What is Ozempic and how does it work?
Ozempic is the brand name for the glucagon-like peptide-1 (GLP-1) agonist semaglutide made by the company Novo Nordisk 13 . Ozempic was recently approved for human consumption by the US Food and Drug Association (FDA) in 2021 4 . Its main medical use is as a drug to help patients manage type 2 diabetes 6 . Semaglutide has gained popularity over the last few years as a weight loss treatment for those without type 2 diabetes too through prescription from a doctor. It was developed from a previously used GLP-1 agonist, liraglutide, made by the same company e company 11 . However, liraglutide must be administered through daily injections, while semaglutide can be administered weekly due to its longer half-life. It can also be administered orally when given with the absorption enhancer sodium N -[8-(2-hydroxybenzoyl) aminocaprylate (SNAC). Semaglutide is a peptide that has a similar structure to the human (GLP-1) receptor. GLP-1 stimulates the secretion of insulin and inhibits glucagon without causing hypoglycaemia 9 . However, GLP-1 has a short half-life of only a few minutes so GLP-1 agonists like semaglutide were developed to help patients with type 2 diabetes lose weight quicker. These agonists also delay gastric emptying and reduce appetite by inducing satiety. They stimulate satiety in the brain directly, through crossing the blood-brain barrier and indirectly through neural afferents 15 .
How effective is Ozempic for weight loss?
Numerous studies have been conducted to evaluate the efficacy of semaglutide for weight loss. A meta-analysis was carried out to discover the effects of semaglutide for weight loss in patients without type 2 diabetes. Four studies with 3,613 participants were analysed 15 . Across the studies 2,350 were given semaglutide and 1,263 were given a placebo. The meta-analysis found that there was an 11.85% mean difference in weight loss between the semaglutide and placebo groups across all four trials. This shows that semaglutide causes significant weight loss compared to the placebo so is effective for people without type 2 diabetes. Another study showed that semaglutide also effects energy intake as lunch energy intake was 35% lower in the semaglutide group compared to the placebo group 3 . It also showed that there was a lower intake of energy of high fat foods meaning semaglutide reduces appetite and hunger. Metabolic rate did not differ between treatments showing that weight loss was not due to increased energy expenditure but rather a decrease in energy intake. However, weight was shown to have come back after discontinuing the treatment, meaning patients must take semaglutide permanently to retain the weight loss, this is known as ‘Ozempic rebound’ although it can come about with any brand of semaglutide 14 .
What are the advantages and disadvantages of taking Ozempic?
The advantages and disadvantages of semaglutide were analysed to understand its side effects and whether any significant harm could come to patients who take it. A review on the risk of developing gastrointestinal adverse effects showed that the semaglutide group were 1.59 times more likely to develop these compared to the placebo group 15 . Over the four trials the semaglutide group were more twice as likely to stop treatment due to these adverse effects, 6% of the semaglutide group discontinued use compared to only 2.9% of the placebo group. Another study found that nausea was the most common side effect found in patients who were prescribed semaglutide at 44% 10 . Other adverse effects were found such as diarrhoea, vomiting and abdominal pain affecting 30%, 24% and 20% respectively in clinical trials. A real-life study found that 49% of patients experienced adverse effects which caused 3% of patients to discontinue treatment resulting in less weight loss 5 . In laboratory mice it was found that some developed thyroid C-cell tumours which was because of higher doses of semaglutide administered 10 . This means people with a family history of medullary thyroid carcinoma are discouraged from taking semaglutide 12 . Long-term studies show that after 1 year 24%-26% baseline weight was lost compared to only 15%-17% baseline weight after 10 years 7 . An advantage of taking semaglutide include the evidence of it reducing cardiovascular events in patients with type 2 diabetes 1 . A SELECT trial suggested that semaglutide may have an impact on cardiovascular events in obese patients without type 2 diabetes, but the results of this trial are yet to be published 8 . These trials showed that major adverse cardiovascular events were reduced by 20% in those taking semaglutide but admits more research is needed to assess the risks of semgalutide as a treatment for this. Semaglutide also proves to be more effective than other Type 2 diabetes treatments such as metformin and thiazolidinediones as it induced more weight loss without the risk of hypoglycaemia 2 . Although these advantageous effects lifestyle changes should also be made such as eating healthier as these are important in tackling obesity too.
Conclusion
In conclusion, Ozempic (semaglutide) is shown to be a viable option for weight loss both in people with and without type 2 diabetes. Although, there are adverse side effects such as nausea, vomiting and diarrhoea there are benefits to taking Ozempic. Along with the weight loss semaglutide has been seen to reduce cardiovascular effects. However, some of these studies have been funded by Novo Nordisk so there may be some bias and hesitation with publishing any negative results. Ozempic has been proven to be effective in short-term trials, but more long-term studies need to be done to fully understand the effects of semaglutide on patients with and without type 2 diabetes. The SELECT trial will be the first trial to evaluate this and its results are set to be published soon 8 . As Ozempic is being approved for adolescents, more research is being done to assess the paediatric benefits and limitations of semaglutide for the treatment of paediatric obesity 16 .
References
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