Lucy Davies, 33, from Pontypridd, Wales, dropped from 16st 11lb to 7st 12lb after starting the weight-loss injection Mounjaro in September 2024. Four months into her treatment, she began to lose her hair in clumps - and says the side effect has left her "more self-conscious" than she was before losing almost nine stone.
"I was in the shower washing my hair and it was coming out in clumps," she recalled. "I kept washing it and it would come out in clumps again. As I was brushing it, it just kept falling out. I really panicked."
Daily calories dropped to as little as 500
The insurance consultant, a mum of one, says the medication left her unable to face food, cutting her daily intake from around 5,000 calories to as little as 500. "Some days I was eating nothing. I couldn't even stand the smell of food," she said.
Although Lucy had naturally fine hair before, she says the extreme shedding was unlike anything she'd experienced. "I have had thin hair, but nowhere near where it is now," she said. "If I don't have extensions, I can't wear it down anymore." The thinning has affected her entire scalp, and she can now see her scalp on top. "It's gone very thin on top and I have to be careful how I style it."
Thousands spent on regrowth products
Desperate for regrowth, Lucy spent thousands of pounds on high-end haircare products and supplements, including K18 and collagen. "I've bought all the proper haircare like K18 and collagen, and it just doesn't seem to be making a difference," she said. "The collagen is £45 for two weeks and K18 is about £80 a bottle. I'm spending thousands and not seeing any improvement."
She also took hair vitamins from the day she started Mounjaro after being warned that hair loss was a possible side effect - it is listed as a side effect of weight loss jabs.
What SkinnyJab says about GLP-1 hair loss
Caroline Balazs, a nurse practitioner and founder of SkinnyJab, says hair loss is a real and measurable side effect across multiple GLP-1 medications. "In our experience, we appear to see more hair loss among patients taking Mounjaro than Wegovy, although it is generally thought that the GLP-1 element may be responsible," she explained.
"Fat tissue produces oestrogen, which helps keep hair in its active growth phase," she added. "When somebody loses a significant amount of fat, falling oestrogen levels may allow the effects of testosterone and DHT to become more prominent, potentially contributing to hair loss. There is not yet concrete evidence confirming this mechanism in relation to GLP-1 medications, but it warrants further research."
She also pointed to possible changes in thyroid hormones and cortisol levels, noting these medications affect metabolism and could be contributing factors. To combat shedding, she advises patients to maintain a high protein intake and consider treatments such as topical minoxidil.
'I still see myself as big'
While some hair has slowly begun to grow back around her hairline, Lucy says it remains a fraction of what it once was. "I read that it can happen and that it normally settles down, and it did eventually, but it hasn't grown back to what it should have done," she explained.
Despite her physical transformation, losing weight has not brought the happiness she imagined. "A lot of people think losing the weight makes you happy, but to be honest I'm still not happy," she said. "It's still a mental battle every day. I still see myself as big. I feel like I lived more before because I'd just eat what I wanted and do what I wanted. Now I check calories all day, every day. I'm way more critical of myself now. I'm way more self-conscious now. It hasn't helped me."
Maintaining her weight has become mentally exhausting. "When I go on holiday, I'm paranoid. I'm on the scales on holiday to see how much weight I've put on. I enjoy the holiday, but there's always the stress of what I'm eating. Even though I know I can lose the weight, it's a constant fear."
She now weighs 7st 13lb but still struggles with confidence issues after being left with loose skin and hair loss. The psychological impact became so severe that Lucy took two months off work for her mental health and has since started counselling. "It's going to be a long time," she said.
Still not comfortable at the beach
She says the medication has transformed her physically, making her far more active and able to enjoy walking, but her confidence has not caught up. "I have a nine-year-old son and I wanted to do more with him, feel more comfortable when I'm out and be able to go to the beach with him. But now I've lost the weight, I still wouldn't do that. We're going swimming next week and my friend said, 'Bring your bathers,' but I still wouldn't go in. It's worse now."
Lucy now eats between 1,200 and 1,500 calories a day while remaining on a maintenance dose of Mounjaro, and plans to stop the medication once she finishes her current pen. "If I find I can't do it alone, I'm happy to stay on the maintenance dose, but I'm not losing any weight on it now," she said.
Support is available for anyone struggling with eating disorders through Beat, via the organisation's website.
