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Weight Loss Medication

GLP-1 Medications for Weight Loss

GLP-1 Medications for Weight Loss: A Comprehensive Guide to Incretin Hormones and Their Role in Obesity Treatment

Weight management is a multifaceted journey, and for those struggling with obesity, finding effective solutions is often difficult. In recent years, GLP-1 (glucagon-like peptide-1) medications have emerged as a promising avenue for weight loss. These medications are now joined by dual-receptor medications that also involve GIP (glucose-dependent insulin tropic polypeptide).  Together GLP-1 and GIP are hormones classified as “incretins”.  In this comprehensive guide, we’ll delve into the intricacies of GLP-1 and other incretin hormones, explore their basic biology, and discuss their pivotal role in weight management.

What Is GLP-1 and How Does It Work?

GLP-1, a naturally occurring hormone secreted by the intestines, plays a crucial role in regulating blood sugar levels. It also has a significant effect on satiety, or the feeling of being full. Let’s break down its functions:

  • Insulin Release: GLP-1 stimulates insulin secretion from the pancreas, aiding in glucose control. This is why GLP-1 medications are used to treat type 2 diabetes as well as being used to promote weight loss. While the approval of these medications for weight loss is a relatively recent occurrence, they have been approved for the treatment of type 2 diabetes since 2005.
  • Blocking Glucagon: GLP-1 also lowers blood sugar levels by blocking glucagon, a hormone that increases blood sugar levels.
  • Slowing Stomach Emptying: Beyond blood sugar management, GLP-1 slows down gastric emptying, leading to increased feelings of fullness and reduced appetite. This also contributes to the most common side effects of the medications, which will discuss in detail later.
  • Increase Satiety and Decrease Hunger: GLP-1 also influences hunger and feelings of fullness by acting directly on areas of the brain that regulate hunger and satiety. This is likely the primary way that GLP-1 medications induce weight loss.

How Effective Are GLP-1 Agonist Medications for Weight Loss?

There are two GLP-1 agonist medications that are most commonly used for chronic weight management in individuals with overweight or obesity (without type 2 diabetes):

Wegovy (Semaglutide):

  • How it works: Semaglutide, the active ingredient in Wegovy, acts as a GLP-1 agonist on receptors at multiple locations in the body to mimic the effects of the GLP-1 hormone naturally secreted from the intestines. The levels of this hormone are often low in people with obesity.
  • Clinical Trials: Studies reveal that Wegovy users experience an average weight loss of approximately 15% of their initial body weight. For example, someone who weighs 225 pounds prior to starting the medication would lose, on average, around 33 pounds. There is variability with some patients losing less and some, significantly more than this. A loss of 10% or more of initial body weight is generally considered highly clinically significant. In clinical trials, 66% of patients on Wegovy lost 10% or more of their body weight. Wegovy has also been shown to reduce the risk of heart attack, stroke, and death from cardiovascular causes in patients with pre-existing cardiovascular disease.

Zepbound (Tirzepatide):

  • How it works: Zepbound is somewhat different than Wegovy in that it is a dual-receptor agonist. It has effects on both GLP-1 and GIP receptors. This combination effect appears to result in more weight loss on average, while often having lower rates of side effects than other medications.
  • Clinical Trials: Clinical trials demonstrate significant weight reduction with Zepbound use. On average, patients treated with Zepbound at the highest dosage lost around 21% of their initial body weight. 83% of patients lost at least 10% of their initial weight, and 56% lost more than 20% of their initial weight. These results represent the most effective weight loss of any FDA approved medication.

Are GLP-1 Agonist Medications Safe?

While GLP-1 medications offer exciting weight loss prospects, safety remains paramount. Here’s what you need to know:

  1. Gastrointestinal Side Effects: The most common side effects of GLP-1 medications are nausea and vomiting. These medications may also cause diarrhea or constipation. For most people these effects are relatively mild and get better with time, but for some the side effects are more severe and may prevent them from being able to take the medications.
  2. “Stomach Paralysis”: You may have heard or read concerns that these medications can cause “stomach paralysis”. Gastroparesis is a condition where the stomach does not empty normally causing food to stay in the stomach for prolonged time and possibly leading to pain, nausea, and vomiting. While it is known that GLP-1 medications slow the emptying of the stomach, there is no evidence that these effects are permanent and much more likely that they resolve with stopping the medication. It is worth noting that one of the most common causes of gastroparesis is diabetes, and it is possible that use of these medications to treat diabetes may be uncovering gastroparesis that was already present.
  3. Thyroid Tumors: All GLP-1 medications carry a warning label that they should not be used in people with a personal or family history of medullary thyroid cancer or a condition known as multiple endocrine neoplasia. These are fairly uncommon diseases, and the warning does not include the far more common form of thyroid cancer know as papillary thyroid cancer. This warning is due to effects noted in animal studies, but there has been no evidence to this point of increased thyroid cancer in humans on GLP-1 medications.

Cost, Insurance Coverage, and Availability

GLP-1 medications are very expensive and often not covered by insurance. This can be very frustrating to both patients and their doctors when it limits access to these highly beneficial medications.

  1. Cost: The retail price of GLP-1 medications for obesity treatment in the United States generally runs around $1000 to $1300 per month. If covered by insurance they may be as low as $25 per month, but many insurance plans including Medicare exclude weight loss medications from coverage. Discount cards are available, but even with these the cost of the drugs is over $500 per month when not covered by insurance.
  2. Insurance Coverage: While GLP-1 medications are usually covered by insurance for the treatment of type 2 diabetes, the coverage for treatment of obesity is much more limited. Medicare does not pay for any weight loss medications currently. Commercial insurance plans vary, but many still do not cover these medications.
  3. Availability: Due to the high demand for these medications, availability has been a significant and ongoing issue. There are often cases where the patient has insurance coverage for the medications, but the medications are not available in pharmacies. These shortages have been going on since the approval of Wegovy and continue to this day.


In the battle against obesity, GLP-1 medications—such as Wegovy and Zepbound —serve as valuable tools to increase chances of long-term success. Long term effective weight management involves a comprehensive approach. Combining GLP-1 therapy with lifestyle modifications, dietary changes, and regular physical activity will lead to optimal results. At Frazine Medical Weight Loss in Paducah, we have the experts and experience to guide and support you on your weight loss journey. Find out more about how we use medications for weight loss here. Click here or call today to set up your initial evaluation.