Spermidine Promotes Human Hair Growth and Is a Novel Modulator of Human Epithelial Stem Cell Functions

In 2011, a study found that spermidine, a polyamine, can stimulate human hair growth and modulate human epithelial stem cell functions. The research involved experiments on human scalp hair follicles and human hair follicle epithelial stem cells. The results showed that spermidine promoted hair shaft elongation and prolonged hair growth. It also upregulated the expression of keratins K15 and K19, which are associated with epithelial stem cells. Spermidine was found to modulate K15 promoter activity and increase the colony forming efficiency, proliferation, and K15 expression of isolated human K15-GFP+ cells. The study also found that spermidine upregulated several key target genes implicated in the control of cell adherence and migration, or endoplasmic reticulum and mitochondrial functions. The study concluded that spermidine may help to counteract multiple forms of hair loss associated with excessive hair shedding and deserves rigorous clinical testing as a candidate anti-hair loss agent.