Disclaimer: This article is for informational purposes only and should not be considered medical advice. Always consult a healthcare professional or a registered dietitian before making significant changes to your diet or starting any supplementation.

The nutrient lipoic acid, also known as alpha-lipoic acid (ALA), functions as an antioxidant and as a cofactor for mitochondrial enzyme complexes involved in energy production. Interest in ALA has grown due to clinical research supporting its use in diabetic neuropathy and its antioxidant properties. This article reviews the biological roles of ALA, dietary and supplemental sources, and practical considerations for maintaining adequate levels.

ALA’s dual solubility in water and fat enables it to participate in multiple cellular processes, including neutralizing reactive oxygen species and supporting mitochondrial enzyme activity. Understanding these mechanisms can help inform dietary and supplementation strategies.

Role in the Body

Specific Functions

ALA serves as a cofactor for mitochondrial enzyme complexes such as pyruvate dehydrogenase and α-ketoglutarate dehydrogenase, which are involved in converting carbohydrates and fats into adenosine triphosphate (ATP). By participating in these reactions, ALA contributes to cellular energy production and metabolic flexibility.

As an antioxidant, ALA can directly scavenge reactive oxygen species (ROS). In laboratory studies, ALA has been shown to support the recycling of endogenous antioxidants including glutathione, vitamin C, and vitamin E, which helps maintain cellular redox balance.

Effects of Deficiency

Overt ALA deficiency in humans is rare because the body synthesizes small amounts. Animal studies indicate that inadequate ALA can impair mitochondrial enzyme activity and increase oxidative stress. In individuals with type 2 diabetes, lower antioxidant capacity and elevated markers of oxidative damage have been observed, and supplementation with ALA has been studied as an adjunct to standard care for diabetic neuropathy.

Dietary Sources

Best Food Sources

Endogenous synthesis of ALA provides only modest amounts, so dietary sources may help support overall status. Foods containing ALA include:

• Spinach—a leafy green providing small amounts of ALA plus vitamins
• Broccoli—contains ALA along with other phytochemicals
• Organ meats (liver, heart)—concentrated in ALA and B vitamins
• Potatoes—offer modest levels of ALA with carbohydrates and fiber
• Tomatoes—contain ALA alongside antioxidants such as lycopene

Supplementation

ALA supplements are available as racemic mixtures (R- and S-isomers) or as the R-isomer alone. Clinical trials in patients with diabetic neuropathy commonly use 600 mg of oral ALA daily. Some studies have evaluated doses up to 1,200 mg per day under medical supervision. The R-isomer is generally considered more bioavailable, though racemic preparations are widely used.

Health Benefits

Randomized controlled trials and meta-analyses have focused primarily on ALA’s effects in diabetic neuropathy and glycemic control:

• Diabetic neuropathy: Clinical trials using 600 mg of oral ALA daily have demonstrated improvements in symptoms of peripheral neuropathy, such as pain and paresthesia.
• Glycemic control: A meta-analysis in Diabetic Medicine (2019) found that 600–1,200 mg of ALA per day was associated with modest reductions in fasting blood glucose and HbA1c levels in patients with type 2 diabetes when added to standard therapy.

Evidence for cardiovascular or cognitive benefits is limited, and further well-designed clinical trials are needed to establish efficacy in these areas.

Daily Requirements

There is no established Recommended Dietary Allowance (RDA) for ALA. Typical dietary intake from food sources is estimated at 1–2 milligrams per day in Western diets. For clinical applications such as diabetic neuropathy, supplemental doses of 600 mg daily are commonly studied, with up to 1,200 mg used under professional supervision. Children, pregnant or breastfeeding women should consult healthcare providers before using supplements.

Tips for Incorporation

• Include leafy greens such as spinach or kale several times per week to support natural ALA intake.
• Rotate organ meats like liver into your meals periodically for concentrated sources of ALA and B vitamins.
• If using supplements, choose a reputable brand and follow dosage instructions consistent with clinical research.
• Maintain a balanced diet rich in vegetables, lean proteins, whole grains, and healthy fats to support overall antioxidant capacity.

Conclusion

Alpha-lipoic acid plays a role as a mitochondrial cofactor and antioxidant. Clinical evidence supports its use at doses of 600 mg per day for reducing symptoms of diabetic neuropathy and improving markers of glycemic control in type 2 diabetes. Dietary sources can provide small amounts, but supplements may be considered under medical guidance for specific conditions. Consult a healthcare professional for personalized recommendations.