Bladderwrack (or Fucus vseiculosus) is a form of brown seaweed used for everything from treating thyroid problems to combatting obesity (1).
The brown color of bladderwrack comes from a pigment called fucoxanthan (2). A closely related compound called fucoidan gives bladderwrack anti-coagulant properties, in addition to many other varied health benefits (3).
Bladderwrack is best known for its use in treating thyroid disorders. In fact, it was the first source of iodine ever found, making it the go-to natural remedy for thyroid issues (4).
Bladderwrack can help the thyroid in many ways, regardless of whether one’s thyroid is overactive or underactive. It has also been shown to treat problems that accompany a defective thyroid, such as weight gain, by acting as a weight loss supplement and pain reliever (5).
The Natural Medicines Comprehensive Database reports that many studies have proven that bladderwrack is effective in helping to balance the thyroid by controlling the hormones in the body and keeping them at normal levels (6).
As with most drugs and supplements, however, these effects are not the same in each person who uses bladderwrack. While some may see a dramatic change for the better, others may see no effects whatsoever. More research studies are called for before doctors can give a definitive answer on whether bladderwrack is the best treatment for this issue or not (7).
Aside from its function as a thyroid moderator, bladderwrack can also help with many other bodily issues. The presence of fucoidans in bladderwrack has been proven to inhibit adipogenesis, one of the most-researched methods of cell differentiation (8, 9).
It can also inhibit another type of cell differentiation called adipocyte differentiation via MAPK signaling (10).
When applied at the cellular level, bladderwrack can also reduce adipocyte glucose uptake while inducing lipolysis (11).
In a recent human trial, bladderwrack was also shown to have an effect on estrogen in the female body. The study showed that women with irregular menstrual cycles saw stabilization of their estrogen levels when they took bladderwrack. They also saw a longer menstrual cycle as a result (12).
This was said to be caused by a lowering of estrogen levels, which was secondary to fucophorethols, which possess anti-aromatase aspects often related to breast-cancer treatment (13).
In the past, the fact that Asian women have longer menstrual cycles than women in other parts of the world was attributed to the fact that soy is a large part of the Asian diet (14, 15). However, recent studies have shown that perhaps the consumption of bladderwrack is the reason behind this (16, 17).
Beyond its associations with the thyroid and estrogen levels, bladderwrack has been shown to have anti-coagulation properties. In fact, some studies have shown that the anti-coagulating power of bladderwrack is 2.3 times higher than that of heparin, the drug most used in hospitals to for this purpose (18).
Another compound in bladderwrack called Undaria Pinnatifida or Wakame has been shown to lower blood pressure, as well as cause ACE inhibition (19).
When eaten as a vegetable, bladderwrack has been shown to reduce cholesterol levels (20).
Bladderwrack also has antioxidant, anti-inflammatory, and anti-carcinogenesis properties, meaning that it can not only reduce pain and inflammation, but can also keep cancer from growing and spreading in the body (21, 22).
Bladderwrack has a long list of alleged benefits, but there are also some serious side effects one should consider before they add bladderwrack to their diet. For example, one should not use bladderwrack if they are already using synthetic hormones or other medications to manage their thyroid. It should also not be used if one is pregnant, breastfeeding, or using other forms of seaweed such as kelp to manage health issues, as combining these things could lead to serious health problems (26).
Most side effects that come from the use of bladderwrack are a result of introducing too much iodine into the body. These side effects can include rapid heartbeat, anxiety, and sudden and inexplicable weight loss (26).
The anti-coagulate properties of bladderwrack can also be a problem. There is conflicting research on this aspect of bladderwrack, but the consensus is that different strains of seaweed may contain different strains of structural fucoidans, which could lead to clotting problems (27). In particular, the Okinawa Mozuku (Cladosiphon okamuranus) species has been shown to negatively prolong clotting time (28).
Bladderwrack can be used as a vegetable and added to salads and other dishes, or it can be taken as a dietary supplement in the form of a capsule. The amount of bladderwrack that a person should take is dependent on that individual and their own individual health needs (29).
However, beneficial effects of bladderwrack were seen beginning with non-concentrated dosages of just 500mg per day (30).
Bladderwrack is an appealing dietary supplement, due to the fact that it can be eaten in its natural form and added to various salads and other dishes. It has long proven to be a terrific help in regulating thyroid function, and it can help combat many other problems such as blood coagulation, high estrogen levels, skin issues, high cholesterol, and high blood pressure.
The only drawback to using bladderwrack regularly is that it can potentially cause high levels of iodine in the body, and can interact with medications. However, if one consults with a doctor on a regular basis and doesn’t ingest more than the suggested amounts of bladderwrack, it can be an extremely helpful supplement that can help regulate many processes in the body.