The GLP-1 week has a shape, and the evidence is thinner than it looks

The week has a shape

Weekly GLP-1 drugs are usually discussed as if they deliver a steady effect, but a prospective real-world preprint tracking patient-reported experience finds a rhythm inside the week. Food noise prevalence in patients on weekly GLP-1 agonists ranges from 4.3% to 23.8% over a 6-week period, peaking on dosing days, which means the experience patients report is not flat across the cycle. Hunger moves too: hunger levels fluctuate within the weekly dosing cycle, with mean scores of 39.9 on Day 1, 31.1 on Day 2, and 41.6 on Day 7, on a scale running from 0 to 100. m:…6015

Cravings are common even when the drugs are working. In the same preprint, 76.8% of participants reported food cravings at least once over the 6-week study period, with moderate intensity being the most frequently reported. That finding matters for how clinicians and patients judge whether a dose is doing enough. A patient whose hunger is lowest just after the injection and climbs toward the end of the week may look fine at a clinic visit timed near the dose and struggling at a visit timed a few days later, even though nothing about the treatment has changed. m:…6015

The implication is practical rather than theoretical. If food noise, hunger and cravings move across the week, then a snapshot at a scheduled visit is a weak measure of how the treatment feels day to day. The preprint is patient-reported evidence, which is both its strength and its limit: it captures what people actually experience, and it depends on people reporting that experience consistently across the study period. m:…6015

The evidence at 52 weeks

A second preprint, a network meta-analysis of obesity treatment initiation, asks a different question: what do we actually know with confidence at 52 weeks. Retatrutide 12 mg, tirzepatide 15 mg, and cagrilintide-semaglutide 2.4/2.4 mg demonstrate the greatest placebo-adjusted weight reduction at 52 weeks, which puts the newer multi-receptor drugs at the top of the ranking for weight loss. But the ranking is not the same as certainty. Only tirzepatide 15 mg and semaglutide 2.4 mg have high-certainty evidence for 1-year obesity treatment initiation, so the drugs with the largest reported reductions are not the ones with the strongest evidence behind them. m:…9925

The same analysis carries a warning about side effects that is easy to miss next to the weight numbers. Thirteen of 32 obesity pharmacotherapy strategies increased adverse-event-related permanent discontinuation compared to placebo, which means a meaningful share of the options on the table come with a higher chance that patients stop treatment because of adverse events. A treatment decision that only weighs kilograms will miss that trade-off, and the meta-analysis puts it in the same frame as the benefit. m:…9925

Diabetes changes the stakes

Diabetes changes the decision itself. In the meta-analysis, weight reduction in adults with type 2 diabetes is 62% of that observed in adults without diabetes, so the same drug delivers less weight loss where diabetes is present. That attenuation is reported with a 95% confidence interval of 0.58 to 0.66, which is a tight range around a substantial gap, not a borderline finding. m:…9925

And diabetes carries its own risk beyond weight. A systematic review and meta-analysis finds that type 2 diabetes is associated with higher odds of incident colorectal cancer, with an odds ratio of 1.28 and a 95% confidence interval of 1.13 to 1.46, and a higher hazard of incident colorectal cancer, with a hazard ratio of 1.27 and a 95% confidence interval of 1.23 to 1.31. Individuals with type 2 diabetes also show a higher standardized incidence ratio of colorectal cancer, at 1.40 with a 95% confidence interval of 1.39 to 1.45. m:…0371

Put together, the picture for a clinician is more complicated than a league table of weight loss. The weekly experience fluctuates, the strongest evidence covers only the established drugs, the benefit is smaller when diabetes is present, and diabetes itself is tied to a higher risk of colorectal cancer. None of that argues against treatment. It argues for choosing with the full picture in view: the rhythm of the week, the certainty of the evidence, the expected benefit for this patient, and the risks that sit outside the weight chart. m:…6015 m:…9925 m:…0371