Bladderwrack Benefits, Side Effects and Dosage

What is Bladderwrack Extract?

Bladderwrack extract is taken from the bladderwrack algae, also known as Fucus vesiculosus, rockweed, black tang, bladder fucus, cutweed or Dyer’s fucus.

This perennial green-brown seaweed grows along the Eastern and Western North American coastlines and European coastlines north of the Mediterranean (x). The seaweed has fronds of up to 2 meters long, studded with many small air bladders.

Bladderwrack is not the same as bladderwort, an inland aquatic plant found in lakes and streams. Recipes from Eastern countries commonly use seaweed as a culinary ingredient, especially amongst coastal populations, but it’s not as popular in Western countries.

However, the popularity of seaweed like bladderwrack has grown as our understanding of its health benefits improve.

Bladderwrack is an excellent source of iodine (a mineral necessary for proper thyroid function), and is also rich in nutrients such as vitamins A, B complex, C, D, E and K. It contains minerals like sodium, potassium, calcium, magnesium, iron, copper, zinc and manganese. Plus, it’s rich in all nine essential amino acids and boasts potent antioxidant properties (x) (x).

Bladderwrack Extract Benefits

Benefits Thyroid Health

Since the third century, people have used seaweed to treat goiters and other thyroid issues. Today, science indicates that the iodine and selenium in bladderwrack help regulate the thyroid gland and may stimulate it to produce the hormone thyroxine (x).

Bladderwrack may also boast anticancer properties that could effectively limit thyroid tumor growth. It may also protect thyroid cells from inflammatory damage by slowing the breakdown of collagen and elastin (x).

Plus, research indicates bladderwrack may lower blood cholesterol levels, which can benefit those with a slow metabolism associated with thyroid dysfunction (x, x).

Aids in Weight Management

In 1862, French physician Louis Victor Duchesne-Duparc noted that patients treated for psoriasis with bladderwrack reported significant weight loss. Scientists now believe that through its thyroid hormone stimulatory action, the iodine content of bladderwrack improves metabolism, which results in weight loss–even without reducing food intake (x, x).

Bladderwrack contains compounds called fucoidan and alginate that may also aid in weight loss. Studies conducted on alginate suggest it may help curb appetite, thereby aiding weight loss (x, x, x). Fucoidan may reduce lipid (fat) accumulation and could therefore potentially prevent obesity (x, x).

Natural Antimicrobial and Antiviral

The fucoidan and alginate in bladderwrack don’t just fight fat–they could also fight off infections. Studies suggest they have significant antiviral properties, and although research continues, early studies indicate they may kill polio, herpes, and even HIV. In one in vitro (test tube) study, alginic acid inhibited the HIV virus, although this has not yet been studied in humans (x, x, x, x).

Bladderwrack may also kill the candida bacterium, which causes fungal nail infections; meningitis, a deadly brain and spinal cord infection; and e.coli, which causes severe food poisoning (x, x).

Supports Vision

Bladderwrack benefits vision and eye health in two different ways. First, it contains high amounts of beta-carotene, which the body converts into vitamin A, a key nutrient for healthy vision. Vitamin A protects your cells from damage, strengthening the immune system and promoting healthy skin, mucus membranes and eyes.

Secondly, bladderwrack may inhibit the activity of adenovirus type 3 and cytomegalovirus, two culprits linked to eye infections (x).

Lowers Estrogen Levels

Because of the effect bladderwrack has on the body’s levels of cholesterol, from which sex hormones are produced, it may lower circulating estrogen levels while shortening the duration of menstrual cycles. This could be useful in treating estrogen-dependent diseases. In two studies, researchers linked bladderwrack to significantly lowered estrogen levels (x, x, x).

These conclusions may be linked to the fact that there is generally a lower incidence of estrogen-dependent cancers among women in Asian countries, who consume not only more soy, but also more kelp than women in Western countries (x, x).

Natural Anticancer Properties

Research suggests bladderwrack could aid in the fight against cancer. It may inhibit enzyme activity that causes cancer, support cells that kill cancer, and stop cell growth in existing cancers (x, x, x).

Studies show that the fucoidan in it works with the immune system to limit cancerous tumor growth (x).

In other studies, fucoidan stopped the spread of colorectal and breast cancers, lung carcinoma and melanoma in vitro (x, x).

Anti-Aging Properties

One study suggests that bladderwrack may have an anti-aging effect on the skin.

Human skin becomes thicker and less elastic with age. But applying the extract topically twice daily over five weeks could significantly decrease skin thickness and increase skin elasticity for a firmer, youthful appearance (x).

In fact, bladderwrack extract combined with clawed forkweed could even reduce the appearance of cellulite for smoother skin (x).

Fights Diabetes

In a human study, a combination extract of bladderwrack and another seaweed in the same family reduced insulin sensitivity and blood glucose levels (x). This could prove beneficial for diabetics, and since normal blood sugar levels keep your heart healthy, it may also benefit long-term cardiovascular health.

Relieves Arthritis Symptoms

Folk medicine has used bladderwrack as a remedy for arthritis and rheumatism for centuries. Recent studies have highlighted its anti-inflammatory action, which could reduce painful swelling and stiffness associated with arthritis (x).

Digestive Support

The alginic acid in bladderwrack serves as a short-term remedy for both constipation and diarrhea (x). It may also relieve heartburn, since common antacids like Gaviscon use alginic acid to ease stomach acid buildup (x) .

Bladderwrack Infographic

Bladderwrack Side Effects

As long as you adhere to the recommended dosage, bladderwrack is safe to take for healthy adults, according to multiple human and animal studies (x).

Mild side effects may include nausea, stomach upset and diarrhea. Do not take bladderwrack if you are nursing, pregnant, or trying to become pregnant. Stop taking bladderwrack at least two weeks before a surgery, as it could slow blood clotting.

Talk to your doctor before taking bladderwrack if you have a heart condition, tuberculosis, adrenal insufficiency, anemia, hypertension or kidney disease. You should also talk to your doctor before taking this supplement if you’re postmenopausal and have been diagnosed with osteoporosis.

Iodine Toxicity

While bladderwrack can benefit your thyroid, exceeding the recommended dietary allowance of 150 mcg daily can induce or aggravate hyperthyroidism. This is due to it’s high iodine content; taking large iodine doses every day may harm thyroid function (x, x).

Since it affects your thyroid, talk to your doctor before taking it if you have an existing thyroid condition or if you are taking medication for a thyroid condition.

The Bottom Line

A type of seaweed native to rocky coastlines, bladderwrack is a marine multi-tasker, rich in nutrients that support vision, fight infections and aging, protect your thyroid, aid in weight management and more.

Author: Ryan Quigley
Graduate of Longwood University in Virginia. Part-time sports journalist covering the Vegas Golden Knights.