Most people get enough vitamin B12 in their diet, but a deficiency may occur in certain health conditions (such as poor nutrition, stomach/intestinal problems, infection, cancer)
NAC provides cysteine, which is the rate-limiting amino acid in glutathione synthesis
It neutralizes free radicals that can cause oxidative damage to cells, which is a leading factor in the aging process and the development of age-related diseases
Kostyuk VA, Potapovich AI, Cesareo E, Brescia S, Guerra L, Valacchi G, Pecorelli A, Deeva IB, Raskovic D, De Luca C, Pastore S, Korkina LG (2010) Dysfunction of glutathione S-transferase leads to excess 4-hydroxy-2-nonenal and H 2 O 2 and impaired cytokine pattern in cultured keratinocytes and blood of vitiligo patients
Am J Clin Pathol 111(6):733-40, 1999
Visible results in just a few weeks, with significant hair growth improvements observed after 3 months of consistent usage