Weight Loss Injections: 2025 Update – Mounjaro, Ozempic & the Evolving Evidence
It hasn’t taken long for Ozempic to become a household name, and now, its successor, Mounjaro (tirzepatide), is making even bigger waves. These GLP-1 receptor agonists, originally designed to manage type 2 diabetes, have revolutionized the way we approach weight loss, but as more people embark on treatment, we’re learning more about their long-term effects, limitations, and best practices.
With needles barely bigger than a mosquito’s proboscis you can’t feel an Ozempic or Mounjaro injection
What’s New? The Rise of Mounjaro & More Treatment Options
Since our original article in 2023, the field has evolved significantly. The most notable addition is Mounjaro (tirzepatide), which targets two pathways instead of just one, making it even more effective than Ozempic (semaglutide) for weight loss.
How Does Mounjaro Compare to Ozempic?
More Effective Weight Loss: Studies show that Mounjaro leads to greater weight loss than Ozempic at equivalent doses.
Dual-Action Mechanism: It acts on GLP-1 and GIP receptors, enhancing its appetite-suppressing effects.
Potentially Milder Side Effects: Some patients experience less nausea and digestive discomfort compared to Ozempic.
With the growing popularity of weight loss injections, demand has skyrocketed, leading to shortages at times. Additionally, Wegovy (a higher-dose version of semaglutide specifically for weight loss) remains another option for those unable to access Mounjaro; Zepbound (a weight loss branding for the tirzepatide in Mounjaro) is also arriving on the market.
The Muscle Mass Concern: Should You Worry?
A key emerging concern is muscle loss during treatment. While weight loss is the goal, it’s becoming clear that a significant portion of the lost weight can come from muscle mass, not just fat.
Why does this matter? Losing muscle slows metabolism and increases the risk of weight regain after stopping treatment.
How can we mitigate this? Strength training and protein intake are now strongly recommended alongside GLP-1 medications.
We advise a baseline body composition scan (through My Vital Metrics in London or Bodyview in Hampshire) before starting treatment (or shortly after) to track fat vs. muscle loss. This can be repeated at intervals throughout treatment to ensure muscle loss is not disproportionate.
Long-Term Use: What the Data Now Shows
As more people have used these medications for 18+ months, we’re now seeing clearer trends in their effectiveness over time.
Plateau Effect: Many patients experience a weight loss plateau after 12-18 months, where further progress slows despite continued medication. At Lisle Medical we track your weight closely to ensure we understand where you are in this journey and can keep reviewing suitability and safety of treatment.
Rebound Weight Gain: Some individuals regain up to two-thirds of the weight lost after stopping treatment, particularly if lifestyle changes aren’t firmly established. You must use the time on treatment to retrain yourself to shop, cook and eat more healthily.
Because of these findings, we now suggest:
Limiting treatment duration rather than committing to indefinite use.
Maximizing dose (within individual tolerance) during the treatment window to achieve significant weight loss efficiently.
Prioritizing lifestyle changes (dietary adjustments, exercise, and long-term behavioral changes) to prevent rebound weight gain when stopping treatment.
Our Approach at Lisle Medical
At Lisle Medical, we provide a structured, medical and monitored approach to weight loss injections, ensuring:
Face-to-face GP consultations to assess suitability with baseline blood tests.
Individualized dosing & monitoring based on side effects and effectiveness.
Ongoing medical supervision to track progress, muscle mass, and metabolic health.
Guidance on post-treatment strategies to maintain results without long-term reliance on medication.
Unlike some providers who offer quick prescriptions without follow-up, we integrate wider medical expertise to ensure safe and effective treatment tailored to your health needs.
Should You Consider Weight Loss Injections in 2025?
If you’re struggling with weight loss, particularly if diet and exercise alone haven’t worked and appetite is your challenge, Mounjaro/Zepbound or Ozempic/Wegovy could be options worth exploring. However, it’s essential to have a clear plan that includes:
Proper monitoring to track muscle vs. fat loss.
Realistic expectations about potential weight plateaus.
A sustainable exit strategy to prevent rebound weight gain.
If you’re considering treatment, book a consultation with Lisle Medical to discuss whether these medications are right for you.
Private GP appointments are available in-clinic or via home visits.
Book today to take the next step toward sustainable weight management.
Weight Loss Injections as A Tool, Not a Magic Fix
Weight loss injections are powerful tools, but they work best as part of a wider health strategy - you will still have to put in the hard work. With the latest evidence, our approach has evolved to focus on not just losing weight, but keeping it off in a healthy, sustainable way.
If you’re interested in starting, continuing, or transitioning off these treatments, we’re here to provide expert medical guidance every step of the way in a safe and sensible manner.
