Ozempic is the brand name for the drug semaglutide which was developed by Novo Nordisk in 2012 for the treatment of type 2 diabetes and as an anti-obesity medication. It is administered by subcutaneous injection and it is also known under the brand names Wegovy for the higher-dose injectable version and Rybelsus for the oral version. Several studies examining the mechanism behind its weight loss effect and its effectiveness in helping people trim down their weight have made it a popular medication for long-term weight management.
A Definitive Discussion of the Mechanism and Effectiveness of Semaglutide: How Does Ozempic Work for Weight Loss and Is It Really Effective for Weight Management?
The United States Federal Drug Administration has approved the higher-dose version Wegovy for the treatment of individuals living with obesity and other weight-related medical problems in June 2021. However, due to a shortage in Wegovy and viral claims on social media explaining the purported effectiveness of semaglutide in reducing weight, people without type 2 diabetes began using Ozempic as an off-label weight loss medication beginning in 2022.
Characteristics and Mechanism
Ozempic and other similar brands of semaglutide are a peptide similar to the hormone glucagon-like peptide-1. Take note that this hormone is produced by the L-cells of the small intestine and certain neurons within the nucleus of the solitary tract in the brainstem in response to food intake. It acts on the pancreas to stimulate insulin secretion and inhibit glucagon secretion. The release of this hormone also reduces appetite, slows digestion, and increases satiety or the feeling of fullness. This is the exact same mechanism behind Ozempic.
It is important to underscore the fact that Ozempic is specifically a glucagon-like peptide-1 receptor agonist. Hence, as an agonist, it triggers a biological response that is similar to the action of glucagon-like peptide-1. This is similar to other diabetes medications such as exenatide from AstraZeneca, albiglutide from GlaxoSmithKline, dulaglutide and tirzepatide or Mounjaro from Eli Lilly, and lixisenatide from Sanofi. This class of medications has been considered as a first line of pharmacological therapy for type 2 diabetes.
Nevertheless, to summarize how Ozempic works, it mimics the action of the naturally occurring glucagon-like peptide-1, thus resulting in insulin secretion and glucagon inhibition. Insulin is essential in lowering blood sugar levels and glucagon is responsible for increasing the release of stored carbohydrates from the liver or glycogenolysis and the synthesis of new glucose or gluconeogenesis. Additional studies also revealed that semaglutide enhances the growth of cells responsible for insulin production called pancreatic beta cells.
The specific mechanism behind the weight-loss properties of Ozempic stems from the natural effect of glucagon-like peptide-1 in reducing appetite, slowing digestion, and increasing satiety. The presence of this hormone or similar chemicals in the body helps in lowering instances of hunger, decreasing unscheduled food cravings, and reducing body fat. Glucagon-like peptide-1 or its agonist such as semaglutide specifically signals the brain that the body has eaten enough food and delays the rate at which food leaves the stomach.
Effectiveness and Known Side Effects
The effectiveness of Ozempic and other brands of semaglutide has been investigated and documented by researchers. An expert opinion from S. A. Doggrell mentioned that semaglutide could be considered one of the best glucagon-like peptide-1 receptor agonists because its pharmacokinetics make it ideal for once-a-week dosing. The therapeutic mechanism and other benefits of this drug have been observed at an established dosage of 0.5 milligrams and 1.0 milligrams taken via the subcutaneous administration route once a week.
Researchers J. Blundell et al. investigated specifically its effect on appetite, energy intake, control of eating, food preference, and body weight through a randomized, double-blind, placebo-controlled, two-period crossover trial. The 12-week trial revealed that after a standardized breakfast, the drug led to a lower ad libitum energy intake during lunch and the subsequent evening meal and snack. This resulted in a 24 reduction in total energy intake across all ad libitum meals throughout the day compared to placebo.
H. C. Tan, O. A. Dampil, and M. M. Marquez conducted a systematic review and meta-analysis of published studies that investigated the effectiveness of subcutaneous semaglutide as a weight loss medication for obese individuals without diabetes. Results from a total of 3613 individuals showed that the drug is effective for weight loss with an 11.85 percent reduction from baseline compared to placebo. The same result was observed in another research by W. T. Garvey et al. that investigated the two-year effects of this drug.
There are side effects to Ozempic and other brands of semaglutide. The maximum recommended dosage is 2.4 milligrams for 16 to 20 weeks. The limits in duration were determined to reduce the impact of common side effects like gastrointestinal disorders. Researchers have also warned that the drug increases retinopathy or preventable blindness due to blood vessel damage to a small extent. It is also contraindicated in people with a personal or family history of medullary thyroid carcinoma or with multiple endocrine neoplasia type 2.
FURTHER READINGS AND REFERENCES
- Blundell, J., Finlayson, G., Axelsen, M., Flint, A., Gibbons, C., Kvist, T., and Hjerpsted, J. B. 2017. “Effects of Once‐Weekly Semaglutide on Appetite, Energy Intake, Control of Eating, Food Preference and Body Weight in Subjects with Obesity.” Diabetes, Obesity and Metabolism. 19(9): 1242-1251. DOI: 1111/dom.12932
- Doggrell, S. A. 2018. “Semaglutide in Type 2 Diabetes – Is It the Best Glucagon-Like Peptide 1 Receptor Agonist?” Expert Opinion on Drug Metabolism & Toxicology. 14(3): 371-377. DOI: 1080/17425255.2018.1441286
- Garvey, W. T., Batterham, R. L., Bhatta, M., Buscemi, S., Christensen, L. N., Frias, J. P., Jódar, E., Kandler, K., Rigas, G., Wadden, T. A., and Wharton, S. 2022. “Two-Year Effects of Semaglutide in Adults with Overweight or Obesity: The STEP 5 Trial.” Nature Medicine. 28(1): 2083-2091. DOI: 1038/s41591-022-02026-4
- Tan, H. C., Dampil, O. A., and Marquez, M. M. 2022. “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. 37(2): 65-72. DOI: 15605/jafes.037.02.14
