It is generally assumed that this is because insulin increases glucose uptake into tissues. (jissn.biomedcentral.com)
RESULTS: In L6 muscle cells, short - term incubations (2 - 12 h) with 10 -LRB--3) m alpha - lipoic acid increased glucose uptake by 40 - 80 %, approximately the same extent as 10 -LRB--6) m insulin. (chiro.org)
The alpha - lipoic acid also increased glucose uptake in red quadriceps (approximately 300 %, p < 0.01) from ob / ob mice without added insulin. (chiro.org)