GLP-1 medications explained: what is the difference between them?
Semaglutide. Tirzepatide. Once-weekly injections. Pills. The GLP-1 landscape can feel overwhelming. Here is a clear guide to your options.
What a GLP-1 receptor agonist is
GLP-1 is a hormone your body naturally produces in response to eating. It signals to your brain that you are full, slows the rate at which food leaves your stomach, and reduces the secretion of glucagon, a hormone that raises blood sugar.
GLP-1 receptor agonists are medications that mimic this hormone but stay active in your body far longer than the natural version. The result is reduced hunger, slower digestion, lower blood sugar and, over time, significant weight loss.
Semaglutide: two brands, one drug
Ozempic and Wegovy contain the same active ingredient. The difference is approval and dose:
Both are once-weekly injections under the skin. The pen is pre-filled and the needle is very fine; most patients describe it as nearly painless. An oral form is now approved for weight loss too.
Tirzepatide: two brands, one drug
Tirzepatide is newer and targets two hormones — GLP-1 and GIP. This dual action produces even greater weight loss in clinical trials.
Trials showed an average loss of 22.5% of body weight at the highest dose — among the most striking results ever seen in a non-surgical intervention.
Side effects to know about
The most common are gastrointestinal: nausea, vomiting, constipation and diarrhoea. These are most likely when starting or increasing the dose and typically improve over time. Starting low and titrating up slowly — the standard approach — significantly reduces them. Our side effects guide covers the first 12 weeks in detail.
More serious but rare risks include pancreatitis, gallbladder disease, and a theoretical risk of thyroid C-cell tumours seen in rodent studies — a personal or family history of medullary thyroid cancer is a contraindication. Your physician reviews your complete medical history before prescribing.
Which is right for you?
There is no one-size-fits-all answer. The right choice depends on your medical history, whether you have diabetes, what your insurance covers, and your own preferences — including whether you would rather take a pill than an injection. A physician board certified in obesity medicine weighs all of that during your visit and recommends the most appropriate option.
This article is general health information, not medical advice for your situation, and does not create a physician-patient relationship. If you are unwell, speak with a physician.
