Accepted answer
On the detail: timing is the most useful diagnostic feature here and it is the one most often omitted from the question.
Constipation outlasts the nausea because it has two causes and only one of them resolves. Gastric emptying accommodates over weeks; total intake, and therefore stool volume and the osmotic load reaching the colon, does not recover until intake does. This is why fibre alone can make it worse — you add bulk to a system that is short of water and short of motility.
Concretely, 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.
SURMOUNT-1 reported gastrointestinal events as the most frequent adverse events, mostly mild to moderate and mostly during escalation, with discontinuation for adverse events in the single digits per cent[1].
Fix the fixable causes first — fluid, electrolytes, sleep, intake — before concluding that the compound is responsible.
edited 25 Mar 2025 by p_mkhize — added a caveat about sampling