Weight Loss Injections Part 1: An Overview

by Brenda Hoehn on Aug 23, 2023

Weight Loss Injections Part 1: An Overview

Weight Loss Injections Part 1: An Overview

Whispers of a “miracle” weight loss drug among celebrities and socialites began in early 2022.

Recently, the medication has garnered even more attention as articles on the “Ozempic® craze” point out the countless celebrities who have admitted (or denied) using it to help them lose weight faster than ever.

But what is Ozempic®?

Are there other medications like it?

And which populations medically qualify for a prescription?

In this four-part series, we’ll be focusing on the purpose, functions, and more of:

  • Mounjaro® (tirzepatide),
  • Ozempic®/Wegovy® (semaglutide),
  • And Victoza®/Saxenda® (liraglutide).

Please keep reading to learn how these medications function and how they may benefit bariatric patients.

Why Are These Medications Prescribed?

The FDA initially approved tirzepatide, semaglutide, and liraglutide to improve treatment for patients with type 2 diabetes.

The FDA later approved semaglutide and liraglutide for chronic weight management and has fast-tracked the approval process for tirzepatide, too.

These medications are self-administered injections in the upper arm, abdomen, or thigh. Patients may choose which of the three injection sites they prefer.

For maximum results, patients with type 2 diabetes or obesity (or both) should pair any of these medications with lifestyle changes, such as exercise and a healthy diet.

About Blood Sugar & Type 2 Diabetes

Patients with type 2 diabetes will tell you how vital HbA1C levels are.

Doctors commonly use HbA1C tests to diagnose prediabetes and diabetes and to implement effective diabetes management.

An HbA1C blood test is simple and measures your average blood sugar (glucose) level (represented as a percentage) over the three months leading up to the day of the test.

High blood sugar levels associated with the development of prediabetes and type 2 diabetes occur when the body’s blood cells become resistant to insulin (insulin resistance).

HbA1C results fall into three categories:

  1. Normal – below 5.7%
  2. Prediabetes – between 5.7 and 6.4%
  3. Diabetes – 6.5% and greater


According to the CDC, more than 1 in 3 adults have prediabetes. Of that population, 80% don’t know they are prediabetic, a scary statistic, as prediabetes increases the risk of developing health conditions/events such as:

  • Type 2 Diabetes
  • Heart Disease
  • Stroke

Weight loss may improve the body’s response to its insulin, decreasing blood sugar levels. A weight loss of 5%-7% can be enough to lower the risk of developing type 2 diabetes.

Type 2 Diabetes

Type 2 diabetes develops when an individual develops insulin resistance, leading to consistently high blood sugar levels.

High blood sugar levels increase the risk for serious health complications, like:

  • Heart disease,
  • Kidney disease,
  • And vision loss.

Type 2 diabetes can be prevented or delayed with healthy lifestyle changes, such as:

  • Losing weight
  • Following a healthy diet
  • Regularly exercising

Generally, patients with type 2 diabetes should aim to maintain an HbA1C level at or below 7%.

About Blood Sugar & Obesity

In the U.S., current data projects that 49% of adults may have obesity or severe obesity (measured by BMI) by 2030. This table provides BMI ranges correlating an underweight classification to a class three obesity classification.

Blood sugar and insulin regulation are vital components of weight management in individuals with obesity:

Insulin Resistance & Obesity

According to, “Insulin is a storage hormone that promotes fat production and prevents fat from breaking down.”

Consistently elevated insulin levels characterize low insulin sensitivity (insulin resistance).

As long as insulin levels remain elevated, the body will not burn through glycogen stores (excess blood sugar stored in the liver, muscles, and fat cells) fast enough to burn enough fat to lose or maintain body weight.

Blood Sugar Regulation & Improved Metabolic Function

High insulin sensitivity (the opposite of insulin resistance) increases the body’s ability to properly partition excess glucose between muscles, liver, and fat cells for storage, promoting metabolic flexibility.

The flexibility improves the body’s capacity to switch between burning fat cells and other blood sugar sources, depending on availability.

Incretins: GLP-1 & GIP

Incretin hormones are gut peptides. When someone eats, the nutrients from the food trigger these hormones to secrete, triggering the beginnings of insulin secretion. These hormones are vital in combatting the disordered biological processes associated with obesity and type 2 diabetes.

Together the incretin hormones GIP (from the upper gut) and GLP-1 (from the lower gut) are responsible for the incretin effect, an insulin secretory response two to three times higher from ingesting glucose than intravenous glucose administration.

GIP plays the most significant role in the incretin effect. Patients with type 2 diabetes appear to have a weakened or absent response to GIP secretion.

Incretins are responsible for about 70% of the insulin response after meals. Thus, a weakened incretin effect is responsible for glucose intolerance in type 2 diabetics. However, research suggests that improvements in glycemic control can improve GIP effectiveness.

GLP-1 plays a minor role in mediating the incretin effect’s insulin response but affects various organ systems; most relevantly, it reduces appetite and food intake, resulting in long-term weight loss and glycemic control improvement.

GLP-1 Receptor Agonists & “Twincretins”

GLP-1 RAs and GIP RA (receptor agonists) compounds mimic the incretin effect hormones. After a short period following a meal, GLP-1 and GIP levels drop drastically and quickly. However, receptor agonists provide long-lasting, elevated levels to increase the hormones’ beneficial effects.

GLP-1 RAs’ weight loss-inducing effects are independent of their impact on blood sugar levels. GLP-1 reduces appetite and food intake by slowing gastric emptying and increasing satiety.

Thus, GLP-RA effects apply to hunger cues (meal onset) and caloric intake, not the body’s ability to burn calories.

Yet, this ability to regulate a patient’s diet does contribute to glycemic control improvement, which, as mentioned, improves the body’s response to GIP secretion and consequently regulates insulin secretion.

Until recently, drug manufacturers only used GLP-1 RAs in medications that regulate type 2 diabetes and obesity.

However, due to recent developments, manufacturers have started to produce medications that utilize both GLP-1 RAs and GIP RAs, dubbing these medications “Twincretins.” As it appears that the two receptor agonists’ combined effects increase a medication’s efficacy.

Obesity’s Chronicity & Long-Term Management

Current research on tirzepatide, semaglutide, and liraglutide consistently remarks that obesity is a chronic condition. However, this research is relatively recent.

For decades, many medical professionals did not have the data to help them understand obesity’s chronicity. This lack of understanding meant that patients with obesity often did not receive appropriate treatment plans for their chronic condition.

Developing tirzepatide, semaglutide, and liraglutide have created a clearer picture of the relationship between an individual’s biology and psychology and how it affects weight gain and weight loss.

As medical professionals have learned more about obesity’s chronicity, they have started promoting chronic weight management.

Chronic Weight Loss Management: Long-Term Medication Use

Many individuals are singularly focused on how fast they can lose a certain amount of weight, which doesn’t often lead to long-term weight management success.

While weight loss still plays a role, chronic weight management focuses on two primary endpoints:

Improving one’s overall health

Improving one’s quality of life

Therefore, FDA-approved semaglutide and liraglutide weight loss medications are “chronic weight management” products for long-term use.

The extensive trial period between tirzepatide, semaglutide, and liraglutide is 72 weeks. So, how these medications would affect patients past that period is still unclear. While researchers can hypothesize long-term effects from current information, they require more substantial long-term trials to set a precedent for a long-term use protocol.

Our “Weight Loss Injections” Series Contributor

ProCare Health would like to recognize award-winning Dietitian and Nutritionist Katie Chapmon as a contributor to this comprehensive series on the various medications bariatric patients may want to discuss with their doctors.

With over ten years of hands-on clinical experience in bariatric surgery and weight management, Chapmon’s wealth of educational and reliable information is valuable for the patients that use our resources to navigate pre-and post-bariatric surgery life.

ProCare Health’s “Weight Loss Injections” Series

The following three parts of this series will explore the clinical details of tirzepatide, semaglutide, and liraglutide and how these medications affect the body regarding type 2 diabetes and weight management.

To view the other blogs in this series, you may use the following links:

For more of our educational resources, please view our blog.