GLP-1 receptor agonists.

What a GLP-1 receptor agonist is

GLP-1 (glucagon-like peptide-1) is a hormone your gut releases after eating. It tells the pancreas to release insulin when blood sugar rises, slows how quickly the stomach empties, and signals fullness to the brain. A GLP-1 receptor agonist is a medication that activates the same receptor — producing those effects more strongly and for longer than the natural hormone.

The class was developed for type 2 diabetes. Because reduced appetite and slower digestion also produce weight loss, several GLP-1 medications are now prescribed for weight management in adults with obesity or overweight with a related condition.

How they work

• Appetite. Acting on the brain’s appetite centres reduces hunger and food-focused thoughts.
• Digestion. Slower gastric emptying means meals feel satisfying for longer.
• Blood sugar. Insulin is released in response to food, and glucagon (which raises blood sugar) is suppressed.

Tirzepatide adds a second action: it also activates the GIP receptor, another gut-hormone pathway involved in appetite and metabolism. That dual action is why it’s described as a GLP-1/GIP agonist rather than a pure GLP-1.

Medications in this class

Who they’re for

For weight management, GLP-1 treatment is generally considered for adults with a BMI of 30 or above, or 27 and above with a weight-related condition such as high blood pressure, high cholesterol or prediabetes. BMI is a screening threshold, not the whole picture — a provider also weighs your history, current medications and goals.

How dosing usually progresses

GLP-1 medications are started low and increased gradually — titration — so the body adjusts and side effects stay manageable. A typical semaglutide schedule runs 0.25 mg → 0.5 mg → 1 mg → 1.7 mg → 2.4 mg, each step held for around four weeks. Tirzepatide runs 2.5 mg → 5 mg → 7.5 mg → 10 mg → 12.5 mg → 15 mg on the same cadence. Your provider sets the pace; not everyone needs the top dose. If you’re switching from another program, you usually continue at or near your current dose rather than restarting.

Side effects

The most common are digestive — nausea, constipation, diarrhoea, reduced appetite — and are usually strongest in the first weeks after a dose increase, then ease. Eating smaller meals, avoiding very fatty foods and staying hydrated helps. Less common but important: gallbladder problems, pancreatitis, and low blood sugar when combined with insulin or sulfonylureas. GLP-1 medications carry a boxed warning about thyroid C-cell tumours seen in rodents; they are not prescribed to people with a personal or family history of medullary thyroid carcinoma or MEN 2. Tell your provider about all conditions and medications.

Compounded vs. brand-name

Compounded semaglutide and tirzepatide contain the same active ingredient as the brand products but are prepared for an individual prescription by a state-licensed compounding pharmacy. They are not FDA-approved and don’t undergo FDA review for safety, effectiveness or manufacturing. A provider may prescribe a compounded option where it’s medically appropriate — for example a dose not commercially available, or during a shortage. More on compounded medications

What it costs at NiceRx

Plans include the provider evaluation, medication and delivery, at the same price at every dose. No insurance required and nothing is charged unless a provider prescribes. Full pricing

Disclaimer: This page is for information only and is not medical advice. Compounded medications are prepared by state-licensed compounding pharmacies and are not FDA-approved. A provider licensed in your state determines whether any treatment is appropriate for you.