Accepted answer
The incidence figures are dose-related but the timing is escalation-related, and conflating the two produces most of the bad advice in this area. Adverse events cluster in the one to two weeks following each dose increase, then decay.
The telogen effluvium timing signature is the diagnostic feature: hair enters the shedding phase two to four months after the insult, so shedding that starts at month three of rapid loss and peaks around month four to five is the expected pattern. Shedding that starts in week two is not telogen effluvium and warrants a different question. In either case the follicle is not destroyed and regrowth is the rule.
The gallbladder signal tracks the rate of weight loss more than it tracks the drug. Rapid mobilisation of adipose tissue increases biliary cholesterol saturation and reduces gallbladder motility; that combination is lithogenic whether the loss came from a drug, a very-low-energy diet or bariatric surgery. The drug contribution on top of that is present but smaller than the rate contribution.
The pooled gastrointestinal adverse-event rates across the STEP programme and the SURMOUNT programme are reported in the primary publications and in the FDA and EMA assessment reports, and the assessment reports are more useful because they give the placebo-arm rates alongside the active-arm rates in the same table.
The caveat that actually matters: this is pattern recognition from published data, not a clinical assessment of you. Anything severe, persistent or accompanied by systemic features belongs with a clinician the same day.
Write down in advance which symptoms mean stop and seek care. It is a short list and it is much easier to write when you are well.
edited 3 Jun 2026 by Dr_Rosalind_Achebe — corrected a unit error in the worked example
2Minor: the trial name is hyphenated in the original publication. – tobias_maartens 8 months ago add a comment