Mixed muscle protein synthesis can be assessed using stable isotopes like D5 Falon to measure incorporation into muscle tissue versus the precursor pool.

“we used uh D5 Falon which is basically a doated one of the hydrogens on the fal alanine is deuterated and you can basically you're looking at how much of that label gets incorporated into the the mixed muscle of the of the or sorry the mixed muscle um versus how much is in the precursor pool which is the intracellular fluid”