GLP-1 medications

This page is about the molecules semaglutide and tirzepatide, and about how a Faber prescription is handled. It is not a product label. The trial results further down come from studies of commercially manufactured medications. Those studies did not evaluate a compounded preparation, and they are not a description of what a Faber prescription will do.

Semaglutide

Semaglutide is a GLP-1 receptor agonist: a lab-made version of a hormone the gut releases after a meal. GLP-1 is one of the signals the gut and brain use around appetite. In studies of commercially manufactured semaglutide, higher doses were associated with a quieter appetite, slower stomach emptying, and a more measured insulin response when blood sugar rises. Those regimens use a once-weekly injection, started at a low dose and increased gradually.

Tirzepatide

Tirzepatide acts on two receptors, GLP-1 and GIP. Semaglutide acts on GLP-1 only. GIP is another gut hormone, involved in insulin response and in how fat tissue handles energy. That dual action is the difference between the two molecules. Tirzepatide is also taken as a once-weekly injection, started low and increased gradually. Comparisons between the two molecules below refer to studies of commercially manufactured medications, not to a compounded preparation.

A compounded prescription

If a U.S.-licensed clinician prescribes semaglutide or tirzepatide through Faber, a licensed U.S. pharmacy prepares that prescription for one person. Compounded medications are not FDA-approved. A compounded preparation and a commercially manufactured medicine are different products. They are not interchangeable, and a prescription for one is not a prescription for the other.

Nothing is dispensed until a clinician has reviewed the health intake and decided a prescription is appropriate.

What the research studied

The figures in this section are from peer-reviewed trials of commercially manufactured semaglutide or tirzepatide. Faber’s compounded preparation was not the product in those trials. Individual results vary, and these numbers are not a forecast for a Faber prescription.

Semaglutide is among the most studied medicines used for weight loss. The largest weight study, STEP 1, was published in the New England Journal of Medicine. It followed 1,961 adults with overweight or obesity who took 2.4 mg weekly of a manufactured semaglutide medication, or a placebo, for 68 weeks. The semaglutide group lost 14.9% of body weight on average, versus 2.4% on placebo. About 86% lost at least 5% of body weight, and half lost 15% or more. A separate trial, SELECT, followed 17,604 people and found that manufactured semaglutide reduced major cardiovascular events such as heart attack and stroke by 20% in people with overweight and existing heart disease.

For tirzepatide, SURMOUNT-1, also published in the New England Journal of Medicine, followed 2,539 adults with obesity or overweight who took a manufactured tirzepatide medication or placebo for 72 weeks. At the highest dose, participants lost 22.5% of body weight on average, versus 2.4% on placebo. Nine in ten lost at least 5%, and 63% lost 20% or more. In SURMOUNT-5, a head-to-head trial of the two manufactured medications published in 2025, tirzepatide produced 20.2% average weight loss versus 13.7% for semaglutide over 72 weeks.

Side effects, and who these are not for

In the trials above, the most common side effects were digestive: nausea, diarrhea, constipation, and vomiting. They were usually mild or moderate, and most noticeable when the dose increased. In STEP 1, 7 of every 100 participants stopped the manufactured semaglutide medication because of side effects. In SURMOUNT-1, nausea was reported by about 1 in 3 people at higher doses of manufactured tirzepatide. Rare but serious risks reported with these medicines include pancreatitis and gallbladder disease.

These medicines are not used in pregnancy or when pregnancy is planned, or when there is a personal or family history of medullary thyroid cancer or MEN 2. The reviewing clinician screens for this. This page is not a complete list of risks. The prescribing clinician and the dispensed product’s information are the source for a specific prescription.

Questions

Are compounded semaglutide and tirzepatide FDA-approved?

No. Compounded medications are not FDA-approved. FDA approval applies to specific commercially manufactured products, not to a compounded preparation made for an individual prescription.

Does insurance cover this?

No. In this telehealth setup, treatment is paid directly. The price includes the clinician’s review, medical supervision for the length of treatment, and the prescribed medication if a prescription is written.

How is it taken?

As a once-weekly injection, started at a low dose and increased gradually if the clinician continues it. Tablet and nasal forms are not offered.

Tirzepatide or semaglutide?

In SURMOUNT-5, manufactured tirzepatide produced greater average weight loss than manufactured semaglutide. Manufactured semaglutide has a longer track record and, for now, the cardiovascular outcome data from SELECT. Those are studies of manufactured products. Cost, tolerability, and health history still decide the prescription, and the clinician makes that decision. The two molecules are different tools. A compounded preparation of either one is not a substitute for a manufactured medicine.

How fast did people lose weight in the trials?

In the manufactured-medication trials, a common pace at an effective dose was about 1 to 2 pounds a week across the full study, which ran well over a year. The fastest loss was often in the middle of the study, not the first week. That pace is an average from those trials. It is not a result for a compounded preparation, and individual variation is large.

Do diet and exercise still matter?

The medication is studied for its effect on appetite. It does not decide what is eaten. Trial participants also received lifestyle counseling. A meaningful share of weight lost can be lean muscle if protein intake and resistance training are neglected. Faber’s plan includes diet changes, protein, strength training, and cardio alongside any prescription.

What happens if the medication stops?

Weight often returns when the medication stops and the surrounding habits have not changed. The plan therefore includes diet changes, high protein intake, strength training, and cardio. When it is time to reconsider the prescription, the clinician helps decide between continued use, a lower maintenance dose, or tapering off.