Glycine Propionyl-L-Carnitine (GPLC)
For some men, one of the contributing factors to failure to maintain a satisfactory erection is diabetes or pre-diabetes (ie. insulin resistance) that is increasingly common in middle-aged med. Fortunately, GPLC is a powerful vasodilation amino acid that can increase blood flow, and it has been shown to benefit erectile strength specifically in men with blood sugar control issues.
Similar to Resveratrol, GPLC has been studied clinically for its ability to improve erectile function in men currently taking PDE-5 inhibitors. After 24 weeks of treatment of GPLC supplementation on top of existing PDE-5i usage, there were marked improvements in the ability to achieve and maintain erections, with 68% of patients experiencing improved erectile function compared to using PDE-5 inhibitors alone.
Also, GPLC enhances anaerobic work capacity (with reduced lactate production) in men, which permits longer sessions in the bedroom before exhaustion.
V. Gentile, P. Vicini, G. Prigiotti, A. Koverech, and F. Di Silverio, “Preliminary observations on the use of propionyl-L-carnitine in combination with sildenafil in patients with erectile dysfunction and diabetes,” Curr. Med. Res. Opin., 2004.
Jacobs PL, Goldstein ER, Blackburn W, Orem I, Hughes JJ: Glycine propionyl-L-carnitine produces enhanced anaerobic work capacity with reduced lactate accumulation in resistance trained males. J Int Soc Sports Nutr. 2009, 6: 9-10.
Bloomer, R. J., Smith, W. A., & Fisher-Wellman, K. H. (2007). Glycine propionyl-L-carnitine increases plasma nitrate/nitrite in resistance trained men. Journal of the International Society of Sports Nutrition, 4, 22.