Emilly Murray's Dramatic Weight Loss on Mounjaro
Emilly Murray, a 35-year-old mum-of-three from Aintree, Liverpool, achieved a remarkable transformation with Mounjaro. Starting at 16 stone and a size 22, she dropped to nine stone and a size 6-8 in less than a year. This GLP-1/GIP receptor agonist, known generically as tirzepatide, helped her overcome persistent 'food noise' that had plagued her dieting efforts. Previously, she'd lost weight on her own to reach 16 stone but struggled with constant cravings. Mounjaro changed that within hours of her first dose, putting her in charge of her eating habits.
Mounjaro works by mimicking hormones that regulate blood sugar, slow gastric emptying, and reduce appetite, leading to significant calorie deficits and fat loss. For patients like Emilly, who purchase it privately at £200 per month for the 7.5mg dose, the results are profound—but not without challenges. Her total monthly cost, including an extra £70 on heating, hits £270 every four weeks. Yet, she insists it's "worth every penny," enabling her to run after her kids and climb stairs without breathlessness.
The Chilling Side Effect: 'MJ Freeze' and Rising Heating Bills
One unexpected Mounjaro side effect has Emilly "spending her life freezing." Known on TikTok as "MJ Freeze," this heightened cold sensitivity affects hundreds of weight loss jab users during winter. She noticed it after her first jab, shivering in bed with a hoodie on. This winter, she hasn't felt her toes or fingers once, describing it as an unnatural chill that worsens with water intake—crucial for staying hydrated on these medications.
To cope, Emilly keeps her heating at 22 degrees for over six hours daily, wears multiple layers including dressing gowns at home, and uses heated blankets, gloves, slippers, and a hot water bottle. Her energy bill skyrocketed from £85 to £155 monthly, a £70 increase directly tied to combating the cold. Daily tasks suffer too: school runs require thermals under pants, two t-shirts, a jumper, big coat, and gloves—yet she still freezes "to her core."
"It is absolutely horrendous... I love being seven stone lighter - but it has come with an unwanted side effect."
— Emilly Murray
Emilly attributes "MJ Freeze" to the massive calorie deficit from her 7st loss. "Our bodies are used to eating high amounts—so your body has a lot less energy to burn for heat," she explains. "I have not met a single person on Mounjaro who hasn't had MJ Freeze."
Why Does Mounjaro Cause Feeling Cold? Understanding the Mechanism
While Emilly links it to reduced calorie intake, dietitian Sioned Quirke, specializing in weight management, offers a nuanced view. "There is no robust clinical trial evidence that GLP-1 drugs directly cause people to feel cold as a pharmacological side effect," she states. Instead, it's tied to adaptive thermogenesis post-weight loss.
- Reduced subcutaneous fat: Fat acts as insulation; rapid loss via Mounjaro exposes the body to cold more easily.
- Lower caloric intake: Diet-induced thermogenesis drops, as does resting energy expenditure.
- Metabolic slowing: The body conserves energy, reducing heat production.
These changes are common with any significant weight loss, amplified by Mounjaro's potent appetite suppression. Compared to alternatives like semaglutide (Ozempic or Wegovy), tirzepatide's dual GLP-1/GIP action may accelerate fat loss, potentially intensifying insulation loss. Patients on GLP-1 therapies should monitor for this, especially in colder climates like the UK.
