Supplement analysis backed by scientific evidence · PT

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Moderate evidenceHeart & metabolic

Alpha-Lipoic Acid

Alpha-lipoic acid has genuine, replicated evidence for reducing the symptoms of diabetic peripheral neuropathy at 600 mg/day, where it is an approved treatment in some countries. Its popular use as a weight-loss or general antioxidant supplement is not supported — the pooled weight effect is under 1 kg.

What the science says

  • Reduces symptoms of diabetic peripheral neuropathy Moderate evidence

    The SYDNEY 2 trial randomised 181 patients to oral ALA 600, 1200 or 1800 mg/day or placebo for 5 weeks. Total Symptom Score fell 4.9 points (51%) at 600 mg versus 2.9 points (32%) on placebo, with response rates of 62% versus 26%. Higher doses added no extra benefit but caused more nausea, vomiting and vertigo, making 600 mg/day the best risk-benefit dose.

  • Symptom relief is clearer than disease modification Limited evidence

    Benefits are consistently seen on patient-reported pain, burning and paraesthesia scores. Objective measures — nerve conduction velocity and neuropathic impairment — improve much less reliably, and longer trials have not convincingly shown that ALA slows progression of the underlying neuropathy.

  • Weight loss Limited evidence

    A meta-analysis of 12 placebo-controlled trials found ALA reduced body weight by just 0.69 kg (95% CI -1.27 to -0.10) and BMI by 0.38 kg/m², with no significant effect on waist circumference. These are statistically significant but clinically meaningless changes; ALA is not a weight-loss agent.

  • Glycaemic and antioxidant markers Limited evidence

    Trials report small improvements in insulin sensitivity and in oxidative stress markers such as malondialdehyde, but these are surrogate endpoints in short, small studies. No trial has shown that ALA improves hard clinical outcomes in diabetes.

Dosage & safety

Studied dose600 mg/day of racemic alpha-lipoic acid is the evidence-based dose for neuropathic symptoms, taken on an empty stomach roughly 30 minutes before a meal since food reduces absorption. Trials have used up to 1800 mg/day without extra benefit. Older European studies used 600 mg/day intravenously for 3 weeks. R-ALA is the biologically active isomer and is better absorbed, so roughly half the racemic dose is used.
SafetyNausea, vomiting and vertigo are dose-dependent and become common above 600 mg/day. Rash and urticaria occur occasionally. ALA can lower blood glucose, so people on insulin or sulfonylureas should monitor for hypoglycaemia. A rare but well-documented risk is insulin autoimmune syndrome (hypoglycaemia from anti-insulin antibodies), reported mainly in people of Japanese and Korean ancestry carrying HLA-DRB1*04:06. ALA chelates metals, so separate it from iron, calcium and magnesium supplements by several hours. Use caution in heavy alcohol use or thiamine deficiency, where thiamine should be repleted first. Safety in pregnancy is not established.

Scientific references

Where to buy

California Gold Nutrition, Alpha Lipoic Acid, 600 mg, 120 Veggie Capsules

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