STEP UP MRI substudy reports body composition on semaglutide 7.2 mg at EASD 2025

Novo Nordisk listed an oral presentation on body composition from its STEP UP trial of semaglutide at the 2025 annual meeting of the European Association for the Study of Diabetes (EASD), with presentation materials dated September 25, 2025 and credited to investigator Jøran Hjelmesæth ^[1].

STEP UP is the trial program testing a higher weekly dose of semaglutide, 7.2 mg, alongside the 2.4 mg dose already familiar to US patients as Wegovy. The body composition analysis reported at EASD is described in the company's congress materials as a STEP UP body composition presentation ^[1]. The underlying substudy used magnetic resonance imaging (MRI) rather than the more common DXA scan to separate how much of the weight people lost came from fat tissue versus lean tissue.

What the source material does and does not show

Here is the honest limitation of this report: the only source available is Novo Nordisk's congress listing page, which confirms the presentation's title, presenter and September 25, 2025 date ^[1]. The slide-level results — the percentage of weight loss attributable to adipose tissue versus lean tissue, the number of participants scanned, the duration of follow-up, and any side-by-side comparison with DXA-derived figures — are not contained in the material reviewed for this story. Those numbers are not yet known from the sources at hand, and we are not going to guess at them.

That matters because the whole point of an MRI substudy is the number it produces. Lean-tissue loss on GLP-1 drugs has become one of the most argued-about topics in obesity medicine, and the figure that gets quoted in headlines depends heavily on which scanner produced it. DXA and MRI do not measure the same thing in the same way, so a trial can generate two different-sounding answers about muscle loss from the same group of patients. Any claim that the MRI numbers are higher or lower than the DXA numbers in STEP UP should be traced back to the actual presentation or a peer-reviewed publication, not to secondhand summaries.

Why it matters for patients

For someone taking or considering semaglutide, body composition data speaks to a practical worry: when the scale goes down, what exactly is leaving the body. Fat loss is the goal of treatment. Loss of lean mass — which includes muscle but also organ tissue, connective tissue and water — is the part that draws concern, particularly for older adults and for people who expect to stay on treatment for years.

The measurement-method issue is not academic. If a study using one imaging method reports that a quarter of lost weight was lean tissue, and another method puts the share lower, patients and clinicians reading news coverage can come away with very different impressions of the same drug. Understanding that the tool shapes the headline is useful context when comparing across trials, including trials of tirzepatide (Mounjaro, Zepbound) and other agents that have reported their own body composition results using various methods.

It is also worth noting that semaglutide 7.2 mg is a higher dose than the 2.4 mg approved in the United States for weight management. Whether and when a 7.2 mg dose reaches US pharmacies is a separate regulatory question that this body composition analysis does not answer.

What happens next

The presentation was delivered at EASD on September 25, 2025 ^[1]. The next step to watch is publication of the full substudy in a peer-reviewed journal, which would put the MRI figures, the DXA comparison and the statistical methods on the record where they can be checked. Until then, specific percentages circulating in coverage should be checked against the primary presentation.