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Key points
- Semaglutide is an injectable diabetes drug that suppresses appetite by slowing digestion and altering brain chemistry.
- Clinical trials show that only a third of people using semaglutide will see drastic weight loss (over 20 percent) in one year.
- We don't know what semaglutide does to the bodies and brains of people without diabetes if used long-term.
The World Health Organization (WHO) estimates that over 1 billion people worldwide are overweight.1 This statistic has caused health officials to panic, as research suggests that being overweight increases a person's risk of developing illnesses (e.g., cancer and cardiovascular disease).2 This research implies that if people continue to gain weight, we could be on the verge of a global health crisis.
But what exactly does the WHO's statistic tell us about body fat? And can we use this estimate to predict human health? These questions need to be considered before developing weight interventions.
The body mass index (BMI) equation is used to calculate the WHO's weight estimate. This equation determines body fatness by taking a person's weight in kilograms and dividing that by their height in meters squared. Individuals with a BMI over 25 are considered overweight. The practicality of using BMI to determine body fatness has been debated, as the BMI equation doesn't include muscle mass, bone density, or fat distribution.3,4 Consequently, a lean person with a high muscle mass might have a BMI over 25. Moreover, having a high BMI doesn't always indicate increased illness risk (e.g., metabolic syndrome).3,4,5
Considering these disadvantages, the WHO's fatness estimate might be exaggerated, and we should be cautious using it to predict health outcomes. We need to acknowledge that additional factors besides weight influence a person's health trajectory, including healthcare access, stress, poverty, and environmental threats (e.g., chemicals). 6,7,8,9
Nonetheless, the WHO's warning of an impending global health crisis has accelerated the approval of weight-loss drugs for weight-loss treatment, the most recent example being Wegovy (i.e., semaglutide).10;19
Semaglutide: The Magic Diet Drug?
Wegovy and Ozempic are the commercial names for medications containing a drug called semaglutide. Semaglutide medications were first created to manage blood sugar levels for people with diabetes–these drugs were not intended for weight loss.
Semaglutide controls blood sugar levels by mimicking glucagon-like peptide-1 (GLP-1), a natural bodily hormone involved in insulin and appetite regulation.11 After we eat, GLP-1 stimulates insulin release from the pancreas. This insulin removes extra sugar from the blood and places that sugar into cells for energy.
People with type-2 diabetes, however, have low GLP-1 levels. This means their pancreas can't produce and release enough insulin to remove extra sugar from the blood.11 Consequently, people with type-2 diabetes experience hyperglycemia (e.g., excess blood sugar), a condition that can cause severe organ and nerve damage if left untreated.11 Semaglutide is a lifesaver for people with type-2 diabetes because it keeps their blood sugar levels stable.12
In addition to regulating blood sugar, GLP-1 makes us feel full after we eat. GLP-1 does this by slowing down gastric emptying13;14 and sending fullness signals to the brain's "feeding center," the hypothalamus.15 These bodily changes prevent us from overeating.
The Semaglutide Trend
Because it suppresses appetite, semaglutide has become a popular weight-loss drug among celebrities and the general public. The hashtag #ozempic alone has nearly 300 million views on TikTok.8;22;23
Nonetheless, despite its popularity, not everyone can access semaglutide. First, you need a prescription. The U.S. Drug Administration (FDA) and the UK's National Institute for Health and Care Excellence (NICE) recommend that only overweight (e.g., BMI over 35) and health-compromised (e.g., high blood pressure) individuals are prescribed semaglutide for weight loss.10,19
While doctors have willingly prescribed semaglutide to others who don't meet these requirements, including many wealthy individuals, it is unclear if doctors will do the same for the general public.18 Semaglutide is also expensive: A month's supply of Ozempic costs between $1,000 to $1,500 US dollars without insurance.18
To increase public access to semaglutide, the UK has begun prescribing Wegovy at no cost to people who meet certain requirements (e.g., BMI over 35).20 These new prescriptions will add to the almost 40,000 new Wegovy prescriptions written each week worldwide.22
As more people use semaglutide for weight loss, though, we need to pause and examine what this drug does to the body.
The Limitations and Side Effects of Semaglutide
Recent clinical trials show that injecting semaglutide into the stomach once a week for 68 weeks causes weight loss.21 For 70 percent of overweight (i.e., BMI over 25) individuals using semaglutide, this means a 10-14-percent weight loss in about a year.21 However, only 32 percent of overweight people in this study saw a more dramatic weight loss of over 20 percent during this time.21 These findings suggest that, while some people will experience weight loss with semaglutide use, weight loss will be modest for most.
Another consideration is semaglutide's side effects. It is important to remember why semaglutide causes weight loss: It changes how food is moved through the gut and how the brain processes appetite. These bodily changes have consequences–over half of people taking semaglutide have experienced nausea and a third have had gastrointestinal issues (e.g., diarrhea, vomiting, and constipation).21 In one clinical trial, 74% of individuals who used semaglutide reported a gastrointestinal disorder at the study's completion.21 These findings acknowledge that semaglutide isn't a miracle weight-loss drug, but, rather, a drug that disrupts the desire to eat at often uncomfortable costs.
The Future of Semaglutide Use for Weight Loss
Several questions remain about semaglutide's use for weight loss. First, NICE recommends that people stop using Wegovy after two years.10 The problem with restricting semaglutide use to two years is that people have experienced rapid weight regain when they stop using it.18 This is because a person can still experience body dissatisfaction, disordered eating, and psychological discomfort (e.g., anxiety; depression) after weight loss. Consequently, medical professionals will need to monitor a person's physical and psychological well-being both during and after semaglutide use.
If used long-term, we also need to explore what semaglutide use does to a person's physical and psychological well-being. There are currently only a few research studies investigating the long-term effects of semaglutide on the bodies and brains of individuals without diabetes.
Finally, more must be done to prevent people from obtaining semaglutide if they don't need it. Because of the drug's popularity, we have already seen a semaglutide shortage that has prevented people with diabetes from getting their medication.17 Semaglutide can also contribute to eating disorder development and relapse. The allure of this drug's weight loss potential can be triggering for people struggling with body and self-dissatisfaction. It reinforces food restriction as an appropriate lifestyle and allows these individuals' disordered relationships with food and the self (e.g., body shame) to endure.
With semaglutide use rising, we need to start asking what potential health problems this drug will create.
References
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12. Marso, S.P., Bain, S.C., Consoli, A., Eliaschwitz, F.G., Jódar, E., Leiter, L.A.,...& Vilsbøll, T. (2016). Semaglutide and cardiovascular outcomes in patients with type 2 diabetes. The New England Journal of Medicine, 375, 1834-1844. doi: 10.1056/NEJMoa1607141.
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16. Donnelly, M. (2022). Hollywood's secret new weight loss drug revealed: The hype and hazards of ozempic. Variety. Retrieved from: https://variety.com/2022/film/actors/weight-loss-ozempic-semaglutide-ho….
17. Oceane, D. & Huet, N. (2023). Ozempic: How a tiktok weight loss trend caused a global diabetes drug shortage - and health concerns. EuroNews.Next. Retrieved from: https://www.euronews.com/next/2023/03/02/ozempic-how-a-tiktok-weight-lo….
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