The denominator of response
10-15 per cent of people using GLP-1 drugs lose minimal weight or none at all. One study puts the average loss at one-quarter of body weight. Daniel Drucker at the University of Toronto says the spread is large and the molecular mechanism is not yet understood. The average does not describe the person who barely responds.[1]
Clinical trials and real-world data show that women tend to lose more weight than men on these drugs. A 2024 study of postmenopausal women taking semaglutide found greater loss among those who also received hormone-replacement therapy. A study published in February reported a similar pattern for tirzepatide. Drucker also notes that animal studies in which oestrogen reduces food intake do not establish the human mechanism.[1]
Matching is still early
The Endocrine Society says precision medicine for obesity remains largely aspirational. Ruth Loos at the University of Copenhagen says good data on the genetic contribution to drug response are still scarce. The sex and hormone-therapy pattern does not by itself sort who barely responds.[1]