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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