Alpha-lipoic acid
Summary
Alpha-lipoic acid is best studied in diabetic nerve symptoms: a pooled analysis of 10 oral trials found less burning, stabbing and numbness (grade A), though a 4-year trial missed its main nerve-function goal. Weight loss was about 1.3 kg more than placebo. Nausea rises with dose.
Key facts
How it works
ProposedLipoic acid is a cofactor for mitochondrial enzymes such as pyruvate dehydrogenase. As a supplement it is proposed to reduce oxidative stress and improve nerve blood flow.[1]
What the human research says
Human trials only, one row per outcome. The form column shows what each trial actually tested. Grades follow our evidence-grading policy.
At a glance: strongest evidence per outcome
| Outcome | Grade | Effect | Strongest evidence | Rows |
|---|---|---|---|---|
| Nerve symptoms | Grade A | Improved | Meta-analysis of 10 trials · n = 1,242 · 2023 | 2 rows |
| Metabolic markers | No effect | No effect | Meta-analysis of 11 trials · n = 704 · 2025 | 1 row |
| Nerve function | No effect | No effect | RCT · n = 460 · 2011 | 1 row |
Every graded row
| Outcome | Effect | Grade | Best evidence | PMID |
|---|---|---|---|---|
| Diabetic nerve symptom scores | Improved | Grade A | Meta-analysis · n = 1,242 · 2023 Adults with diabetic sensorimotor polyneuropathy in 10 RCTs Form: Oral alpha-lipoic acid · Dose: 600–1,800 mg/day · Duration: Varied across trials Total symptom score and global satisfaction improved versus placebo with a dose-related trend; vibration threshold, nerve conduction and NIS-LL did not improve. | 37630823 (opens PubMed)Source [1] |
| Burning, stabbing pain and numbness of the feet | Improved | Grade B | RCT · n = 181 · 2006 Adults with diabetes and distal symmetric polyneuropathy Form: Alpha-lipoic acid · Dose: 600, 1,200 or 1,800 mg once daily · Duration: 5 weeks Symptom scores fell more with all three doses than placebo; 600 mg gave the best balance because nausea, vomiting and vertigo rose with dose. | 17065669 (opens PubMed)Source [2] |
| Cholesterol, triglycerides and glucose markers in overweight adults | No effect | No effect | Meta-analysis · n = 704 · 2025 Adults with BMI ≥25 in 11 RCTs Form: Alpha-lipoic acid · Dose: Varied across trials · Duration: Varied across trials No significant change in triglycerides, cholesterol, HOMA-IR or fasting glucose. | 40180416 (opens PubMed)Source [5] |
| Nerve function composite over 4 years | No effect | No effect | RCT · n = 460 · 2011 Adults with mild to moderate diabetic polyneuropathy Form: Alpha-lipoic acid · Dose: 600 mg/day · Duration: 4 years The primary composite of nerve tests did not differ from placebo; some secondary impairment scores favoured lipoic acid. | 21775755 (opens PubMed)Source [3] |
Forms
| Form | Elemental % | Absorption (human data) | GI tolerance | Studied for |
|---|---|---|---|---|
| Racemic alpha-lipoic acid (R/S) | Varies | Most trials cited here used standard alpha-lipoic acid; no head-to-head human outcome data versus R-lipoic acid in these sources. | Nausea, vomiting and vertigo rose with dose from 600 to 1,800 mg/day.[2] | Most nerve-symptom and weight trials |
| R-lipoic acid (R-ALA, sodium R-lipoate) | Varies | The natural form; no outcome trials comparing it with the racemic form are cited here. | No separate tolerance data in the sources cited here. | Marketed as the natural form |
Studied doses
Doses studied in human trials ranged from 600 mg/day for 4 years to 1,200–1,800 mg/day for 5 weeks; older trials gave 300–600 mg/day intravenously for 2–4 weeks.[3][2][6]
Interactions
Published interactions only: each row cites a source. No row means none was found in our sources, not that a combination is safe.
Medicines
- Diabetes medicinesReviewTrials enrolled people with diabetes on their usual treatment; the 2017 weight analysis and nerve trials did not report hypoglycaemia, but glucose effects could add to these medicines.[4]
Who should be careful
- Sensitive stomach
- Nausea and vomiting increased at 1,200–1,800 mg/day.[2]
- Pregnancy and breastfeeding
- The trials cited here did not enrol pregnant or breastfeeding people.[1]
Talk to your pharmacist or clinician before starting a supplement, especially if you take prescription medicines.
Where to buy Alpha-lipoic acid
Products from brands we partner with that contain Alpha-lipoic acid. Listing a product is not a claim that it works; check the amount per serving against the doses studied above, and the label for other ingredients.
- SupersmartPaid linkAlpha Lipoic Acid2 capsules: 500 mg alpha-lipoic acid (250 mg per capsule); 30 servingsShop at Supersmart (opens in new tab)Price and label checked 2026-10-11 on the brand’s site.
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Frequently asked questions
Does alpha-lipoic acid help diabetic nerve pain?
Pooled trials found better symptom scores, especially at higher doses, but nerve conduction tests did not improve and a 4-year trial missed its main goal.[1][3]
What dose was best in trials?
In a 5-week trial, 600 mg once daily worked about as well as 1,200–1,800 mg with fewer stomach side effects.[2]
Does it help with weight loss?
Pooled trials found about 1.3 kg more weight loss than placebo, a small effect.[4]
Is R-lipoic acid better?
R-lipoic acid is the natural form, but the trials cited here mostly used standard lipoic acid and none compared outcomes head to head.
Sources
- [1]Effects of Oral Alpha-Lipoic Acid Treatment on Diabetic Polyneuropathy: A Meta-Analysis and Systematic Review.. Nutrients, 2023. meta-analysis
- [2]Oral treatment with alpha-lipoic acid improves symptomatic diabetic polyneuropathy: the SYDNEY 2 trial.. Diabetes Care, 2006. RCT
- [3]Efficacy and safety of antioxidant treatment with α-lipoic acid over 4 years in diabetic polyneuropathy: the NATHAN 1 trial.. Diabetes Care, 2011. RCT
- [4]Alpha-lipoic acid (ALA) as a supplementation for weight loss: results from a meta-analysis of randomized controlled trials.. Obes Rev, 2017. meta-analysis
- [5]Alpha-lipoic acid on intermediate disease markers in overweight or obese adults: a systematic review and meta-analysis.. BMJ Open, 2025. meta-analysis
- [6]A systematic review and meta-analysis of α-lipoic acid in the treatment of diabetic peripheral neuropathy.. Eur J Endocrinol, 2012. meta-analysis
What changed
- Corrected the effect arrow (↑ improved, ↓ worsened for participants) on: Diabetic nerve symptom scores; Burning, stabbing pain and numbness of the feet.
- First draft. Every PMID checked against NCBI E-utilities (title, journal and year taken from the PubMed record) and each evidence row written from its PubMed abstract.