Ascophyllum nodosum
Ascophyllum nodosum


Ascophyllum nodosum is a type of brown seaweed. It is found along the shorelines in cold areas of the world, such as Northern Canada, United States, and Europe. Ascophyllum nodosum is now protected in many countries because of over-harvesting for a chemical called alginate.

Ascophyllum nodosum is taken by mouth for dental health, weight loss, or as a source of the mineral iodine. Don't confuse Ascophyllum nodosum with other kinds of seaweed like Bladderwort, Blue-green Algae, Brown Algae, Fucus vesiculosus, or Laminaria, or with the chemical Algin that comes from seaweed.
When taken by mouth: Ascophyllum nodosum is POSSIBLY SAFE for adults when taken daily for up to 6 months. Side effects are rare but might include stomach problems. Ascophyllum nodosum can accumulate high levels of heavy metals. Purchasing a product that is certified as being free of heavy metals can reduce the risk of heavy metal exposure.

Special Precautions & Warnings:

Pregnancy and breast-feeding: There isn't enough reliable information to know if Ascophyllum nodosum is safe to use when pregnant or breast-feeding. Stay on the safe side and avoid use.


Natural Medicines 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.
Likely effective Effectiveness definitions
Possibly effective Effectiveness definitions
Likely ineffective Effectiveness definitions
Possibly ineffective Effectiveness definitions
Insufficient evidence Effectiveness definitions
  • Tooth plaque. Early research shows that taking Ascophyllum nodosum (ProDen PlaqueOff) might help to reduce the build-up of plaque on the teeth.
  • A mild form of gum disease (gingivitis). Early research shows that taking Ascophyllum nodosum (ProDen PlaqueOff) does not prevent gingivitis.
  • Iodine deficiency. Ascophyllum nodosum contains iodine. Early research shows that taking Ascophyllum nodosum can increase iodine levels in women who have low levels of iodine in the body.
  • Obesity.
  • Stomach or intestinal problems.
  • Other conditions.
More evidence is needed to rate the effectiveness of Ascophyllum nodosum for these uses.

Dosing & administration

The appropriate dose of Ascophyllum nodosum 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 Ascophyllum nodosum. 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.

Interactions with pharmaceuticals

It is not known if Ascophyllum nodosum interacts with any medicines. Before taking Ascophyllum nodosum, talk with your healthcare professional if you take any medications.

Interactions with herbs & supplements

There are no known interactions with herbs and supplements.

Interactions with foods

There are no known interactions with foods.


Ascophyllum nodosum contains nutrients such as large sugars (carbohydrates), fats, and the mineral iodine. Ascophyllum nodosum might help the body kill cancer cells and reduce swelling.
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This monograph was last reviewed on 23/10/2022 19:42:21 and last updated on 13/11/2020 01:27:01. Monographs are reviewed and/or updated multiple times per month and at least once per year.
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