How much iodine is in kelp powder?Updated 8 days ago

Kelp naturally absorbs iodine from seawater, making it one of the most abundant natural sources of this mineral. However, iodine levels in kelp vary significantly — they depend greatly on species, growing location, harvest season, and post-harvest processing methods. Due to this variation, we currently provide an estimate of our kelp powder’s iodine content and are working to obtain independent laboratory verification.

What we estimate for Fettle’s kelp (tentative):

Based on the literature and our internal (preliminary) assays, we believe our kelp powder contains a few hundred to low-thousands of µg of iodine per gram (before dilution in food). But this is a rough estimate. Until we receive results from our independent third-party lab, we cannot guarantee an exact figure.

Why you shouldn’t overdo it (safety reminder):

• Iodine is essential for thyroid health, but too much can stress the thyroid, especially in animals predisposed to thyroid problems.
• Because kelp’s iodine content may vary, adhering to the serving guide is critical to avoid accidental overdose.
• If your pet has known thyroid disease or is on medications, always consult your vet before adding any iodine-rich supplements.

What’s next:

We are in the process of having third-party lab testing done on each batch of our kelp powder to precisely measure iodine content (and rule out contaminants). Once we get those results, we’ll update this article and display exact iodine values on our packaging and online listings.

References

Bouga, M., & Combet, E. (2015). Emerging data on the iodine content of seaweed: identification of species with potential health benefits. Journal of Applied Phycology, 27, 1221–1231. Link

Teas, J., Pino, S., Critchley, A., & Braverman, L. E. (2004). Variability of iodine content in common commercially available edible seaweeds. Thyroid, 14(10), 836–841. Academia.edu summary

Nitschke, U., & Stengel, D. B. (2016). Commercially available seaweed and kelp products: valuable iodine source or risk of excess intake? Food Chemistry, 190, 486–492. Academia.edu copy

Ytrehus, I., et al. (2024). Stress storage treatments significantly reduce iodine content in kelp. Journal of Applied Phycology. Springer Link PDF