Semaglutide: Overview, how it works, and more

What is semaglutide?

Semaglutide is a GLP-1 agonist and works by mimicking a hormone called glucagon-like peptide, or GLP-1, that naturally circulates in your body. This hormone is released when you eat and signals to your body to increase insulin, which brings down blood sugar levels. Semaglutide also slows the emptying of the stomach and signals to your brain that you are full. When you take semaglutide, those GLP-1 receptors stay activated for a prolonged period of time, which improves blood sugar, slows down stomach emptying, and reduces appetite.

Semaglutide brand names

Semaglutide is prescribed under three brand names: Ozempic, Wegovy, and Rybelsus. And there are some key differences. For one, Ozempic and Wegovy are both given by weekly injection while Rybelsus is a daily tablet you swallow. Here’s more about all three:

• Ozempic was FDA-approved in 2017 for controlling blood sugar in people with type 2 diabetes. In 2020, the FDA granted Ozempic a label expansion, approving its use for people with cardiovascular issues — those with obesity and without — to reduce the risk of heart attack and stroke.

• Rybelsus was approved next, in 2019, as the first GLP-1 for managing blood sugar in people with type 2 diabetes that does not need to be injected and can instead be taken by mouth in pill form.

• Lastly came Wegovy, which was FDA-approved for chronic weight management in 2021 for adults who are either living with obesity (having a body mass index of 30 or greater) or living with overweight (a BMI of 27 or greater) plus at least one qualifying health condition, such as high blood pressure, type 2 diabetes, or high cholesterol. Three years later, in 2024, the FDA also approved it to reduce the risk of cardiovascular death, heart attack, and stroke for people who have obesity or overweight as well as cardiovascular disease. And then in 2025 it was approved to reduce the risk of worsening kidney disease and cardiovascular death in adults with type 2 diabetes and chronic kidney disease.

Semaglutide uses

Semaglutide is used for two primary reasons: to help people lose weight and to help manage blood sugar in people with type 2 diabetes. While specific trials show slightly different results, semaglutide can reduce HBa1c levels between 0.6% and 1.6%. HBa1c is a measure of blood sugar levels over time and is how the effectiveness of a type 2 diabetes medication is measured.

For weight loss, semaglutide can lead to an average 15% weight loss in a little over a year (an average of 33 pounds in 68 weeks), according to a study in The New England Journal of Medicine. While those results are significant, it’s still important to combine semaglutide with healthy habits to maximize the benefits. “The goal isn’t just to achieve reduction in your appetite, the goal is to improve health,” says Dr. Jamy Ard, M.D., a professor in the departments of epidemiology and prevention and internal medicine at Wake Forest University School of Medicine. “And part of improving health is being more physically active and eating a healthier diet — things most of us need to do. That’s why it’s important to not just think that if you take the drug, your health will be optimized.”

In studies, Rybelsus (the oral version) does not deliver the same level of weight loss or blood sugar control as Ozempic or Wegovy (the injectable versions). “With the pill, you don’t get the same blood concentration levels and it doesn't stick around as long,” says Ard. “But some people still prefer Rybelsus because it’s what their insurance will pay for, they don’t want to do an injection, or they don’t tolerate the injectable version well.”

Semaglutide dosage

Each form of semaglutide comes in multiple doses, with patients starting out on the lowest dose and gradually working their way up. “Your provider will look to see if you’re getting the response that will help you accomplish your health goals while minimizing side effects,” says Ard. “If we’re seeing the results we want, we can hold at that dose and move up later if needed.”

Ozempic dosing

Ozempic pens come 0.25 mg, 0.5 mg, 1.0 mg, and 2.0mg doses. Patients start with 0.25mg for four weeks, then move up to 0.5 mg for the next four weeks. At that point you can stay there if your blood sugar is being controlled, or you can move up to one of the two higher Ozempic doses if you need more help managing blood sugar.

Wegovy dosing

Wegovy comes in five doses: 0.25 mg, 0.5 mg, 1.0 mg, 1.7 mg, and 2.4 mg. Similar to Ozempic, you start with the 0.25 dose for four weeks, then can keep moving up in dose every four weeks until your healthcare provider thinks you are at the right Wegovy dosage.

Rybelsus dosing

Rybelsus tablets come in three doses: 3 mg, 7 mg, and 14 mg. Patients take the smallest dose daily for 30 days, then go up to the middle dose. After 30 days, your provider will check your blood sugar and decide if you need to go up to 14 mg or not.

Alternatives to semaglutide

If you are interested in a GLP-1 besides semaglutide, the main alternatives are liraglutide (Victoza is for type 2 diabetes while Saxenda is approved for weight loss) and tirzepatide (Mounjaro is approved for type 2 diabetes and Zepbound is for weight loss). A big difference between semaglutide and tirzepatide is that semaglutide mimics the action of one hormone – GLP-1 – while tirzepatide mimics the action of two, a GLP-1 and something called a GIP, or glucose-dependent insulinotropic polypeptide.

Semaglutide warnings and precautions

While semaglutide is generally considered safe, there are some people who should not take semaglutide, including those who have a personal or family history of medullary thyroid carcinoma (MTC) or multiple endocrine neoplasia syndrome type 2 (MEN 2). It is also not recommended for people with a history of pancreatitis. You should also not take semaglutide if you are pregnant and, if you’re taking it post-delivery, it’s recommended you should not breastfeed. “Weight loss is never an objective during pregnancy because of its impact on the fetus,” says Ard. “And if you’re breastfeeding, semaglutide could negatively impact your milk.” Make sure you go over your complete health history with your prescribing doctor before beginning to take semaglutide.

Semaglutide interactions

You may worry that because semaglutide slows down your digestion, it can impact how well you absorb other medications, but Ard says that’s not really an issue. “If a medicine stays in your stomach longer, it can get absorbed there — it doesn’t need to get to your intestines to be absorbed,” says Ard. “You also aren’t delaying the emptying of your stomach to such an extreme that medications don’t get where they need to go.”

That said, there are some medications that should be used cautiously while taking semaglutide, including other drugs that lower blood sugar like insulin. That’s because the combination could lower your blood sugar too much, resulting in hypoglycemia. Go over all medications and supplements — both prescription and over the counter — that you’re taking with your provider before you start taking semaglutide.

Semaglutide cost and coupons

How much semaglutide will cost depends largely on whether or not your insurance plan covers it. Coverage is much more likely for semaglutide prescribed for type 2 diabetes instead of weight loss. “A large portion of people do not have insurance coverage for anti-obesity medications, but they might for Ozempic,” says Dr. Kimberly Gudzune, M.D., medical director for the American Board of Obesity Medicine and an associate professor of medicine at Johns Hopkins.

If your insurance does not cover your medication, the list price is $1,349 for a month’s supply of Wegovy, $997 for Ozempic, and $997 for Rybelsus. That said, you may be able to use a prescription discount card or qualify for a manufacturer-sponsored patient assistance program. To get a better idea of how much Wegovy will cost you, check with your insurer, healthcare provider, or pharmacist.

Paying for semaglutide can be a frustrating experience because of how coverage seems to constantly be changing. “Every day there’s some new insurance group that says they’re going to start covering it and another that says they aren’t going to cover it anymore because it’s too expensive,” says Ard.

Semaglutide storage

There are a few things to keep in mind when deciding where to keep your Ozempic, Wegovy, or Rybelsus medications.

Ozempic storage

Ozempic should be kept in a refrigerator until you’re ready to use it. Once you start using a pen, you can keep it either in the fridge or at room temperature for up to 56 days. You don’t want it to go above 86 degrees or freeze.

Wegovy storage

Wegovy should also be kept in the refrigerator but you can keep it at room temperature for up to 28 days as long as you haven’t removed the cap. Like Ozempic, you should make sure your Wegovy doesn’t get too hot or freeze.

Rybelsus storage

Unlike the injectable versions of semaglutide, Rybelsus should be kept at room temperature. An important note is that you should not store the pills in a pill organizer box — keep them in the blue-capped bottle until you’re ready to take them. The bottle is designed to keep moisture away from the pills, ensuring they stay effective.

The bottom line

Semaglutide is a GLP-1 that helps improve blood sugar and reduce appetite. It can improve A1C levels as well as lead to weight loss — up to 15% in a little over a year. There are three different brand names of semaglutide: Ozempic, a weekly injectable approved for type 2 diabetes, Wegovy, a weekly injectable approved for weight loss, and Rybelsus, a daily oral pill approved for type 2 diabetes. As a general rule of thumb, the injectable versions work better than the oral version. All forms of semaglutide can lead to side effects, but they tend to be mild and mostly gastrointestinal, like nausea and diarrhea. To make sure you’re safe while taking semaglutide, talk to your doctor about any side effects you’re taking as well as other medications or health issues you may have.