That decline is part of why it's drawn research interest in the first place: if a molecule occurs naturally and its levels drop as tissue repair capacity drops, it becomes a reasonable candidate for studying repair signaling directly
Methylenetetrahydrofolate (MTHFR), the One-Carbon Cycle, and Cardiovascular Risks
Our research library covers it properly, including the studies that found increased slow-wave sleep and the ones that found no effect or the opposite, and I would rather send you there than summarise a split literature in a paragraph on a product page
10.1093/hmg/ddaa077 Hum
Hair Growth and Follicle Health Hair follicles are highly dynamic structures that cycle through growth and rest phases
Xu X, Cao J, Mu Y, Zhang H, Wang Y L, Chen M, Li Y, Hua Q