Kelp Supplement Review

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  Evaluated for:
Effectiveness Rating Effectiveness Rating
Thyroid disorders
-1 (Possibly Ineffective)
Cancer prevention
-1 (Possibly Ineffective)
Blood pressure
-1 (Possibly Ineffective)


  • Kelp refers to various species of brown algae that grow large in the depths of the ocean. Kelp is just one kind of seaweed, loosely defined as any type of oceanic vegetation; the term seaweed also includes other non-kelp plants and algae.
  • Kelp, which is rich in iodine (as well as heavy metals such as arsenic, lead, and cadmium), is also known as bladderwrack, not to be confused with bladderwort.
  • Oral bladderwrack is used to treat thyroid disorders and iodine deficiency. While iodine is needed for proper thyroid function, enough iodine is found in iodinated salt.


  • Kelp has the potential to concentrate heavy metals, such as arsenic or cadmium.
  • Kelp is a source of iodine. Overdosing can cause or worsen thyroid disorders, acne, and gastric irritation.
  • Kelp may impair fertility. It may prolong the length of the menstrual cycle and have anti-estrogenic effects in pre-menopausal women.

It is possible to overdose on kelp supplements, and this can cause harm. Patients with thyroid disorders must be careful with iodine supplementation and should take iodine only under medical supervision.

DOSAGE:There is no recommended dosage, although dosages containing more than 150 mcg iodine per day can cause hyperthyroidism or exacerbate existing hyperthyroidism.

CONCLUSION:We do not recommend taking this product.

“Kelp.” Natural Standard –The Authority on Integrative Medicine. Natural Standard, 2013.
“Bladderwrack.” Natural Medicines Comprehensive Database. Therapeutic Research Faculty, 2013. 8 November 2013.
Kelp. EBSCO Publishing (2011) 1-3
Skibola, C.F. et al. The effect of focus vesiculosus, an edible brown seaweed, upon menstrual cycle length and hormonal status in three pre-menopausal women: a case report. BMC Complementary and Alternative Medicine(2004) 4:10
Mussig, K. et al. Iodine-Induced Thyrotoxicosis After Ingestion of Kelp-Containing Tea. J Gen Intern Med (2006) 21:C11-C14
Kurihara, K. et al. Glutamate: from discovery as a food flavor to role as a basic taste. The American Journal of Clinical Nutrition (2009) 90:719S-22S

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