Spiering, B. A., Kraemer, W. J., Volek, J. S., Ratmess, N. A., VanHeest, J. L., Sharman, M. J., Rubin, M. R., French, D. N., Judelson, D. A., & Maresh, C. A. (2005). Testosterone and androgen receptor responses to resistance exercise: Effects of L-carnitane supplementation. Medicine and Science in Sports and Exercise, 37(5), Supplement abstract 1245.

Recreationally weight-trained males (N = 10) took L-carnitane supplements or a placebo for 21-days followed by an acute heavy-resistance challenge (4 x 10 repetitions of back squat, bench press, bent over row, and shoulder press). Testosterone concentrations were measured before, during, and after exercise. Post-exercise measures were immediately after exercise and serially every 10 minutes for 60 minutes. Androgen receptor content was measured by muscle biopsies of the vastus lateralis 48-72 hours pre- and one hour post-exercise.

L-carnitane supplementation significantly increased testosterone concentrations pre- and post-exercise. Post-exercise androgen receptor content was significantly higher post-exercise only in the placebo condition. Post-exercise androgen receptor content was similar post-exercise for both conditions.

Implication. L-carnitane supplementation increased pre-exercise androgen receptor content and increased testosterone concentrations post-exercise. These responses may promote recovery from resistance exercise.

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