What is Semaglutide?
Semaglutide is a synthetic peptide that mimics a hormone your gut naturally makes called GLP-1 — short for glucagon-like peptide-1. Your body releases GLP-1 after you eat. It tells your pancreas to release insulin, signals your brain that you're full, and slows down how fast food leaves your stomach. Semaglutide is an engineered version of that hormone, built to last much longer in the body than the natural version does. It has been widely studied under brand names like Ozempic and Wegovy and is one of the most researched metabolic peptides in recent history.[2]
How Semaglutide Works
Think of GLP-1 receptors like a dimmer switch for appetite and blood sugar. Your natural GLP-1 flips that switch briefly after a meal, then disappears within minutes. Semaglutide grabs the same switch and holds it in the "on" position for roughly a week. That prolonged signal does three main things researchers care about:
- Lowers blood sugar — it prompts the pancreas to release insulin when glucose is high, and dials back a counter-hormone called glucagon that would otherwise raise blood sugar.
- Reduces appetite — it acts on hunger centers in the brain, making people feel full sooner and less interested in food overall.
- Slows gastric emptying — food moves from the stomach into the intestine more slowly, which blunts post-meal blood sugar spikes.
The molecule is also chemically modified so it resists being broken down quickly, and it binds to a blood protein called albumin — both tricks that stretch its activity from minutes to days.[2]
What the Research Shows
Semaglutide has been tested in a large family of clinical trials. Here are some of the key findings in plain terms:
- Weight loss in people with type 2 diabetes (STEP 2): In a rigorous phase 3 trial lasting 68 weeks, adults with overweight or obesity who also had type 2 diabetes lost an average of about 9.6% of their body weight on the 2.4 mg weekly dose, compared to roughly 3.4% on placebo. Nearly 69% of those on the higher dose lost at least 5% of their body weight, versus about 29% on placebo. Gastrointestinal side effects — mostly nausea — were common but generally mild to moderate.[1]
- Weight loss without diabetes: A systematic review and meta-analysis confirmed that semaglutide consistently produced meaningful weight reductions in people with obesity who did not have diabetes, outperforming placebo across multiple studies.[6]
- East Asian populations (STEP 6): A phase 3 trial in Japan and South Korea found that adults in this population lost an average of 13.2% of body weight over 68 weeks on 2.4 mg weekly — notable because Asian populations tend to face obesity-related health risks at lower BMI thresholds. The same trial measured abdominal visceral fat — the dangerous fat stored around organs — and found it dropped by about 40% in the 2.4 mg group versus roughly 7% with placebo.[3]
- Glycemic control: The SUSTAIN and PIONEER trial programs studied semaglutide specifically for blood sugar management in type 2 diabetes and found it superior to placebo and comparable or better than several other diabetes drugs for reducing HbA1c — a marker of long-term blood sugar control.[2]
- Oral formulation research: Studies have also investigated an oral (pill) form of semaglutide, expanding the research options beyond weekly injections.[2]
What Semaglutide Is Being Studied For
In the research setting, semaglutide is primarily investigated for:
- Glycemic control in type 2 diabetes
- Weight reduction in adults with overweight or obesity, with or without type 2 diabetes[1][6]
- Weight reduction in adolescents with obesity
- Reducing abdominal visceral fat[3]
- Cardiometabolic risk factors associated with excess body weight[4]
- Oral delivery methods for GLP-1 receptor agonism[2]
It is important to note that this is a research compound. Nothing on this page constitutes medical advice, and semaglutide should only be handled in properly authorized research contexts.
How Semaglutide Is Dosed in Research
Research protocols have used a range of doses and schedules depending on the target population and study goal. The subcutaneous (under-the-skin) injectable form is typically studied on a once-weekly schedule, while an oral formulation has been explored on a daily basis. Doses studied for glycemic outcomes have generally been lower than those studied for weight management. For a full breakdown of specific doses, populations, and study durations used in clinical research, refer to the dosage chart on this page. You can also use the calculator to explore how research doses scale across different parameters.
Mixing and Storing Semaglutide
In research settings where semaglutide is supplied as a lyophilized (freeze-dried) powder, it must be reconstituted — meaning liquid is added to dissolve it — before use. Bacteriostatic water is the most commonly used diluent in research protocols; it contains a small amount of benzyl alcohol that helps prevent microbial growth and extends the usable life of the solution. The powder should be reconstituted gently — swirl, do not shake — to avoid damaging the peptide's structure. Once mixed, the solution is typically stored in a refrigerator at 2–8 °C (36–46 °F) and kept away from light. Most reconstituted research solutions are used within 28 days. Unused, unreconstituted vials are generally stored frozen. Always follow the specific storage instructions provided with the research material, as formulations can vary between suppliers.
Sources
- Semaglutide 2·4 mg once a week in adults with overweight or obesity, and type 2 diabetes (STEP 2): a randomised, double-blind, double-dummy, placebo-controlled, phase 3 trial. — Lancet (London, England), 2021. PMID 33667417.
- Wegovy (semaglutide): a new weight loss drug for chronic weight management. — Journal of investigative medicine : the official publication of the American Federation for Clinical Research, 2022. PMID 34706925.
- Semaglutide once a week in adults with overweight or obesity, with or without type 2 diabetes in an east Asian population (STEP 6): a randomised, double-blind, double-dummy, placebo-controlled, phase 3a trial. — The lancet. Diabetes & endocrinology, 2022. PMID 35131037.
- As Ozempic's Popularity Soars, Here's What to Know About Semaglutide and Weight Loss. — JAMA, 2023. PMID 37099334.
- Safety of Semaglutide. — Frontiers in endocrinology, 2021. PMID 34305810.
- Efficacy and Safety of Semaglutide for Weight Loss in Obesity Without Diabetes: A Systematic Review and Meta-Analysis. — Journal of the ASEAN Federation of Endocrine Societies, 2022. PMID 36578889.