The present invention relates to a process for the production of a homogenous mixture of two or more branched chain keto acids wherein in a first step, two or more free keto acids are mixed, and in a second step, the mixed keto acids are co-crystallized with one or more alkaline earth metal salts, and foodstuff, food supplement or pharmaceutical products containing a mixture of branched-chain keto acids for supporting muscle structure, increasing muscle performance and improving general wellbeing with simultaneous relief of nitrogen detoxification metabolism by reduced nitrogen supply compared to the intake of the corresponding amino acids and an improved nitrogen metabolism in the body.
