Semaglutide review: weight loss and CRP

On 29 August 2026 a systematic review and meta-analysis in the International Journal of Obesity pooled nine randomised controlled trials of subcutaneous semaglutide, the GLP-1 receptor agonist sold as Ozempic and Wegovy, covering 6,239 adults with overweight or obesity who did not have diabetes^[1]. Across those nine trials, semaglutide produced a mean 12.04 percentage-point greater reduction in body weight than placebo, alongside a 40.90% greater fall in C-reactive protein (CRP), a blood marker doctors use as a general signal of inflammation^[1]. Both differences were statistically significant at p<0.00001.

What the review found

The review, led by Milluzzo and colleagues, combined data from nine trials enrolling a total of 6,239 participants without diabetes. Pooled across those trials, subcutaneous semaglutide reduced body weight by a mean of 12.04 percentage points versus placebo (95% confidence interval, 13.08 to 11.00), and reduced waist circumference by a mean of 9.36 cm (95% CI, 10.27 to 8.45)^[1]. CRP fell by a mean of 40.90% versus placebo (95% CI, 46.37 to 35.42)^[1]. On safety, the risk of serious adverse events did not differ significantly between semaglutide and placebo (risk ratio 1.12, 95% CI 0.76 to 1.65, p=0.55)^[1].

What the CRP number does, and doesn't, mean

CRP is a nonspecific marker. The liver produces it in response to interleukin-6 signalling, and it rises with almost any source of systemic inflammation, from infection to injury to excess body fat. Visceral fat tissue itself generates inflammatory signalling, so when a treatment produces weight loss at this scale, a falling CRP is an expected downstream effect, not automatic proof that semaglutide is acting on inflammation through some separate pathway. The review did not report other inflammatory markers, such as interleukin-6 or tumour necrosis factor-alpha, that would help separate a weight-loss-driven CRP change from a more direct effect^[1]. Researchers commonly use CRP in cardiometabolic studies because it is cheap to measure and widely available in routine bloodwork, not because it is the most specific marker of a drug's inflammatory action. A pooled analysis like this one also assumes the nine included trials are similar enough in population and methods to combine into a single average, an assumption meta-analysts test but cannot fully remove. Readers should treat the CRP figure as a marker that moved in the expected direction alongside major weight loss, not as evidence of a distinct anti-inflammatory mechanism.

How this lines up with the existing semaglutide evidence

The pooled 12.04% figure sits below the 14.9% mean weight loss that the STEP-1 trial reported at 68 weeks on the top semaglutide dose used for weight management^[3]. That gap is expected. STEP-1 tested one dose in one trial, while the new review pools nine trials that vary in dose, duration and formulation, and pooling tends to pull the average down relative to any single trial's best result. Semaglutide is authorised in the EU under the brand Wegovy for chronic weight management in adults with a body mass index of 30 or above, or 27 to 30 with a weight-related comorbidity, used together with diet and physical activity^[2]. The regulatory basis for that authorisation, and the country-specific access rules that follow from it, are on our semaglutide regulation page.

What this review doesn't tell us

This is a systematic review of trial data, not a new clinical trial, and it inherits the limits of the trials it pools. It excluded people with diabetes by design, so the findings do not extend to that population. It reports a single inflammatory marker, CRP, rather than a fuller inflammatory profile, and it does not establish whether the CRP change predicts any specific clinical benefit for an individual patient, such as a lower risk of a heart attack or a joint replacement. The review also does not break results down by dose, sex, baseline weight or how long each underlying trial ran, so it cannot tell an individual reader how their own CRP is likely to move. The authors themselves call for longer-term studies to confirm a sustained efficacy and safety profile across different clinical populations^[1]. The cardiovascular-outcomes question for semaglutide in people with overweight or obesity and existing cardiovascular disease is a separate, already-established finding covered on our semaglutide peptide page; this review does not add new outcome data on that front. It is a weight-loss and biomarker synthesis, not an outcomes trial.

Where this fits

For readers tracking the broader semaglutide evidence base, this review adds a specific, quantified answer to a question that circulates informally: does the weight loss come with a measurable change in a standard inflammation marker. The answer, in this pooled dataset, is yes for CRP. What it is not is a signal to start, stop or change a dose. Semaglutide remains a prescription-only medicine across the EU, UK and US, and any decision about starting treatment, or interpreting a personal CRP result, belongs with a prescribing clinician who knows the full clinical picture. See the semaglutide overview for the wider trial record and country-specific regulatory detail.