...for pyruvate to have any direct effect on the muscle, its delivery to the muscle would have to be increased, which would necessitate at least transient increases in blood pyruvate. However, no studies have determined the efficacy of elevating blood or muscle pyruvate content after chronic supplementation. The results of the present studies indicate that oral dosages of isolated pyruvate, similar to those that are widely reported to be effective, do not elevate its content in the blood...

It seems clear that at least a portion of the ingested pyruvate is degraded in the stomach and/or intestine. Each of our subjects complained of increasing borborygmous, flatulence, and nausea as the dosage of pyruvate was increased, as has been previously reported (15, 16). Two of our subjects did not participate in the final trial with the highest pyruvate dosage (25 g) due to adverse effects. Although we cannot eliminate the possibility of clearance by the liver, the inability to elevate blood pyruvate content would seem to preclude the possibility of orally ingested pyruvate having an effect on target tissues, such as the pancreas or skeletal muscle, and cause altered insulin and/or peptide C release or an increase in muscle glucose uptake.

Int J Sport Nutr. 1999 Jun;9(2):146-65.

Effects of in-season (5 weeks) creatine and pyruvate supplementation on anaerobic performance and body composition in American football players.

Stone MH, Sanborn K, Smith LL, O'Bryant HS, Hoke T, Utter AC, Johnson RL, Boros R, Hruby J, Pierce KC, Stone ME, Garner B.

Exercise Science Department, Appalachian State University, Boone, NC 28608, USA.

The purpose of this investigation was to study the efficacy of two dietary supplements on measures of body mass, body composition, and performance in 42 American football players. Group CM (n = 9) received creatine monohydrate, Group P (n = 11) received calcium pyruvate, Group COM (n = 11) received a combination of calcium pyruvate (60%) and creatine (40%), and Group PL received a placebo. Tests were performed before (T1) and after (T2) the 50 week supplementation period, during which the subjects continued their normal training schedules. Compared to P and PL, CM and COM showed significantly greater increases for body mass, lean body mass, 1 repetition maximum (RM) bench press, combined 1 RM squat and bench press, and static vertical jump (SVJ) power output. Peak rate of force development for SVJ was significantly greater for CM compared to P and PL. Creatine and the combination supplement enhanced training adaptations associated with body mass/composition, maximum strength, and SVJ; however, pyruvate supplementation alone was ineffective.