Ozempic®, celebrated for its weight loss benefits, functions by promoting a feeling of fullness, resulting in reduced calorie consumption. Unraveling the science behind this effect is essential for those considering or currently using Ozempic®.
If you’ve heard of Ozempic®, you’ve probably heard that it’s an effective drug for helping people lose weight. But what you might not be so clear on is how it actually works.
In short: Ozempic® works by making you feel full. That means you would eat less and, therefore, lose weight.
But what happens inside the body to bring on this effect is a slightly longer story. Whether you’re already taking Ozempic® or think it could help you, here’s what you need to know.
Ozempic® is a weekly injectable medication that’s used to control blood sugar in people with type 2 diabetes, when diet and lifestyle changes aren’t enough to keep their levels in check.
Often, it’s also prescribed off-label to help with weight loss. In fact, the UK’s National Institute for Health and Care Excellence (NICE) recommends semaglutide, the active ingredient in Ozempic®, as a way to manage weight alongside healthy changes to diet and exercise.
Semaglutide is a type of drug called a glucagon-like peptide-1 (GLP-1) receptor agonist. Drugs like these work by mimicking the actions of glucagon-like peptide-1, a gut hormone the body produces when we eat. It’s the various actions of GLP-1 that make you feel full.
There are a handful of ways that Ozempic® works to lower your appetite and support weight loss. Because Ozempic® copies the way that GLP-1 behaves, the drug can bring on the same effects as the natural hormone.
The feeling of being hungry comes from the brain. It receives different signals from the body when we’re in need of more food, and then releases its own chemical messengers that stimulate appetite. When we’ve eaten enough, the brain gets a different set of messages telling it to make us feel full.
GLP-1 is released about 15-30 minutes after you start eating, and it can communicate directly with the brain to tell it to dial down our appetite. It can activate neurons that reduce hunger and cravings while inhibiting the release of chemicals that make us want to eat.
One of GLP-1’s main jobs is helping the pancreas produce insulin after a meal. This suppresses our appetite.
When we eat, the body breaks down the food into sugar (glucose). Insulin is then released to help our cells absorb this sugar from the blood so that the body can use it as energy. Once we’ve eaten enough to meet our energy needs, insulin levels rise to deal with all the sugar in the blood, and this signals to the brain that we’re full.
Ozempic® mimics that signal when blood sugar goes up, telling the pancreas to make insulin in response.
When a meal has been completely digested and your stomach is empty, hormones are released to tell the brain we need an energy top-up—and this results in us feeling hungry. Usually, this process takes around 80-120 minutes.
Ozempic® slows down the movement of food through your stomach, so that it takes more time for it to empty. That means that you’ll feel fuller for longer.
As well as supporting weight loss, Ozempic® can have other impacts on our health. Researchers are still looking into all the different ways that drugs like Ozempic can be used.
Because being overweight is linked to heart disease, the weight you lose while taking Ozempic® may lower the risk of those conditions developing. Plus, GLP-1 interacts with various cells and organs in ways that are beneficial to our heart—for example, in helping reduce blood pressure and inflammation.
In one clinical trial, people with type 2 diabetes who had a high risk of heart problems were less likely to have a stroke or heart attack when taking semaglutide.
Another more recent trial looked at people who were overweight and had heart disease but not diabetes. It found that taking semaglutide weekly was associated with a 20% reduction in major cardiovascular events like heart attack or stroke. Although it’s worth noting that the dose taken in the trial was 2.4 mg, which is higher than the maximum available dose of Ozempic® when it’s used for weight loss (1 mg).
The scientific evidence we have so far suggests that it could.
In overweight people who don’t have type 2 diabetes, semaglutide has been shown to lower excess levels of both sugar and insulin in the blood. These markers indicate that the body is more sensitive to the effects of insulin. Again, the dose of semaglutide used in this study was 2.4 mg.
As the name suggests, insulin resistance is when cells in your body become less receptive to the effects of insulin—meaning that we can’t absorb sugar from the blood as effectively. It can develop when blood sugar is consistently too high: more insulin is pumped out to absorb it, but if this keeps happening our cells can become desensitised over time, so insulin’s effects “wear off”. Excess insulin could then stick around in the blood, which can lead to health problems like heart disease and type 2 diabetes.
Semaglutide regulates the release of insulin in response to rises in blood sugar from eating. This keeps blood sugar levels under control and can help the body become better at absorbing glucose.
GLP-1 also limits the production of glucagon, a hormone that tells the liver to release more glucose. This helps prevent blood sugar from getting too high.
The drug’s effect on weight loss also plays a role here: when fat accumulates (especially around the abdomen), these tissues release signals and proteins that can impair how sensitive the body is to insulin. Losing even a moderate amount of weight can help reverse this effect.
People who are overweight (but don’t have type 2 diabetes) are more likely to have insulin resistance than those who aren’t, but this isn’t always the case.
Like any medication, Ozempic® isn’t recommended for everyone. Nor will two people necessarily get the same results from using it. Ozempic® is recommended for people with a BMI of at least 30 (for people from certain ethnic backgrounds, BMI can be 27 or higher), who have at least one other health condition that’s related to their weight.
It’s also really important that you make healthy changes to your diet and lifestyle while taking the Ozempic®. The scientific evidence we have so far about the drug shows that it’s effective when taken in this way, so it may not work as well if you just take it on its own.
With Tuli’s weight loss programme, you’ll get a repeat prescription for weight loss medication plus expert guidance on how to build healthy lifestyle habits. We’ll send weekly advice from a dietician and check in with you regularly—we’ll be there to support you every step of the way.
Plus, it’s currently recommended that Ozempic® is used for a maximum of two years—so the lasting changes you make will help you maintain your weight loss once you stop taking it.
People who are pregnant or breastfeeding shouldn’t take Ozempic®. It may also not be recommended for people with a personal or family history of thyroid cancer. Check in with your doctor to be sure.
Finally, there have been recent reports that some people taking GLP-1 agonist drugs like Ozempic® have experienced self-harming and suicidal thoughts. The UK’s Medicines and Healthcare Products Regulatory Agency (MHRA) are currently looking into this, but if you start experiencing any suicidal or self-harming thoughts when taking the drug, contact your doctor right away.
For those who would benefit from taking it, semaglutide has been shown to work well. In one clinical trial, people taking a weekly injection of semaglutide alongside lifestyle changes lost 14.9% body weight on average.
Because the dose in this trial (2.4 mg) was higher than what’s prescribed when Ozempic® is used for weight loss, your results on Ozempic® may differ. But you should still see results: the first three months of the trial followed the same dosing schedule as Ozempic® (starting on 0.25 mg semaglutide, increasing to 0.5 mg and 1.0 mg every four weeks), and people lost an average of 6% body weight by the 12-week mark.
Ozempic® is a prescription-only medication. And because it’s not licensed for weight loss, it’s not available on the NHS for people who don’t have type 2 diabetes. That means you need to get a private prescription to take it.
Tuli’s partner GPs can issue private prescriptions for Ozempic® through our weight loss programme.
Here’s how it works: first, you fill out a short questionnaire that we’ll review to check that the programme is right for you. Our partner healthcare providers can then write you a prescription that you can pick up at your local pharmacy.
We’ll check in with you weekly to see how you’re going and send you advice from a dietician to help you make healthy changes to your habits and lifestyle. If the programme is working for you, you can renew your prescription every four weeks.
Find out if you’re eligible for the programme by filling out this short form—it takes less than five minutes.
