New study confirms link between fat jabs and hair loss, after thousands of users complained of shedding and bald patches

Thousands of people who have used GLP-1 medication to lose weight have complained it has also affected the thickness of their hair—and now a new study has confirmed the link. 

The appetite-suppressing drugs have revolutionised how obesity is treated, but new research has shown that some jabs may increase the risk of rapid hair loss, and both female and male pattern baldness. 

Known as GLP-1 receptor antagonists, and sold under the brand names Ozempic for diabetes and Wegovy for weight management, the ‘miracle’ jabs mimic a gut hormone to regulate appetite and blood sugar. 

In the UK, fewer than 200,000 people are thought to be accessing the jabs through the NHS, but over 1.4million are estimated to be using them privately, according to the health think-tank, the King’s Fund. 

But despite their life-changing effects, the jabs have been hit by controversy as thousands of users who have championed the weight loss effects of GLP-1s have complained of distressing hair loss, which in some extreme cases, has left them with bald patches. 

In January 2024, the US Food and Drug Administration (FDA) began investigating the potential link between the jabs and alopecia—despite research showing that for the majority of these drugs, hair loss only affects less than 5 per cent of users. 

But now US researchers have linked GLP-1s to rapid hair loss—medically known as telogen effluvium (TE)—male and female pattern baldness, and nonscarring hair loss. 

However, they noted no association with alopecia areata—an autoimmune disease that attacks the body’s hair follicles—was discovered.

Presenting the study at the European Academy of Dermatology and Venereology 2025 Congress, senior author Yagiz Matthew Akiska, said: ‘[GLP-1’s] metabolic and cardiovascular benefits are at this point pretty well established. 

‘However, as their prescribing expands [we] are are seeing more and more unexpected side effects being reported in the literature.

‘One of the most interesting ones that we are seeing is hair loss, specifically nonscarring hair loss.’ 

He added: ‘As clinicians should recognise that hair shedding and hair loss is an emerging, real-world side-effect of GLP1-s.’ 

In the current retrospective study, researchers from the George Washington University School of Medicine and Health Sciences, analysed over 1 million patients who did not have a history of hair loss or other causes, such as thyroid disease, for the condition. 

Adjusting for potentially confounding factors such as age, sex, race and BMI, they identified 547,993 GLP-1 users who had filled at least two prescriptions for the jabs and had at least two health visits between 2014 and 2024. 

These participants were matched with 547,993 non-users who also did not have a history of—or predisposition to—hair loss. 

Over the 10-year period, the incidence of rapid hair loss, pattern baldness and nonscarring hair loss all increased to a greater extent in patients on the weight loss jabs than in non-users. 

They found that after just six months of being on the jabs, a person’s risk of nonscarring hair loss increased by 26 per cent. 

And for pattern baldness—a common cause of hairloss in both men and women, characterised by a receding hairline which eventually progresses to partial or complete baldness in men—the risk was even greater, at 62 per cent. 

After a year, the risk of rapid hair loss was greatest, with the chances of developing the distressing condition being 76 per cent higher with weight loss drug use.’

Mr Akiksa said: ‘For many patients, hair loss becomes pretty important as a side effect because they’re also trying to lose weight, they’re concerned about their appearance, or they’re trying to control their diabetes.

‘On top of it, they’re dealing potentially with hair loss, which can be very debilitations for them.’ 

Whilst this class of drugs work by by targeting receptions that relate to digestion and insulin production which aren’t directly linked to hair growth, the stress on the body—caused by rapid weight loss—can interfere with the hair’s natural cycle. 

Dr Roshan Vara, a hair transplant surgeon, previously told the Daily Mail that a dramatic change in nutrient intake can trigger deficiencies in essential nutrients hair requires to grow. 

‘Products like Mounjaro or Wegovy can mean patients are unintentionally placed under a calorie restriction,’ Dr Vara explained. 

‘This restriction causes your skin and hair to suffer as the body prottises essential functions, diverting nutrients away from our hair and into internal organs.’ 

But the good news is that once nutrients are reintroduced, the hair will begin to grow back, though it could take up to six months. 

As such, Dr Akiska said: ‘We should start thinking about more proactive strategies to mitigate these risks.’ 

Doctors have advised weight loss jabbers to pay close attention to what they are eating and drinking, even in they have a reduced appetite, and to speak to a medical professional if hair loss persists despite managing stress and eating a nutrient-dense diet. 

Mr Michael Buontempo, a resident physician at Dartmouth-Hitchcock Medical Centre, who was not involved in the current study, told Medscape Medical News: ‘Hair loss matters for quality of life, but it’s usually reversible. 

‘The best mitigation is pacing weight loss and maintaining nutrition rather than stopping effective therapy.’ 

Mr Buontempo added that the current study reinforces what doctors are seeing elsewhere, but stressed that this suggests that hair loss is one of the many side effects of rapid weight loss, rather than the drug itself.