R-alpha lipoic acid (R-ALA) supplementation improves blood glucose in diabetic animals, but there have been no long-term clinical trials in humans testing its use for glucose control (HbA1c). This double-blind study pre-/post-test control group (PL) design sought to determine the effect of R-ALA on HbA1c. Twenty type-2 diabetics were randomly assigned to 200 mg capsules of R-ALA (n=13; 8M 5F) or PL (n=7; 2M 5F) 3 times daily, 30 minutes before meals (600 mg total) for 91 days. Samples were obtained for HbA1c at baseline and day 91. No significant differences between R-ALA and PL groups were found at baseline or day 91. However, three distinct reactions to the supplement were noted. The first group (n=3) responded to R-ALA with a >25% drop in HbA1c range from 6.1-12.5 to 6.2- 9.0 mg/dL and/or halved their anti-diabetic medication. The second group (n=5) had no change in HbA1c. The third group (n=5) had changes in medication or concurrent chronic adverse events that should have raised HbA1c, but did not beyond that of the placebo. Conclusions: Three months of R-ALA supplementation may lower HbA1c in a small number of individuals. However, to further confirm these findings, larger studies of longer duration are needed.
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