Thiosel Selenomethionine Supplement
Thiosel Selenomethionine Supplement
Thiosel Selenomethionine Supplement
Thiosel Selenomethionine Supplement

"I slept better than I have in years and I feel rested when I wake up. My mood has improved tremendously!!" - Lianne


Thiosel Selenomethionine Supplement

Formulated to support thyroid hormone conversion, protect against oxidative damage, boost immune system, and reduce antibodies†. Experience the difference of an organically-sourced selenium supplement.

$ 77.00

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Supports thyroid conversion†

  • Pre Conversion

    Helps prepare for hormone creation†

  • Pro Conversion

    Helps support when hormones are created†

  • Post Conversion

    Helps protect from oxidative stress†



With thousands of multivitamins and minerals on the market, there's never been one quite like this. Thiosel is a powerful antioxidant formulated with whole-food, organically sourced selenomethione, ideal for supporting thyroid hormone conversion with lowered risk of toxicity.†(1)


selenomethionine INFO



Whole-Food, Selenomethionine

This nutrient-rich whole-food selenium is made in a physiological dose, formulated to support healthy absorption†, detoxification, and thyroid conversion.


Unlike inorganic selenate and selenite which are absorbed by a simple diffusion process and have a greater risk of selenium toxicity,  Thiosel contains organically-sourced selenomethionine for it's absorption into body proteins through the amino acid transport mechanism (1, 2).   


Suggested Use: As a dietary supplement, take one (1) capsule daily, preferably with food, or as directed by a healthcare professional.




1 Capsule


Selenium (as Selenomethionine): 200 MCG 

% of DV: 365%

Other Ingredients: Vegetable cellulose capsule

Daily Value based on a 2,000 calorie diet.




1. Prime & Convert

Thiosel is formulated to help support the thyroid gland during thyroid conversion and protect from oxidative damage for improved focus, and energy.†

2. Fuel

Thiodine provides fuel for the thyroid gland to help make thyroid hormones, and detox bromine and fluoride for improved thyroid function and metabolism.†

3. Detox

Thiosalt is formulated to help support halide detox, restore electrolytes, and support adrenal function for immune strength, focus, and energy.* 



Miss Lizzy Answers

Founder, patient, advocate, wife, and mom, I'm here to answer your questions!

Is Thiosel suitable for Hashimoto's?


According to research and patient experience, selenium may be a vital nutrient for people with Hashimoto's especially when supplementing with an iodine supplement like Thiodine. Selenium plays a vital role in thyroid hormone creation because it helps protects the thyroid from oxidative damage, as well as convert thyroid hormones into energy. 

Some experts recommend taking a physiological dose of selenium (as selenomethionine) of 200 mcg- 400 mcg/day. Of course we always recommend working with a medical practioner and doing what's right you.

For those with Hashimoto's and the MTHFR continue to the next question for more information.


Can I take Thiosel if I have MTHFR Gene C667 and A1298


With genetics testing through sites like 23andme and books like "Dirty Genes," MTHFR and methylation are big topics these days. Especially in the thyroid and Hashimoto's communities. In simple terms, some people with markers for the MTHFR C667T and A1298C have reported issues in methylation or "breaking things down for use or removal." (5) 

When the MTHFR genes are working correctly, the body can break down minerals for use and removal more effectively. When the MTHFR genes are not working effectively, some people might experience high iron levels with low ferritin, high levels of B12, folate, and selenium. 

MTHFR can be a complex topic, so it is especially important to work with a medical professional who has experience in genetics and MTHFR. 

Recently we learned my husband has the MTHFR C667 and A1298. So we had his homocysteine and selenium levels tested and discovered they were relatively high. For this reason, he is careful about supplementing with selenium until he can talk with his doctor about MTHFR and methylation. As a customer, I think of you as someone in my family. I want to research and information so you can make informed choices for your health.


Can I get selenium from brazil nuts and food?


The amount of selenium in brazil nuts and other foods can vary a lot based on the soil nutrients, just like the Goiter Belt's low levels of iodine. In other countries where Brazil nuts are grown, the selenium content of the soil and farming conditions can vary quite a lot. For this reason, food sources may be unreliable sources of selenium. When it comes to health issues like Hashimoto's and Hypothyroidism, "in-range" selenium levels seem to play a significant role. Personally, and for my family, I want to be precise about my selenium intake.†


Are there risks in consuming too much selenium?


Yes. Like anything in life and health, the key is finding what's "just right" for your unique needs. At doses greater than 900 mcg/day and chronically high intake, selenium toxicity is possible. Selenium toxicity symptoms may include gastrointestinal upset, tremors, dermatitis, fatigue, irritability, garlic odor of the breath, abnormal nails, hair loss, and peripheral neuropathy. Treatment of high levels of selenium may involve reducing selenium consumption. (6,7). It's my hope to help you find answers, not create problems. So please always consult a medical practioner.


Is there a test for selenium levels?


There are a couple of options for selenium testing. First is the RBC test, which measures serum selenium levels in the blood. Typically the RBC is ordered through a doctor's office and may be covered by insurance. According to patient groups, the ideal selenium level will be at the upper end of the lab's reference range. If selenium levels are mid to low within the range, selenium supplementation may be beneficial. Another popular method for testing mineral levels, including selenium, is through Hair Tissue Mineral Analysis. While insurance may not cover HTMA, a skilled practitioner may be able to provide mineral analysis for your unique situation. Again, please consult your doctor. This information is not meant as advice and should never replace the advice of your doctor.


Are there any interactions with other supplements or medications?


We are not aware of interactions between Thiosel and our other supplements but interactions may exist with other supplements and medications. Please consult your doctor or pharmacist before taking this or any supplement.


14 Day Returns Policy


Important 2020 Policy Changes

For health and safety reasons due to Covid-19, we can't accept returns of opened product bottles. Only unopened products can be submitted for return and within 14 days of delivery.

Before ordering please make sure our supplements are right for you, including consulting with your doctor or medical practitioner. 

Read our returns policy to learn more.




Miss Lizzy Supplements are extensively researched and explicitly hand-selected for people who have thyroid issues (or just know something isn't right) and want to take the guesswork out of finding the best supplements.


Certified quality sets us apart. Miss Lizzy stands for the highest quality in thyroid supplement manufacturing. Our supplements are manufactured under cGMP in the USA for quality, consistency, and purity under the US Pharmacopeia. 

Individually Sourced

It's our commitment at Miss Lizzy to source each ingredient individually from the best USP grade suppliers, and custom manufacturer all our supplements to ensure you are getting premium-grade, high-potency supplements without extra fillers or additives.

The U.S. Food and Drug Administration has not evaluated statements made on this website. Our products are not intended to diagnose, treat, cure, or prevent any disease. Information provided by this website or this company is not a substitute for individual medical advice. Caution: Do not exceed the recommended dose. Pregnant or nursing mothers, children under the age of 18, and individuals with a known medical condition should consult a physician before taking any dietary supplement. Do not use if safety seal is damaged or missing from any product. Keep out of reach of children.








7. Selenium can interact with certain medications, and some medications can have an adverse effect on selenium levels. 

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