What Are GLP-1 Injections? What Do They Do and Who Can Use Them?

GLP-1 injections are prescription treatments that belong to a group of medicines that mimic the effect of the naturally occurring Glucagon-Like Peptide-1 hormone in the body. The GLP-1 hormone plays a role in insulin response, blood sugar balance, gastric emptying, appetite and satiety after meals.

For this reason, GLP-1 injections are especially discussed in type 2 diabetes treatment, metabolic health follow-up and weight management processes in certain individuals. The World Health Organization states that GLP-1 therapies are medicines that should be considered with medical evaluation in metabolic diseases such as obesity and type 2 diabetes. According to WHO, these medicines are not suitable for everyone and should be prescribed by taking individual health history, clinical indications and physician evaluation into account.

GLP-1 injections are not weight-loss food supplements. These medicines should not be considered as a social media trend or a rapid weight-loss method, but as prescription treatments that require medical follow-up. The decision to use them should be made by evaluating blood values, body mass index, diabetes risk, existing diseases, medications used and lifestyle factors together.

What Do GLP-1 Injections Do?

GLP-1 injections act through multiple mechanisms in the body. They may affect the satiety center in the brain, reduce appetite, slow gastric emptying, support insulin secretion and help post-meal blood sugar fluctuations progress in a more controlled way.

The World Health Organization states that GLP-1 receptor agonists are medicines that may help lower blood sugar, support weight loss and reduce the risk of cardiovascular and kidney complications in some people with type 2 diabetes. In WHO’s 2025 Essential Medicines List update, semaglutide, dulaglutide and liraglutide were addressed as GLP-1 receptor agonists, while tirzepatide was addressed as a GLP-1/GIP dual receptor agonist.

However, these effects do not mean that the medicine directly burns fat. GLP-1 injections are not direct fat burners. Weight loss usually occurs indirectly through reduced appetite, smaller portions, prolonged satiety and decreased daily calorie intake.

Which Active Ingredients Do GLP-1 Injections Contain?

GLP-1 injections may contain active ingredients with different durations of action and usage characteristics. These medicines should be evaluated at the medical active ingredient level, not by brand name. Treatment selection should be made according to the person’s metabolic status and physician evaluation, not according to the popularity of the medicine.

The main active ingredients also addressed by the World Health Organization in the context of current metabolic diseases include semaglutide, liraglutide, dulaglutide and tirzepatide. WHO evaluates these active ingredients especially within the framework of type 2 diabetes, obesity and high-risk metabolic conditions.

Semaglutide

Semaglutide is one of the active ingredients among GLP-1 receptor agonists. It may be evaluated to support blood sugar control in type 2 diabetes treatment. It may also be considered by physician decision in the weight management process for people who meet certain medical criteria.

Semaglutide may affect appetite, satiety and gastric emptying. However, it is not suitable for every individual. Before treatment, blood sugar, HbA1c, liver and kidney functions, thyroid history, pancreas and gallbladder status should definitely be evaluated.

Liraglutide

Liraglutide is one of the active ingredients used as a GLP-1 receptor agonist. It may be evaluated in processes related to blood sugar control, appetite regulation and weight management. Suitability for use should be determined according to the person’s clinical condition.

Liraglutide may offer a safer process when planned together with healthy nutrition, movement routine and medical follow-up. However, it should not be used only with the desire to lose weight and without physician evaluation.

Dulaglutide

Dulaglutide is one of the GLP-1 receptor agonists that can be evaluated to support blood sugar control in type 2 diabetes treatment. It was included among GLP-1 receptor agonists together with semaglutide and liraglutide in WHO’s Essential Medicines List update.

Dulaglutide can be included in the treatment plan especially in people with metabolic risks and when deemed appropriate by the physician. Blood sugar follow-up, digestive system side effects and general health status should be monitored during use.

Tirzepatide

Tirzepatide is a dual-acting active ingredient associated with the GIP receptor mechanism in addition to the GLP-1 effect. The World Health Organization addressed tirzepatide as a GLP-1/GIP dual receptor agonist in its 2025 Essential Medicines List update.

Tirzepatide may be considered with physician evaluation in the field of type 2 diabetes and weight management. However, it requires special attention in people with pregnancy, breastfeeding, history of pancreatic disease, gallbladder problems or serious gastrointestinal diseases.

How Are GLP-1 Injections Used?

GLP-1 injections are usually administered as subcutaneous injections. Some forms may be used daily, while some forms may be used weekly. Treatment is often started with a low dose, and the dose is gradually increased according to the person’s tolerance.

Increasing the dose too quickly may increase gastrointestinal side effects such as nausea, vomiting, bloating, stomach fullness, constipation or diarrhea. Therefore, dose adjustment must be made by a physician. The person should be clearly informed about how to apply the medicine, which area to inject and which symptoms require contacting a doctor.

Who Can Use GLP-1 Injections?

GLP-1 injections are not suitable for everyone. The decision to use them should be made by considering the person’s body mass index, metabolic risks, diabetes status, cardiovascular disease risk, kidney functions and general health history.

According to the World Health Organization’s information on GLP-1 therapies, these medicines may be considered as a long-term treatment option in adults with obesity; however, they must be prescribed by a physician according to individual health history and clinical indications. WHO also emphasizes that GLP-1 therapies should be addressed together with structured behavioral changes that include healthy nutrition and physical activity for better results.

In general, individuals with a body mass index of 30 and above or people with a body mass index of 27 and above who have additional metabolic risks such as type 2 diabetes, hypertension or insulin resistance may be evaluated by a physician. However, suitability is personal and should not be decided only by these criteria.

Who Should Be Careful Or Cannot Use Them?

GLP-1 injections should be evaluated more carefully in some people. History of thyroid cancer or familial risk, history of pancreatitis, gallbladder diseases, serious gastrointestinal diseases, pregnancy and breastfeeding period are included in this group.

In these situations, the decision to use medication should only be made after a detailed medical evaluation. In addition, appetite-suppressing treatments should be handled carefully from a psychological perspective in people with a history of eating disorder. GLP-1 injections may support weight management; however, they may create health risks when used in the wrong person or without control.

Which Doctor Should Be Consulted Before GLP-1 Injection?

The most appropriate evaluation for GLP-1 injections is usually performed by Endocrinology and Metabolic Diseases or Internal Medicine specialists. Depending on the person’s needs, dietitian, psychologist, cardiology or gastroenterology support may also be added to the process.

Permanent weight management cannot be achieved only with medication. Eating habits, movement routine, sleep, stress, emotional eating behavior and metabolic risks should be addressed together. Therefore, the GLP-1 process may be safer and more sustainable when planned with a multidisciplinary approach.

Which Tests Should Be Done Before GLP-1 Injection?

Before starting GLP-1 injections, the person’s metabolic status should be objectively evaluated. This evaluation is important both to determine suitability for medication and to understand the underlying causes of weight gain, insulin resistance or blood sugar irregularity.

Frequently evaluated tests include:

• Fasting Blood Sugar: Helps evaluate blood sugar metabolism.
• HbA1c: Shows the average blood sugar level over the last 2-3 months.
• Fasting Insulin And Insulin Resistance: May give an idea about metabolic risk.
• Liver Function Tests: Important for fatty liver and medication suitability.
• Kidney Function Tests: Evaluated for treatment safety and general health follow-up.
• Lipid Profile: Shows cholesterol and triglyceride levels.
• Thyroid Function Tests: Important for weight change and metabolic evaluation.

In some individuals, additional imaging, gallbladder evaluation or advanced metabolic tests may be required. Which tests will be performed should be determined by the physician according to the person’s health history.

Common Misconceptions About GLP-1 Injections

Some information circulating widely in society about GLP-1 injections may cause unrealistic expectations. These medicines may be effective; however, they can be considered a safe treatment option only when used in the right person, at the right dose, for the right duration and under regular follow-up.

False: GLP-1 Injections Provide Permanent Weight Loss

GLP-1 injections may support weight loss; however, permanent weight loss cannot be achieved with medication alone. Weight loss may be seen during medication use because appetite is suppressed. However, if eating habits and lifestyle do not change, weight regain may often occur after the medication is stopped.

The World Health Organization also states that GLP-1 therapies should be addressed together with behavioral interventions that include a healthy diet and physical activity in order to achieve better results. Therefore, GLP-1 injections should not be seen as a permanent solution alone, but as supportive treatments used within medical follow-up.

False: GLP-1 Injections Burn Fat

GLP-1 injections do not have a direct fat-burning effect. These medicines may indirectly contribute to weight loss by reducing appetite, prolonging satiety and decreasing daily food intake.

For fat loss to be permanent, adequate protein intake, an exercise routine that preserves muscle mass, balanced nutrition and regular follow-up are required. Otherwise, rapid weight loss may lead to problems such as muscle loss and metabolic slowdown.

False: GLP-1 Injections Are Safe For Everyone

GLP-1 injections are not suitable for everyone. In some disease histories or special situations, the use of these medicines may be risky. Physician evaluation is definitely required in thyroid diseases, pancreatic problems, gallbladder diseases, gastrointestinal problems, pregnancy and breastfeeding periods.

WHO also states that GLP-1 therapies are not suitable for everyone and should only be prescribed by a medical practitioner according to individual health history and clinical indications.

False: GLP-1 Injections Make The Body Lazy

GLP-1 injections do not make the body lazy. However, the body may adapt over time to the hormonal effect provided externally. When the medication is stopped, appetite signals may become more evident again, and weight regain may occur if old eating habits continue.

Therefore, the goal in the GLP-1 process should not only be to lose weight, but to turn the appetite control period provided by the medication into an opportunity for healthy nutrition, movement and behavior change.

What Happens In The Body When GLP-1 Injection Is Stopped?

When GLP-1 injection is stopped, appetite and satiety mechanisms may change again. Hunger signals suppressed by the medication may return, gastric emptying may approach its previous speed, and the person may start to feel hungry more quickly.

The most common situation in this process is the risk of weight regain. Especially if permanent nutrition and movement habits were not created during medication use, the person may return to their old eating pattern. Therefore, the discontinuation process should also be planned with physician and, when necessary, dietitian support.

Possible situations after stopping GLP-1 injection include:

• Increased Appetite: Hunger signals may become more evident.
• Shortened Satiety Duration: The person may feel hungry earlier after meals.
• Weight Regain: Weight regain may occur if lifestyle has not changed.
• Low Motivation: Some people may experience a feeling of loss of control.
• Anxiety: The process of stopping the medication may be psychologically challenging.

What Should Be The Main Purpose Of GLP-1 Injection Use?

The purpose of GLP-1 injections should not only be to reduce the number on the scale. The main goal should be to improve blood sugar balance, reduce metabolic risks, support appetite control and help the person develop sustainable lifestyle habits.

Therefore, GLP-1 treatment should be considered as a temporary support tool. During medication use, eating behavior should be changed, physical activity should be increased, sleep and stress management should be reviewed, and preparation should be made for the period when the medication is stopped.

Evaluate Your Metabolic Status Before GLP-1 With Happ Health

GLP-1 injections are prescription treatments directly related to metabolic health. As stated by the World Health Organization, these medicines are not suitable for everyone and should be planned with physician evaluation by considering individual health history.

Happ Health, as a digital health platform, offers a solution that facilitates access to online endocrinology and metabolic disease specialists. By receiving expert advice based on your blood test results, weight management goals, diabetes risk, and metabolic health status, you can create a more informed roadmap for your health.

References

• World Health Organization. Obesity: GLP-1 Therapies. 2025.
• World Health Organization. WHO Updates List Of Essential Medicines To Include Key Cancer, Diabetes Treatments. 2025.
• World Health Organization. WHO Issues Global Guideline On The Use Of GLP-1 Medicines In Treating Obesity. 2025.