When will I start seeing results on a GLP-1?

The first change may not be the scale

GLP-1-based medicines act on appetite and satiety pathways. In the first few weeks, some patients describe feeling full earlier, eating smaller portions or thinking about food less often. 'Food noise' is a popular term for persistent thoughts or urges around food, although it is not a formal diagnosis.

These appetite changes can occur before weight loss becomes visually obvious.

By around three months, the trend is clearer

Clinical trials show that weight reduction begins early and accumulates over time. In STEP 1, weight loss with semaglutide was already evident at the first formal assessment and continued across the treatment period.

By around three months, many patients can see a clearer direction of travel, but the pace varies. This is a useful review point, not a universal deadline.

Think in months, not days

Modern obesity trials commonly run for more than a year because obesity treatment is not designed as a rapid short course. Patients who compare daily scale changes can easily mistake normal fluid variation for treatment success or failure.

Looking at a weekly or monthly trend is usually more informative.

Health improvement is broader than weight

Depending on the patient's starting health, clinicians may also follow blood glucose or HbA1c, blood pressure, waist circumference and lipid measures. Some improvements can occur alongside weight reduction rather than after a specific target weight is reached.

The relevant outcomes should be personalised to the reason treatment was started.

When progress is slower than expected

Slower progress does not automatically mean the medicine has failed. Dose escalation, side effects, adherence, diet, activity and underlying metabolic factors all need to be considered.

Equally, treatment should not continue indefinitely without reviewing whether it is delivering enough benefit for the individual.

References

• Wilding JPH, et al. Once-Weekly Semaglutide in Adults with Overweight or Obesity. New England Journal of Medicine. 2021. PubMed

• Blundell J, et al. Effects of once-weekly semaglutide on appetite, energy intake, control of eating, food preference and body weight in subjects with obesity. Diabetes, Obesity and Metabolism. 2017. DOI: 10.1111/dom.12932. PubMed

• Aronne LJ, et al. Tirzepatide as Compared with Semaglutide for the Treatment of Obesity. New England Journal of Medicine. 2025. DOI: 10.1056/NEJMoa2416394.

Written and clinically reviewed by: Dr Saran Seker, MBBS (Aus), Chief Medical Officer

Last reviewed: September 2026