Rinaldi, Fabio, Barbara Marzani, Daniela Pinto, and Yuval Ramot. “A Spermidine-Based Nutritional Supplement Prolongs the Anagen Phase of Hair Follicles in Humans: A Randomized, Placebo-Controlled, Double-Blind Study”. Dermatology Practical & Conceptual 7, no. 4 (October 31, 2017): 17–21. Accessed March 25, 2025. https://dpcj.org/index.php/dpc/article/view/dermatol-pract-concept-articleid-dp0704a05.