Compounded Semaglutide vs Tirzepatide for Weight Loss
If you are ready to try a GLP-1 medicine for weight loss, the next question is usually which one. Semaglutide and tirzepatide are both weekly shots, and both lower appetite.[1][2] They also differ in ways that matter: how they work, how much weight people lost in trials, and the monthly cost.
Through Starfish.com, you can request compounded semaglutide or compounded tirzepatide by name, or let a licensed clinician choose. This guide compares semaglutide vs tirzepatide so you can decide what matters most to you.
How Each Medicine Works
Semaglutide copies one gut hormone, called GLP-1. Tirzepatide copies two, called GIP and GLP-1.[3] Both help the body release insulin when blood sugar is high, slow how fast the stomach empties and can lower appetite.[1][2]
Both are injected under the skin once a week. Both start at a low dose that goes up in steps. Semaglutide is usually raised after 4 weeks, and tirzepatide no more often than every 4 weeks.[1][2]
Semaglutide and Tirzepatide Side by Side
| Compounded semaglutide | Compounded tirzepatide | |
|---|---|---|
| How it works | Acts on one hormone target (GLP-1)[3] | Acts on two hormone targets (GIP and GLP-1)[3] |
| How often | One shot a week[1] | One shot a week[2] |
| Average weight loss in the head-to-head trial | 13.7% of body weight after 72 weeks[4] | 20.2% of body weight after 72 weeks[4] |
| Most common side effects | Stomach and bowel, such as nausea and diarrhea[5] | Stomach and bowel, such as nausea and diarrhea[6] |
| Birth control pills | List all your medicines in your questionnaire | May make hormonal birth control pills work less well[2] |
| Monthly price with us | The lower of the two | The higher of the two |
What the Head-to-Head Trial Found
The best way to compare two medicines is a trial that tests them side by side. One such trial followed 751 adults with obesity who did not have type 2 diabetes. Each person took the highest dose of either medicine they could tolerate, along with advice on diet and activity.[4][3]
After 72 weeks, people on tirzepatide had lost an average of 20.2% of their body weight. People on semaglutide had lost an average of 13.7%.[4] About 32% of the tirzepatide group lost a quarter or more of their weight, compared with about 16% of the semaglutide group.[3]
Both groups lost a large amount of weight, and these are averages. Some people lost more and some lost less. Everyone in the trial knew which medicine they were taking.[4]
Request Either Medicine by Name
Tell us which you prefer, or let the clinician decide. A licensed clinician reviews your answers before prescribing.
Side Effects Compared
Both medicines mainly cause stomach and bowel side effects. In the head-to-head trial, these were the most common side effects in both groups, and most were mild to moderate.[4] About 6% of people on tirzepatide and 8% on semaglutide stopped because of side effects.[3] The trial was not designed to prove one is safer than the other.[3]
The serious warnings are much the same for both, including pancreatitis and a thyroid tumor warning from studies in rats.[1][2] One practical difference is birth control. Tirzepatide may make hormonal birth control pills work less well, so a barrier method such as condoms is advised for 4 weeks after starting and after each dose increase.[2][7] If you need a backup method, we also offer the FC2 female condom, an internal condom that ships to your door.
Which One Fits You
There is no single right answer. Both led to large weight loss,[4] and the choice often comes down to these points:
- Weight loss. Tirzepatide led to more weight loss on average in the head-to-head trial.[4]
- Cost. Compounded semaglutide has the lower monthly price with us.
- Birth control. If you rely on birth control pills, tirzepatide needs a backup method at times.[2]
- Your health history. A licensed clinician weighs your answers before prescribing either one.
These trials did not test compounded versions, so they show what each medicine can do rather than how any one compounded product performs. Compounded semaglutide and tirzepatide are prepared by licensed pharmacies that their state boards of pharmacy oversee.[8] They are not FDA-approved, because each is prepared for an individual patient.[8]
Whichever you choose, a licensed clinician reviews your questionnaire. If treatment is appropriate, you get a prescription, usually within 1 to 2 hours, and the medication is mailed to you from the pharmacy.
FAQ
Is tirzepatide better than semaglutide for weight loss?
On average, yes. In the head-to-head trial, people lost 20.2% of their weight on tirzepatide and 13.7% on semaglutide after 72 weeks.[4] Semaglutide still led to large weight loss, and it costs less per month with us.
What is the cheapest way to get a GLP-1 without insurance through telehealth?
Of the two we offer, compounded semaglutide has the lower monthly price. Both prices include the medication and shipping, and no insurance is needed. See compounded semaglutide for the current price.
Can I ask Starfish.com for a specific GLP-1?
Yes. You can request semaglutide or tirzepatide by name in your questionnaire, or let the clinician choose.
Are the side effects of tirzepatide vs semaglutide different?
They are similar. Both mainly cause nausea, diarrhea and other stomach and bowel side effects, mostly mild to moderate.[4] The main practical difference is birth control. Tirzepatide may make hormonal birth control pills work less well, so a backup method such as condoms is advised for 4 weeks after starting and after each dose increase.[2][7]
Choose Your GLP-1 Treatment
A licensed clinician reviews your answers and, if treatment is right for you, issues a prescription within 1 to 2 hours. Your medication is mailed to you.
References
- U.S. National Library of Medicine, MedlinePlus. “Semaglutide Injection.” https://medlineplus.gov/druginfo/meds/a618008.html
- U.S. National Library of Medicine, MedlinePlus. “Tirzepatide Injection.” https://medlineplus.gov/druginfo/meds/a622044.html
- Patient Care. “Tirzepatide Demonstrates Greater Weight Loss Than Semaglutide in Head-to-Head Study.” Summary of Aronne LJ, et al., New England Journal of Medicine, 2025. https://www.patientcareonline.com/view/tirzepatide-demonstrates-greater-weight-loss-than-semaglutide-in-head-to-head-study
- Aronne LJ, et al. “Tirzepatide as Compared with Semaglutide for the Treatment of Obesity.” New England Journal of Medicine, 2025. https://doi.org/10.1056/NEJMoa2416394
- Wilding JPH, et al. “Once-Weekly Semaglutide in Adults with Overweight or Obesity.” New England Journal of Medicine, 2021. https://doi.org/10.1056/NEJMoa2032183
- Jastreboff AM, et al. “Tirzepatide Once Weekly for the Treatment of Obesity.” New England Journal of Medicine, 2022. https://doi.org/10.1056/NEJMoa2206038
- NHS. “Tirzepatide: a medicine to manage type 2 diabetes and treat obesity.” https://www.nhs.uk/medicines/tirzepatide/
- U.S. Food and Drug Administration. “Compounding and the FDA: Questions and Answers.” https://www.fda.gov/drugs/human-drug-compounding/compounding-and-fda-questions-and-answers
