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GLP-1 medication resources

The world of GLP-1 medications can feel overwhelming. Explore each one in plain language: how it works, how it's dosed, and what the research shows.

Semaglutide Tirzepatide Retatrutide Compare all three FAQs

Type: GLP-1 agonist
Taken: Once weekly
Strength: 2.5 mg/mL + B6
Vials: 2 mL or 4 mL
FDA status: Brand versions approved

GLP-1 receptor agonist

Semaglutide

The science, history, and benefits of a breakthrough treatment

Semaglutide copies GLP-1, a hormone your gut naturally releases after meals. It signals fullness to your brain, slows digestion, and helps regulate blood sugar. For many people, the biggest change is quieter "food noise" and fewer cravings.

A short history

Semaglutide was first approved in 2017 to treat type 2 diabetes. Researchers noticed significant weight loss in those patients, which led to the STEP trials and FDA approval for chronic weight management in 2021.

How dosing works

One small injection under the skin, once a week, on the same day each week.
Starts at a low dose and increases about every four weeks to reduce side effects.
Your provider decides when to increase, hold, or adjust based on how you feel.

What the research shows

In the STEP 1 trial, adults lost an average of 14.9% of their body weight over 68 weeks, compared with 2.4% on placebo.

Common compounded formulation

Compounded semaglutide is often prepared at 2.5 mg/mL with vitamin B6 (pyridoxine) 10 mg/mL, for each patient under a prescription. Doses are measured with a standard U-100 insulin syringe.

Vial size	Strength	Semaglutide per vial	Vitamin B6 per vial
2 mL	2.5 mg/mL	5 mg	20 mg
4 mL	2.5 mg/mL	10 mg	40 mg

Typical dose schedule

0.25 mgWeeks 1–410 units
0.5 mgWeeks 5–820 units
1 mgWeeks 9–1240 units
1.7 mgWeeks 13–1668 units
2.4 mgWeek 17 on96 units

Increase only as directed by your prescriber.

See every dose and how long a vial lasts

Weekly dose	Amount	Syringe	2 mL vial lasts	4 mL vial lasts
0.25 mg	0.10 mL	10 units	20 wks	40 wks
0.5 mg	0.20 mL	20 units	10 wks	20 wks
0.75 mg	0.30 mL	30 units	6 wks	13 wks
1 mg	0.40 mL	40 units	5 wks	10 wks
1.25 mg	0.50 mL	50 units	4 wks	8 wks
1.5 mg	0.60 mL	60 units	3 wks	6 wks
1.75 mg	0.70 mL	70 units	~2.9 wks	~5.7 wks
2 mg	0.80 mL	80 units	2.5 wks	5 wks
2.4 mg	0.96 mL	96 units	~2.1 wks	~4.2 wks

Approximate supply, once weekly. Your prescriber sets your dose and any custom schedule.

Read the full semaglutide guide Open the dose calculator

Type: GIP + GLP-1 agonist
Taken: Once weekly
Strength: 15 mg/mL + B6
Vials: 2 mL or 4 mL
FDA status: Brand versions approved

GIP + GLP-1 dual agonist

Tirzepatide

Transforming weight loss through dual-hormone therapy

Tirzepatide activates two hormone receptors, GIP and GLP-1, instead of one. Together they improve how your body handles sugar and fat and reduce appetite more strongly than GLP-1 alone for many people.

A short history

Tirzepatide was approved for type 2 diabetes in 2022 and for chronic weight management in 2023, after the SURMOUNT trials showed some of the largest average weight loss seen with a medication at the time.

How dosing works

One injection under the skin, once a week.
Starts low and increases in steps about every four weeks.
Your provider finds the dose that balances results and comfort.

What the research shows

In SURMOUNT-1, adults on the highest dose lost an average of 20.9% of their body weight over 72 weeks, compared with 3.1% on placebo.

Common compounded formulation

Compounded tirzepatide is often prepared at 15 mg/mL with vitamin B6 (pyridoxine) 10 mg/mL, for each patient under a prescription. Doses are measured with a standard U-100 insulin syringe.

Vial size	Strength	Tirzepatide per vial	Vitamin B6 per vial
2 mL	15 mg/mL	30 mg	20 mg
4 mL	15 mg/mL	60 mg	40 mg

Typical dose schedule

2.5 mgWeeks 1–417 units
5 mgWeeks 5–833 units
7.5 mgWeeks 9–1250 units
10 mgWeeks 13–1667 units
12.5 mgWeeks 17–2083 units
15 mgWeek 21 on100 units

Increase only as directed by your prescriber.

See every dose and how long a vial lasts

Weekly dose	Amount	Syringe	2 mL vial lasts	4 mL vial lasts
2.5 mg	≈0.17 mL	17 units	12 wks	24 wks
5 mg	≈0.33 mL	33 units	6 wks	12 wks
7.5 mg	0.50 mL	50 units	4 wks	8 wks
10 mg	≈0.67 mL	67 units	3 wks	6 wks
12.5 mg	≈0.83 mL	83 units	2.4 wks	4.8 wks
15 mg	1.00 mL	100 units	2 wks	4 wks

Approximate supply, once weekly. Your prescriber sets your dose and any custom schedule.

Read the full tirzepatide guide Open the dose calculator

Type: GIP + GLP-1 + glucagon
Taken: Once weekly
Strength: 15 mg/mL + B6
Vials: 4 mL or 10 mL
FDA status: Investigational

GIP + GLP-1 + glucagon

Retatrutide

The next generation in weight loss and metabolic health

Retatrutide is a "triple agonist." On top of GIP and GLP-1, it also activates the glucagon receptor, which may increase how much energy your body burns. Researchers are studying it for obesity, diabetes, and fatty liver disease.

Where it stands

Retatrutide is investigational and not FDA approved. Phase 3 trials have now reported results, but it hasn't been approved yet. Compounded retatrutide is available only under a patient-specific prescription with licensed prescriber supervision.

What the research shows

In the 80-week phase 3 TRIUMPH-1 trial, adults on the 12 mg dose lost an average of 28.3% of their body weight, compared with 2.2% on placebo. Full peer-reviewed results are still to come.

Common compounded formulation

Compounded retatrutide is often prepared at 15 mg/mL with vitamin B6 (pyridoxine) 10 mg/mL, for each patient under a prescription. Doses are measured with a standard U-100 insulin syringe.

Vial size	Strength	Retatrutide per vial	Vitamin B6 per vial
4 mL	15 mg/mL	60 mg	40 mg
10 mL	15 mg/mL	150 mg	100 mg

Typical dose schedule

2 mgWeeks 1–413 units
4 mgWeeks 5–827 units
6 mgWeeks 9–1240 units
9 mgWeeks 13–1660 units
12 mgWeek 17 on80 units

Increase only as directed by your prescriber. Hold or reduce the dose if stomach side effects occur. Maximum 12 mg weekly.

See every dose and how long a vial lasts

Weekly dose	Amount	Syringe	4 mL vial lasts	10 mL vial lasts
2 mg	≈0.13 mL	13 units	30 wks	75 wks
4 mg	≈0.27 mL	27 units	15 wks	37 wks
6 mg	0.40 mL	40 units	10 wks	25 wks
9 mg	0.60 mL	60 units	6 wks	16 wks
12 mg	0.80 mL	80 units	5 wks	12 wks

Approximate supply, once weekly. Your prescriber sets your dose and any custom schedule.

Investigational use only. Retatrutide is not FDA approved. This compounded formulation is prepared under a patient-specific prescription with licensed prescriber supervision.

Read the full retatrutide guide Open the dose calculator

Brand-name semaglutide (Wegovy, Ozempic) and tirzepatide (Zepbound, Mounjaro) are FDA approved. Compounded versions are not FDA approved and are prepared under a patient-specific prescription. All GLP-1 medications require an evaluation by a licensed prescriber.

Side by side

Semaglutide vs. tirzepatide vs. retatrutide

The right choice depends on health history, goals, and how the body responds, and it's made with a prescriber. Here's how they compare.

Feature	Semaglutide	Tirzepatide	Retatrutide
Hormones targeted	GLP-1	GIP and GLP-1	GIP, GLP-1, and glucagon
How often	Once weekly	Once weekly	Once weekly
Average weight loss in trials	14.9% at 68 weeks	20.9% at 72 weeks	28.3% at 80 weeks (phase 3)
Common compounded strength	2.5 mg/mL with vitamin B6	15 mg/mL with vitamin B6	15 mg/mL with vitamin B6
Vial sizes	2 mL (5 mg) or 4 mL (10 mg)	2 mL (30 mg) or 4 mL (60 mg)	4 mL (60 mg) or 10 mL (150 mg)
Maintenance dose	2.4 mg weekly	15 mg weekly	12 mg weekly (maximum)
FDA status	Brand versions approved	Brand versions approved	Investigational, not FDA approved
Often a fit for	People starting GLP-1 therapy who want the longest track record	People who want stronger appetite control or haven't reached goals on GLP-1 alone	People working with a prescriber on an investigational option, under close supervision

Results

Results of GLP-1 usage

Results vary from person to person. These are ranges commonly reported with consistent use.

Semaglutide

Weeks 4–84–15 lbs
Early loss is driven mostly by lower appetite, smaller portions, and fewer cravings.
Weeks 12–1515–26 lbs
As your dose increases, appetite control and healthier eating habits become more consistent.

Tirzepatide

Weeks 4–86–18 lbs
Reduced appetite and cravings lead to early, noticeable changes.
Weeks 12–1518–30 lbs
Continued appetite regulation and steady habits support more significant progress.

FAQs

Answers to common questions

What is GLP-1 and how does it work?

GLP-1 is a hormone your gut releases after you eat. GLP-1 medications mimic it. They help your body release insulin when blood sugar rises, slow how quickly your stomach empties, and act on appetite centers in the brain, so you feel full sooner and stay full longer.

Who is a good candidate for GLP-1 therapy?

Generally, adults with a BMI of 30 or higher, or 27 or higher with a weight-related condition such as high blood pressure, type 2 diabetes, or high cholesterol.

GLP-1 medications aren't right for everyone. People who are pregnant, or who have a personal or family history of medullary thyroid cancer or MEN 2, are usually not candidates. Your provider reviews your full history before prescribing.

What are common side effects?

The most common are nausea, diarrhea, constipation, vomiting, and feeling full quickly. They're usually mild and ease as your body adjusts, which is why doses start low and increase gradually.

Severe stomach pain that doesn't go away, signs of an allergic reaction, or trouble swallowing need medical attention right away.

How long does it take to see results?

Many people notice less appetite within the first few weeks. Weight loss builds over months as your dose increases. The major clinical trials measured results after about 16 to 18 months of treatment.

Can I use GLP-1 if I have diabetes?

Often, yes. Semaglutide and tirzepatide were first approved to treat type 2 diabetes. If you take insulin or a sulfonylurea, your provider will adjust your plan, because combining them can raise the risk of low blood sugar.

Not sure which option fits?

Reach out with your questions. We'll explain the differences in plain language.