Most of us track the scale on our GLP-1 patients. The DXA data says we should be paying just as much attention to what the scale can't see. In the STEP 1 body composition substudy (140 participants on semaglutide 2.4 mg for 68 weeks), mean weight loss was about 15%. When you work through the DXA numbers, roughly 39% of the weight lost was classified as lean mass. That number gets quoted a lot, usually without context. A few things worth sitting with: • DXA "lean mass" includes water, glycogen, and organ tissue, so it likely overstates true skeletal muscle loss. • Fat mass still fell far more than lean mass, and visceral fat dropped by about 27%. • Lean mass as a share of total body mass actually went up. Some lean loss is expected. The clinical questions are how much, in whom, and what you're doing about it from the first visit: protein targets, resistance training, and when you re-measure. Then the SURMOUNT-1 DXA data on tirzepatide came out, and the comparison to placebo surprised a lot of providers. Poll: In the SURMOUNT-1 DXA substudy, how did the share of weight lost as lean mass on tirzepatide compare with placebo? Comment your guess below. The answer and the full protocol (protein targets, training prescription, and a re-measurement schedule) are in the GLP-1 and weight loss module in the Classroom tab Tuesday . We'll dig into this on Tuesday's call at 4 PM Arizona time (3 PM PT, 6 PM ET). Adding A Dexa or body Comp to your Practice?? A cash-pay DEXA scan typically costs between $75 and $390, with a national median price of around $149. Cost Breakdown by Facility Type - University / Research Labs: $40 – $80 (often used for public or promo exercise-science studies) - Independent DEXA & Wellness Clinics: $99 – $195 (standard self-pay pricing, frequently includes basic body-composition reports and consultations) - Longevity / Med-Spa / Concierge Clinics: $175 – $250+ (often bundled with resting metabolic rate [RMR] or VO2 max testing) - Hospital Imaging Departments: $200 – $600+ (generally the most expensive option and usually focused on clinical bone-density orders rather than fitness/body-composition tracking)