Spermidine is a polyamine known to have antioxidant effects and to regulate cell apoptosis and senescence. It has been used in trichology for many years for the purpose of lengthening the anagen phase of the hair cycle, playing an important role in promoting follicular mitosis.
Spermidine, among other features, is also able to promote melanogenesis.
Specifically, it is known that Spermidine is involved not only in the stimulation of mitosis at the follicular level, but also has an important role in the prevention of cellular senescence.

Senescence is a cellular state in which the cell is no longer able to fulfill its physiological functions and perform mitosis and takes part in the normal process of cell apoptosis at a reduced rate. The state of senescence is correlated with DNA damage due to excessive cell duplications that have led to telomere consumption or due to chromatin alterations. Under physiological conditions, cells that are in a senescent state are consumed and destroyed by macrophages. The accumulation of senescent cells within an organ or tissue can impair its function and is strongly correlated with age: in fact, aged tissues tend to have a greater amount of senescent cells.

Spermidine’s role in the prevention of cellular senescence is also particularly important in maintaining anagen and, probably, is also the cause of such anagenic activity since, as mentioned above, senescent cells are unable to proceed to mitosis and minimizing follicular senescence means maximizing mitosis and, therefore, hair production.

Specifically, Spermidine is a chemical normally also produced by our body, but whose production declines with age. It reduces damage by reactive oxygen species, promotes apoptosis, has an anti-inflammatory, improves mitochondrial function and, finally, moderates and reduces DNA damage by telomere consumption. (Wirth et al., 2021)