Fucus Vesiculosus - What is it & How to use

Fucus vesiculosus contains varying amounts of iodine. The iodine might help prevent or treat some thyroid disorders. Fucus vesiculosus also might have antidiabetic effects, and may affect hormone levels. But more information is needed.


Natural Medicines Comprehensive Database rates effectiveness based on scientific evidence according to the following scale: Effective, Likely Effective, Possibly Effective, Possibly Ineffective, Likely Ineffective, Ineffective, and Insufficient Evidence to Rate.

The effectiveness ratings for FUCUS VESICULOSUS are as follows:

Insufficient evidence to rate effectiveness for…

  • Obesity. Early research suggests that taking Fucus vesiculosus along with lecithin and vitamins doesn’t help people lose weight.
  • Achy joints (rheumatism).
  • Arthritis.
  • “Blood cleansing”.
  • Constipation.
  • Digestive problems.
  • “Hardening of the arteries” (arteriosclerosis).
  • Iodine deficiency.
  • Thyroid problems, including an over-sized thyroid gland (goiter).
  • Other conditions.

More evidence is needed to rate the effectiveness of Fucus vesiculosus for these uses.


The appropriate dose of Fucus vesiculosus depends on several factors such as the user’s age, health, and several other conditions. At this time, there is not enough scientific information to determine an appropriate range of doses for Fucus vesiculosus. Keep in mind that natural products are not always necessarily safe and dosages can be important. Be sure to follow relevant directions on product labels and consult your pharmacist or physician or other healthcare professional before using.

Safety Concerns

Fucus vesiculosus is POSSIBLY SAFE when applied to the skin. It is POSSIBLY UNSAFE when taken by mouth. It may contain high concentrations of iodine. Large amounts of iodine can cause or worsen some thyroid problems. It may also contain heavy metals, which can cause heavy metal poisoning. Treatment of thyroid problems should not be attempted without medical supervision.

Special precautions & warnings:

Pregnancy and breast-feeding: Fucus vesiculosus is POSSIBLY UNSAFE during pregnancy and breast-feeding. Don’t use it.

Bleeding disorders: Fucus vesiculosus might slow blood clotting. In theory, Fucus vesiculosus might increase the risk of bruising or bleeding in people with bleeding disorders.

Diabetes: Fucus vesiculosus may affect blood sugar levels. If you have diabetes and take medications to lower your blood sugar, adding Fucus vesiculosus might make your blood sugar drop too low. Monitor your blood sugar carefully.

Infertility: Preliminary research suggests that taking Fucus vesiculosus might make it harder for women to get pregnant.

Iodine allergy: Fucus vesiculosus contains significant amounts of iodine, which could cause an allergic reaction in sensitive people. Don’t use it.

Surgery: Fucus vesiculosus might slow blood clotting. There is a concern that it might cause extra bleeding during and after surgery. Stop taking Fucus vesiculosus at least 2 weeks before surgery.

Thyroid problems known as hyperthyroidism (too much thyroid hormone), or hypothyroidism (too little thyroid hormone): Fucus vesiculosus contains significant amounts of iodine, which might make hyperthyroidism and hypothyroidism worse. Don’t use it.

Interaction with medication

Be cautious with this combination.
Fucus vesiculosus can contain significant amounts of iodine. Iodine can affect the thyroid. Lithium can also affect the thyroid. Taking iodine along with lithium might increase the thyroid too much.
Medications for an overactive thyroid (Antithyroid drugs)
Fucus vesiculosus can contain significant amounts of iodine. Iodine can affect the thyroid. Taking iodine along with medications for an overactive thyroid might decrease the thyroid too much, or may affect how antithyroid medications work. Do not take Fucus vesiculosus if you are taking medications for an overactive thyroid.

Some of these medications include methimazole (Tapazole), potassium iodide (Thyro-Block), and others.

Medications that slow blood clotting (Anticoagulant / Antiplatelet drugs)
Fucus vesiculosus might slow blood clotting. Taking Fucus vesiculosus along with medications that also slow clotting might increase the chances of bruising and bleeding.

Some medications that slow blood clotting include aspirin, clopidogrel (Plavix), diclofenac (Voltaren, Cataflam, others), ibuprofen (Advil, Motrin, others), naproxen (Anaprox, Naprosyn, others), dalteparin (Fragmin), enoxaparin (Lovenox), heparin, warfarin (Coumadin), and others.

* The Content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition.