Supplement research

Alpha Lipoic Acid

What is Alpha Lipoic Acid?

Lipoic acid is a mitochondrial co-factor. It is an antioxidant and is thought to have insulin-like effects.

Proposed Benefits of Alpha Lipoic Acid

Lipoic acid acts as an antioxidant and so protects the body against excessive free radical production. Lipoic acid may also help control blood glucose levels and is proposed to improve diabetic neuropathy.

Mechanism of Action of Alpha Lipoic Acid

The increased formation of reactive oxygen species (free radicals) in various tissues is often associated with strenuous physical exercise. These reactive oxygen species may be related to muscle damage and soreness. As lipoic acid is an antioxidant, it may reduce the formation of reactive oxygen species.

It has been suggested that as an antioxidant, alpha lipoic acid may be potentially used to treat diseases with excessive oxidant stress.

It is  proposed that alpha-lipoic acid prevents or improves nerve conduction attributes, endoneural blood flow and nerve ATPase activity in experimental diabetes and so in humans may improve positive neuropathic sensory symptoms.

Research on Alpha Lipoic Acid

In vitro (studies in the laboratory rather than the human body) studies have shown that alpha lipoic acid enhances the antioxidant defences and the function of endothelial cells (1).

Animal studies have suggested that alpha lipoic acid acts as a hypoglycaemic agent and so may improve glucose utilisation in individuals with diabetes.

Several human clinical trials have assessed the therapeutic efficacy and safety of alpha-lipoic acid in diabetic neuropathy. The studies have used a variety of different study designs with varying treatment dose, duration, sample size and patient populations. Studies showing a benefit used at least 600mg of alpha-lipoic acid (2). The effects on symptoms was accompanied by improvement of neuropathic deficits. Oral treatment for 4-7 months tended to reduce neuropathic deficits and improve cardiac autonomic neuropathy. Some preliminary data suggest that over 2 years there is possible long-term improvements in motor and sensory nerve conduction in the lower limbs.

A 2003 double-blind placebo controlled study has assessed the efficacy and safety of alpha lipoic acid in a group of 120 stable diabetics with symptomatic diabetic sensorimotor polyneuropathy (3). In this study it should be noted that alpha-lipoic acid was administered intravenously (600mg/day). A Total Symptom Score, which is measure of positive neuropathic sensory symptoms was used as an assessment tool. After 14 treatments, the total symptom score of the alpha-lipoic acid group improved significantly, as compared to the placebo group. The  authors of this study reported that intravenous alpha-lipoic acid, which is a potent antioxidant, rapidly and to a significantly and meaningful degree, improved positive neuropathic sensory symptoms such as pain. The improvement was attributed to improved nerve pathophysiology.

Currently there is a long-term multi-centre trial of the oral treatment with alpha-lipoic acid to investigate the progression of diabetic polyneuropathy using clinically meaningful and reliable primary outcome measures that combines clinical and neurophysiological assessment. The results of this study will be useful for the future clinical recommendations for alpha-lipoic acid.

Rating of Efficacy for Alpha Lipoic Acid

7/10

References

1. Jones W., Li X., Qu Z.C., Perriott L., Whitesell R. and May J.M. Uptake, recycling, and antioxidant actions of alpha-lipoic acid in endothelial cells. Free Radical Bio & Med. 33:83-93, 2002.
2. Ziegler D., Reljanociv M., Mehnert H. and Gries F.A. Alpha-lipoic acid in the treatment of diabetic polyneuropathy in Germany: current evidence from clinical trials. Exper & Clin Endocrin & Diabetes. 107:421-430, 1999.
3. Ametov A.S., Barinov A., Dyck P.J., Hermann R., Kozlova N., Litchy W.J., Low P.A., Nehrdich D., Novosadova M., O'Brien P.C., Reljanociv M., Samigullin R., Schuette K., Strolov I., Tritschler H.J., Wessel K., Yakhno N., Ziegler D. and SYDNEY Trial Study Group. The sensory symptoms of diabetic polyneuropathy are improved with alpha-lipoic acid: the SYDNEY trial. Diabetes Care. 26:770-776, 2003.