In contrast to glutathione, NAC is efficiently transported into the cell where it is readily converted to L-cysteine for glutathione synthesis
Sep 2001;131(9):2300-2303
Also, GH has been shown to increase muscle mass and strength after 3 years (Jorgensen et al., 1994) and after 1015 years (Elbornsson, Gotherstrom, Bosaeus et al., 2013, Gotherstrom, Elbornsson, Stibrant-Sunnerhagen et al., 2009) although no effect was detected on fiber type with 6 months of treatment on a different report (Cuneo, Salomon, Wiles et al., 1992)
2013 Mar;61(3):233-9.
Seek medical advice
It is important to note that only the oxidized forms of NAD (NAD + and NADP + ) were included in the comparative validation due to instability of reduced forms (NADH and NADPH) in MS analyses