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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.

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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.

How to take it

TimingAbout 30 minutes before a meal; the 600 mg dose can be taken once daily.
With food?On an empty stomach — food noticeably reduces absorption.
Worth knowingIf you drink heavily or may be thiamine deficient, replete thiamine first; and be aware of the rare insulin autoimmune syndrome reported mainly in people of Japanese and Korean ancestry.

Interactions

With medications

  • insulin and sulfonylureas

    ALA lowers blood glucose and can cause hypoglycaemia on top of the drug. monitor glucose and tell your prescriber before starting

With other supplements

  • iron, calcium, magnesium and zinc

    ALA chelates metals, which reduces absorption of both the mineral and the ALA. separate by at least 3-4 hours

Well-established interactions only — this is not a complete list. Always tell your doctor and pharmacist what you take.

Frequently asked questions

Does alpha-lipoic acid help diabetic neuropathy?

Yes, for symptoms — alpha-lipoic acid has moderate evidence for easing burning, pain and tingling in diabetic peripheral neuropathy at 600 mg/day. In the SYDNEY 2 trial, 62% responded versus 26% on placebo, though ALA has not convincingly been shown to slow the underlying nerve damage.

Does alpha-lipoic acid help with weight loss?

No. A meta-analysis of 12 placebo-controlled trials found alpha-lipoic acid reduced body weight by just 0.69 kg — statistically significant but clinically meaningless, so the evidence for weight loss is limited.

How and when should I take alpha-lipoic acid?

Take 600 mg of alpha-lipoic acid once daily on an empty stomach, about 30 minutes before a meal, since food reduces absorption. Higher doses up to 1800 mg/day added no benefit and caused more nausea, vomiting and vertigo.

Can alpha-lipoic acid be taken with magnesium, iron or zinc?

Separate them: alpha-lipoic acid chelates metals, reducing absorption of both the mineral and the ALA, so space them at least 3-4 hours apart. If you take insulin or sulfonylureas, ALA can also lower blood glucose, so monitor for hypoglycaemia.

Scientific references

Where to buy

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

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