Based on a common mechanism of action with gabapentin, we investigated the effects of L-methionine on hot flashes in postmenopausal women.
After a 1 week baseline period, 51 postmenopausal women experiencing at least 5 moderate-severe hot flashes per day were randomized to 1 of 3 groups in a 13:13:25 ratio: placebo/placebo, placebo/L-methionine, or L-methionine/L-methionine, respectively (Phase 1/Phase 2). Phase 1 was 12 weeks long and Phase 2 was 8 weeks long. Subjects took 1g po bid in Phase 1 and 2g po bid in Phase 2 of either L-methioinine or placebo. All subjects also took folate 1mg and methylcobalamin 0.5mg a day to help minimize the L-methionine-induced elevation in serum homocysteine. The primary outcome variable was the percent change in hot flash composite score from baseline to Week 12 obtained from subjects’ daily hot flash diaries.
In Phase 1 and Phase 2, there were no significant differences between the L-methionine and placebo groups for any of the hot flash outcome measures. At Week 12, there was a mean 37.4% decrease in hot flash composite score compared to baseline in the L-methionine group and a mean 33.4% decrease in the placebo group (p = 0.60). There were expected significant increases in fasting serum homocysteine (1.7 and 5.8 µmol/L) and fasting serum methionine (13.9 and 22.3 µmol/L) at Weeks 12 and 20, respectively, associated with the 2 dosages of L-methionine therapy relative to placebo therapy.
L-methionine therapy appears to be ineffective in the treatment of hot flashes in postmenopausal women.
Keywords: hot flashes, clinical trial, methionine, amino acid, menopause, homocysteine