T3 Conversion Booster | T3 Thyroid Support Supplement

Newly Reformulated with 4x Ashwagandha (200 mg/serving)

T3 Conversion Booster | T3 Thyroid Support Supplement (60 Day Supply)

$43.99 or subscribe and save 5%

Ready to help your body naturally produce more of the most powerful thyroid hormone? T3 Conversion Booster provides you with natural vitamins and botanicals that have been documented to support and enhance peripheral T4 to T3 conversion, the process by which your body creates T3. These hand-picked, scientifically proven, and thoughtfully dosed ingredients can help improve thyroid function, reduce thyroid-related symptoms, and boost metabolism*. 

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Manufactured in The USA

Third-party tested for purity

60-day Money Back Guarantee


Will T3 Conversion Booster single-handedly manage 100% of your thyroid symptoms and render your thyroid medication unnecessary?

Definitely not!

But it is a physician-formulated thyroid support supplement designed to help your body and thyroid create more of the most powerful thyroid hormone that exists: T3.

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Now is probably also a good time to mention that it has been used by tens of thousands of thyroid patients and boasts over 1,900+ reviews from people just like you.

And as an added cherry on top, when you purchase any supplement from Dr. Westin Childs you get the added benefit of knowing:

  • Every product is relentlessly tested and formulated using a combination of clinical experience and research.
  • We go above and beyond in testing and evaluating our supplements for safety and efficacy using transparent third-party tests. Every lot is tested by an ISO-accredited laboratory for heavy metals, pathogens, mold, toxins, and bacteria ensuring the best possible product for you.
  • Every order is backed by our 60-day money-back guarantee.


T3 is the most powerful thyroid hormone in the body and the majority of it is produced through a process known as peripheral thyroid conversion.

In this process, your body takes T4 and transforms it into T3 by removing iodine.

Without this step, your body would be unable to create and use thyroid hormone because the most abundant thyroid hormone (T4) is inactive.

Whether you are taking a T4-only thyroid medication like levothyroxine or something is impeding your body’s ability to create T3, this process is critical to helping you feel your best.

And the natural and botanical ingredients found in T3 Conversion Booster allow this process to move forward unencumbered:

  • Guggul extract (Commiphora mukul) (oleogum-resin) 500 mg – Guggul is a botanical compound gathered from the sap of a tree native to India that has been used in Ayurvedic medicine for centuries. Studies have shown that this compound has broad benefits on inflammation, liver health, obesity, and acne. In addition, it has also been documented to have pro-thyroid benefits as it increases iodine uptake into the thyroid gland and enhances thyroid peroxidase function.*
  • Rosemary Extract (rosemarinus officinalis)(leaf)(5% rosemarinic acid) 50 mg – By acting as a powerful antioxidant and anti-inflammatory agent, rosemary extract may help protect the thyroid gland from inflammation-induced damage. It’s also been shown to have beneficial effects on T4, T3, and TSH, and may promote TSH receptor function. On top of these pro-thyroid benefits, it’s also been shown to have anxiolytic and anti-depressant effects.*
  • Ashwagandha (withania somnifera)(root) 50 mg – Acting as an adaptogenic compound, Ashwagandha has been shown in studies to increase T4 and T3 levels, normalize the TSH in patients with subclinical hypothyroidism, and improve cortisol regulation. This isn’t even taking into account the beneficial effects that Ashwagandha has on weight loss and the building of muscle mass, both of which are problems thyroid patients struggle with. These combined benefits make Ashwagandha one of the best adaptogens for thyroid support.*
  • Zinc (as zinc citrate) 5 mg – Perhaps one of the most well-known thyroid-supporting nutrients, zinc helps directly support T4 to T3 Conversion as well as the binding of thyroid hormone to the nuclear receptor due to its incorporation in the zinc-finger domain. Zinc is included in this formula in an effective dose sufficient to support this function while also limiting your risk of developing GI distress which is common with other forms and doses of zinc.
  • Selenium (as l-selenomethionine) 100 mcg – Selenium is required for important enzymes, called selenoproteins, to function. These selenoproteins help convert T4 to T3 in various tissues and support the production of glutathione in the thyroid gland. In low selenium states, your thyroid gland is more prone to oxidative damage when it creates thyroid hormone which puts you at increased risk for autoimmune thyroid disease. Replacing selenium not only protects the thyroid gland but also supports the production of T3 directly. Selenomethionine is one of the most usable forms of selenium which is why it’s included in this formula.

You can create all of the T3 in the world, but if your cells can’t use it, it’s basically useless.

That’s why in addition to containing a T4 to T3 conversion boosting blend, T3 Conversion Booster also contains a thyroid cellular sensitivity blend.

And the job of this blend is to allow your newly created T3 to do its job by interacting with the thyroid nuclear receptor found in the nucleus of all of your cells.

The specialty ingredients that help this process work efficiently include:

  • Vitamin A (as retinyl palmitate) 450 mcg RAE – Vitamin A forms a complex on the thyroid hormone receptor that enhances the binding of thyroid hormone. In other words, without sufficient vitamin A, T3 is much less effective. And given that roughly 45% of the U.S. population doesn’t consume enough vitamin A in their diet, there’s a very high chance your thyroid body doesn’t have what it needs. This effect on thyroid hormone binding is so powerful that suboptimal vitamin A reduces total T3, total T4, free T3, and free T4. T3 Conversion Booster contains a pre-activated form of vitamin A which is easily usable by thyroid patients.
  • Zinc (as zinc citrate) 5 mg – Perhaps one of the most well-known thyroid-supporting nutrients, zinc helps directly support T4 to T3 Conversion as well as the binding of thyroid hormone to the nuclear receptor due to its incorporation in the zinc-finger domain. Zinc is included in this formula in an effective dose sufficient to support this function while also limiting your risk of developing GI distress which is common with other forms and doses of zinc.

Thyroid biosynthesis is a fancy word that describes the production of thyroid hormone from the thyroid gland.

Each and every day, your thyroid is supposed to produce about 80 to 100 mcg of T4 and around 30 mcg of T3.

If you have been diagnosed with hypothyroidism then you know that this number is much less.

But you can enhance its production by providing your body with the building blocks that it needs to create thyroid hormones.

And the thyroid biosynthesis blend found in T3 conversion Booster can help you do just that which is why it contains:

  • Iodine (from organic Icelandic kelp)(laminaria digitata)(stem and leaf) 75 mcg – Iodine creates the backbone of thyroid hormone and is required in optimal amounts for thyroid hormone production. Iodine deficiency is the most well-documented cause of hypothyroidism and is completely preventable. Based on the physiologic needs, regulatory bodies recommend that adults consume 100 to 300 mcg of iodine per day. Unfortunately, the average American consumes around 130 mcg per day which creates a deficiency of up to 20 to 90 mcg that can build up over time. The iodine in T3 Conversion Booster combats this problem by making up the difference.
  • Vitamin D3 (cholecalciferol) 200 IU – Vitamin D protects your thyroid gland from autoimmune thyroid disease and thyroid cancer. Research has also shown that the severity of hypothyroidism tracks closely with the degree of Vitamin D deficiency that one experiences. T3 Conversion Booster contains the most activated form of vitamin D, cholecalciferol, in low doses so you can take advantage of vitamin D3-supporting thyroid benefits while also allowing you to safely combine it with higher doses of vitamin D as needed.
  • Vitamin E (as d-alpha tocopheryl succinate) 33.5 mg – Vitamin E helps protect the integrity of your cell membranes and acts as a powerful antioxidant which may indirectly help improve thyroid function.

*Note on iodine: some people believe that iodine is harmful for those with thyroid conditions but this is 100% incorrect. Iodine cannot be created by the body and it is required for thyroid hormone production. Doses of iodine between 100 mcg and 300 mcg have been proven to be safe, effective, and even therapeutic for thyroid patients (including those with Hashimoto’s). The iodine in T3 Conversion Booster is complemented with selenium to protect against iodine-induced thyroid damage.

Dr westin childs photo

Why Dr. Childs Recommends It

T3 is the most important thyroid hormone in your body. As a thyroid patient, you should put most of your effort and energy into improving T3 levels if you want to feel better!

T3 Conversion Booster was specifically formulated to naturally help your body create more of that powerful thyroid hormone. And because so many thyroid patients aren’t converting well, enhancing this process is a no-brainer for just about every thyroid patient.

Used by over 80,000+ people who have left over 10,000+ reviews

Ingredients That Work

Ingredients and dosages are thoughtfully chosen, relentlessly tested, and continually refined.

Physician Formulated

All formulas have been created by Dr. Westin Childs based on his clinical experience and evaluation of peer-reviewed scientific research.

Made in the USA

Our supplements are proudly made in the USA, with globally sourced ingredients, in a GMP-compliant facility and shipped from Mesa, Arizona.  

Third-Party Tested

Every single supplement lot is third-party tested for heavy metals, microbes, mold, and contaminants by an ISO-accredited lab testing facility.

Free Domestic Shipping

Every order (regardless of price) placed in the U.S.A. will ship free with USPS.

60-Day Money Back Guarantee

If you don’t love your supplements then you can return them for a full refund! No questions asked and no hoops to jump through. 

Frequently Asked Questions

Yes! T3 Conversion Booster was designed to be used with all thyroid medications including those that contain T3 like Cytomel and liothyronine, and formulations of NDT like Armour Thyroid, NP Thyroid, and Adthyza.

For best results, take it 30-60 minutes away from your thyroid medication (either before or after).

In short, maybe, but not always.

In general, thyroid support supplements typically do not have a big impact on thyroid lab tests especially when compared to prescription thyroid medications.

This is because they each contain different ingredients and each has a different mechanism of action.

Thyroid medications typically have a bigger impact on thyroid lab test levels like TSH, free T3, free T4, and reverse T3.

Thyroid support supplements like T3 conversion booster tend to work more at the cellular level which impacts symptoms but doesn’t always impact thyroid lab test results.

This isn’t always the case, though, as some people do see changes to their lab tests when using these types of supplements.

But because of the reasons listed above, the best way to determine if it’s working for you is by evaluating how you are feeling, not your thyroid lab tests.

Yes! T3 Conversion booster is still beneficial to those without a thyroid and for those with a nonfunctioning thyroid gland (those who have undergone RAI).

The reason is simple:

Even if you don’t have a thyroid gland, you still need to produce T3 and because thyroid conversion occurs outside of the thyroid gland, it doesn’t really matter if your thyroid is present or not.

It can be argued that T3 Conversion Booster is even more important for those who no longer have a thyroid gland because they are all almost exclusively taking T4-only thyroid medications like levothyroxine which require conversion to become active.

Each of these supplements supports your thyroid in a different way and here’s an easy way to differentiate them:

T3 Conversion Booster primarily helps your thyroid convert T4 into T3 and produce more T3 thyroid hormone.

Thyroid Adrenal Reset Complex provides support to the thyroid-adrenal connection.

Thyroid Glandular+ provides direct support to the thyroid gland as well as the pituitary gland.

Each supports a difference aspect of thyroid function which is why they can all be safely combined and used together.

T3 Conversion Booster is considered a low thyroid support supplement so you generally would not want to take it if you are in a state of thyroid overactivity or hyperthyroidism.

Having said that, there are a few situations where it may make sense to use low thyroid support if you have been labeled with hyperthyroidism:

#1. If your thyroid has been surgically removed. If your thyroid has been removed then you are considered to be hypothyroid even if the reason for the removal was due to hyperthyroidism.

#2. If your thyroid has been ablated with radioactive iodine. If your thyroid has been ablated then you are considered to be hypothyroid even if the reason for the ablation was due to hyperthyroidism.

#3. If you are undergoing block and replace therapy or add-back therapy for hyperthyroidism.

Block and replace therapy is an uncommon treatment used in some situations where a patient with hyperthyroidism will take both thyroid medication like levothyroxine as well as thyroid blocking medication like methimazole.

If you are undergoing this kind of treatment (which is uncommon) then you can consider thyroid support supplements as well.

In general, if you are using thyroid-blocking thyroid medication like methimazole then you probably shouldn’t use T3 Conversion Booster.

On the other hand, if you are taking any sort of thyroid medication replacement like levothyroxine (or any others) then you can consider using T3 Conversion Booster.


If you are trying to lower reverse T3 levels then focusing on free T3 makes a lot of sense.

Here’s why:

Your body has the option to turn T4 into either T3 or reverse T3. When you push the pathway down the T4 to the T3 route, you will necessarily reduce how much T4 is available for reverse T3 production.

In other words, anything that decreases T4 to reverse T3 conversion will increase free T3 and anything that increases T4 to T3 conversion will decrease reverse T3.

T3 Conversion Booster contains two ingredients that can sometimes be problematic for those who are pregnant: vitamin A and ashwagandha.

These aren’t necessarily harmful, but you will get differing opinions on their use during pregnancy depending on who you are talking to.

For this reason, we always recommend that you get approval from your ob/gyn or midwife (or whoever is caring for you during pregnancy) prior to using any supplement including this one.

Yep! You don’t need to be taking thyroid medication in order for T3 Conversion Booster to be beneficial.

It just so happens that most people who take it are already taking thyroid medication as well but there are plenty of people who aren’t and they have had success using it.

Great question!

We’d all like to believe that our doctors are 100% up to date on the latest research as it pertains to all aspects of our health and thyroid but that just isn’t the case.

If they were then we wouldn’t have an epidemic of unhappy thyroid patients who still struggle with low thyroid symptoms despite taking their thyroid medication and doing everything else correctly.

For now, the existing thyroid treatment paradigm leaves a lot to be desired which means extra help outside of traditional medications and treatments are often needed.

These treatments in the form of supplements and lifestyle changes are only necessary for those people who are not feeling 100% right now.

If you are someone who is not experiencing symptoms like fatigue, weight gain, cold intolerance, pain, depression, and so on, then you’d have no need to use thyroid support supplements like T3 Conversion Booster.

But if you are like many other thyroid patients out there who are still suffering then it would be worth considering!


Instead of containing T3 thyroid hormone, T3 Conversion Booster contains natural ingredients that help your body produce a healthy level of T3.

This means that there is never a risk of overproducing T3 and that it can be added to medications that contain T3.

The recommended dose is 2 capsules taken each day (with or without food) before noon and at least 30-60 minutes away from your thyroid medication (if you take any).

At 2 capsules each day this supplement will provide you with a 60-day supply.

Unlike Cytomel and liothyronine which contain T3 thyroid hormone, T3 Conversion Booster contains all natural ingredients in the form of vitamins and botanical ingredients.

T3 Conversion Booster can be taken indefinitely and I recommend using it for as long as it is helping you feel better.

Thyroid function is slow to respond when compared to other hormone systems in the body.

It takes 6 weeks of daily use of any thyroid hormone or thyroid support supplement before your body will reach a steady state which means it will take at least this long before you start noticing a difference in how you feel.

After 6 weeks you will start to see some improvement but it may take several months for you to feel its full effects.

The best way is to pay attention to how you are feeling! Most people know it’s working because they feel an increase in energy, an improvement in well-being, and an improvement in their thyroid symptoms.

What type of improvement you may experience depends largely on how your thyroid is impacting your overall health.

Each person has a slightly different set of symptoms so how they respond to T3 Conversion Booster will vary as a result of this.

No, getting your T3 tested is not required before using this supplement. Having said that, you are certainly welcome to do that if you’d like!

Over the last 8 years, tens of thousands of thyroid patients have used T3 Conversion Booster and it is generally very well tolerated.

Yes! In addition, it does NOT contain wheat, gluten, yeast, soy protein, dairy products, fish, shellfish, peanuts, tree nuts, eggs, artificial colors, artificial sweeteners, or artificial preservatives.

Yes! T3 Conversion Booster has been used by thousands of patients with Hashimoto’s without any issues. I formulated T3 Conversion Booster with a small dose of iodine accompanied by selenium to protect against any iodine-related issues.

Remember: Iodine is required by all humans because we can’t produce it on our own and we need it for thyroid hormone production. The key to using iodine safely is to use the right dose and combine it with selenium. This supplement was specifically formulated to meet these requirements which is why it is quite safe.

Each serving of T3 Conversion Booster contains 75mcg of Iodine which is well below the recommended high range of iodine intake of 300mcg per day.

All domestic orders receive free shipping regardless of price. Orders are typically processed within 1 business day, they are shipped out via USPS Ground Advantage and typically arrive within 1-3 business days.

We also offer intentional shipping to most countries as well! International orders ship free if the order value is greater than $250 USD. Otherwise, the price of shipping is calculated on the checkout page. We primarily use USPS for international shipments.

All of my products come with a 60-day money-back guarantee. I’m confident that my products will work for you but, in case they don’t, for whatever reason, you can return them for a full refund within 60 days. It makes purchasing them a no-brainer!

You can find more information about our return and refund policy by clicking here.


We go above and beyond what is required by the FDA for supplement companies.

Every single lot that we produce is third-party tested for heavy metals, pathogens, bacteria, mold, and yeast.

The results are then displayed publicly on this page.

Don’t hesitate to reach out! Please email us at hello@restartmed.com and we will do our best to get back to you within a day or so! You can also call us here: (480) 331-9431.

Questions about our quality standards? Please see this article for more information.


T3 Conversion Booster is still helpful even for those without a thyroid.

This is for several reasons including:

#1. Thyroid conversion occurs outside of the thyroid gland. In other words, this process is still important and continues to occur even if your thyroid gland has been removed or has been damaged.

And #2. Most thyroid patients without a thyroid are using T4-only thyroid medications like levothyroxine and Synthroid.

We know from research studies that patients without a thyroid are usually unable to obtain optimal T3 levels with T4 thyroid medications alone.

For this reason, it’s usually more important for someone without a thyroid to take T3 thyroid support supplements.

Scientific References

#1. https://pubmed.ncbi.nlm.nih.gov/23378454/

#2. https://pubmed.ncbi.nlm.nih.gov/7196691/

#3. https://pubmed.ncbi.nlm.nih.gov/15531495/

#4. https://pubmed.ncbi.nlm.nih.gov/6785400/

#5. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3921055/

#6. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5618598/

#7. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6166548/

#8. https://pubmed.ncbi.nlm.nih.gov/28895880/

#9. https://pubmed.ncbi.nlm.nih.gov/24533019/

#10. https://pubmed.ncbi.nlm.nih.gov/23001627/

#11. https://pubmed.ncbi.nlm.nih.gov/23255045/

#12. https://pubmed.ncbi.nlm.nih.gov/9537635/

#13. https://pubmed.ncbi.nlm.nih.gov/31805673/

#14. https://pubmed.ncbi.nlm.nih.gov/28213641/

#15. https://pubmed.ncbi.nlm.nih.gov/21406454/

#16. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4049553/

#17. https://pubmed.ncbi.nlm.nih.gov/25591468/

#18. https://pubmed.ncbi.nlm.nih.gov/11396709/

#19. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3063534/

#20. https://www.ncbi.nlm.nih.gov/books/NBK28/

#21. https://pubmed.ncbi.nlm.nih.gov/16131334/

#22. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3746228/

#23. https://pubmed.ncbi.nlm.nih.gov/17541266/

#24. https://pubmed.ncbi.nlm.nih.gov/30982439/

#25. https://pubmed.ncbi.nlm.nih.gov/25758370/

#26. https://pubmed.ncbi.nlm.nih.gov/20688624/

#27. https://pubmed.ncbi.nlm.nih.gov/10201332/

#28. https://pubmed.ncbi.nlm.nih.gov/31056723/

#29. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5307254/

#30. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8658851/

#31. https://pubmed.ncbi.nlm.nih.gov/26313901/

#32. https://pubmed.ncbi.nlm.nih.gov/1384621/

#33. https://pubmed.ncbi.nlm.nih.gov/1284327/

#34. https://pubmed.ncbi.nlm.nih.gov/26098657/

Additional information

Weight 0.25 lbs
Dimensions 2.5 × 2.5 × 5 in

*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure or prevent any disease.

**Results may vary.

Customer Reviews

Based on 2029 reviews
Lynne S.
Help at last!

Have been feeling better since information I received from Dr. Childs and the medication I have received. I have learned a great deal about hypothyroidism through his articles. Great to have found a source for medicine and information

Sandy D.

I have not noticed a change/loss yet in my weight. I understand it takes time so I am not giving up. I will continue with your products. Thank you for checking in.

Albert M.
Short Term Inprovement

Have been taking T3 Conversion Booster for about a month. My TSH has dropped a bit and RT3 has also dropped a bit. T3 also up a bit. Will continue to supplement since I’m going in the right direction

T3 Conversion Booster

I have taking the T3 Conversion Booster for about 45 days now and can feel a difference in my energy levels. I cannot wait get my levels tested!

Jeris H.
Feel better

I just started this a little over a month ago. I do feel better than I did while taking levothyroxine. We’ll see what the next 45 days goes.

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T3 Conversion Booster | T3 Thyroid Support Supplement (60 Day Supply)
$43.99 or subscribe and save 5%
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