How to Find the Best Iodine-Free Protein Powder

📌 Overview and Key Takeaways

This is a Nutrition Coach’s guide to finding the best iodine-free protein powder.

Discover how to meet your protein needs without iodine.

Last Updated
Jul 30, 2026

Author and Medical Reviewer

Written by Jack, CNC

Jack is a National Academy of Sports Medicine Certified Nutrition Coach.

Disclaimer: This communication is for general informational purposes only and is not a substitute for personalized medical advice. Consult a licensed healthcare professional before making changes to your diet.

Iodine-Free Protein Powder

What Is Iodine?

Iodine is a naturally-occurring mineral found in certain foods such as seafood, fish, dairy, and egg yolks.

It plays an important role in the body, supporting the production of thyroid hormones which help regulate metabolism – how your body turns food into energy.

That said, some people need to follow a low-iodine diet.

What Is the Low-Iodine Diet?

A low-iodine diet is an eating plan designed to reduce the amount of iodine you consume.

Many thyroid cancer patients are advised to follow this diet as part of their treatment plan, especially in the weeks before radioactive iodine (RAI) therapy.

If you are about to undergo RAI therapy, consult a medical professional before making changes to your diet.

What Is the Best Protein Powder Without Iodine?

There is no truly iodine-free protein powder, but nut-based protein powders, such as Almond Protein Powder, tend to contain very little iodine.

Note that the US Food and Drug Administration (FDA) only regulates the addition of iodine to infant formulas, the iodization of salt, and the addition of salt and iodine to foods.

It does not require food manufacturers to declare the amount of iodine in their products.

Because of this, you should assume that most protein powders contain at least some iodine.

Protein powders made with dairy-based proteins, such as whey and casein, can contain high amounts of iodine.

So if you are on a low iodine diet, avoid whey and casein.

You might also want to avoid protein powder that contains carrageenan.

This common food additive is derived from seaweed, which is one of the foods that naturally contains the most iodine.

Again, if you need a protein powder that contains no iodine at all, you are likely out of luck.

But if you can settle for a few micrograms per serving, there are a few options, including nut-based protein powders like Almond Protein Powder.

According to the USDA database, 100 grams of almonds contains less than 1 milligram of iodine, so one serving of Unflavored Almond Protein Powder contains little to no iodine.

🚫 Avoid Food Additives

It is worth adding that if you are on a low iodine diet in preparation for radioactive iodine treatment, you should consider how the ingredients in your protein powder might affect your gut health.

Regularly consuming emulsifiers, thickeners, artificial sweeteners, and other ultra-processed additives might alter the makeup and function of your gut microbiome – the community of microbes living in your digestive tract (North Clin Istanb, 2020).

These shifts, known as gut dysbiosis, have been shown to interfere with radioactive iodine (RAI) uptake (Front Microbiol, 2025).

It is important to note that much of this research is still emerging, so more studies are needed to clarify these relationships.

That said, the preliminary findings suggest that because protein shakes and powders are something you consume regularly, if not every day, the cumulative effects of small amounts of potentially harmful ingredients is worth taking seriously.

⚠️ Here is a list of the most common food additives in protein shakes and powders:

• acacia fiber
• acacia gum
• acesulfame potassium
• artificial flavors
• ascorbic acid
• aspartame
• calcium carbonate
• carrageenan
• cellulose gum
• dextrin
• dicalcium phosphate
• dipotassium phosphate
• erythritol
• gellan gum
• guar gum
• gum arabic
• inulin
• locust bean gum
• maltitol
• maltodextrin
• mono- and diglycerides
• ‘natural’ flavors
• rice bran extract
• rice dextrin
• rice hulls
• rosemary extract
• silica
• silicon dioxide
• sodium alginate
• soluble corn fiber
• sorbitol
• soy lecithin
• sucralose
• sunflower lecithin
• tocopherols
• tricalcium phosphate
• xanthan gum
• xylitol
• zinc oxide

As a rule of thumb, if you cannot find an ingredient in nature or make it at home, it is probably a food additive.

🚫 Avoid Protein Concentrates and Isolates

I also recommend avoiding protein concentrates and isolates.

Most protein shakes and powders are made from one or both of these ultra-processed protein sources, which have been mechanically and/or chemically stripped of everything but the protein.

This includes the enzymes, fiber, and other natural digestive aids that help you break them down.

You therefore might not digest them in the same way that you do whole foods, which could affect your gut health.

For example, one study shows that regularly consuming protein concentrates and isolates might disrupt your gut microbiome (Nutrients, 2018).

Another study shows that it could cause the formation of toxic byproducts in your gut (Mol Nutr Food Res, 2024).

Although further research is needed, you can play it safe by choosing protein shakes and powders made from minimally-processed protein sources like egg whites and almonds.

Our customers find them to be more gut-friendly.

Order Samples to see for yourself.

Sources

1. Frontiers in Microbiology (Front Microbiol). Bifidobacterium depletion promotes goiter via gut-thyroid axis: evidence from Mendelian randomization and experimental validation. 2025.
2. Northern Clinics of Istanbul (North Clin Istanb). Food additives and microbiota. 2020.
3. The Journal of Experimental Medicine (J Exp Med). The gut microbiome: Relationships with disease and opportunities for therapy. 2019.
4. Internal and Emergency Medicine (Intern Emerg Med). Gut microbiota, intestinal permeability, and systemic inflammation: a narrative review. 2023.
5. Nutrients (Nutrients). Effect of a Protein Supplement on the Gut Microbiota of Endurance Athletes: A Randomized, Controlled, Double-Blind Pilot Study. 2018.
6. Molecular Nutrition & Food Research (Mol Nutr Food Res). In Vitro Fermentation of Animal and Plant Protein Isolates by the Human Gut Microbiota Under High and Low Carbohydrate Conditions. 2024.

Editorial Guidelines

---

This article was written by a Certified Nutrition Coach and reviewed by a Registered Dietitian. We rely on peer-reviewed research and trusted medical sources, and regularly update our content to ensure accuracy and clarity.