How Semaglutide Works For Weight Loss

In June 2021, the FDA approved semaglutide (Wegovy), a once-weekly injection, for chronic weight management in adults when used in combination with a healthy diet and exercise. The medication had made headlines before its approval when the manufacturer reported 15% to 18% weight loss findings during clinical trials


Not everyone is eligible for treatment with semaglutide. Doctors can prescribe it for adults who have obesity, with a body mass index (BMI) of greater than 30; or overweight, with a BMI greater than 27 accompanied by weight-related medical problems such as high blood pressure, type 2 diabetes, or high cholesterol.

But there is significant demand for the drug. In 2019, more than 11 percent of the population was diagnosed with diabetes, while more than four in ten adults classified as obese in 2020.

What Is Semaglutide

Semaglutide is an injectable medication that belongs to a class of medications called glucagon-like peptide-1 (GLP-1) agonists. GLP-1 is a hormone that affects the regulation of blood sugar by stimulating glucose-dependent insulin secretion. Insulin is a hormone that promotes sugar uptake by the cells, stores sugar as glycogen, promotes the building of fat, and signals the body to build skeletal muscle.


GLP-1 inhibits the release of the hormone glucagon, which slows down the release of sugar into the blood so that you burn more fat and slows down gastric emptying to make you feel full longer while reducing the desire for food intake.


How Semaglutide Works

Semaglutide mimics the GLP-1 hormone in your body, which helps to control your blood sugar by blocking the liver from releasing sugar into your bloodstream, slows down how fast your stomach empties food, and causes your pancreas to release insulin.


Like GLP-1, Semaglutide prevents fat storage, improves glucose control, and helps the body to better absorb food, use insulin and reduce blood cholesterol levels. It also works by inhibiting the action of ghrelin, a hormone that stimulates appetite. Ghrelin is produced by the stomach and is released when you are hungry. It has been found to be very similar to GLP-1, only it doesn’t help control blood glucose levels.

Ghrelin and GLP-1 are used together by the body to regulate blood sugar levels. They operate in tandem to help control hunger.  When you eat, both hormones are released and secreted into the bloodstream. When your blood sugar levels drop, ghrelin is released to stimulate the release of GLP-1, which then goes in to help raise your blood glucose back up. The result: you are less hungry. While GLP-1 is a bit more complex, ghrelin can be credited for helping regulate hunger and keep you on track with your diet.

Semaglutide helps insulin to work more effectively in the body. It stimulates the release of insulin from the pancreas, which improves glucose control. Semaglutide works by helping your body break down and use long-term stores of fat to produce the insulin it needs for proper blood sugar control.

What Semaglutide Is NOT

Semaglutide is not a type of insulin or a substitute for insulin. Semaglutide simply stimulates your pancreas to release insulin when glucose (sugar) is present. Because semaglutide relies on your body’s own insulin to be released from the pancreas, semaglutide isn’t used when your pancreas can’t make insulin, such as in patients in type 1 diabetes.


Semaglutide is not a stimulant. While other weight loss medications, like phentermine, have stimulating effects that help curb your appetite, Semaglutide works differently. This means that it is safe for more people, especially those with high blood pressure, sleep issues, anxiety and more.


Semaglutide Side Effects

What you should avoid while on semaglutide:


  • Foods to Avoid: It is recommended to limit sugar, fast-digesting carbs, and processed foods. Fried foods and fatty foods, such as fast food, processed foods, carbonated and sugary drinks, and foods high in sugar and saturated fat are likely to make you nauseous while on semaglutide.
  • Alcohol: Limit how much alcohol you’re drinking while taking semaglutide, especially if you are diabetic. Alcohol can have an effect on your blood sugar, and there is a risk that it may drop too low in combination with semaglutide, especially if you are drinking on an empty stomach. Alcohol can irritate your stomach, too. This might make you feel worse in combination with some of the GI side effects from the medication.

Semaglutide Safety

Semaglutide is considered to be safe and effective when used as indicated. “Safe” doesn’t mean that there aren’t risks. Semaglutide is FDA approved for weight loss in the branded version Wegovy.


The common side effects of Semaglutide are:

  • Nausea
  • Vomiting
  • Diarrhea
  • Stomach pain
  • Constipation

Semaglutide is not recommended for those with a history of thyroid cancer,  type-1 diabetes, history or pancreatitis, people who are pregnant, or if on other blood sugar lowering medications. Studies show a clear benefit of adjunct treatment with semaglutide in post-bariatric patients. However, consultation with your healthcare provider is necessary to determine if it’s right for you.


Losing The  Weight On Semaglutide

Weight loss will be gradual since you will slowly work your way up to the target dose of semaglutide, at which time you will see the most amount of weight loss.


This was the case in the clinical trials, where participants had their dose adjusted until they reached 2.4 mg once weekly. In the phase 3 trial that measured outcomes at 20 weeks, most participants were able to reach the full dose and also lost weight as their dose was increased. They saw additional weight loss over the remaining 48 weeks at the full dose. Study participants received treatment for a period of 68 weeks (about 1.5 years) during each of the four trials conducted by the company.


It is important to keep in mind that weight loss can take time, and you’ll see the best results when you are using your medication in combination with a healthy diet and exercise. Sometimes the medication may not work for you, or you may not be able to tolerate the full dose due to side effects.

Keeping The Weight Off After Semaglutide Treatment Stops

Studies do not currently have data past 68 weeks. However, an effective medical weight loss program is designed to help you begin adopting healthy lifestyle changes that will promote lasting weight loss where medication is no longer needed. Being on semaglutide can help you learn to control your portion sizes. However, if you go back to how you were eating once off semaglutide, and do not adopt the necessary lifestyle changes to maintain the weight loss, it is likely that you will gain the weight back.  Using semaglutide can be one piece of the weight-loss puzzle.  Other areas that could affect weight are hormone balance, thyroid function, nutritional balance, lifestyle changes, and medications.