Semaglutide: How safe is the new weight-loss jab?

“Hollywood's worst kept secret!” made headlines. This particularly well-kept secret involves an expensive new weight-loss drug called Semaglutide. If you take celebrity magazines at face value, fans of these $1,200-a-month injections include Kim Kardashian and Elon Musk.
But in mid-February, the weight loss treatment was off the A-list when chemists on the UK's high street announced they would start selling semaglutide injections from spring 2023. At the time of writing, UK prices have not been disclosed.
So what is semaglutide? is it safe? Could it be a game changer in addressing the broader public health crisis of obesity?
What is semaglutide?
Semaglutide is produced by Danish pharmaceutical giant Novo Nordisk and marketed under the names Ozempic and Wegovy. Ozempic, in particular, made international headlines after going viral on TikTok last year, with the #MyOzempicJourney trending to showcase incredible physical transformations. Wegovy is a product sold in the UK.
Semaglutide is the latest in a line of analogs of GLP1, a gut hormone that signals the pancreas to increase insulin secretion. Semaglutide and all its predecessors are actually weaponized versions of GLP1, originally designed to treat type 2 diabetes.
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Their main superpower is that they survive in the blood much longer than GLP1, which occurs naturally in the human body, has a half-life of just two minutes. Early-approved GLP1 analogs, including AstraZeneca's exenatide and Novo Nordisk's liraglutide, required daily injections. In contrast, people with type 2 diabetes only need weekly injections of semaglutide, which increases insulin secretion and accelerates the absorption of glucose from the blood into muscle and fat.
How Can Semaglutide Help You Lose Weight?
But wait, what does this have to do with weight loss? Well, this has to do with another function of GLP1 as a gut hormone.
Our brains need to know two key pieces of information in order to control food intake. First, it needs to know how much fat we carry. Why? Because our fat is our long-term energy store and a marker of how long we can survive in the wild without any food.
The second piece of information our brain needs to know is how much and what we are currently eating, or have just eaten. These are short-term signals that come from our intuition. Every time we take a bite of food, from the moment we start chewing until it comes out the other end, hormones are released. The vast majority of these gut hormones, including GLP1, make us feel full when they signal the brain.
So a side effect of a long-acting GLP1 analog like semaglutide is that it signals the brain and makes us feel full. What happens when we feel full? We eat less. What happens when we eat less? We lose weight. In fact, clinical trials of semaglutide showed that people lost an average of 15% of their body weight after two years of weekly injections!
Is semaglutide safe?
The results of the semaglutide trial seem to show that it is safe, certainly in the short to medium term. However, as with all medicines, side effects need to be considered. These relate to another biological role of gut hormones, which is regulating the passage of food through our digestive system.
For example, gut hormones, including GLP1, are released rapidly when our bodies sense that a toxin has been ingested. The sudden surge of gut hormones causes the contents of our stomach to squirt up or down in an unpleasant and explosive way. Therefore, semaglutide side effects may include nausea and diarrhea. To be clear, most people do not experience these side effects.
I believe this drug could be a game changer in treating obesity. Losing 15% of your body weight in two years is amazing.
However, there are a few things. First, should celebrities and others who can afford it get the drug over the counter? Given the effects on blood sugar levels, questions about dosing and side effects, and limited data on long-term safety, semaglutide and other similar compounds should only be available by prescription, at least for now.
Second, it's important to know that, like any other treatment, once the medication is stopped, the weight will return. Therefore, for many people who are medically eligible to receive semaglutide, it may be a lifelong treatment.
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