients in a hospital setting and is currently pursuing her passion in writing.


Shaira is a licensed pharmacist (Bachelor of Pharmacy) and an experienced content writer. She enjoys inspiring and informing her readers through research-backed, comprehensive health content. Shaira draws from her personal experience working with real-life patients in a hospital setting and is currently pursuing her passion in writing.