Semaglutide is an injectable glucagon-like peptide-1 (GLP-1) agonist that’s administered once weekly. It was originally approved in 2017 — at a much lower dose — to help control blood sugar in type 2 diabetes under the brand name Ozempic. People taking Ozempic to help control blood sugar also tend to lose weight as an additional benefit.
Because of this, Novo Nordisk studied the medication in people without type 2 diabetes, but at a higher dose. Now, semaglutide is 503A FDA-approved for weight loss in adults with a body mass index (BMI) greater than or equal to 30mg/kg² alone or 27 mg/kg² with at least one weight-related comorbidity (e.g., high blood pressure, high cholesterol).
Semaglutide should be used in combination with lifestyle changes, including a healthy diet and exercise.
GLP-1 is an incretin hormone that plays a role in your appetite and digestion. Incretins — hormones released by your small intestine — are sent out by your body after you’ve eaten a meal to help lower your blood sugar by triggering insulin and blocking other sources of sugar. It also slows down how quickly food leaves your stomach (called gastric emptying).
The result of these actions causes you to feel full — lowering your appetite and causing you to lose weight. Medications like GLP-1 agonists are referred to as incretin mimetics since they “mimic” these effects.
As mentioned above, GLP-1 agonists, like semaglutide, were originally used to treat type 2 diabetes due to their blood sugar-lowering effects. However, the weight loss side effect has been shown to benefit people without type 2 diabetes as well.
Semaglutide is available as a single-use injection.
You’ll get the injection once a week, on the same day each week. It can be given at any time of day, and you can take it with or without food.
Semaglutide is typically injected just under the skin (subcutaneously) in your abdomen. Avoid injecting the medication into the same spot every time — change your injection site with each dose. But injecting in the same body area (e.g., abdomen) is OK as long as you’re rotating sites within the area each time.
Since semaglutide slows down how quickly food leaves your stomach, you may experience side effects like nausea and vomiting. Once you get started on the medication, your provider will slowly raise your dosage every 2 weeks to help make these effects more manageable.
The target maintenance dose is 2.4 mg once weekly. Before reaching the target dose, a typical dosing schedule may look like:
0.10 mg once weekly for the first two weeks, 0.20 mg once weekly for the next two weeks, 0.40 mg once weekly for the next two weeks, 0.60 mg once weekly for the next two weeks, 0.80 mg once weekly for the next two weeks, and then 1.0 mg once weekly for the final two weeks of the first 3 months. The next 2 month treatment will reach the 2.4 mg.
Some people may not be able to reach or tolerate the target dose due to side effects. If this is the case, your provider may wait another month before raising your dose. However, they may have you discontinue the medication if you’re unable to reach or stay on the target dose.
As mentioned earlier, gastrointestinal (GI) side effects tend to happen most frequently when using this medication — the most common being nausea, diarrhea, and vomiting. You may experience these effects more strongly when your provider raises your dose.
Additional common side effects can include:
Constipation
Stomach pain
Headache
Fatigue
Indigestion
Dizziness
Bloating
Burping
In some cases, semaglutide may cause more serious side effects. The medication has a boxed warning — the FDA’s most serious warning — regarding a potential thyroid C-cell tumor risk. Although this risk hasn’t been confirmed in humans, GLP-1 agonists have been linked to thyroid C-cell tumors in animal studies. Because of this, you shouldn’t take semaglutide if you have a personal or family history of thyroid tumors.
Other serious side effects can include:
Pancreatitis (inflamed pancreas)
Cholelithiasis (gallbladder disease)
Kidney damage
Low blood sugar
Allergic reactions (swelling of the face, tongue, or throat; difficulty breathing)
Eye problems in people with type 2 diabetes
Fast heart rate
Suicidal thoughts and behaviors are another risk listed on the medication’s labeling because it’s been reported with other weight loss medications. Let your provider know right away if you’re experiencing any changes in mood or behavior or if you’re having suicidal thoughts.
Since semaglutide can lower your blood sugar, it can react with other blood sugar-lowering medications like insulin and insulin secretagogues — medications like sulfonylureas that cause insulin to be released — and result in dangerously low blood sugar levels.
If you’re taking one of these medications, your provider may lower your dose while starting you on semaglutide. And as a general rule, if you have type 2 diabetes, it’s important to diligently monitor your blood sugar before and during treatment to ensure that your readings stay within a safe range.
Another potential interaction is with oral medications. Semaglutide slows down how quickly food leaves your stomach, which may affect how certain oral medications are absorbed by your body when they’re taken together. Because of this, you’ll want to monitor for any changes with your medication after you start taking semaglutide.
Yes, it is believed that Semaglutide can help curb your appetite. In addition to slowing gastric emptying to make you feel full for longer, GLP-1 also plays a direct role in how your appetite is regulated.
One of the reasons there’s a lot of buzz around semaglutide is the amount of weight people lost during clinical trials. Typically, we tend to see an average of 5% to 10% weight loss with other medications.
Oral weight loss medications tend to be less expensive than the injectable options, but you may not lose as much weight. Let’s review a few of the more popular weight loss medications and how they compare to semaglutide.
Currently, Semaglutide is only FDA-approved to help with blood sugar control in type 2 diabetes and to lower the risk of major cardiovascular events (like heart attack and stroke) in people with both type 2 diabetes and heart disease. If you are taking Semaglutide for either of these reasons, you’ll take it as directed by your healthcare provider since you are using it to manage a chronic condition. But if you do not have type 2 diabetes and are looking to try Semaglutide to help you lose weight, we’ll have a better idea of long-term safety once the FDA reviews data for this new indication. What we do know is that study participants received treatment for a period of 68 weeks (about 1.5 years) during each of the four trials conducted by the company.
Yes. Semaglutide is considered to be safe and effective when used as indicated. But safe doesn’t mean that there aren’t risks. Semaglutide also carries a boxed warning about thyroid C-cell tumors occurring in rodents (with unknown risk in humans), and Semaglutide shouldn’t be used if you or your family have a history of certain thyroid cancers. Semaglutide should not be used in people with type-1 diabetes or a history of pancreatitis. Semaglutide should be used cautiously for people on other blood sugar lowering medications.
