Thorne Verified: Soy-Free

Thorne Verified - Soy Free

Every Thorne product is made with the purest possible ingredients. Products with our Soy-Free Certification have been thoroughly tested to ensure they are soy-free.

What is a soy allergy?

Soy protein is one of the eight most common food allergens.1 In the United States, an allergy to soy, which often starts during infancy or childhood, affects as many as 1.5 million adults.1 According to the American Academy of Pediatrics' Committee on Nutrition, 10-14 percent of infants with a dairy allergy will react similarly to soy formulas.2

On this page, we will help you navigate what you need to know about a soy allergy, including the health concerns commonly associated with soy, what foods are obvious or hidden sources of soy, what Thorne products contain ingredients derived from soy, and what Thorne does to assure that you are aware of soy-containing products and to avoid hidden soy.

What are typical soy allergy symptoms?

If you have a soy allergy, then your immune system identifies certain soy proteins as harmful foreign substances and mounts an antibody reaction against the protein(s). Although soy allergies are common, they are typically not as severe as other food allergies. There are exceptions, of course, particularly in cases of cross-reactivity, such as with a peanut allergy, in which case a reaction to soy can be severe - even life threatening.

Soy allergies are most common in infants and toddlers and are often caused by a reaction to soy-based infant formulas. Such reactions usually manifest as digestive symptoms - colic, diarrhea, and vomiting. Although a child often outgrows a soy allergy, it can extend into adulthood with typical symptoms being hives, itching, runny nose, and digestive complaints.

Which foods contain or might contain soy?

The most common and obvious sources of dietary soy include anything directly derived from soybeans, including soy milk, soy flour, tofu, tempeh, soy sauce, tamari, soy nuts, soy grits, bean sprouts, edamame, miso, and natto. Less obvious foods that typically contain soy or are derived from soy include oyster sauce, teriyaki sauce, high-protein cereals, and some gluten-free breads.

Many processed foods also contain soy. For example, you might see some of these ingredients on a food label, which are, or might be, derived from soy: textured vegetable protein, hydrolyzed soy protein, MSG, mono- and diglycerides (emulsifiers used in ice cream, chewing gum, bread, nut butters, instant mashed potatoes, mayonnaise, and more), lecithin, and vegetable broths.

This website sponsored by the University of Wisconsin provides a more complete list of foods to avoid and foods to approach with caution, as well as foods to substitute for soy:

What about soy oil or foods derived from soy oil?

Soy oil is typically not a problem for a person with a soy allergy because it does not contain the allergenic protein component. However, cruder, less refined soy oils - expeller, cold-pressed, or extruded - can contain small amounts of soy protein. Soy lecithin can also contain small amounts of soy protein, although it is often not enough to trigger an allergic reaction in most individuals. The FDA says this in regard to soy oil: "Major food allergen" does not include a highly refined oil derived from one of the eight foods or food groups or any ingredient derived from such an oil.3

How can I tell if the food or dietary supplement I purchase contains soy protein?

By federal law, food and dietary supplement labels must indicate when a food or supplement contains an ingredient derived from soy. The eight most common food allergens (milk, wheat, eggs, soy, fish, shellfish, peanuts, tree nuts) must be listed separately and in bold font at the end of the ingredient list on a food label, and outside the Supplement Facts box on a dietary supplement label.

What does Thorne do to ensure there is no hidden soy protein in a dietary supplement?

In addition to clearly labeling products that are derived from soy, we carefully track all raw materials back to our vendors, who must verify the presence or absence of allergens, including soy.

Then, when the raw materials arrive at our facility, every ingredient for every product is quarantined when it first enters our facility. Allergen-containing ingredients are separated by allergen - milk, soy, fish, shellfish, etc. - and quarantined until they can be tested and moved into production. All ventilation systems are closed systems to avoid cross-contamination. After production of a particular product, the manufacturing equipment used is taken completely apart and thoroughly cleaned before it is used again to make another product.

On the rare occasion when there is concern about potential contamination, the product is tested for the presence of soy protein in our in-house, state-of-the-art laboratory. Our laboratory uses the well-known and well-accepted Enzyme-Linked Immunosorbent Assay (ELISA) method to analyze for amino acid sequences that would indicate the presence of soy proteins. See below in the FAQs about specific products tested.

Soy allergies and nutrient deficiencies

Soy is a good source of protein, thiamin, riboflavin, iron, calcium, zinc, vitamin B6, and folic acid. However, unless you have other dietary restrictions, these nutrients are readily available in other non-soy food sources.

Frequently asked questions about soy in Thorne products.

Q: Are your phytosome products soy-based?

A: Our phytosome products were previously derived from soy lecithin; now, however, most of them are derived from sunflower lecithin.

    Q: Do soy-derived phytosomes typically result in an allergic reaction?

    A: Because the lecithin from soy oil is not refined, there can be traces of soy protein. However, because the protein, if present, would be in trace amounts, it would not likely trigger an allergic reaction. If you have a severe soy allergy, then it is best to avoid them, however.

    Q: Does Thorne test soy-based products for the presence of soy protein?

    A: A number of Thorne products were tested for the presence of soy proteins using Elution Technologies Soy Protein ELISA Test.

      Q: Did any products test for significant levels of soy protein?

      A: The products that were found to have a significant amount of soy protein were products we have since switched to sunflower-based phytosomes - curcumin phytosome, green tea phytosome, and silybin phytosome.


      1. Gupta R, Warren C, Smith B, et al. Prevalence and severity of food allergies among US adults. JAMA Netw Open 2019;2(1):e185630. doi:10.1001/jamanetworkopen.2018.5630

      2. Bhatia J, Greer F. Use of soy protein-based formulas in infant feeding. Pediatrics 2008;121(5):1062-1068. doi: 10.1542/peds.2008-0564

      3. [Accessed Nov. 23, 2020]