Clinical perspective, offered as context rather than as advice.

Bone density monitoring on lean mass: DEXA bone density at baseline and month 12.

Lumbar spine T-score: -0.12 → -0.8 (stable to slightly improved)
Femoral neck T-score: -0.13 → -0.9 (stable)

No significant bone loss despite 54 lbs of weight loss. Key factors: adequate calcium (1200mg/day), vitamin D (5000 IU/day), resistance training 3x/week, and adequate protein. Weight-bearing exercise is critical for maintaining bone density during rapid weight loss.

TirzTom said:

fiona_glasgow said: ...the muscle loss concern with lean mass...

Muscle fiber type changes during GLP-1-mediated weight loss, relevant to lean mass: preliminary biopsy data suggests that weight loss shifts the skeletal muscle fiber type distribution:

• Decreased Type IIx (glycolytic, fast-twitch) fibers
• Increased Type I (oxidative, slow-twitch) fibers
• Improved mitochondrial density and function
• Enhanced insulin-stimulated glucose uptake per fiber

This "metabolic remodeling" of muscle may contribute to improved insulin sensitivity independent of total lean mass changes. The muscle you keep becomes metabolically better, even if there's less of it[1].

TirzTom said:

fiona_glasgow said: ...the muscle loss concern with lean mass...

Sharing my comprehensive lab data relevant to lean mass:

Protocol: Semaglutide 2.4mg/wk, resistance training 3x/week, protein 1.4g/kg/day.

The improvements in lean mass are clearly reflected in these numbers. The inflammatory marker reduction (hsCRP) is particularly striking.

Following on from TirzTom — and this may be the naive question:

Did your prescriber agree with that reading, and if not what was their objection?

Moderator note: leaving this open. It is being argued well and the disagreement is the useful part. Carry on.