Weight loss injections: what they do and what they don't
GLP-1 receptor agonists like semaglutide (Ozempic, Wegovy) and tirzepatide (Mounjaro) suppress appetite effectively. Clinical trials show average weight loss of 15-20% of body weight over 12-18 months. For people with obesity-related health risks, that's significant and sometimes necessary.
We're not here to argue against medication. Some of our members use GLP-1s alongside Nico. What we want to talk about is the part that gets less attention: what these drugs do to your body composition, what happens when you stop, and why the support system around them is largely absent.
The side effects people actually experience
The commonly reported side effects of weight loss injections include nausea, vomiting, diarrhoea and constipation, particularly in the first weeks as dosage increases. Most people adapt. Those are the ones the prescriber mentions.
The side effects that matter more long-term are less discussed. A 2023 study in Diabetes, Obesity and Metabolism found that roughly 40% of weight lost on semaglutide was lean mass, primarily muscle. Losing muscle changes your metabolic rate, your strength, your bone density, and your ability to maintain weight loss later.
After a certain age, rebuilding lost muscle becomes genuinely difficult regardless of how much protein you eat or how consistently you train. The body doesn't recover muscle the way it recovers fat.
What happens when you stop
The majority of people discontinue GLP-1 treatment within the first year, whether from side effects, cost, or supply issues. The research on what happens next is consistent: most of the weight returns within 12 months of stopping.
The weight that comes back is predominantly fat, not the muscle that was lost. So the person ends up at a similar weight but with a worse body composition than before they started: less muscle, more fat, a lower metabolic rate.
The injection overrides your appetite signal. It doesn't change the metabolic patterns, the food responses, or the habits that drove the weight gain. When the override stops, the original patterns resume, but now they're operating on a body with less muscle to burn energy.
What's missing from the current approach
The NHS and most private prescribers treat GLP-1s as a standalone intervention. You get the prescription, maybe a leaflet on healthy eating, and a follow-up appointment in three months. There's rarely a structured programme to help you learn what your body actually needs while the medication is suppressing your appetite.
That window, while you're on the drug and your appetite is managed, is the best possible time to build habits. Your cravings are quieter. Your glucose is more stable. You have cognitive bandwidth to actually learn which meals work for your body, what movement patterns improve your metabolic markers, how sleep affects your glucose the next day. The injection buys you time. The question is whether anyone helps you use it.
How Nico approaches this differently
Nico uses a continuous glucose monitor to show you how your body responds to food, movement, sleep and stress in real time. An AI coach reads that data and guides you through specific habit changes, week by week, based on what's actually happening in your metabolism.
For people not on GLP-1s, this is the whole programme: see the data, understand the patterns, change the habits, shift your metabolic set-point so the weight stays off without ongoing restriction.
For people on GLP-1s, Nico serves a different purpose. While the medication manages appetite, the glucose data reveals which foods spike you, which meals sustain your energy, what your body does with carbohydrates versus proteins versus fats. You're building a personalised operating manual for your metabolism, so that when (or if) you come off the medication, the habits are already in place.
Several of our members use both. The combination makes sense: the injection handles the appetite side, the glucose data handles the learning side. One without the other leaves a gap.
The question worth asking
If you're considering weight loss injections, the relevant question isn't whether they work. They do. The question is what you'll know about your own metabolism after 12 months on them.
Whether you use medication or not, understanding how your body actually processes energy is the thing that makes weight loss last. A glucose monitor shows you that in real time. Coaching helps you act on it. That's what Nico is built around.
Ready to see what your metabolism is actually doing?