Tirzepatide vs. Semaglutide: 50 Pounds vs. 33 in a Head-to-Head Study

Two blockbuster weight-loss shots. One study putting them in the same ring. And a clear winner on the scale.

In the head-to-head SURMOUNT-5 trial, adults on tirzepatide lost an average of 20.2% of their body weight in 72 weeks, about 50 pounds. People on semaglutide lost 13.7%, about 33 pounds. Here's what that means for you, how each medicine works, how the side effects stack up, and who might do better on which.

Meet the two medicines

Both are weekly injections first approved for type 2 diabetes, then for weight loss.

• Semaglutide is sold as Ozempic for type 2 diabetes and Wegovy for weight loss. Wegovy also comes as a daily pill, and it's approved to lower heart attack and stroke risk in adults with heart disease and excess weight.
• Tirzepatide is sold as Mounjaro for type 2 diabetes and Zepbound for weight loss. Zepbound is also approved for moderate to severe sleep apnea in adults with obesity.

How each one works

After you eat, your gut releases hormones that tell your brain you've had enough. Both medicines copy those signals, but not the same number of them.

• Semaglutide copies one hormone, GLP-1. It turns down hunger and slows how fast food leaves your stomach.
• Tirzepatide copies two, GLP-1 and GIP. Early research suggests the GIP signal may add to the appetite effect.

Think of hunger as a volume knob. Semaglutide turns it down with one hand. Tirzepatide uses two.

The head-to-head results

SURMOUNT-5 followed 751 adults with obesity but without diabetes for 72 weeks. Each person climbed to the highest dose they could handle: 10 or 15 mg of tirzepatide, or 1.7 or 2.4 mg of semaglutide.

The gap held at every milestone. About 82% of people on tirzepatide lost at least 10% of their weight, versus 61% on semaglutide. Nearly half on tirzepatide lost 20% or more, versus about a quarter on semaglutide.

In relative terms, that's about 47% more weight loss with tirzepatide.

Side effects: closer than you'd think

If you were hoping one was much gentler, the study didn't find a big difference.

• About 3 in 4 people in each group had some side effect (76.7% on tirzepatide, 79% on semaglutide). Most were stomach-related, like nausea, diarrhea, or constipation, and most were mild to moderate.
• They mostly hit during dose increases, then eased.
• Slightly fewer people quit tirzepatide because of side effects: 6.1%, versus 8.0% on semaglutide.
• Serious side effects were uncommon in both groups (4.8% on tirzepatide, 3.5% on semaglutide).

The researchers note the trial wasn't designed to prove one is safer. Both medicines share the same main warnings, including a thyroid tumor warning from animal studies and risks of pancreatitis and gallbladder problems.

The fine print worth knowing

• It was open-label. Everyone knew which medicine they were taking.
• The drugmaker paid for it. SURMOUNT-5 was funded by Eli Lilly, which makes tirzepatide.
• Semaglutide has a higher dose now. Wegovy is now approved up to 7.2 mg a week for some adults. That dose wasn't tested against tirzepatide.

Which one fits whom?

The scale isn't the only thing that matters. Here's how the choice often breaks down:

• If the biggest possible loss is your goal, tirzepatide had the edge in the only head-to-head study.
• If you have heart disease and excess weight, Wegovy has an FDA-approved use for lowering heart attack and stroke risk in that group. Mention your heart history.
• If you have sleep apnea, Zepbound is FDA-approved to treat moderate to severe sleep apnea in adults with obesity.
• If you're under 18, Wegovy is approved for teens 12 and older. Tirzepatide for weight loss is for adults.
• If you stalled or struggled on one, ask about the other. Your clinician can weigh your history and side effects.
• If needles are a dealbreaker, there are now pill and troche options to discuss, though the head-to-head results apply to the weekly shots.

Why Nirvanix prescribes tirzepatide

Nirvanix focuses on tirzepatide, the medicine that came out ahead in the head-to-head trial. You can start with Nx Lean, a weekly injection, or ask about Lean Balance, a troche that dissolves in your mouth. Accelerate & Thrive pairs tirzepatide with NAD+ in one plan, though adding NAD+ hasn't been shown to boost weight loss.

A licensed clinician reviews your health history online, with no waiting room. You start at 2.5 mg a week and step up when you're ready, and the consultation and shipping are included. New to the medicine? See how compounded tirzepatide differs from Zepbound.

The bottom line

In the only head-to-head trial, tirzepatide helped people lose about half again as much weight as semaglutide, with similar side effects. The right choice still depends on your health, your history, and how your body responds, which is exactly what a clinician is for.

Curious whether tirzepatide fits you? Take the two-minute quiz.