Semaglutide vs. tirzepatide: which is right for you?

Semaglutide and tirzepatide are the two most-prescribed weight-loss injections in the U.S., and patients ask us about the difference every week. The short answer: they're cousins, not twins. Here's how to think about choosing between them.

How they're alike

Both are weekly injections you give yourself with a tiny needle — most people compare it to a mosquito bite. Both quiet appetite, slow digestion, and steady blood sugar. Both were developed first for type 2 diabetes and later approved (or used off-label, in compounded form) for weight management. And both produce far more weight loss than diet and exercise alone in clinical trials.

Where they differ

Semaglutide activates one hunger-regulating receptor: GLP-1. Tirzepatide activates two: GLP-1 and a second one called GIP. That second signal seems to do two things — it amplifies the appetite-suppressing effect, and it may help the body use fat for fuel more efficiently.

In head-to-head data, the average tirzepatide patient loses more weight than the average semaglutide patient. The SURMOUNT trials showed roughly 20–22% body-weight loss on tirzepatide's higher doses versus 15–17% on semaglutide's. That's a real difference — but it's an average, and individual responses vary widely.

Side effects are similar, but not identical

Both medications share the same playbook: nausea, fullness, occasional constipation or diarrhea, especially when stepping up doses. Some patients tolerate one better than the other. If semaglutide gives you persistent nausea, tirzepatide isn't guaranteed to be gentler — but for some people, it is. And vice versa.

The 'best' GLP-1 is the one you actually tolerate and stay on. The most effective dose in a trial means nothing if you can't get past week three.

Cost and access

Brand-name versions (Wegovy, Zepbound) are often expensive without insurance, and insurance coverage for weight loss is uneven. Compounded versions — made by licensed compounding pharmacies — are usually significantly cheaper and have made these treatments accessible to a much wider group of people.

NowYou's pricing is transparent on the weight-loss page; there are no hidden fees and you can cancel anytime.

How to choose

A few rules of thumb your provider will weigh with you:

• If your weight-loss goal is large (say, 20%+ of body weight), tirzepatide's data is stronger.
• If you've previously tolerated semaglutide well, sticking with it is reasonable.
• If cost is the deciding factor, the cheaper option you'll actually stay on is the better option.
• If you have type 2 diabetes alongside weight management goals, your provider will factor that in heavily.

What we recommend

Don't choose blind from a blog post — including this one. Complete the intake, and a licensed provider will recommend the right starting medication and dose based on your history and goals. Switching between the two later is usually straightforward if your first choice doesn't feel right.

Whichever you start on, give it three months before judging the result. Real metabolic change takes time.