3 years ago I’d have told you GLP-1 agonists were a diabetes drug. Now half of my new client enquiries at BTX, our personal training studio in Hampstead, mention them. The shift has been faster than any medication rollout I’ve seen in my career, and the gap between what these drugs are approved for and how they’re actually being used is enormous.
Here’s what people are actually asking me:
Should I go on Ozempic to drop 10kg before summer? My friend is on Mounjaro, is it safe?
What’s Tirzepatide? Is it better?
What about Retatrutide, I’ve heard it’s the next thing?
The short answers, in order: probably not; it depends on who’s prescribing it; yes, it’s a stronger version of Ozempic; and Retatrutide is a triple agonist still in phase 3 trials.
The longer answers are the point of this piece.
What These Drugs Actually Do
GLP-1 agonists mimic a hormone your gut releases after you eat. They slow stomach emptying, suppress appetite centrally in the brain, and improve insulin sensitivity. The appetite suppression is the mechanism everyone wants, and most people on these drugs eat 20 to 40% less without feeling hungry.
Semaglutide is sold as Ozempic (for type 2 diabetes) and Wegovy (for weight management). Tirzepatide is sold as Mounjaro; it’s a dual agonist, hitting both GLP-1 and GIP receptors, which produces stronger weight loss. Retatrutide is still in trials. It’s a triple agonist (GLP-1, GIP, and glucagon) and the early data is dramatic, with participants losing 24% of body weight on average over 48 weeks. It isn’t licensed yet.
Who These Drugs Actually Help
If you have a BMI of 35 or above, type 2 diabetes, metabolic syndrome, or a long history of failed weight loss attempts with proper clinical investigation behind each failure, GLP-1 agonists can change your health for the better. On the NHS, Mounjaro is now available for a specific cohort (BMI above 35 with weight related comorbidities), and if that’s you, the risk and benefit calculation is favourable.
That’s not most people reading this.
Who’s Being Sold Them Inappropriately
Private clinics in London will prescribe you Ozempic or Mounjaro with a 10 minute online consultation and a self declared weight. If you’ve got 5 to 10kg to lose, you’re being sold a drug that was designed for people whose health is in real danger from their weight. The side effect profile (pancreatitis, gastroparesis, gallstones, muscle loss, and potential thyroid implications based on rodent studies) isn’t trivial. For someone 30kg overweight, those risks are proportional. For someone trying to lose a stone before a wedding, they’re not.
The Muscle Loss Nobody Mentions
This is the one that concerns me most. Studies on semaglutide weight loss consistently show that 25 to 40% of the weight lost is lean mass, in other words muscle. If you’re already in your 40s or 50s with declining muscle mass, dropping another 3 to 5kg of muscle during a GLP-1 cycle is a problem you carry for the rest of your life. Muscle doesn’t come back easily, and the metabolic cost of losing it is permanent.
Most private prescribers don’t tell you this. They weigh you, hand you the pen, and send you home. There’s no InBody scan, no blood work, no protein target, no resistance training protocol, no exit strategy.
If You’re Going to Use Them, Do It Properly
At BTX we work with clients who’ve been prescribed GLP-1 agonists, privately or on the NHS, and our weight loss coaching builds the protocol around the drug. Full blood work with Dr Matt Milner. InBody 770 at baseline and every 4 weeks. Protein target set at 2 to 2.4g per kilogram of lean body mass. Strength training or resistance training 3 to 5 times a week to protect muscle. A planned taper and exit protocol so you don’t regain 60% of the weight within a year, which is what the long term data shows for people who stop these drugs with no behavioural support in place.
If you want the drug to work for you and not against your long term health, this is how. Want a personal trainer in London to build this around your prescription? Book a free strategy call at bodytransformationlondon.com, or DM “STRONG” on Instagram @jamescooperbtx.