References: VITAMIN B9

Studies and references:

https://nutriandco.com/fr/pages/vitamine-b9-benefits#:~:text=The%20benefits%20for%20hair%20and%20brighter%20hair&text=Vitamin%20B9%20favorites%20the,more%20dense%20and%20more%20brilliant.

https://www.centre-clauderer.com/chute-cheveux/acide-folique-cheveux/ #:~:text=However, although the acid does not have an effect on regrowth.