What is GLP-1 and GLP-1 RA?
Key Takeaways
Glucagon-like peptide-1, or GLP-1, is a natural hormone in the body. It acts in a few different ways to help keep blood sugar under control and promote weight loss.
GLP-1 receptor agonists, or GLP-1 RAs, are medications that mimic the actions of GLP-1. They are only available with a doctor’s prescription.
Medications in this class include semaglutide (Ozempic, Rybelsus, Wegovy), liraglutide (Saxenda, Victoza), and dulaglutide (Trulicity).
Some GLP-1 RAs are approved for treating diabetes, while others are approved for weight loss.
GLP-1 RAs are intended to be used alongside a healthy lifestyle, including enough exercise and a healthy diet.
A group of medications known as GLP-1 RAs have been getting a lot of attention lately. This group includes semaglutide (Ozempic, Rybelsus, Wegovy), liraglutide (Saxenda, Victoza), and dulaglutide (Trulicity). Some of these medications are used to treat diabetes, while others are used to promote weight loss. Many people are curious about these medications and how they work.
What is glucagon-like peptide-1 (GLP-1)?
GLP-1 RAs work by mimicking a natural hormone in the body known as glucagon-like peptide-1, or GLP-1. Researchers are still working to understand all of the actions of GLP-1 in the human body, because this hormone was discovered relatively recently. However, we do know about its main actions, which are related to blood sugar control and body weight.
GLP-1 and Diabetes
GLP-1 modulates other hormones that regulate blood sugar:
It stimulates the secretion of insulin, which is a hormone that brings blood sugar down. This helps to reduce the rise in blood sugar after a meal.
It reduces the secretion of glucagon, which is a hormone that normally raises blood sugar. This also helps to keep blood sugar from rising too high.
Levels of GLP-1 normally rise after a meal. After we eat, blood sugar usually goes up, and GLP-1 is part of the body’s natural response. It helps to keep blood sugar within a healthy range, preventing it from rising too high and causing damage to the body.
GLP-1 and Weight Loss
There are also a few other actions of GLP-1 which are related to food consumption:
It slows down the emptying of the stomach.
It acts in the brain to reduce hunger and food cravings.
By doing both of these things, GLP-1 helps to reduce the amount of food that a person eats. GLP-1 helps to keep you feeling full for a while after you eat, and it also helps to prevent you from experiencing a strong desire to eat when your body doesn’t really need food.
People with obesity have been shown to have decreased levels of GLP-1 in their bodies. In this way, using medications that mimic GLP-1 can be thought of as a way to restore a healthy level of GLP-1 activity, which then helps to bring body weight back into a healthier range.
What are GLP-1 agonists/GLP-1RAs
Medications that act on the GLP-1 system are officially known as glucagon-like peptide-1 receptor agonists, or GLP-1 RAs. However, variations on this term are sometimes seen, such as GLP-1 agonists or simply GLP-1s. These terms are referring to the same group of medications.
Any hormone in the body works by binding to proteins called receptors, which are located on the surface of cells. In order to act, GLP-1 needs to activate the GLP-1 receptor. A GLP-1 receptor agonist, or GLP-1 RA, activates the GLP-1 receptor, which causes the same action that the GLP-1 hormone itself would normally cause. That’s how these medications are able to mimic GLP-1.
There are a few different medications in this group that are approved for use in Singapore:
Semaglutide. There are three approved versions of this medication. Ozempic is given weekly by injection, and is used to treat diabetes. Rybelsus is also used to treat diabetes, but it’s a tablet that’s taken by mouth daily. Wegovy is also given weekly by injection, but it’s used for weight loss.
Liraglutide. There are two approved versions of this medication. Victoza is given by injection daily, and is used to treat diabetes. Saxenda is also a daily injection, but is used for weight loss.
Dulaglutide. The only approved version of dulaglutide is Trulicity, which is given by injection weekly and is used to treat diabetes.
GLP-1 RAs help to keep blood sugar under control, mainly by changing the body’s secretion of the main hormones that deal with blood sugar levels. Currently, these medications are only approved for treating type 2 diabetes.
There has been some research showing that they may be beneficial for people with type 1 diabetes as well, but more research is needed before the Health Sciences Authority will consider approving GLP-1 RAs for this population.
They also help to promote weight loss in two main ways. They slow down the emptying of the stomach, which helps to keep people feeling full for longer after eating. They also act in the brain to reduce hunger and cravings. As a result, people taking a GLP-1 RA will find themselves eating less food, and this generally leads to weight loss over time. One large clinical trial showed that people taking semaglutide lost an average of 10.9% of their body weight over a 6 month period.
Additional GLP-1 RA Benefits
The impacts on blood sugar and body weight are generally the primary effects that people are looking for when they start taking GLP-1 RAs. However, these medications have also been shown to have additional benefits as well.
GLP-1 RAs appear to have a protective effect against heart disease. People taking a GLP-1 RA have been shown to have a 14% lower risk of heart attacks, strokes, and cardiovascular-related death.
These medications also help to protect the kidneys. In one large study, people taking semaglutide experienced a 15-20% improvement in kidney function, while those taking a placebo experienced an 18% decline. In other studies, those taking a GLP-1 RA were found to be 21% less likely to experience progression of their kidney disease, to require dialysis, or to die from kidney disease.
It’s believed that these additional benefits are mainly a result of the better blood sugar control and weight loss that these medications bring. Both diabetes and obesity raise the risk of heart disease and kidney disease. By treating those conditions, GLP-1 RAs reduce this risk.
However, there may also be a direct impact of the medications on certain organs. In fact, receptors for GLP-1 have been found in many different types of tissues throughout the body, and this could help to explain the protective effect of GLP-1 RAs. They may have more benefits that we don’t yet know about. Many research studies are ongoing to discover more about these medications and their effects.
Side effects of GLP-1 related drugs
All medications have side effects, and GLP-1 RAs are no exception. The main side effects of GLP-1 RAs are related to the digestive system. People may experience:
Nausea and vomiting
Abdominal pain and bloating
Indigestion or acid reflux (heartburn)
Constipation or diarrhea
Weakness during exercise
Headache
These effects can be uncomfortable, but are generally not dangerous. They usually get better over time, as the body adjusts to the medication. A GLP-1 RA is first started at a low dose, to help the body get used to it. The dose is then gradually increased over a period of several weeks to months. Doing this helps to reduce the side effects, because it gives the body more time to adjust. There are also some lifestyle changes that can help to reduce the side effects, such as taking smaller meals and plenty of water, avoiding very fatty or fried meals, avoiding lying down for a few hours after eating, and taking a small snack before exercising.
GLP-1 RAs are generally considered to be safe for long-term use. Some people who are using a GLP-1 RA for weight loss may choose to come off the medication once they reach a weight loss plateau. It does take some planning to avoid gaining weight back after stopping the medication, but with the right support, this can be accomplished. For those who prefer to continue taking the medication long-term to help maintain their weight loss, this is also an option.
How can you get a GLP-1 RA?
GLP-1 RAs are prescription medications. They’re only available with a prescription from a specialist doctor. If you’re considering taking a GLP-1 RA, you’ll need to make an appointment with a doctor, who will determine whether the medication would be safe and effective for you. If so, then they’ll prescribe it for you.
It’s very important to recognize that, while some GLP-1 RAs are approved for weight loss, they aren’t intended to be used alone. Instead, the medication is most effective when used as an adjunct to a healthy lifestyle, including enough exercise and a healthy diet.
Most people find it challenging to develop and stick to a healthy lifestyle plan that will work for their lives. Having the support of a team of healthcare professionals can be very helpful. Clients in our NOVI Optimum Plus medical weight loss program receive support from nutritionists and health coaches, along with medical supervision from our specialist physicians, to give them the best possible chance to achieve their weight loss goals.