Do GLP-1 Agonists Cause Thyroid Cancer (Wegovy, Saxenda, Etc.)

Do GLP-1 Agonists Cause Thyroid Cancer (Wegovy, Saxenda, Victoza, Etc.)

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Do the most popular weight loss medications of our time like Wegovy and Saxenda cause thyroid cancer?

There’s a very high probability that they do and this is particularly concerning for most of the people that will be reading my blog, because, spoiler alert, it’s pretty much all about thyroid-related problems. 

Even though that’s the case, there are still some pretty strong arguments for the use of GLP-1 agonists (at least in my opinion) so don’t freak out just yet. 

Before we talk about the association and connection between their use and the risk of thyroid cancer, let’s take a step back and talk about some basics: 

What Are GLP-1 Agonists & Why Should You Care? 

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Before we talk about that, let’s take a step back and talk about some basics here. 

What the heck are GLP-1 agonists? These are incredibly popular weight loss medications (1) that were originally designed to treat diabetes. 

They were subsequently found to have a profound impact on weight which is why they are now being marketed as weight loss medications. 

And, for those wondering, yes, they work. 

In fact, I’ve personally recommended and prescribed them to patients who have been writing about their use for many years. 

You can see these articles that I’ve written on the benefits of Saxenda and Victoza and see several case studies with before and afters here and here

But just because I’ve recommended them in the past doesn’t mean I still necessarily will recommend them today. 

My opinion has evolved and changed over time as I’ve looked at these studies and as I’ve seen what is possible with other treatments. 

And when you look at the potential pros and cons of these GLP-1 agonists, they don’t always make sense. 

After all, you really wouldn’t want to take a medication if the negative side effects of that medication outweighed the positive ones. 

For purposes of this article, when I make reference to GLP-1 agonists and their risks I am really referring to any of the medications found inside this class which includes: 

These are the brand names of these medications so you also might know them as:

  • Dulaglutide
  • Exenatide
  • Semaglutide
  • Liraglutide
  • Lixisenatide

This isn’t a full list but it hits all of the major and most popular brands and names. 

Why does this all matter right now?

For one big reason:

It’s likely the case that the entire class of GLP-1 agonists may be the most talked about medications ever. 

I mean that seriously because it’s never been the case that so many people are talking about the impact that they can have on weight loss, diabetes, insulin resistance, and appetite suppression. 

The market cap for GLP-1 receptor agonist medications was just 11.3 billion in 2019 and is predicted to grow at a compounded rate of 6.1% of each all the way to 2027

the predicted growth of the glp-1 market over the next 4 years

In other words, if this risk of thyroid cancer is real (and I think it is) we will potentially see an explosion in thyroid cancer and its related problems in the coming decade. 

It’s easy to get caught up in the hype of shiny new things on the internet but you have to remember that pharmaceutical medications do carry real risks and there have been plenty of instances where medications cause serious harm to a lot of people.  


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GLP-1 Agonists & Thyroid Cancer: Is The Risk Real?

With this as the backdrop, let’s discuss the connection between thyroid cancer risk and the use of these medications. 

So is the risk real?

It’s hard to say definitively that there’s fire but we can confidently say that there’s an awful lot of smoke. 

And where there’s smoke, you can often find fire, even it takes a little while to actually find it. 

This potential risk of thyroid cancer is a huge deal for patients for two important reasons:

The first? Obviously, cancer of any type is not something that you want to deal with. 

And second? If weight is your primary concern then getting thyroid cancer is one of the worst to get. 

The treatment for thyroid cancer is thyroid removal and once the thyroid has been removed, weight loss becomes incredibly difficult if not almost impossible. 

When I first started recommending GLP-1 agonists for weight loss back in 2016 and 2017 there was some small evidence that they were associated with thyroid cancer. 

At the time, I wasn’t really concerned because the studies were small and were done primarily in animals. 

Times have changed a bit and newer and larger studies have been done since that time. 

The most recent study from France titled “GLP-1 receptor agonists and the risk of thyroid cancer” (2) concluded that there was, in fact, an increased risk of all thyroid cancer and medullary thyroid cancer with the use of GLP-1 receptor agonists, in particular after 1-3 years of treatment”. 

And this study was quite large as far as studies go. 

They evaluated 3.7 million patients with diabetes and found roughly 2,500 cases of thyroid cancer.

Based on hazard ratios, this equates to roughly a 58% increased risk of developing all thyroid cancers and a 78% increased risk of developing medullary thyroid cancer compared to controls.

Percentages can sometimes be misleading, especially when we are talking about numbers that are fairly small so looking at the incidence is also helpful.

Based on the total population size of 3.5 million and the roughly 2,500 people who developed thyroid cancer, this puts us at an incidence of around 0.07%.

With numbers like these, it’s easy to get carried away and make a mountain out of a molehill because, at the end of the day, a 0.07% risk is not very high. 

I’m not saying there’s nothing to worry about, by any means, because this incidence matters a whole lot to the 2,500 people who did end up with thyroid cancer. 

But I am saying that with low numbers like these, it makes it easy to create a connection where there is none which can make evaluating this data particularly difficult.

But, even if it is the case that the risk of thyroid cancer turns out to be complete noise, it still wouldn’t change the fact that most people would be better off avoiding GLP-1 agonists for the reasons listed here.

This isn’t the only study to suggest there is a link between thyroid cancer and the use of this class of medications.

For additional perspective, here’s a list of more studies that show the same: 

It’s worth pointing out that while there is still debate on this topic, the larger and bigger studies on this issue seem to support a connection between the two. 

So even if there is existing debate, it seems that the trend is moving toward a real connection rather than a non-existent one. 

Should You Worry If You Are Taking A GLP-1 Agonist?

At the end of the day, you need to take a hard look at your own personal situation and see if the risk, however small, is something that you are willing to handle. 

My own personal opinion is that it’s ideal to avoid these medications if at all possible because it is my belief that it is possible to lose weight and feel better without the need for prescription medications. 

And going this all-natural route is always the preferred first route because the benefits are just so great. 

At the same time, I also realize that not everyone thinks like me and there are plenty of people out there who want to get faster results because their weight is causing a negative psychological impact. 

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There are also others who are just operating on bad advice because they are listening to governmental agencies about what is best for their health. 

It’s mind-blowing to me that people are taking nutritional advice from agencies that try to convince them that frosted mini wheats are healthy than eggs (7) or that pizza counts as eating a vegetable and yet that is the world we live in. 

Either way, there will be people who will want to use these medications (perhaps even you) so here are some takeaways to consider before you do: 

How to Minimize Your Risk of Side Effects & Maximize the Benefits

#1. If you do use them, use them for a short period of time. 

Based on the studies, it appears that the length of time that you take these medications matters. 

The risk of thyroid cancer doesn’t seem to appear until about the 1-3 year mark. 

This means there may be a situation in which using them temporarily may allow you to take advantage of faster weight loss while also minimizing the risk of cancer. 

And if you were to use them, this would be the preferred way. 

If you were to combine the use of GLP-1 agonists with fasting, a whole-food diet, and regular exercise, you really shouldn’t have a problem hitting your target goal within about 1 year or so. 

This is the method that I frequently recommended using GLP-1 agonists when I was prescribing them and it worked out well for many people. 

There were countless reports of people who were able to adjust their lifestyle, lose weight, and get off of these medications within a set time frame. 

#2. Think about your total cancer risk for perspective. 

Even though the risk of thyroid cancer with the use of GLP-1 agonists is small, let’s assume for a minute that it is large. 

Even if it was large, there would still be a scenario in which it may make more sense to temporarily increase your risk of thyroid cancer for a short time to take advantage of the decreased risk of cancer that losing weight provides. 

We know that at LEAST 13 different cancers (8) are associated with obesity including:

  • Brain
  • Kidney
  • Breast
  • Uterus
  • Gallbladder
  • Stomach
  • Liver
  • Ovaries
  • Pancreas
  • Thyroid
  • Meningioma
  • Multiple myeloma
  • Colon
obesity and the risks that it imposes on your overall health

And obesity doesn’t just stop there in terms of its negative impact on your health. 

It also increases your risk of developing conditions like cardiovascular disease, stroke, high blood pressure, high cholesterol, PCOS, low testosterone, diabetes, and more. 

When you look at your total health in the context of the pros and cons of weight loss, it’s easy to see a scenario in which trading a small increased risk of thyroid cancer for the potential decreased risk in multiple health conditions AND a reduced risk of overall cancer, is worth it. 

Now this all assumes that you’ve tried and failed other medications and treatments, though. 

Because why take any risk period when you can just healthily eat and fast your way out of obesity WITHOUT accepting any risks for medications?

This is obviously the preferred way but I’m just highlighting the fact that sometimes it may make sense to use a GLP-1 agonist for its overall benefits on your health. 

This method of looking at the pros and cons is always the best way to look at any therapy but, when you do, make sure you take into account all pros and cons. 

side effects associated with the use of liraglutide

I’ve really only mentioned the biggest con of GLP-1 agonists which is a potential risk of thyroid cancer but there are others to consider such as muscle loss as well. 

Just make sure to include all of these factors in your decision! 

What to Do Instead:

So is it worth it to use GLP-1 agonists for weight loss for most people?

I would say that decision is entirely up to you but no matter what you do, I would strongly consider looking into something like this FIRST:

Step #1. Spend your time and energy getting on a whole-food diet. 

It doesn’t matter which one, just pick one and stick to it.

You can get rapid results with the carnivore diet, the vegan diet, the ketogenic diet, the Mediterranean diet, and much more. 

I know people are going to freak out because I mentioned both the vegan diet and the carnivore diet in the same sentence but that was intentional.

I live in a world where there is no single best diet (much to the chagrin of low-carb and vegan diet acolytes) but this is what my experience suggests. 

In fact, I’ve seen plenty of people lose rapid weight on diets rich in just fruits. 

I’m not saying one is healthier than the other but what I am saying is that they all have the potential to help you lose weight.

And the more options you have as a patient, the better. 

Between all of these options, you should be able to find a whole-food diet that suits your tastebuds and preferences so that you can stick to it. 

Yes, this will take time and energy but it will be worth it. 

Step #2. Get yourself on a fasting routine or protocol. 

Fasting is such an effective and overlooked treatment that it’s almost criminal

Not only is it effective, but it’s also as close to free as you can get!

What else is cheaper than NOT eating food and only drinking water?

I think the idea of fasting turns people off because they don’t like being uncomfortable or hungry but the reality is that fasting is much easier than you think. 

The hunger pangs you get with fasting subside and your body acclimates to burning fat as an energy source. 

If you are serious about weight loss, pick up a form of fasting and stick to it. 

Step #3. Start exercising… like yesterday. 

Like diet, there are so many different effective ways to exercise so don’t get bogged down in the details here. 

Pick the type of exercise that feels fun to you and just go out and do it. 

My personal recommendation would be to combine a high-protein diet (around 0.6 to 1 gram of protein per pound) and combine that with resistance strength training. 

This combination is incredibly potent for weight loss because it helps you build muscle mass, improve metabolism, and naturally balance fat-regulating hormones like leptin and insulin. 

Step #4. If you need extra oomph then spend time looking into bio-identical T3 thyroid hormone and/or testosterone for TRT. 

If augmenting your weight loss with the use of prescription medications is something you’d like to do then why not first start with bio-identical hormones rather than man-made synthetic drugs?

T3 thyroid hormone, the most powerful thyroid hormone available, is often used by bodybuilders who are trying to lose weight and can be very effective. 

It should only be used in those with low thyroid function but you can pretty much guarantee that those with obesity have some level of thyroid dysfunction making it a great alternative. 

You can also look into testosterone replacement therapy or TRT. 

TRT can also help with weight loss, help you build muscle mass, and improve other symptoms like mood and libido

Step #5. If you’ve tried everything else listed here then consider adding a GLP-1 agonist but only for a short period of time (no more than 1 year). 

If you choose to use a GLP-1 agonist make sure to combine it with the other 4 steps (at least steps 1-3) above. 

This will ensure that you can use it for the least amount of time possible thereby reducing your risk of negative side effects. 

Final Thoughts

Do GLP-1 agonists cause thyroid cancer?

Most likely, yes. 

And even though my personal recommendation is to avoid them as much as possible, there are situations in which it may make sense to use them temporarily. 

Just remember:

Never rely solely on the use of prescription medications for weight loss. 

If you don’t alter or change your lifestyle then once you stop them you will end up right where you started. 

Or worse, you will need to take them long-term and open yourself up to side effects that we don’t fully understand since these medications are so new. 

Now I want to hear from you:

Are you someone who has taken or is currently taking a GLP-1 agonist?

If so, why are you taking it? For weight loss, diabetes, or some other reason?

Were you aware of the risk of thyroid cancer with the use of this medication?

Are you thinking about using a GLP-1 agonist? Did this information change your mind?

Leave your questions or comments below! 

Scientific References









GLp-1 agonists & thyroid cancer_ what you should know

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About Dr. Westin Childs

Hey! I'm Westin Childs D.O. (former Osteopathic Physician). I don't practice medicine anymore and instead specialize in helping people like YOU who have thyroid problems, hormone imbalances, and weight loss resistance. I love to write and share what I've learned over the years. I also happen to formulate the best supplements on the market (well, at least in my opinion!) and I'm proud to say that over 80,000+ people have used them over the last 7 years. You can read more about my own personal health journey and why I am so passionate about what I do.

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33 thoughts on “Do GLP-1 Agonists Cause Thyroid Cancer (Wegovy, Saxenda, Victoza, Etc.)”

  1. I’ve heard that if you take a medication like Ozempic and then stop, the weight will all come back. Is this true? Or, would you be able to maintain the weight loss with diet/lifestyle modifications?


    • Hi Lynn,

      It depends on how you use them and what sort of lifestyle changes you make. If you just take them without adjusting your diet, exercise, and other factors that contributed to your weight, to begin with then, yes, the weight will come back when you stop.

  2. Can you comment on the gut microbiome and healthy weight? I just ordered a probiotic with Akkermansia and butyrate in it and it is supposedly a natural glp-1 agonist. The product is Metabolic Health from a company called Pendulum.

    • Hi Laura,

      There are some weak natural GLP-1 agonists but they are not where near as strong as the medications. Still, worth a shot for many given their potential benefits, at least in my opinion.

  3. Is there any alternative drug instead of Ozempic I can try with potentially less cancer risk. I want to try one, (short term like you said in your article 6 months ) is there anything else I could try instead that works well but with less risk?

    • Hi George,

      There are several but they all have pros and cons and various side effects that you will need to weigh:

      Generally speaking, the more powerful a weight loss medication is the more likely it is to have serious side effects. So if you want to decrease the side effects risk with a medication then you are sacrificing its effectiveness.

      For this reason, and many others, the best option is almost always diet and exercise.

  4. This article was fantastic! I have been on the fence about taking Wegovy that was prescribed to me. It’s expensive and out of stock! Both my Mother and Sister are on a thyroid medication and both are overweight! I am overweight but when I have my thyroid checked they ALWAYS say it’s fine, even though I have all the symptoms! I am beyond frustrated! For now I will opt out of the shots due to the thyroid risk.

    • Hi Dakota,

      Glad you found it helpful! I think it’s always preferred to start with diet, exercise, fasting, and thyroid management before opting for GLP-1 agonists.

  5. I maybe read the research you listed too quickly but did you include all thyroid cancers and not just medullary? Medullary is usually the one associated but now wondering if all of them?

    I’ve learned a lot from you and always recommend. You contribute wonderful knowledge. But today reading how it can be impossible for those who TT to lose weight depressed me some.

    I definitely have a love hate relationship with my limited experience with Semaglutide. It does concern me how easily it is to get.

    • My Endocrinologist has me on Mounjaro .05mg, I’m type 2 and have Hasimoto’s. Is there a problem, I like Mounjaro better than Jardiance and Januvia that I was on.

    • Hi Melissa,

      It is all of them but I believe the risk is higher for medullary specifically. I’d have to look at the data again to say for sure, though.

  6. So I have been prescribed wegovy but can’t find it so then was prescribed saxenda, but still waiting to find that as well. all the while I did fasting and keto for 3 months, was consistent and faithful and worked out. I gained 4 lbs and my A1C went up 0.4. That’s super frustrating. It has to be hormones bc what I did should have worked, even if it was a small amount. So I have chosen to proceed with the meds, when they are found bc this weight has to come off.
    I did recently start taking berberine and I also ordered the leptin resistance stuff to add.

  7. I started using Saxenda 3 years ago for insulin resistance. I lost weight quickly and kept it off for 2 years but slowly gained about 20 of the 30 pounds back in the last year. I exercise regularly, fast, and have eaten low carb for 23 years. I take Armour and Tirosint.
    I have been considering stopping Saxenda since I hear it is getting hard to find and with the weight gain, why risk cancer?
    I have about 6 weeks supply left.
    Do you recommend just stop taking it or slowly decrease the dose until I run out?
    Should I be getting any additional tests for cancer after being on it for over 3 years now?
    How would I know if I have thyroid cancer? What should I watch for?
    I have learned so much from reading your articles. Everything I’ve read and asked my endocrinologist about, he always agrees. I’m thankful for the continuous information and education you provide.

  8. Hello!
    My PCP wanted me to try Ozempic. I did for about 4 months. I started having internal bleeding issues and stopped. I did gain the lost weight back, but have since been able to loose half of that. My leptin hormone level was high before starting Ozempic and now is even higher. I eat a very clean diet and did prior to the use of Ozempic. I have continued this lifestyle alone with strength training and stretching guided by an Exercise Physiologist. I recently have added Physical Therapy due to hip flexor issues from a spinal injury awhile back. My weight gain came I. A period of about 9 months after 4 years of exposure to mold in my workplace and home. I faced a series of health hurdles that came close to taking my life. The weight hurdle is now the only one I have left, but seems to be the only one that is unmovable as is seen in my super high leptin hormone blood test results. What is your recommendation?

    Thank you for taking the time to consider my question.

  9. Have hashimotos, tried the shots in a clinic locally and lost about 6 to 8 lbs over about 2 months but was feeling bad, even taking all the Dr Childs stuff still felt worse and worse and then read someplace that this has side effects and I just quit taking it. Yes I put the weight back on… I exercise 7 days a week, for 2 to 3 hours a day and I eat 90% right at least if not more. Not sure unless I do a 7 day fast that the weight will ever drop. I am now increasing my T2 and T3 and adrenal supplements from Dr childs just to Feel better, if it helps to drop weight great….

    • Perhaps you’re exercising too much? If it’s convincing your body that you’re in a starvation situation, the body will attempt to retain the fat for survival.

      I heard a story about someone in this situation – they had to lower the exercise to 30 minutes a day and increase the sleep by at least 1 hour a night.

  10. Your timing is amazing. Just had a friend post on Facebook saying they’re on Ozempic – but they had a caveat – don’t do it unless you’ve already or are simultaneously attempting to detox because the fat stores toxins, and releasing them all at once can overwhelm your liver.

    I just want to suggest another thing – Maybe only .7% get thyroid cancer, but how do we know that all .7% aren’t hypothyroid or Hashimotos?

  11. “There are also others who are just operating on bad advice because they are listening to governmental agencies about what is best for their health. ”
    Well said!!
    The truth is they don’t know what’s best for an individual’s health. It is up to us to want to learn how our body works and how to improve our health and take matters in to our own hands. I’ve learned this many years ago.

  12. I bought your weightloss program a few years ago and I’ve been taking Victoza since then.
    My question is how do I go off the Victoza, do I lower the dose slowly or do I just stop taking it.
    Will weaning off it slowly help prevent weight gain?
    Thanks for everything you teach us.

  13. I have reverse T-3 and am leptin resistant. I take synthroid and citomel.I am 5’3 an weigh 226. I have tried everything for weight loss. Last spring my doctor put me on mounjaro because of having reconstructive foot surgery. I was fine for a few months but then had nausea and severe cramping to the extent I thought I had diverticulitis again. I was flat on my back during recovery. I was off mounjaro about a month and while recovering in nursing facility the doctor put me back on it. I asked if it could be mounjaro ad was told “no” by doctors and pharmacist. My doctor wants me to start retaking it because of other foot surgery.

  14. Patients with Hashimotos are not at greater risk of thyroid cancer than euthyroid people. So, this means nobody should use these drugs, not even diabetics.

    In the past, you have frequently stressed that most overweight people are leptin resistant, and that these drugs are the only ones addressing this condition. Are you now saying leptin resistance is not an issue for people trying to lose weight?

  15. I thought fasting was bad for thyroid patients. What schedule do you recommend? Also, I saw your smoothie recipe. How can you lose weight with that much fruit?

    • Hi Theresa,

      I will write an article on that topic at some point in the future but, right now, my recommended fasting routines for thyroid patients can be found in my weight loss bundle. They are also included with Glucoslow Fiber as well.

  16. I am way overweight! Earlier this year my doctor prescribed Ozempic. I did take the full prescription. I took the shot once a week for about six weeks. I was nauseous most of the time. The shocking part of my story – Guess What – I actually gained weight on this!! No more Ozempic for me. I must be the only woman on the planet who suffered this nasty experience. Gained about five MORE pounds.

  17. I had my thyroid gland removed 15 years ago due to stage 2 medullary thyroid cancer. I have bloodwork done twice a year and have always had perfect scores. Without my thyroid gland why would it be bad for me to take Ozempic or Wegovy for weight loss. Thanks

    • Hi Jane,

      Even if you put the thyroid cancer risk aside, there are still plenty of other side effects that are worth avoiding. One such example is the fat:muscle loss ratio with GLP-1 agonists is something like 50% meaning for every pound you lose of fat you may also lose up to a pound of muscle. This is incredibly detrimental to metabolism and your ability to maintain the weight you lose long-term. You can learn more about these side effects here:


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