Betaine Anhydrous — the direct methyl donor form (not Betaine HCl, which is a digestive acid support and does not provide BHMT-pathway methyl-donor activity). Donates three methyl groups directly to homocysteine via the BHMT enzyme, converting it to methionine and then SAMe. This pathway operates in liver, kidney, intestine, and adipose tissue, functioning independently of folate and B12. Critical relief valve when the primary folate/B12 methylation cycle is impaired or overwhelmed by genetic variants (MTHFR, MTR, MTRR). Also improves the SAM:SAH ratio — the operative measure of global methylation efficiency — by shifting equilibrium away from SAH accumulation.