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Kelp explained: what it is and where it grows

The NIH describes kelp as a group of seaweeds found in nutrient-rich coastal waters in temperate and subtropical regions. Kelp comes from brown algae near shorelines, and the NIH says it is rich in iodine and used as food and a botanical supplement. Two of the products we reviewed list kelp, and one label prints its amount: 10 mg per serving.

By HowNook's Health desk · Updated

In the products we reviewed
2, 1 print the amount

What kelp is

  • Kelp comes from brown algae that grows near shorelines.1
  • Kelp is a group of seaweeds belonging to the order Laminariales.1
  • Kelp grows in nutrient-rich coastal waters in temperate and subtropical regions.1
  • Laminaria hyperborea is the kelp most commonly found in the United States.1
  • Kelp contains alginic acid salts, carbohydrates, minerals and trace elements.1
  • Kelp is rich in iodine and can absorb calcium, iron and potentially harmful metals from the ocean.1
  • Kelp is used as food, a source of vitamins and minerals, and a botanical supplement.1

How much kelp each product gives

Per serving, as each label prints it

Amount not printed: the dashed line shows the most it can be, the whole blend

ViriFlowNot printed · at most 700 mg
Prostadine10 mg

Before you take it

If you take medicines

Prescription medications
Large doses of kelp can interact with some prescription medications.1

Ask a doctor first

  • Large doses of kelp can be harmful for people with thyroid conditions.1
  • Using kelp as a major food source can cause thyroid abnormalities and metal poisoning.1

These statements have not been evaluated by the FDA. A supplement is not a medicine.

The 2 products we reviewed that list kelp

ProductForm and servingKelp per servingOur scorePrice a bottleBuy
ViriFlow#1 in prostate health supportLiquid drops2 mlNot printedIn a 700 mg proprietary blend9.4$49Check price
Prostadine#7 in prostate health supportLiquid drops2 droppers (2 ml)10 mg8.3$49Check price
Prices checked Oct 11, 2026

Questions people ask

Is kelp seaweed?

Yes, the NIH describes kelp as a group of seaweeds belonging to the order Laminariales. It comes from brown algae that grows near shorelines.

What is in kelp?

Kelp contains alginic acid salts, carbohydrates, minerals and trace elements, according to the NIH. The NIH also says kelp is rich in iodine and can absorb calcium, iron and potentially harmful metals from the ocean.

Is kelp edible?

Yes, the NIH says kelp is used as food and as a source of vitamins and minerals.

Can kelp interact with prescriptions?

Yes, large doses of kelp can interact with some prescriptions. Ask a clinician before starting kelp if you take anything prescribed.

Is kelp safe to eat?

Using kelp as a major food source can cause metal poisoning. Kelp can absorb potentially harmful metals from the ocean. Ask a clinician before starting a kelp supplement.

Which supplements we reviewed contain kelp?

ViriFlow and Prostadine list kelp. Prostadine prints 10 mg per serving, while ViriFlow lists kelp inside a 700 mg proprietary blend without printing its individual amount.

Also in these products

All ingredients

Sources

The products, amounts and prices come from each product's label and checkout, as its review shows them. AI drafts our pages from listed sources, figures are checked against them, and we have not tried the products.

  1. 1NIH LiverTox, Kelpncbi.nlm.nih.gov/bookschecked