| Common name | Alpha Lipoic Acid (ALA) |
| IUPAC name | (R)-5-(1,2-dithiolan-3-yl)pentanoic acid (R-ALA); (±)-form for racemic |
| Synonyms | Thioctic acid; 1,2-Dithiolane-3-pentanoic acid; DL-6,8-Thioctic acid |
| CAS number (Racemic) | 1077-28-7 |
| CAS number (R-ALA) | 1200-22-2 |
| Molecular formula | C₈H₁₄O₂S₂ |
| Molecular weight | 206.32 g/mol |
| Purity (HPLC) | ≥99% (RS-ALA); ≥98% (R-ALA) |
| Appearance | Yellow crystalline powder (RS-ALA); yellow fine powder (R-ALA) |
| Solubility | Slightly soluble in water; soluble in ethanol, acetone, DMSO |
| Melting point | 60–62°C (RS-ALA); 47–48°C (R-ALA) — process at <35°C for R-ALA |
| Mesh size | 40–80 mesh |
| Moisture (LOD) | NMT 0.5% |
| Ash content | NMT 0.1% |
| Heavy metals | NMT 10 ppm; Lead NMT 0.5 ppm |
| Microbial limits | TPC NMT 1,000 CFU/g; Salmonella and E. coli absent |
| Optical rotation (R-ALA) | [α]D²⁵ = −11° to −14° (c=1, ethanol) — confirms R-enantiomer |
| Light sensitivity | Sensitive — use amber/opaque packaging; avoid UV exposure |
| Storage | Cool, dry, away from light; 15–20°C; sealed. R-ALA: refrigerate at 2–8°C |
| Shelf life | 24 months from manufacture (sealed); 18 months for R-ALA (sealed, cool) |
| Regulatory | GRAS status (USA); Kosher/Halal available; EU Novel Food — check jurisdiction |
Every ALA batch is tested by HPLC for purity, with optical rotation verification for chiral form confirmation on R-ALA grades. Heavy metals and microbial safety verified before export.
Every batch confirmed at ≥99% for RS-ALA or ≥98% for R-ALA by HPLC. Full analytical data in COA with each shipment.
R-ALA batches include optical rotation testing confirming the R-enantiomer. Buyers receive confirmation of the naturally-occurring chiral form.
Lead, mercury, arsenic, cadmium tested per USP limits. Pesticide residues screened to EU MRL standards before export clearance.
ALA is photosensitive. All grades are packaged in amber or opaque aluminium foil under nitrogen atmosphere to prevent degradation.
The most common buyer mistake with Alpha Lipoic Acid is treating all ALA as equivalent. The racemic mixture (RS-ALA) is not the same as pure R-ALA in terms of bioavailability, enzyme cofactor activity, or per-milligram clinical effect. Understanding the three forms — and the practical trade-offs between them — is essential for formulating a product that delivers on its label claims.
The table below compares the three forms across the specifications that matter most for supplement and nutraceutical formulators: solubility, stability, commercial availability, typical cost position, and formulation implications.
| Parameter | Racemic ALA (RS-ALA) | R-Alpha Lipoic Acid (R-ALA) | Sodium R-Lipoate (Na-R-ALA) |
|---|---|---|---|
| CAS Number | 1077-28-7 | 1200-22-2 | 176110-81-5 |
| Chiral composition | 50% R-form + 50% S-form | ≥99% R-enantiomer | ≥99% R-enantiomer (Na salt) |
| Bioavailability | Moderate — R fraction absorbed; S fraction partially inhibits R uptake | High — pure R-form, ~2× blood AUC vs. RS-ALA at equal dose | Highest — ionised form absorbs rapidly; superior Cmax |
| Enzyme cofactor activity | Partial — only R-fraction active in mitochondrial complexes | Full — direct cofactor for pyruvate dehydrogenase and α-KGDH | Full — same as R-ALA after de-sodiation in vivo |
| Thermal stability | Good — melting point 60–62°C; suitable for granulation and tableting | Poor — melting point 47–48°C; polymerises above MP; cannot be granulated hot | Good — sodium salt raises MP significantly; stable under normal processing |
| Commercial availability | Widely supplied; the standard commercial grade | Available; specified in higher-priced formats | Available as the stabilised salt |
| Typical dose in supplements | 300–600mg/day | 150–300mg/day | 150–300mg/day (as Na-R-ALA) |
| Cost position | Lowest — most economical per gram | Medium-high — 2–3× RS-ALA cost | Medium-high — similar to R-ALA |
| Best for | Budget-conscious mainstream supplements; products citing clinical RS-ALA studies | Premium capsules; 'natural form' label claims; cool-processed formulations | Premium capsules/tablets requiring standard processing; highest bioavailability positioning |
Supplied as a bulk ingredient for further manufacture. Buyers are responsible for compliance with the regulations of their destination market. This product is not intended to diagnose, treat, cure or prevent any disease.