A wooden spoon containing dried bladderwrack

Herb of the month: Bladderwrack

Medical herbalist Gabriella Clarke introduces bladderwrack.


A type of seaweed found in the Pacific and Atlantic oceans as well as the North and Baltic Sea, bladderwrack (Fucus vesiculosus) is a rich source of Iodine, which has been used to treat thyroid problems and goitre since the early 1800s.

It is rich in antioxidants, such as zeaxanthin and beta-carotene, and a good source of minerals, especially potassium and iodine. It also contains B vitamins as well as vitamins A, C, K and E. In addition bladderwrack is used in the cosmetic industry as an anti-ageing ingredient.

Read on to discover some of its many health benefits:


Bladderwrack may improve irregular menstrual cycles in pre-menopausal women. It may also prolong the length of the menstrual cycle with anti-oestrogenic effects, which may reduce the risk of oestrogen-related cancers[i].


Being so rich in Iodine, a mineral that is essential for the healthy functioning of the thyroid gland, bladderwrack may help to correct hypothyroidism (low thyroid function) as well as Hashimotos disease[ii]. As well as providing Iodine, it also upregulates iodine-processing hormones.


With proven anti-inflammatory properties, bladderwrack may help to ease pain and improve mobility in arthritis sufferers. One study demonstrated that taking a daily dose over a 12-week period significantly reduced the symptoms of osteoarthritis[iii].


Bladderwrack contains two major antioxidants – zeaxanthin and beta-carotene – both of which have been shown to improve eye health. They may also prevent or slow down macular degeneration and cataracts[iv].


Many diet and weight loss supplements contain bladderwrack. It is thought to work because of Iodine’s effect on increasing metabolic rate. However, despite its popularity as a weight loss aid there is little clinical evidence to support this so evidence appears be to only be anecdotal.


Bladderwrack contains a constituent known as align, which has laxative properties, making it a useful remedy for constipation.


  • Bladderwrack should never be used in pregnancy or while breast-feeding
  • It should be avoided in cases of hyperthyroidism and by anyone with bleeding disorders
  • If you are having surgery you should stop taking bladderwrack two weeks before, as it may slow blood clotting
  • Many people are sensitive to iodine and it has been known to cause allergic reactions: always consult a medical professional if you are unsure


[ii] https://restorativemedicine.org/journal/promoting-healthy-thyroid-function-with-iodine-bladderwrack-guggul-and-iris/

[iii] https://www.ncbi.nlm.nih.gov/pubmed/20376172

[iv] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4706936/


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