Testosterone, Free is a measure of the amount of unbound testosterone in the blood that is available for use by the body. Low levels of free testosterone can cause symptoms such as decreased libido, erectile dysfunction, and decreased muscle mass in men.
Alanine is involved in protein and energy metabolism. Higher alanine levels may reflect increased muscle protein breakdown which could be associated with lower free testosterone.
Sasaki, C.A.; da Costa, T.H.. “Exploring the Relationship between Micronutrients and Athletic Performance in Para-athletes: A Systematic Review”. Nutrition (2020). https://www.mdpi.com/2075-4663/11/6/109
Thelen, D.T.; Baguet, A.; Courts, A.C.; Doyle, J.A.; Harris, R.C.; Kim, H.J.; Kuipers, H.; Portengen, L.; Saunders, B.; Schoenfeld, B.J.; Trexler, E.T.; Van Loon, L.J.; Witard, O.C.. “The Effects of Beta-Alanine Supplementation on Performance: A Systematic Review of the Literature”. Nutrients (2020). https://www.mdpi.com/2072-6643/12/8/2261
Arginine is a precursor for nitric oxide which plays a role in vasodilation and blood flow. Reduced arginine and nitric oxide may be associated with erectile dysfunction and potentially lower free testosterone levels.
Gonzalez, Adam M., Jeremy R. Townsend, Anthony G. Pinzone, and Jay R. Hoffman. Supplementation with Nitric Oxide Precursors for Strength Performance: A Review of the Current Literature. Nutrients (2023). https://www.mdpi.com/2072-6643/15/3/660
Davi Vieira Teixeira da Silva, Carlos Adam Conte-Junior, Vânia Margaret Flosi Paschoalin, Thiago da Silveira Alvares, and others. Hormonal response to L-arginine supplementation in physically active individuals. Nutrición Hospitalaria (2014). https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3967014/
A. K. Sikora, A. Ryszewska-Pokraśniewicz, and M. W. Majewski. The Effectiveness of L-arginine in Clinical Conditions Associated with Endothelial Dysfunction. International Journal of Molecular Sciences (2021). https://www.mdpi.com/1422-0067/22/10/5118
