What Is Semaglutide (Ozempic) and How Does It Work?

Your gut sends a chemical message after you eat. That message tells the pancreas it is mealtime, tells the stomach to take its time, and tells the brain you have had enough. Semaglutide is a long-lasting stand-in for that message. It belongs to a class of medications called incretin mimetics (MedlinePlus, U.S. National Library of Medicine, NIH, undated).

Three things follow from that one signal (MedlinePlus, NIH, undated):

• It helps the pancreas release the right amount of insulin when blood sugar is high. Think of a dimmer rather than a light switch — the prompt is tied to your blood sugar being up, not to the clock.
• It slows the emptying of the stomach, so food leaves more gradually, like a drain that has been narrowed.
• It may decrease appetite and cause weight loss.

What it is prescribed for depends on the product and the person. Semaglutide injection is used to control blood sugar in certain patients with type 2 diabetes; to reduce the risk of heart attack, stroke or death in adults with type 2 diabetes and heart and blood vessel disease, and in adults who are obese or overweight with heart and blood vessel disease; to reduce the risk of worsening kidney disease and death in certain adults with type 2 diabetes and kidney disease; and to assist with weight loss in certain people who are obese or overweight and have weight-related medical problems (MedlinePlus, NIH, undated). Brand names for semaglutide injection include Ozempic, Wegovy and Wegovy HD (MedlinePlus, NIH, undated).

So the approved use attached to your prescription varies by brand, by your age and other conditions, and by the country and the edition of labelling or guidance your prescriber is working from. Ask which use yours is for. It comes as a solution in a prefilled dosing pen injected under the skin once a week (MedlinePlus, NIH, undated); the starting amount and any changes over time are your prescriber's decision, not something to adjust on your own.

Tell your doctor beforehand if you have or have had pancreatitis, diabetic retinopathy, gastroparesis or other severe stomach problems, gallbladder disease, or kidney disease (MedlinePlus, NIH, undated).

These are the effects people most often notice, roughly most to least common. Tell your doctor if any of them are severe or do not go away (MedlinePlus, U.S. National Library of Medicine, NIH, undated).

• Nausea — a queasy, off-food feeling, often around meals.
• Vomiting — can arrive with the nausea rather than separately.
• Diarrhea — looser, more frequent stools for a stretch.
• Stomach pain — general ache or cramping in the belly.
• Constipation — harder, less frequent stools; can alternate with diarrhea.
• Heartburn or burping — burning behind the breastbone; frequent burps.
• Runny nose or sore throat — mild cold-like symptoms, no fever needed.
• Headache — ordinary, dull head pain.

These are different from the list above. Each needs a same-day phone call or emergency care — not a wait-and-see (MedlinePlus, U.S. National Library of Medicine, NIH, undated).

• Rash, itching, fainting or dizziness, swelling of the eyes, face, mouth, tongue or throat, or difficulty breathing or swallowing. Go to an emergency room or call 911 — do not drive yourself if your breathing or swallowing is affected.
• Ongoing pain that begins in the upper left or middle of your stomach and may spread to your back, with or without vomiting. Call your doctor immediately; if the pain is severe or you cannot reach anyone, go to an emergency room.
• Pain in the upper stomach, yellowing of the skin or eyes, fever, or clay-colored stools. Call your doctor the same day; go to an emergency room if you are also in severe pain or feel very unwell.
• A lump or swelling in the neck, hoarseness, difficulty swallowing, or shortness of breath. Call your doctor immediately. Semaglutide may increase the risk of thyroid gland tumors, including a type of thyroid cancer, and caused thyroid tumors in rats; it is not known whether it increases tumor risk in humans. Go to an emergency room if your breathing is affected.
• Decreased urination, swelling of the legs, ankles or feet, or changes in your vision. Call your doctor immediately rather than waiting for your next appointment.

Say these in your own words, or read them out as written.

1. "Which of these approved uses is my prescription actually for, and why did you pick this medicine for me?"
2. "Which of my other medicines, including anything else I take for blood sugar, interact with this one — and could I get low blood sugar, with signs like shakiness, sweating or lightheadedness?"
3. "How will we measure whether this is working for me, which numbers or results will you look at, and when will we check them?"
4. "What amount am I starting on, how and when will you change it, and what should I do if I miss my weekly injection?"
5. "Given my other health conditions and my age, what would make you stop this or switch me to something else?"
6. "Who do I call after hours with a side effect, and what do you want me to treat as an emergency room visit rather than a phone call?"
7. "What does this cost me under my insurance, and what happens if the pharmacy cannot get this brand?"