Alpha-lipoic acid

Alpha-lipoic acid (ALA) is a chemical compound naturally found in the human body. It exists in two chemical forms, R-ALA and L-ALA, although only R-ALA is naturally found in the human body, in a protein-bound form. It has sometimes been touted as an "antioxidant", or a "chelator", although the biochemical context in which it naturally operates is much more complex than a simple solvated antioxidant or chelator. In its natural biochemical context, it serves as an important cofactor for many mitochondrial enzyme complexes. In particular, it serves as a necessary cofactor for mitochondrial α-ketoacid dehydrogenases, performing a critical role in mitochondrial energy metabolism. ALA in food sources is protein-bound, just as in the human body, which limits its ability to increase free-form ALA plasma levels upon ingestion.

Alpha-lipoic acid is a cofactor for some of the key enzymes (alpha-keto acid dehydrogenase, pyruvate dehydrogenase, etc) involved in generating energy from food and oxygen in mitochondria and thus plays a critical role in energy production within the cell’s mitochondria. Since one theory of CFS/ME is mitochondria dysfunction, supplementation may aid in energy production and reduce fatigue. Co-administration of ALA with other mitochondrial nutrients, such as acetyl-L-carnitine and coenzyme Q10, appears more effective in improving cognitive dysfunction and reducing oxidative mitochondrial dysfunction.

Uses
In Germany lipoic acid has long been prescribed for diabetic neuropathy, cirrhosis, and mushroom and heavy metal poisonings.

Lipoic acid can be administered intravenously. Supplemental oral ALA is 30-40% absorbed from the gastrointestinal tract. Supplemental forms often comprise a 50-50 mixture of R- and S-lipoic acid enantiomers. The R-form is better absorbed. Liquid formulas are also better absorbed.

Side Effects
Supplementing ALA can result in nausea, malodorous urine, headache, weakness, pain, spasm, and rash. Side effects are more commonly seen it higher doses. It may interact with diabetic medications to cause hypoglycemia.

Diabetic Neuropathy
Meta-analyses of randomized controlled trials suggest that infusion of 300 to 600 mg/day of lipoic acid for 2 to 4 weeks significantly reduced symptoms of diabetic neuropathy. A randomized, double-blind, placebo-controlled trial in 181 patients with diabetic neuropathy found that oral supplementation with either 600 mg/day, 1,200 mg/day, or 1,800 mg/day of lipoic acid for 5 weeks significantly improved neuropathic symptoms. There was no difference between the low, moderate or high dose groups. Improvements in neuropathy from these trials are not always corroborated with electrodiagnostic testing. It is thought, that the beneficial effects of ALA on neuropathy may be due to effects on the small nerve fibers, making it a candidate treatment for small fiber neuropathy.

Multiple Sclerosis
A small pilot study designed to evaluate the safety of lipoic acid in 30 people with relapsing or progressive multiple sclerosis found that treatment with 1,200 to 2,400 mg/day of oral lipoic acid for 2 weeks was safe. Those with the higher serum concentrations of lipoic acid had the lowest serum concentrations of MMP-9 — a marker of inflammation. A 2-year trial of 1,200 mg/day LA in secondary progressive MS demonstrated a significant reduction of whole-brain atrophy and trend toward improvement in walking speed.