Dietary supplement S-adenosyl-L-methionine (AdoMet) effects on plasma homocysteine levels in healthy human subjects: a double-blind, placebo-controlled, randomized clinical trial.

Double-blind, placebo-controlled, randomized clinical trial at Mayo Clinic in Rochester, Minnesota, United States. Healthy adult volunteers aged 18 to 65 years were enrolled; the active AdoMet arm included 26 participants, with 26 assigned to placebo.

S-adenosyl-L-methionine (AdoMet) was given at 800 mg/day for 4 weeks, in tablet form, compared with placebo. Each tablet contained 400 mg AdoMet; the route was not stated.

AdoMet did not significantly change plasma homocysteine compared with placebo and was generally well tolerated. In the AdoMet arm, homocysteine was 8.3 at baseline, 8.8 at week 2, and 8.2 at week 4; between-group p-values for homocysteine were 0.18 at baseline, 0.26 at week 2, and 0.32 at week 4. The authors concluded that 800 mg/day for 4 weeks did not meaningfully affect homocysteine, inflammation, or lipid markers, aside from minor changes in ALT and total cholesterol.

Small sample size, short 4-week duration, and enrollment of healthy volunteers limit generalizability. The single-center design and absence of a route statement also reduce interpretability, and the available outcomes were limited mainly to homocysteine and a few safety and laboratory markers.