How do GLP medications work for weight loss? Here’s what to know before meeting with your doctor
- 4 Minutes Read
GLP-1 weight-loss medications continue to gain popularity. But, before talking with your doctor about prescribing one to assist your weight-loss efforts, here's what you need to know about these newer weight-loss medications.
How GLP-1 and GIP weight-loss medications work
GLP-1 and GIP medications work by activating hormone receptors in the body to slow down the rate at which food moves through the gut, allowing you to feel full sooner and stay full longer, thereby reducing calorie intake.
Most modern weight-loss shots contain either one or two hormones that support weight loss and fall into two families:
GLP-1 (glucagon-like peptide 1) receptor agonist
GIP (glucose-dependent insulinotropic polypeptide) receptor agonist
GLP-1 receptor agonist medications stimulate the GLP-1 receptors to:
- Slow gastric emptying
- Increase satiety and decrease food intake
- Reduce "food noise"
- Secrete insulin (an essential hormone involved in blood sugar regulation)
- Inhibit glucagon (a hormone involved in blood sugar regulation).
GIP receptor agonist medications stimulate the GIP receptors to:
- Enhance GLP-1 appetite-reducing effects
- Improve insulin sensitivity
- Improve fat breakdown
Current GLP-1 weight-loss medications
| Medication name | Brand name | FDA approval year | How it’s taken | Hormone mechanism |
|---|---|---|---|---|
| Tirzepatide | Zepbound | 2023 | Once weekly injection | Dual GIP & GLP-1 agonist |
| Semaglutide | Wegovy | 2021 | Once weekly injection | GLP-1 receptor agonist |
| Liraglutide | Saxenda | 2014 | Once daily injection | GLP-1 |
All three medications were initially approved to treat type 2 diabetes. The new indications include treatment of obesity (BMI > 30) without diabetes and in adults with a BMI > 27, along with at least one weight-related health issue such as high blood pressure, high cholesterol, or diabetes. These medications require a prescription and consistent monitoring by your healthcare provider.
Note: An oral semaglutide pill is expected to be approved by the FDA in 2026 for weight loss. Stay tuned for more information.
How much weight can I expect to lose with these medications?
Most people on GLP-1 weight-loss medications lose 10-17% of their starting weight in a year, and some lose up to 20%. For someone weighing 250 pounds (113.6kg), that's a weight loss of 25-42.5 pounds (11.3 to 19kg).
One study lasting 68 weeks compared liraglutide to semaglutide for weight loss. Patients taking weekly semaglutide lost 15.8% of their body weight compared with 6.4% for those taking liraglutide. Note, however, that Novo Nordisk manufactures both drugs and funded the study comparing their effectiveness.
Reviews of 10 studies found that semaglutide was superior to a placebo among injectable weight-loss medications at reducing participants’ body weight.
Ten studies involving over 9,000 adults showed that individuals taking tirzepatide lost on average, 21.5 pounds (9.81 kg), significantly more than the placebo group.
Most people experience a weight loss of 1 to 2 pounds a week. Results depend on starting weight, dosing, eating, and exercise habits.
What are the possible side effects?
- Nausea
- Diarrhea
- Vomiting
- Constipation
- Abdominal pain
- Headache
- Low blood sugar
- Dizziness
- Increased heart rate
- Kidney problems
- Fatigue
- Allergic reaction
- Drug interactions
- Difficulty meeting optimal fluid and nutrient needs
Less common, but more severe side effects
- Acute pancreatitis
- Acute gallbladder disease
- Thyroid cell tumors
- Depression or thoughts of suicide
- Diabetic retinopathy in individuals with type 2 diabetes
Do not use if the following applies:
- Personal or family history of medullary thyroid carcinoma (MTC)
- History of multiple endocrine neoplasia syndrome type 2 (MEN 2)
- Diagnosis of inflammatory bowel disease or gastroparesis
- Currently working through an eating disorder. This includes individuals who are overweight and have an eating disorder
- Possess a fear of injections
Cost
Some health insurance companies do not cover the cost of these injectable weight-loss medications. However, coverage is more common for individuals prescribed these medications to manage their type 2 diabetes.
Average out-of-pocket costs for the drug can range from $350-$900/month, depending on which medication you are using.
Will I regain the weight if I stop taking these injectable weight-loss medications?
Weight regain is likely after stopping these medications. Simply put, if you do not address the habits that led to the gain in the first place, the weight will come back. However, by making lifestyle changes, you can likely prevent weight regain.
Losing weight is challenging, whether or not you are using GLP-1 medications for weight loss. Set yourself up for long-term success by adjusting your lifestyle while taking the medication. Eating regular, balanced meals, engaging in planned activity, getting adequate sleep, and managing stress all play a vital role.
To connect with others who are also working hard to lose weight, check out MyNetDiary’s Community. Accessible from iOS or Android, Community is a safe place to share successes or ask questions.
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Weight Loss->Other Resources
Dec 16, 2025
