Weight-loss drug side-effects: evidence examined for nausea, hair loss, eye issues
8 reported3 unconfirmed
A review of reported side-effects from GLP-1 weight-loss medications such as Wegovy and Mounjaro finds that some outcomes have strong evidence while others remain unproven. Digestive problems like nausea, vomiting, diarrhoea and constipation are well-documented in clinical trials and listed as very common in patient leaflets, though manufacturers note they usually resolve over time. Eye conditions, including age-related macular degeneration and a rare disorder called non-arteritic anterior ischaemic optic neuropathy, have been linked to the drugs in studies, with pharmaceutical companies accepting the latter as a possible but very rare side-effect. Unexpected pregnancies have been reported among users, leading to recommendations for effective contraception, but conclusive research is lacking because pregnancy was an exclusion criterion in initial trials. Social media reports of facial changes known as “Ozempic face” and foot changes called “Ozempic foot” are not listed in patient information but are recognized by surgeons and podiatrists as consequences of rapid weight loss from any intervention. Hair thinning was highlighted this week in a study of adults with type 2 diabetes, with patient leaflets for Mounjaro and Wegovy listing it as a common side-effect; experts suggest it may be due to rapid weight loss rather than the drugs themselves, and the observed association appears to involve reversible forms of alopecia.
What’s reported
Digestive problems (nausea, vomiting, diarrhoea, constipation) are well-documented in clinical trials and described as very common in patient leaflets.
A study last year found people with diabetes using GLP-1 drugs could face double the risk of age-related macular degeneration.
Some GLP-1 medications have been linked to non-arteritic anterior ischaemic optic neuropathy, a rare condition that can cause sudden and permanent sight loss.
Unexpected pregnancies have been reported among users; the UK Medicines and Healthcare products Regulatory Agency states GLP-1 medicines should not be taken during pregnancy or just before trying to get pregnant due to insufficient safety data.
Facial changes (“Ozempic face”) are not mentioned in patient information but are recognized by surgeons as a result of rapid weight loss.
Hair loss is listed as a common side-effect in patient leaflets for Mounjaro and Wegovy; a new study suggests it may be driven by non-scarring forms of alopecia that are often reversible.
“Ozempic foot” is not found in patient information leaflets; podiatrists note rapid weight loss can reduce fat padding in feet, causing pain.
One study found sleeve gastrectomy weight-loss surgery was associated with a decrease in shoe size a year later.
Open questions
Whether GLP-1 medications interfere with oral contraceptives or increase fertility remains unconfirmed.
Research into whether GLP-1 medications affect male fertility is in its infancy.
The latest hair-loss study did not examine whether the hair loss is reversible.
Key figures
UK Medicines and Healthcare products Regulatory Agency (MHRA)
Sources: The Guardian
