Racemic alpha-lipoic acid (R,S / DL / thioctic acid) vs. Sodium R-lipoate (Na-R-ALA, stabilized R-lipoic acid)
Among 307 on-market alpha-lipoic acid products with an identifiable primary form, 20.5% use Racemic alpha-lipoic acid (R,S / DL / thioctic acid) (63 products) and 17.9% use Sodium R-lipoate (Na-R-ALA, stabilized R-lipoic acid) (55).
| Racemic alpha-lipoic acid (R,S / DL / thioctic acid) | Sodium R-lipoate (Na-R-ALA, stabilized R-lipoic acid) | |
|---|---|---|
| Quality tier | Unrated | Unrated |
| Alpha-Lipoic Acid by weight | — | — |
| Share of market | 20.5% | 17.9% |
| On-market products | 63 | 55 |
| Median declared dose | 120 mg middle half: 50–300 | 150 mg middle half: 50–200 |
| Most common brands | Pure Encapsulations, Genestra Brands, Bluebonnet | Blue Star Nutraceuticals, Universal, SuperSmart |
Doses are declared per serving in mg. “By weight” is the share of the ingredient that is the nutrient itself (e.g. elemental magnesium in a magnesium salt).
Why Racemic alpha-lipoic acid (R,S / DL / thioctic acid) is unrated
Equal mix of the natural R and the S enantiomer. Human comparisons with R-ALA are small: in a randomized crossover in 20 people with progressive MS, 600 mg R-LA gave R-LA AUC and Cmax bioequivalent to 1,200 mg racemic R,S-LA with fewer GI side effects (Cameron 2020); a pilot found variable, age-dependent differences (Keith 2012). No outcome trial compares the forms, so it is not ranked. The pharmaceutical (thioctic acid) tablet form also has PK data (Hermann 2014).
Source: Hermann R et al. 2014, Clin Pharmacol 6:195-204, PMID 25506250; Cameron M et al. 2020, J Clin Pharmacol 60(8):1099-1106, PMID 32212340; Keith DJ et al. 2012, Pharmacol Res 66(3):199-206, PMID 22609537
Why Sodium R-lipoate (Na-R-ALA, stabilized R-lipoic acid) is unrated
One small (n=12) PK study, from the lab that had run the earlier preliminary study, reported significantly higher Cmax and AUC and shorter Tmax for the sodium salt than for R-lipoic acid or racemic ALA, but the comparison extends an earlier preliminary study, and no outcome trials exist -- insufficient to rank. Salt weight is ~10% above acid weight; labels usually declare acid equivalents, so amounts are used as declared.
Source: Carlson DA et al. 2007, Altern Med Rev 12(4):343-351, PMID 18069903