Semaglutide vs. tirzepatide

How each one works

GLP-1 and GIP are incretin hormones your gut releases after you eat. They help the pancreas release insulin when blood sugar rises, slow how fast the stomach empties and act on appetite centers in the brain, so you feel full sooner and think about food less.

Semaglutide mimics GLP-1. Tirzepatide is a single molecule that activates both GIP and GLP-1 receptors. Researchers are still working out exactly how much the GIP action adds, but the dual mechanism is the main reason tirzepatide is thought to produce larger average weight loss.

What the head-to-head trial found

SURMOUNT-5 randomly assigned 751 adults with obesity and without type 2 diabetes to the maximum tolerated dose of branded tirzepatide (Zepbound) or branded semaglutide (Wegovy) for 72 weeks. On average, people on tirzepatide lost about 20.2% of their body weight and people on semaglutide about 13.7%. Nausea affected about 44% of people in each group.

Two cautions apply. These are averages, and individuals vary widely; some people do very well on semaglutide and some don't tolerate tirzepatide. And the trial used branded, FDA-approved products, so its results don't automatically apply to compounded versions.

Side effects and safety

Both medicines share most of their safety profile. Digestive effects such as nausea, vomiting, diarrhea, constipation and stomach pain are the most common, especially when the dose goes up. Both branded products carry a boxed warning about thyroid C-cell tumors seen in rodents, and neither is used by people with a personal or family history of medullary thyroid carcinoma or MEN 2.

Pancreatitis, gallbladder problems, low blood sugar when combined with insulin or sulfonylureas, and dehydration from vomiting or diarrhea are part of the risk discussion for both. Neither is used during pregnancy. One difference: tirzepatide can make birth control pills less effective, so labeling advises a backup or non-oral method for four weeks after starting and after each dose increase.

Form and routine

Both are typically given as a once-weekly injection, with the dose increased gradually over the first months to help your body adjust. At HealifyMD, each is also available as a compounded daily oral capsule. Your clinician sets the schedule and dose, and decides when, or whether, to increase it.

Protecting muscle on either medicine

Rapid weight loss on either drug includes some lean tissue as well as fat. After 40, when muscle is already harder to keep, that's worth planning for from the start, whichever medicine you take.

Resistance training two or three times a week, enough protein spread through the day and steady, not crash-level, weight loss all help. Your clinician can also watch for signs of eating too little, such as dizziness, fatigue or hair shedding, and adjust your dose if appetite suppression goes too far.

Regulatory status: branded vs. compounded

Branded semaglutide is sold as Wegovy and Ozempic, and branded tirzepatide as Zepbound and Mounjaro; these are FDA-approved. The semaglutide and tirzepatide HealifyMD prescribes are compounded by a licensed pharmacy. Compounded drugs are not FDA-approved, the FDA doesn't review them for safety, effectiveness or quality before they're sold, and they are not equivalent to or interchangeable with the branded products. The FDA has also received adverse event reports and dosing-error reports involving compounded GLP-1 medicines, which is why careful dose instructions matter.

Which might fit you

Your clinician will recommend a starting medicine based on your history, other conditions, medications, budget and preferences. The final choice is made together, and switching later is possible.

• Cost is a major factor: semaglutide is $100 less per month at HealifyMD
• You want the larger average weight loss seen in trials: tirzepatide may be discussed, keeping in mind individual results vary
• You use birth control pills: tirzepatide needs a backup method around dose changes, which your clinician will explain
• You had side effects or a plateau on one: switching to the other is sometimes considered
• Neither fits if you have a personal or family history of medullary thyroid carcinoma or MEN 2, are pregnant or planning pregnancy, or have had pancreatitis, until your clinician reviews it