---
title: "Sarcopenia"
definition: "Age-related or weight-loss-related loss of skeletal muscle mass and strength. A clinical concern with high-magnitude weight loss therapy, particularly in older adults."
url: https://retatrutide.med/glossary/sarcopenia
category: "condition"
source: retatrutide.med
sourceType: "glossary term"
license: CC-BY-NC-SA-4.0
canonical: https://retatrutide.med/glossary/sarcopenia
---
## Sarcopenia

Sarcopenia is the progressive loss of skeletal muscle mass and strength. It is most commonly associated with aging but can also occur secondary to chronic illness, disuse, malnutrition, or rapid weight loss. Diagnostic criteria typically combine measurement of muscle mass (often via DXA scan), muscle strength (grip strength), and physical performance (gait speed). Established clinical definitions are published by the European Working Group on Sarcopenia in Older People and similar bodies.

Sarcopenia is associated with increased risk of falls, fractures, functional decline, frailty, and all-cause mortality. In the context of obesity treatment, the concern is "sarcopenic obesity" — the coexistence of excess fat mass and depleted muscle mass — and the related risk of unmasking or worsening sarcopenia through high-magnitude weight loss.

Modern anti-obesity medications including semaglutide, tirzepatide, and retatrutide produce sufficient weight loss that a meaningful proportion of weight lost is lean mass, not just fat mass. While the absolute amount of muscle lost may be similar to what would occur with surgical or dietary weight loss of equivalent magnitude, the rapid pace of pharmacological weight loss focuses attention on lean mass preservation. The clinical recommendation across pharmacological weight loss therapies is to combine treatment with adequate dietary protein (typically 1.2-1.6 g/kg of ideal body weight per day) and resistance exercise to support muscle preservation. Older adults and patients with baseline reduced muscle mass warrant closer monitoring of functional outcomes during treatment.

Retatrutide-specific body composition data from the TRIUMPH program will become more informative as full Phase 3 publications appear, including subgroup analyses of body composition in older adults and in participants with BMI ≥40.