Thyroid supplements use bladderwrack as a source of iodine, a mineral required for thyroid hormone production.
Bladderwrack is a type of seaweed. Thyroid supplements frequently include bladderwrack as a source of:
- Iodine. Iodine is needed to produce thyroid hormone; not getting enough can result in goiter and hypothyroidism.
Fucus vesiculosus, better known as bladderwrack, is an edible brown seaweed commonly found at the coastal regions of the northern Atlantic and Pacific Oceans and the North and Baltic Sea. Bladderwrack gets its name from the air-filled sacs that help it stay afloat.
Similar to other sea plants, bladderwrack has a high iodine content. In fact, iodine was discovered after being isolated from bladderwrack in 1811 and used to treat iodine deficiency.
Today, bladderwrack remains one of the most popular sources of iodine. In particular, bladderwrack a common ingredient in thyroid supplements because of iodine’s key role in healthy thyroid function. In this context, bladderwrack is used to alleviate goiter and hypothyroidism caused by iodine deficiency.
How Bladderwrack Might Help With Thyroid Health
Bladderwrack is a rich source of iodine
Iodine is the most important nutrient for healthy thyroid function because it is needed to produce the two thyroid hormones – triiodothyronine (T3) and thyroxine (T4). Indeed, as much as 80% of the body’s iodine is stored in the thyroid. If you don’t get enough iodine, you may develop hypothyroidism.
Nonetheless, it is also important to note that excess iodine intake can cause or worsen thyroid issues in susceptible individuals such as the elderly. 1 Because of this, it’s best to get your iodine levels checked to see if they fall outside the normal range before considering supplementation.
There are currently no clinical studies on the effects of bladderwrack on thyroid function. However, we do know that iodine – the major component of bladderwrack – is required for healthy thyroid function. Furthermore, supplementing with iodine can improve hypothyroidism and goiter if these conditions are caused by iodine deficiency.
This systematic review looked at the efficacy of iodine supplementation in comparison to placebo for treating iodine deficiency – one of the causes of goiter and hypothyroidism. After examining data from 6 studies, the authors found that most studies reported improvements in iodine levels and a tendency towards goiter reduction.
- The researchers concluded that “The results suggest that iodised salt is an effective means of improving iodine status.”2
Dosage for Thyroid Health
- There is no research-backed dose of bladderwrack
- Single-ingredient supplements typically contain 500-600 mg of bladderwrack powder
- Multi-ingredient thyroid supplements typically contain 50 mg of bladderwrack powder
- Bladderwrack powder. Powdered bladderwrack thallus (stem) sold in capsules.
Supplements in Review Recommendation
- Bladderwrack for thyroid health.
Bladderwrack can help support thyroid function in cases of iodine deficiency. If iodine deficiency is the cause of your thyroid issues, then bladderwrack supplements can be helpful. However, caution should be taken because iodine deficiency is rare, and having too much iodine can be harmful to the thyroid.
It’s best to follow supplement dose recommendations. Doses used by doctors to cure iodine deficiency are high, and are not indicative of the doses you should take in supplement form. As such, it’s best to follow doses suggested by your specific supplement.
- Leung AM and Braverman LE. Consequences of excess iodine. Nat Rev Endocrinol. 2014 Mar; 10(3): 136–142
Did you know? Aside from iodine, bladderwrack also contains another active ingredient called fucoidan. Present in many types of seaweed, fucoidan has been the subject of hundreds of research studies, and may be one of the compounds responsible for Japan’s high life expectancy.
Bladderwrack Uses & Benefits for Thyroid Health
As a dietary supplement, bladderwrack is used to improve hypothyroidism and goiter caused by iodine deficiency. Although this use has not been confirmed by clinical research, it is a well-established fact that iodine deficiency can cause hypothyroidism and goiter.
Having said that, excess iodine intake can cause or worsen thyroid problems, especially in susceptible individuals such as older adults and people with pre-existing thyroid disorders. [Leung AM and Braverman LE. Iodine-induced thyroid dysfunction. Curr Opin Endocrinol Diabetes Obes. 2012 Oct;19(5):414-9. ↩
- Wu T et al. Iodised salt for preventing iodine deficiency disorders. Cochrane Database Syst Rev. 2002;(3):CD003204. ↩
- Arbaizar B and Llorca J. Fucus vesiculosus induced hyperthyroidism in a patient undergoing concomitant treatment with lithium. Actas Esp Psiquiatr. 2011 Nov-Dec;39(6):401-3. ↩
- Shilo S and Hirsch HJ. Iodine-induced hyperthyroidism in a patient with a normal thyroid gland. Postgrad Med J. 1986 Jul;62(729):661-2. ↩
- Müssig K et al. Iodine-induced thyrotoxicosis after ingestion of kelp-containing tea. J Gen Intern Med. 2006 Jun;21(6):C11-4. ↩