Diabetes drugs and weight loss

There are two main groups of type 2 diabetes medicines that lower blood sugar and also may lead to weight loss. The first group is glucagon-like peptide 1 (GLP-1) agonists. The second is sodium glucose cotransporter 2 (SGLT-2) inhibitors.

GLP-1 agonists

GLP-1 agonists for type 2 diabetes are generally taken by a shot, also called an injection. Most are taken once a day or once a week. GLP-1 agonists include the following medicines.

Taken once a day by a shot:

• Liraglutide (Victoza, Saxenda).
• Lixisenatide (Adlyxin).

Taken twice a day by a shot:

• Exenatide (Byetta).

Taken once a week by a shot:

• Dulaglutide (Trulicity).
• Exenatide extended release (Bydureon BCise).
• Semaglutide (Ozempic).

Another form of semaglutide is available in a pill that's taken by mouth once a day. The brand name of that medicine is Rybelsus.

Tirzepatide (Mounjaro) is a similar kind of medicine called a dual-acting GLP-1/GIP agonist. It's also used to control blood sugar and can support weight loss. It is taken once a week by a shot.

All GLP-1 agonists can help with weight loss. But the amount of weight loss depends on the type of medicine and the dose. In general, studies have found that tirzepatide and semaglutide are the most effective for weight loss. Dulaglutide and liraglutide also have been found to be very effective. Other GLP-1 agonists appear to be somewhat less effective for weight loss. But people who take them still have better weight loss results than those who do not take the medicine.

GLP-1 agonists mimic the way a hormone called glucagon-like peptide 1 works in the body. When blood sugar starts to rise after a person eats, these medicines cause the body to make more insulin. The extra insulin helps lower blood sugar.

Lower blood sugar helps control type 2 diabetes. But it's not clear exactly how GLP-1 agonists lead to weight loss. They appear to curb hunger. They also slow the movement of food from the stomach into the small intestine. That means you may feel full faster and longer, so you eat less.

As with any medicine, there is a risk of side effects when taking a GLP-1 agonist. Some side effects can be serious. More common side effects often improve after taking the medicine for a while.

Common side effects include:

• Nausea.
• Vomiting.
• Diarrhea.
• Headache.

Low blood sugar is a more serious risk linked to GLP-1 agonists. The medical term for that condition is hypoglycemia. But the risk of low blood sugar typically only goes up when a person also is taking another medicine that's known to lower blood sugar. Examples include sulfonylureas and insulin.

GLP-1 agonists aren't recommended for people who:

• Have had medullary thyroid cancer or who have a family history of the disease.
• Have had multiple endocrine neoplasia or who have a family history of the disease.
• Have had pancreatitis.
• Are pregnant or are actively trying to get pregnant.
• Are breastfeeding.

Certain GLP-1 agonists may not be appropriate for people who have a health condition that affects the intestines, such as gastroparesis, or for people who have some types of kidney disease.

Studies have linked GLP-1 agonists with certain thyroid tumors in rats. But until more long-term studies are done, the risk to humans isn't known.

SGLT-2 inhibitors

SGLT-2 inhibitors come in a pill that's taken once a day. They include the following medicines:

• Canagliflozin (Invokana).
• Dapagliflozin (Farxiga).
• Empagliflozin (Jardiance).
• Ertugliflozin (Steglatro).
• Bexagliflozin (Brenzavvy).

These medicines work in the kidneys where they help take extra sugar out of the blood that then goes out of the body in urine. This lowers blood sugar. It also can help with weight loss. The weight loss benefits of SGLT-2 inhibitors typically are less than those of GLP-1 agonists.

Side effects of SGLT-2 inhibitors may include:

• Genital yeast infections.
• Urinary tract infections.
• Lightheadedness.
• Dizziness.
• Nausea.
• Kidney injury.
• Weaker bones and a higher risk of broken bones.
• A higher risk of diabetic ketoacidosis.

Rarely, SGLT-2 may be linked to a higher risk of infection in the feet and lower legs. If an infection is serious, it could lead to the need for amputation. People who have had wounds on their feet or other problems with their feet or lower legs should talk with their healthcare professionals about the possible risks before taking an SGLT-2.

SGLT-2 inhibitors aren't recommended for people who have had diabetic ketoacidosis. They also may not be a good choice for people with certain types of kidney disease.

Benefits beyond weight loss

Along with helping to control blood sugar and boosting weight loss, GLP-1 agonists and SGLT-2 inhibitors seem to have other health benefits.

Research has found that some of these medicines may lower the risk of certain serious health conditions, such as kidney disease, heart disease, heart failure and stroke. Many people who take these medicines also see their blood pressure improve. But it's not clear whether these benefits are from the medicine or a result of weight loss.

If you have type 2 diabetes and you want to find out if these medicines might be useful for you to lose weight, talk with your diabetes care team. They can help you decide what's best for your situation.

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