The Hidden Dangers of Losing Weight with Ozempic: What You Need to Know

Over the past couple of years, Ozempic (semaglutide) has gone from a diabetes medication to a weight-loss sensation, hailed by celebrities and everyday users alike. But beneath the headlines and Instagram transformations lies a growing concern in the medical community: the unintended consequences of using Ozempic for rapid weight loss—especially when used in larger, non-prescribed doses by those paying privately.

Let’s dive into some of the most pressing dangers, including one that’s not often talked about: loss of muscle mass.

What Is Ozempic, Really?

Ozempic is a GLP-1 receptor agonist designed to help people with type 2 diabetes manage blood sugar levels. It works by mimicking a hormone that regulates insulin secretion, appetite, and digestion. While its cousin Wegovy is FDA-approved for weight loss, Ozempic is increasingly being used off-label for the same purpose.

The drug slows digestion and reduces appetite, leading many users to shed pounds rapidly—but it doesn’t discriminate between fat and muscle.

Weight Loss or Muscle Loss? The Critical Distinction

One of the major concerns with rapid weight loss from drugs like Ozempic is the significant loss of lean body mass – muscle. A 2021 study published in Obesity found that up to 39% of total weight lost through GLP-1 receptor agonists came from lean mass, not fat. That’s not ideal.

Why does this matter?

Muscle is the one of the best predictors of longevity; in older people it reduces the chance of falling, allowing them to remain independent. It also burns calories — it’s a glucose sink, sucking up all the sugar in the bloodstream.

Muscle mass is essential for strength, metabolism, and long-term health.
Losing muscle can lead to weaker physical performance, higher risk of injury, and rebound weight gain, since muscle is metabolically active and helps burn calories even at rest.

In essence, you might weigh less on the scale, but your body composition could actually be worse in terms of metabolic health and strength.

The Risks of Higher Doses: More Isn’t Better

The hidden dangers of losing weight with Ozempic – people paying privately for Ozempic, often outside traditional medical supervision, are sometimes self-medicating with higher-than-recommended doses in a bid to lose weight faster. The irony is that most people using the drug are effectively self-experimenting with a medication invented to treat diabetes. For diabetes, they were prescribed at between 0.25mg and 1mg. For weight loss, hundreds of millions are taking semi-glutides at 2.4mg and at that dose, it is still uncertain what the long-term effects might be. Along with medical side effects. many celebrity users have also famously reported sickness and nausea; Ex British PM Boris Johnson said:

“One minute I would be fine, and the next minute I would be talking to Ralph on the big white phone,” Johnson said.

Sharon Osbourne lost 3st but gave up when she couldn’t stop losing weight (she reported not being able to put on the roughly 11lb required to be healthy, regardless of what she ate). Lottie Moss (a model and half-sister of Kate Moss) weighed 9st 6lb when she decided to inject weight-loss medication in order to hit 8st 5lb. She took a dose appropriate for someone weighing 15st or more and suffered a seizure.

This is incredibly risky. Higher doses can lead to:

Severe gastrointestinal issues (nausea, vomiting, diarrhea)
Pancreatitis
Gallbladder problems
Nutrient malabsorption
Hypoglycemia (especially when combined with other glucose-lowering drugs)
And in rare cases, thyroid tumors, as seen in rodent studies

There’s also concern about dependency—not in the addictive sense, but the metabolic sense. Once off the drug, many users regain the weight they lost—sometimes quickly—especially if they’ve lost a disproportionate amount of muscle during their weight-loss journey.

Malnutrition and Ozempic – the problem of reducing calories made up largely of UPFs (ultra processed foods).

Although it may sound unusual to discuss malnutrition in the modern era, but with much of obesity being fuelled by diets largely made up of ultra processed foods, as soon as people reduce their calorific intake, without changing or adapting their actual nutrition, it’s highly likely that they will become deficient in many micro minerals and vitamins. UPF contain essential micro nutrients and vitamins in small amounts. Fine if you are eating a lot of them. But cut down suddenly and it’s likely you will be id a deficiency of some sort. A recent study showed that 50% of obese people in the Uk suffer a vitamin deficiency. A good example of this is the singer Robbie Williams recently contracting scurvy, caused by deficiency in vitamin C. Although a small orange a day is enough to fulfil your vitamin C needs, low quality nutrition coupled with cutting down on overall calories led to him getting the condition usually only suffered by 18 century pirates.

Scientific Studies Sound the Alarm

A 2022 study in The New England Journal of Medicine found that while semaglutide users lost an average of 15% of their body weight over 68 weeks, muscle loss was a significant component, especially in those who were not strength training or consuming adequate protein. The same study showed that that after stopping semaglutide, participants regained two-thirds of their lost weight within one year.
In 2023, researchers at Stanford University emphasised the need for resistance training and dietary interventions to preserve lean mass in patients using GLP-1 medications for weight loss.
In a commentary in JAMA, obesity experts emphasised that GLP-1 drugs should be considered chronic treatments, not short-term fixes — similar to how we treat blood pressure or cholesterol.
The International Journal of Obesity highlighted concerns about muscle loss and called for more research into the long-term impacts of these drugs, especially in younger and non-obese populations using them for cosmetic weight loss.

Personal Training and Ozempic

We train several clients who take Ozempic. But we work with them to ensure that they are taking smaller doses (in line with diabetic treatment recommendations) than many who have simply bought privately. We have also tried a month on month off regime that works well. with data from body composition measurements showing that as well as stellar weight loss, those trainees have also gained muscle mass, strength and fitness – so not just weight loss but weight loss with firmer skin, better tone, functional strength for everyday life and all the indicators of healthy longevity.

What Can You Do Instead?

If you’re considering using Ozempic for weight loss — or already are — here are a few things to keep in mind:

Prioritize resistance training: It’s one of the best ways to preserve muscle while losing weight.
Increase your protein intake: Aim for at least 1.6–2.2 grams of protein per kilogram of body weight daily.
Work with a professional: Make sure you’re under the care of a qualified doctor or registered dietitian who can monitor your progress and adjust treatment responsibly. A qualified personal trainer will ensure that you are maintaining and building lean muscle mass as well as keeping your heart and lungs fit.
Think long-term: Sustainable weight loss comes from lifestyle change, not just a prescription.

The hidden dangers of losing weight with Ozempic