Semaglutide vs. Tirzepatide: Which Weight Loss Drug Wins?

If you have been contemplating weight loss medications, there’s a good chance that you feel a little confused. With so many options available, it can feel overwhelming knowing which is the best medication for weight loss. 

 

Two names stand out: semaglutide (Ozempic or Wegovy) and tirzepatide (Mounjaro or Zepbound). 

 

As a Registered Dietitian, I constantly get asked about these medications. 

 

How do they work? Is one better than the other? Are they the ultimate tool for weight loss?

 

While no medication offers a magical solution for weight loss, they can be a powerful ally, especially if you’ve already made good lifestyle changes. But determining which is the best option for you can be quite confusing. 

 

Here, I’ll break down the differences and similarities between semaglutide and tirzepatide. You’ll also learn their effectiveness and potential side effects. 

 

However, keep in mind that this article is for educational purposes only. It doesn’t replace medical advice. Always consult with a healthcare professional before starting any new medication. 

 

GLP-1 Medications 

Both medications, semaglutide and tirzepatide, belong to a class of drugs that mimic hormones you naturally produce in your gut. When you eat, your body releases hormones that signal your brain that you are full, and they help regulate your blood sugar levels. 

 

For those with obesity or type 2 diabetes, these signals might not work as efficiently as they should. That’s where these medications can help. 

 

They aren’t just appetite suppressants; they also work on your hunger and satiety. This helps you stay full longer, which makes you eat fewer calories. 

 

How GLP-1 Medications Work

The main difference between semaglutide vs. tirzepatide lies in the effect they have on your body. 

 

Semaglutide

Semaglutide mimics the action of GLP-1 (glucagon-like peptide-1). As a result, it has the following effects on the body:

 

• It stimulates insulin release when your blood sugar levels are high. 
• Reduces glucagon secretion, which prevents your liver from producing excess glucose. 
• Slows down gastric emptying.

So, how does this help with weight loss?

 

Since your stomach empties more slowly, you feel fuller. It also communicates with the appetite centers in your brain to reduce cravings and prevent grazing.

 

Tirzepatide 

What makes tirzepatide special is its dual action. It acts on two different hormones: GLP-1 and GIP (glucose-dependent insulinotropic polypeptide). 

 

GIP enhances insulin secretion when you eat a meal, supports fat metabolism, and contributes to appetite regulation. And, when you mix GIP with GLP-1, it can create an even more powerful effect on blood sugar control and weight loss. 

 

Key Differences

Effectiveness

Generally speaking, tirzepatide tends to be more effective since it targets two hormones instead of one. 

 

The STEP (semaglutide treatment effect in people with obesity) trials studied people without diabetes who took 2.4 mg of semaglutide weekly. On average, they lost almost 15% of their body weight over 68 weeks, while the placebo group only lost around 2.4%. 

 

The SURMOUNT-1 trial participants took different doses of tirzepatide (5 mg, 10 mg, or 15 mg) for 72 weeks. Those taking the highest dose (15 mg) had the highest weight loss, averaging a 20% body weight reduction. 

 

Another study published in the New England Journal of Medicine compared weight-loss outcomes between tirzepatide and semaglutide. People on semaglutide lost 13.7% of their body weight, while people taking tirzepatide lost 20.2%. 

 

While both options show good weight-loss results, tirzepatide may have a greater effect. 

 

Side Effects

Because these drugs work on the gut, the side effects are very similar. Here are some of the most common side effects: 

 

• Nausea
• Vomiting
• Diarrhea
• Constipation
• Stomach pain 

 

While tirzepatide might be “stronger,” some users report slightly better tolerance, which might be because the GIP components help reduce some of the nausea associated with GLP-1. 

 

However, keep in mind that individual experiences might vary. Some people have a better tolerance, while others have a terrible experience. 

 

Another thing to consider is that these side effects are usually short-lived. They last a couple of days while your body gets used to the medication. If they don’t go away, make sure you speak with a healthcare professional. 

 

Administration 

Both medications are delivered through a subcutaneous injection, meaning they are shots under the skin. You get them once a week using a pen device, which is generally user-friendly, and with a small needle. 

 

You don’t need a medical professional to deliver them. The doctor explains how you can safely get them in the comfort of your home. 

 

Cost and Accessibility 

Both medications can be quite expensive, that is, if you don’t have insurance. Tirzepatide can cost $1,000 to $ 1,600 per month. Semaglutide can go from $900-$1,000 (Ozempic) to more than $1,300 to $1,800 per month for Wegovy. 

 

Some insurance companies can cut the out-of-pocket expense to $100 to $300, helping you save money. However, not all insurance plans cover weight loss medication. It’s important to check your insurance policies to determine if they are covered. 

 

Overall, tirzepatide might be a less expensive option than some semaglutide options (like Wegovy). But you can get affordable prices for both medications. 

 

Which Option is Better for You?

So, who wins?

 

The answer might not be as simple as picking the one with the highest weight loss. Here are some factors to consider: 

 

1. Insurance and Cost: These medications can be expensive if you get them without insurance coverage. Some insurance plans cover one medication but not the other. Check which option you can get covered.
2. Availability: Some medications might go “out of stock” due to high demand. In this case, it’s better to go with the medication you know you can get monthly instead of the one that you might not get that consistently. After all, remember that weight loss medication works through consistency. 
3. Tolerance: If you have a sensitive stomach, your doctor might start you on the lowest dose of semaglutide to see how you handle it. If you struggle with side effects, they might switch you to the other medication. 
4. Health History: While both are great for managing your blood sugar levels, your doctor might lean one way if you need to control your A1c levels. Also, if you have a history of certain thyroid cancers or pancreatitis, neither drug may be safe for you. 

 

Remember that the decision doesn’t depend on you. It’s best to speak with your doctor to help you pick the best weight loss medication based on your goals and needs. 

The Bottom Line 

Both options offer unique advantages and disadvantages. Semaglutide has a longer track record in the area of medical weight loss, but tirzepatide is coming off as a strong contender for those who want a more aggressive approach. 

 

Do keep in mind that these types of medication are meant to be used as a tool, not a magical cure. The best results you can obtain come when you make healthy lifestyle changes along with the medication.

 

Article Reviewed By: Brenda Peralta, Registered Dietitian Nutritionist (RDN) & Certified Diabetes Educator (CDE)