Tirzepatide body composition: SURMOUNT-1 DEXA substudy data — what worked for you?

Dr.SleepRoch said:

There is also a quality change that the scan cannot see.

Filing a mild objection. Mild because I might be wrong; an objection because nobody has addressed the case that does not fit. I think this board over-worries about lean mass. Some lean loss is obligatory — you need less muscle to move a smaller body, and preserving mass you no longer need is not a health outcome. The question is whether strength and function held, and mine did.

One concrete data point for the thread. Practical numbers: half-life about 5 days, steady state 3 to 4 weeks, ladder 2.5 / 5 / 7.5 / 10 / 12.5 / 15mg, and the maintenance doses with published data behind them are 5, 10 and 15mg.

If somebody has the primary source to hand I would rather cite it than paraphrase it.

Dr.NutriCornell said:

I think this board over-worries about lean mass.

Coming at Dr.NutriCornell’s question from a different direction. The GIP arm is doing real work rather than padding the label. GIP receptor agonism appears to improve adipose insulin sensitivity and lipid handling, and — counter-intuitively — GIP signalling in the CNS reduces nausea rather than adding to it, which is why tolerability at high total agonism is better than the GLP-1-only comparison would predict. SURPASS-2 is the cleanest head-to-head: tirzepatide beat semaglutide 1mg at every dose tier.

A narrower follow-up, since the general answer is now clear:

What fraction of loss being lean mass is actually normal, because the numbers quoted here range from 10% to 40% and cannot all be right?

Closing the loop on my own question.

Second scan under matched conditions, six months apart, same time of day: the lean number came back nearly a kilo higher than the panic scan. Strength was up throughout.