I remebered reading that a racemic mix might be better , but I think I originally read it on a 'dot.com' site , so I gave it less credence since they were trying to sell product. But a cursory look provided this input:
" It has been hypothesized that R-ALA would be the most appropriate form of commercial supplement; however, it is prone to polymerization and is absorbed to an even lower extent than racemic-ALA. As a matter of fact, it has been demonstrated that the presence of the S-enantiomer in the racemic mixture prevents the polymerization of R-ALA to some extent, increasing its bioavailability [6]. For this reason, the best nutraceuticals or food supplements available on the market are represented by highly pure forms of food-grade racemic ALA in order to keep the polymer content at a low level ensuring stability over time and optimal absorption. These products are often available in various forms such as fine powder for softgel formulations or ready-to-use granules for tablet preparations."
https://pmc.ncbi.nlm.nih.gov/articles/PMC6723188/