Wegovy vs Mounjaro

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There is a newly approved medication currently known as Mounjaro (tirzepatide), with some promising effects on weight loss. Like any up and coming weight loss drug, it still has plenty of testing and approvals to go through before we see it on the market. But how much potential might it have as a weight loss medication?

Let’s take a look at Tirzepatide, and see what makes it different from other weight loss drugs on the market today.

What is Mounjaro (Tirzepatide)?

With Wegovy being recently approved in 2021, there’s a lot of interest surrounding new medications for weight loss. One of these drugs being researched is called Tirzepatide.

The FDA has recently approved Tirzepatide for diabetes type 2, under the trade name Mounjaro. I expect that a weight loss version of the drug to follow soon.

To be perfectly clear, tirzepatide was first being developed as a diabetic medication, but the clear end goal here is to eventually also market it for weight loss, since that will be the real moneymaker.

This appears to be a new trend in the pharmaceutical development of new diabetic medication. Which is to find out if your diabetic medication can also cause weight loss, then market it under two different brand names, one for diabetes, and one for weight loss.

Tirzepatide works by stimulating the effects of two different hormones in the body:

1. GLP-1
2. GIP

GLP-1 stands for Glucagon-like peptide-1, and is involved in controlling insulin levels. It also makes us feel full. So drugs that stimulate GLP-1 will also suppress appetite.

We see it’s effects on full display with many of the other GLP-1 agonists on the market, such as Wegovy, Saxenda, and Ozempic. All these drugs have potent appetite suppressing qualities, and the ability to cause weight loss… as well as some ability to help with diabetes, although we already have pretty good drugs for diabetes.

GIP stands for Glucose-dependent insulinotropic polypeptide, and is also involved in controlling insulin levels. Stimulating GIP also seems to control appetite and induce feelings of fullness.

So Tirzepatide stimulates both, and overall would help suppress appetite and reduce weight that way.

Tirzepatide vs Semaglutide

When Wegovy (semaglutide) came out, it was labeled a game changer due to it having some of the strongest effects on weight loss we’ve seen so far. However, Wegovy was basically just a higher dose of another diabetes drug called Ozempic, since they’re the exact same drug called semaglutide.

Wegovy and Ozempic are both GLP-1 agonists. Agonist just means it stimulates those effects. Tirzepatide is a dual GLP-1 and GIP agonist, meaning it not only stimulates GLP-1, but another hormone, GIP, that also suppresses appetite.

This means that Tirzepatide could possibly be stronger than Wegovy and have more broad effects on weight loss, since it stimulates an additional hormone. However, the trade-off could be that Tirzepatide may have more unwanted side effects than Wegovy.

Thanks to some recent news, we now have some additional information on Tirzepatide that allows us to make some preliminary comparisons to Wegovy.

Effectiveness

Eli Lilly recently came out with preliminary research for Tirzepatide that suggests that at the highest dosage, Tirzepatide might help people lose almost 20% body weight.

For comparison, research trials found that Wegovy, which is 2.4 mg of semaglutide, helps people lose around 15% body weight.

After subtracting placebo, this suggests that tirzepatide could be around 40% stronger than Wegovy at helping people lose weight.

Side Effects

Now this could also potentially mean that Tirzepatide will have negative effects on the body not found in Wegovy. So stimulating GLP-1 and GIP might end up being a double-edged sword, and cause Tirzepatide to have worse or more side effects than Wegovy.

We already know that GLP-1 agonists have side effects that include strong nausea, vomiting, and diarrhea. They also might cause damage to the liver or pancreas, gallstones, and kidney, and potentially increase the risk of thyroid cancers.

Because we don’t commonly use GIP agonists, we aren’t as sure what additional side effects and long-term risks come with these types of drugs.

The percent of people who experienced common side effects too severely and were unable to continue treatment was about 7% for both Tirzepatide and Wegovy.

Interestingly, Tirzepatide appears to have a slightly less dropout rate, with less frequent gastrointestinal issues than Wegovy.

So it appears that Tirzepatide may actually be more tolerable to take than Wegovy.

Does it mean that it’s safer? Not really. Again, we have no long-term data on tirzepatide, and for all we know it might end up causing brain cancer or something. But these results are promising.

Now these numbers on Tirzepatide are from a news release to investors, and have yet to be confirmed so these may not be final values, and are definitely subject to change.

Also what I’m doing here is not a direct comparison. A direct comparison would be comparing both drugs in the same trial, I’m just comparing numbers from two different trials, so this comparison may be unreliable.

Cost

Finally, some early reports indicate that Tirzepatide should cost around $5500 to $5700 dollars a year. For comparison, Wegovy can be $15000 to $20000 per year without insurance.

I personally think that if newer studies show Tirzepatide to be very close in effectiveness to Wegovy, they’re going to price it just as expensive as Wegovy, if not slightly more expensive given the recent news, since both drugs are direct competitors and are very similar in effectiveness.

Could Tirzepatide be a game changer?

At the moment, we really can’t say for sure. Despite the promising research trials, it hasn’t been approved for weight loss yet. A lot of promising drugs disappear due to unforeseen side effects that make it dangerous to use in humans.

Even if it does come to market, it might still be pulled later on when we find long-term health problems. Just look at fen-phen, it was prescribed to millions of patients before we found out it could potentially cause fatal pulmonary hypertension and heart valve problems.

We don’t know if Tirzepatide will suffer the same fate, however Tirzepatide is a new class of weight loss and diabetes medication, a dual GLP-1 and GIP agonist, so it’s kind of the first of its kind. Being the first of its kind has the benefits of potentially pioneering new types of therapies, but also suffers from a lot of unknowns.

Now, Tirzepatide is not the only dual GLP-1 and GIP agonist in development, so perhaps one of these other new drugs will eventually reach the market first.

Always remember that weight loss medication is not a substitute for a good weight loss diet and lifestyle. Medication will only work for so long, and weight regain after discontinuing any medication is a very common occurrence.

But this new class of weight loss medication is definitely of strong interest to clinicians like myself, as a tool to help some patients kick-start their weight loss. So I’ll be keeping an eye on their development, and if you want to stay up to date, please subscribe to the channel and hit the notification bell.

Learn more about

• What to Expect With Wegovy
• Comparing other GLP-1 Agonists for Weight Loss
• 5 Things To Know Before Starting Weight Loss Medication
• Other weight loss medications

See also

• 
  Comparing Weight Loss Drugs in 2024
  Ozempic and Mounjaro are highly effective at treating obesity, however there are many other approved and off-label options that also work.
• 
  Bupropion vs Contrave vs Naltrexone
  Contrave is a synergistic combination of buproprion and naltrexone, which can be replicated to some degree using the generics individually.
• 
  New Obesity Drugs in 2024
  New obesity drugs target more than just GLP-1 and do much more than suppress appetite for a more nuanced approach to weight loss.
• 
  Mounjaro: Who Loses the Most Weight?
  White or Asian younger women who use metformin and have lower sugar and lipid levels tend to experience more weight loss with Mounjaro.
• 
  How does Oforglipron compare?
  Orforglipron, Semaglutide, and Danuglipron are oral GLP-1 agonists that are all similar enough that cost may end up being the winning factor.