Alpha Lipoic Acid (ALA / thioctic acid)
Alpha-lipoic acid (also called ALA or thioctic acid) is a substance the body makes for itself and uses in the way cells turn food into energy. It is also found in tiny amounts in foods such as broccoli, spinach and red meat, and is sold as a food supplement. There is no UK-authorised health claim for alpha-lipoic acid: EFSA assessed the health-claim applications and did not substantiate them. The use it is best known for is easing the symptoms of diabetic nerve pain (diabetic peripheral neuropathy), but the studied product is a prescription pharmaceutical licensed in Germany — not a UK food supplement — and the best-quality review of the evidence found it probably makes little or no difference. This page describes what alpha-lipoic acid is, what people take it for, and what the UK guidance and the research actually say.
Camden Medicals editorial · Last reviewed 12 June 2026 · Next review June 2027
- Cross-checked against
- NHS
- NICE
- BNF
- EFSA
- FSA
Camden's own editorial team graded each health claim below on the strength of the published evidence — trials weighed with Cochrane RoB 2, systematic reviews with AMSTAR 2, under the CEGA method. See the grade beside every condition.
- Class
- Other
- Typical daily dose
- Diabetic peripheral neuropathy trial dose (Thioctacid®): 600 mg once daily oral. Higher doses (1200-1800 mg) showed similar efficacy but more GI side effects in SYDNEY-2. UK food supplement labels typically 100-600 mg/day.
- Top use evidence
- Mixed
On this page
What it is
Alpha-lipoic acid (ALA), chemically α-lipoic acid or thioctic acid, is a sulphur-containing organosulphur compound — a 6,8-dithiooctanoic acid — that the human body synthesises in mitochondria and uses as an essential cofactor for several oxidative-decarboxylation enzyme complexes (pyruvate dehydrogenase, α-ketoglutarate dehydrogenase, branched-chain amino acid dehydrogenase). In its endogenous role it is covalently bound (lipoamide); supplementation provides free ALA, which has different pharmacology.
ALA exists as two enantiomers: the naturally occurring R-(+)-α-lipoic acid (R-ALA) and the synthetic S-(–)-α-lipoic acid (S-ALA). Most commercial supplements are racemic R/S 50:50 mixtures, manufactured by total synthesis. R-ALA-only products and the more bioavailable sodium R-α-lipoic acid (Na-R-ALA) are sold at premium prices; the clinical-trial literature is mostly on the racemic mixture (because that is what the German pharmaceutical Thioctacid® delivers).
ALA is uncommon in food — small amounts in broccoli, spinach, kidney, heart, and tomato. Endogenous synthesis is generally adequate for the cofactor role; supplementation provides a pharmacological dose far above natural intake. The licensed clinical use of ALA in Germany and several other European countries is as a pharmaceutical preparation (Thioctacid®, Tioctacid®, Tialip®) for symptomatic relief of diabetic peripheral neuropathy — at oral doses of 600-1800 mg/day or by intravenous infusion in hospital settings.
At a glance
- No UK-authorised health claim. EFSA assessed the alpha-lipoic-acid health-claim applications (nerve protection, insulin sensitivity, blood glucose, blood cholesterol, protection of lipids from oxidative damage) and did not substantiate any of them. Marketing must stay descriptive.
- The use it is best known for is easing diabetic nerve-pain symptoms — but the studied product is the German prescription preparation (Thioctacid / Tioctacid), and the 2024 Cochrane review found alpha-lipoic acid probably makes little or no difference to neuropathy symptoms at six months.
- It can lower blood glucose, so it may add to the effect of insulin and sulphonylureas. If you take diabetes medicines, talk to your diabetes team before taking it and monitor your glucose.
- A rare reaction called insulin autoimmune syndrome (Hirata disease) has been reported with alpha-lipoic acid, mostly in people of Japanese or Korean background who carry the HLA-DRB1*04:06 gene.
What people use it for
Adults taking it for "antioxidant support" or "energy"
Alpha-lipoic acid is widely sold for general "antioxidant" or "energy" support; the current evidence does not support these uses. There is no UK-authorised health claim. EFSA assessed the application that dietary alpha-lipoic acid protects body lipids from oxidative damage and did not substantiate it — the proposed cause-and-effect relationship was not established. UK descriptions must stay factual (a substance the body makes and uses in energy metabolism, present in small amounts in food) rather than effect-claiming.
Popular, not provenInsufficientPeople with diagnosed diabetic peripheral neuropathy
Alpha-lipoic acid is taken by some people for the symptoms of diabetic nerve pain; the evidence is genuinely mixed and the studied product is a prescription pharmaceutical, not a UK food supplement. Short-term trials such as SYDNEY-2 (Ziegler 2006) reported improved neuropathy symptoms over 5 weeks, but the 2024 Cochrane review — the most rigorous synthesis — concluded that alpha-lipoic acid probably makes little or no difference to neuropathy symptoms at six months. The four-year NATHAN-1 trial did not meet its primary endpoint. NICE and the NHS do not recommend alpha-lipoic acid for this use; first-line options for diabetic nerve pain are medicines such as duloxetine, amitriptyline, gabapentin or pregabalin. Anyone with diabetic neuropathy should discuss management with their GP or diabetes team rather than self-supplementing. [7,8,9]
Popular, not provenMixedPeople with diabetes (without neuropathy) looking at it for blood-sugar effects
Alpha-lipoic acid is sometimes discussed for blood-sugar control; the evidence does not support it as a stand-alone measure and there are safety reasons for caution. It may modestly lower glucose, but it does not replace prescribed diabetes therapy, it can add to the glucose-lowering effect of insulin or sulphonylureas, and EFSA did not substantiate the blood-glucose and insulin-sensitivity claims it assessed. Diabetes UK advises that supplements have no clear benefit for managing diabetes unless a deficiency or a clinician directs their use. Anyone with diabetes considering it should talk to their diabetes team and monitor glucose closely.
Popular, not provenInsufficientPeople looking at it for weight loss
Alpha-lipoic acid is sometimes promoted for weight loss; the evidence does not support this use and no claim is permitted. Some small, short-term trials report modest weight reduction, but the findings are heterogeneous and not recognised by UK or EU regulators. It is not a weight-loss treatment and UK marketing cannot make weight-loss claims for it.
Popular, not provenInsufficient
How it works
ALA is a redox-active disulphide cofactor that participates in mitochondrial energy metabolism (essential for pyruvate dehydrogenase function) and acts as a chain-breaking antioxidant in both lipid and aqueous phases. Its dihydrolipoic acid (reduced) form regenerates other antioxidants — ascorbate, glutathione, vitamin E — and chelates transition metals. The clinical-trial signal in diabetic neuropathy is modest and the mechanism by which ALA improves neuropathic symptoms is not fully characterised.
Common myths
Myth""ALA mops up free radicals, so it must protect your cells.""
RealityAlpha-lipoic acid does take part in antioxidant chemistry in the laboratory, but EFSA assessed the human health-claim application for protection of body lipids from oxidative damage and did not substantiate it — the cause-and-effect relationship was not established. UK marketing cannot make antioxidant claims for alpha-lipoic acid at any dose.
Myth""ALA is the same as omega-3 alpha-linolenic acid.""
RealityCommon confusion of two different "ALA" abbreviations. Alpha-lipoic acid is a sulphur-containing cofactor; alpha-linolenic acid is an omega-3 fatty acid found in flaxseed, walnuts, and rapeseed oil. Different molecules, different uses, different safety profiles.
Myth""600 mg of ALA from a UK supplement is the same as Thioctacid® 600 mg.""
RealityThe dose number is the same. The clinical evidence is on the German pharmaceutical preparation manufactured under pharmacopoeia standards. Generic UK food supplements may differ in enantiomer ratio, stability, dissolution, and excipients. For diabetic neuropathy specifically, patients should discuss with a GP whether the licensed pharmaceutical is appropriate — not self-supplement.
Myth""ALA is a weight-loss supplement.""
RealityThere is no authorised weight-loss claim for alpha-lipoic acid, and it was not the subject of a substantiated EFSA opinion. Small trials show modest short-term weight reduction; this is not the basis for a clinical weight-loss recommendation, and UK supplement marketing cannot make weight-loss claims for it.
Common online questions
Synthesised from the questions UK shoppers most often ask online about Alpha Lipoic Acid (ALA / thioctic acid). Each answer is editorial and links to its evidence in the Sources list below.
Can ALA help my diabetic neuropathy?
The evidence is mixed. Short-term trials such as SYDNEY-2 reported improved nerve-pain symptoms over 5 weeks at 600 mg/day, but the 2024 Cochrane review — the most rigorous synthesis — concluded that alpha-lipoic acid probably makes little or no difference to neuropathy symptoms at six months, and the 4-year NATHAN-1 trial did not meet its primary endpoint. The studied product is the German prescription preparation, not a UK food supplement. NICE and the NHS do not recommend alpha-lipoic acid for this use; first-line options are medicines such as duloxetine, amitriptyline, gabapentin or pregabalin. Discuss management with your GP or diabetes team. [7,8,9]
Is ALA an antioxidant?
Alpha-lipoic acid takes part in antioxidant chemistry in the laboratory — it is a redox-active disulphide that can recycle other antioxidants. However, EFSA assessed the proposed human health claim that dietary alpha-lipoic acid protects body lipids from oxidative damage and did not substantiate it. The difference between laboratory chemistry and a substantiated human claim matters: UK marketing cannot make antioxidant claims for alpha-lipoic acid.
Can I take ALA with my diabetes medication?
Talk to your diabetes team first. ALA can compound the hypoglycaemic effect of insulin and sulphonylureas. If you do start ALA on top of diabetes therapy, monitor blood glucose more frequently and have a hypoglycaemia plan. Anyone of Japanese, Korean, or other East Asian background should also be aware of the rare insulin autoimmune syndrome (Hirata disease) reported with ALA supplementation in HLA-DRB1*04:06 carriers.
Is ALA safe in pregnancy?
There is insufficient pregnancy-specific safety data on supplemental ALA. Endogenous ALA is part of normal physiology; supplemental doses (300-1800 mg/day) have not been adequately studied in pregnancy. The default position is to avoid concentrated ALA supplements during pregnancy and breastfeeding unless your obstetric team specifies otherwise.
⚖️ The official position
What may lawfully be claimed about Alpha Lipoic Acid (ALA / thioctic acid) in Great Britain. This is a regulatory position, not an evidence grade.
No health claim is authorised for Alpha Lipoic Acid (ALA / thioctic acid) in Great Britain.
This page describes the evidence and online discussion without making a claim.
UK regulatory landscape
UK regulatory tier: Food supplement
EFSA claim status
EFSA assessed the Article 13(1) health-claim applications for alpha-lipoic acid — protection of the nerve system and increased insulin sensitivity (EFSA Journal 2011;9(6):2202), and protection of body lipids from oxidative damage, maintenance of normal blood cholesterol, increased beta-oxidation of fatty acids, maintenance of normal blood glucose, and gene regeneration (EFSA Journal 2010;8(10):1474) — and did not substantiate any of them; a cause-and-effect relationship was not established. Diabetic-neuropathy use is a medicinal indication held by a German licensed pharmaceutical (Thioctacid / Tioctacid), not by the UK food-supplement framework.
UK regulatory rules evolve. This summary is editorial — businesses should consult regulatory counsel; consumers should consult their pharmacist or GP.
🩺 What the guidance says
What UK and international health bodies say. Guidance leads; Camden’s own evidence review follows below.
NHSInsufficient evidence
Peripheral neuropathy — Treatment
The NHS describes how peripheral neuropathy is managed — treating the underlying cause (such as better diabetes control), and using medicines such as amitriptyline, duloxetine, pregabalin or gabapentin for nerve pain. It lists alpha-lipoic acid among the alternative and complementary supplements some people try, noting that the evidence for them is not always clear.
NICENot assessed
Neuropathic pain in adults: pharmacological management in non-specialist settings
NICE's guideline on the drug management of neuropathic pain (including painful diabetic neuropathy) recommends offering a choice of amitriptyline, duloxetine, gabapentin or pregabalin as initial treatment, with tramadol only for acute rescue and capsaicin cream for people who cannot tolerate oral treatments. It does not list alpha-lipoic acid as a treatment option.
SOCIETY-OTHERInsufficient evidence
Herbal and food supplements
Diabetes UK states that vitamin, mineral and herbal supplements have no clear benefit for managing diabetes unless a person has a deficiency or has been advised to take them by their healthcare team. It cautions that some supplements can affect how diabetes medicines work or worsen complications such as kidney disease, and advises people to tell their healthcare team about anything they take.
EFSAInsufficient evidence
Scientific Opinion on health claims related to alpha-lipoic acid (protection of the nerve system; insulin sensitivity)
EFSA's panel assessed the proposed health claims that alpha-lipoic acid protects the nerve system and increases insulin sensitivity. It concluded that a cause-and-effect relationship had not been established for either claim; neither was substantiated. This is part of why no authorised alpha-lipoic-acid health claim exists in Great Britain.
EFSAInsufficient evidence
Scientific Opinion on health claims related to alpha-lipoic acid (oxidative damage, blood cholesterol, blood glucose, beta-oxidation)
EFSA's panel assessed proposed claims that alpha-lipoic acid protects body lipids from oxidative damage, maintains normal blood cholesterol, increases beta-oxidation of fatty acids, and maintains normal blood glucose. It concluded that the cause-and-effect relationships had not been established; none was substantiated.
GB-NHCNot assessed
Great Britain nutrition and health claims (NHC) register
Only claims on the Great Britain NHC register may be used in commercial communications in Great Britain. The register carries no authorised health claim for alpha-lipoic acid. Absence of a claim reflects regulatory status — no positive EFSA opinion was issued — not a finding that any effect has been disproven.
🔬 Camden’s evidence review
The research Camden reviewed, graded on its strength. This is our own appraisal — it sits beneath the official guidance above, never above it.
Symptomatic diabetic peripheral neuropathy (oral)
EvidencemixedThe research Camden reviewed is genuinely conflicting. SYDNEY-2 (Ziegler 2006, n = 181 with distal symmetric polyneuropathy) randomised participants to oral alpha-lipoic acid 600, 1200 or 1800 mg/day or placebo for 5 weeks; all active arms improved Total Symptom Score versus placebo (~50% vs ~32% reduction), with 600 mg/day giving the best risk-benefit balance. Several earlier meta-analyses of short-term symptom scores were favourable (Mijnhout 2012; Hsieh 2023; Prado 2024) but carried very high statistical heterogeneity and high risk of bias. The 2024 Cochrane review (Baicus, 3 RCTs, 816 participants, all at high risk of attrition bias) concluded that alpha-lipoic acid probably has little or no effect on neuropathy symptoms at six months (moderate-certainty GRADE). The trials used the German pharmaceutical preparation, not generic supplement-grade material. [7,9,10,11,12]
Diabetic peripheral neuropathy (4-year prevention of progression)
EvidencelimitedNATHAN-1 (Ziegler 2011, n = 460) randomised mild-to-moderate diabetic distal symmetric sensorimotor polyneuropathy patients to oral alpha-lipoic acid 600 mg/day or placebo for 4 years. The primary composite endpoint (NIS-LL plus seven neurophysiologic tests) was not significantly different between groups (P = 0.105). Secondary outcomes — Neuropathy Impairment Score (NIS), NIS-LL, and the NIS-LL muscle-weakness subscore — showed improvement and reduced progression on alpha-lipoic acid (P < 0.05). Tolerability was similar, though serious adverse events were higher on alpha-lipoic acid (38.1%) than placebo (28.0%) — which needs careful interpretation in a long-term diabetes population. [8]
Antioxidant / oxidative-damage claim (general health)
EvidenceinsufficientEFSA assessed the application that dietary alpha-lipoic acid protects body lipids from oxidative damage (EFSA Journal 2010;8(10):1474) and did not substantiate it — a cause-and-effect relationship between intake and the claimed effect was not established. There is no authorised antioxidant claim for alpha-lipoic acid in Great Britain.
Weight reduction
EvidenceinsufficientThere is no authorised weight-loss claim for alpha-lipoic acid and it was not the subject of a substantiated EFSA opinion. Several small, short-term trials report modest weight reduction (about 1-2 kg over 8-20 weeks at 600-1800 mg/day), but the findings are heterogeneous and not recognised by UK or EU regulators for clinical use.
Safety
ALA at supplement doses (100-600 mg/day) is generally well-tolerated in healthy adults. Two specific concerns to know about — hypoglycaemia interaction with insulin and sulphonylureas, and a rare insulin-autoimmune-syndrome (Hirata disease) signal in East Asian populations. Pregnancy data are insufficient.
Talk to your pharmacist or GP first if you:
- You have diabetes and take insulin, sulphonylureas, or other glucose-lowering medication — ALA may compound the hypoglycaemic effect; monitor glucose and review medication doses with your team.
- You take levothyroxine — ALA may chelate the thyroid hormone; space dosing by ≥4 hours.
- You are receiving cancer chemotherapy or radiotherapy — antioxidant supplements during treatment should be cleared with the oncology team.
- You are of Japanese, Korean, or other East Asian background — rare insulin autoimmune syndrome (Hirata disease) is associated with ALA supplementation in HLA-DRB1*04:06 carriers.
- You are pregnant, breastfeeding, or planning pregnancy — supplemental ALA has not been adequately studied; default to avoidance.
- You take an antiplatelet or anticoagulant — theoretical bleeding-risk additive at very high doses.
Common side effects: Generally well-tolerated. Dose-dependent: nausea, vomiting, vertigo at higher doses (1200-1800 mg/day). Skin reactions (urticaria, pruritus) reported uncommonly. Mild hypoglycaemia at any dose if combined with diabetes medication.
Pregnancy and breastfeeding
Endogenous ALA is part of normal physiology; supplemental ALA at 100-600 mg/day has not been adequately studied in pregnancy. The default position is to avoid concentrated ALA supplements during pregnancy unless your obstetric team specifies otherwise.
Insufficient lactation-specific safety data. Default to avoidance during breastfeeding.
Talk to your GP, midwife, or pharmacist before starting any supplement during pregnancy or breastfeeding.
More clinical detail (for clinicians and informed readers)
Contraindications
- Documented ALA hypersensitivity.
- History of insulin autoimmune syndrome.
- Severe hepatic or renal impairment (relative — pharmacokinetics altered).
Drug interactions
- Insulin / sulphonylureas / other antidiabetic agents — additive hypoglycaemic effect. Monitor glucose; medication-dose review may be needed.
- Levothyroxine — possible chelation/binding interaction; space dosing by ≥4 hours.
- Cytotoxic chemotherapy (especially platinum-based agents) — antioxidants may interfere with treatment-dependent oxidative-stress mechanisms; clear with oncology team.
- Warfarin / DOACs / antiplatelets — theoretical additive bleeding risk at high doses; supervised co-administration.
- Cisplatin specifically — animal-model evidence that ALA may protect from cisplatin nephrotoxicity (potentially a desired effect or an interaction depending on clinical context); discuss with oncology.
This is not an exhaustive list. Always tell your prescriber and pharmacist about every supplement you take.
Common side effects
- GI symptoms (nausea, dyspepsia) — dose-dependent, more common at ≥1200 mg/day.
- Headache and dizziness occasionally reported.
Rare side effects
- Skin reactions (urticaria, pruritus, contact dermatitis).
- Hypoglycaemia in adults on insulin or sulphonylureas.
- Insulin Autoimmune Syndrome (Hirata disease) — primarily reported in Japanese and Korean populations carrying HLA-DRB1*04:06; presents as recurrent unexplained fasting hypoglycaemia from anti-insulin antibodies.
- Anaphylactoid reactions to IV ALA (hospital pharmaceutical context, not UK supplements).
How to take it
- Typical supplemental range
- Diabetic peripheral neuropathy trial dose (Thioctacid®): 600 mg once daily oral. Higher doses (1200-1800 mg) showed similar efficacy but more GI side effects in SYDNEY-2. UK food supplement labels typically 100-600 mg/day.
- Timing
- On an empty stomach (~30 minutes before food) for best absorption — food significantly reduces ALA bioavailability.
How to spot quality
Look for
- Form named explicitly: "R-(+)-alpha-lipoic acid" (natural enantiomer), "S-(-)-alpha-lipoic acid" (synthetic), or "racemic R/S" mixture.
- Sodium R-α-lipoic acid (Na-R-ALA) declaration if marketing as bioavailability-enhanced.
- Dose declared in mg of free ALA (not as a thiol-equivalent or as a multiple of an extract).
- GMP-certified manufacture; stability declaration (ALA is moisture- and heat-sensitive — short shelf life if poorly stored).
- Empty-stomach dosing instruction on the label (food materially reduces absorption).
Red flags
- "Antioxidant" or "free radical" wording — EFSA did not substantiate these claim applications for ALA. Not permitted on UK labels.
- "Diabetic neuropathy" / "nerve pain" / "diabetic nerve" wording — these are medicinal claims. The licensed indication is held by the German pharmaceutical, not by UK food supplements.
- "Weight loss" / "fat burning" / "metabolic boost" wording — no authorised claim; not permitted under the GB nutrition and health claims framework.
- High-dose products (≥1200 mg/day) marketed for general use — higher doses do not have stronger evidence and increase GI side effects.
- Combinations with insulin or sulphonylureas without prescriber-supervision warning — hypoglycaemia interaction.
Commonly combined with
Other ingredients that share a biological pathway, cofactor relationship, or evidence-backed protocol with this one. Mechanisms below cite primary physiology — not folk pairing. Doses are literature ranges, not recommendations. Talk to your pharmacist or GP before changing your stack, especially if you take prescription medication.
N-Acetyl Cysteine (NAC)
Limited evidenceAntioxidant cluster — ALA + NAC both feed the glutathione redox cycle.
ALA both water- and lipid-soluble universal antioxidant; recycles vitamin C, vitamin E, glutathione. NAC is glutathione precursor (cysteine substrate). Mechanism complementary on glutathione-cycle axis.
Evidence: Camden nac NB-435 + ALA cluster.
Doses studied: 300-600 mg ALA + 600-1200 mg NAC daily.
Found in Camden: Purifera® NAC N-Acetyl-Cysteine 600mg 120 Capsules
Vitamin C
Limited evidenceAntioxidant trio with vitamin E — ALA recycles oxidised vitamin C and vitamin E.
ALA universal antioxidant cycle: ALA reduces oxidised glutathione; reduced glutathione reduces oxidised vitamin C; reduced vitamin C reduces oxidised vitamin E. UK Article 13.1 vitamin C oxidative-stress claim.
Evidence: UK Article 13.1 vitamin C claim authorised. [6]
Doses studied: 300-600 mg ALA + 80-1000 mg vitamin C daily.
Magnesium
Limited evidenceMitochondrial-cluster pairing — ALA mitochondrial-cofactor + magnesium ATP-Mg energy-metabolism cofactor.
ALA cofactor for pyruvate dehydrogenase + α-ketoglutarate dehydrogenase mitochondrial enzymes; magnesium cofactor for ATP-bound enzymes throughout energy metabolism.
Evidence: UK Article 13.1 magnesium energy-metabolism claim. [6]
Doses studied: 300-600 mg ALA + 200-400 mg magnesium daily.
Found in Camden: Magnesium Complex 120 Capsules
Sources
Numbered references cited above plus general authoritative reading. Citations in the body link to the matching number here.
How to read these sources:
- Tier 1 (UK authoritative): NHS, NICE, BNF, EFSA, FSA, GB NHC Register, SACN, MHRA.
- Tier 2 (primary literature): peer-reviewed RCTs cited by PMID.
- Tier 3 (mechanistic): in-vitro / animal-model literature — interpret with caveat.
- NHS — Peripheral neuropathy, treatment
- NICE CG173 — Neuropathic pain in adults: pharmacological management in non-specialist settings
- Cochrane Review 2024 — Alpha-lipoic acid for diabetic peripheral neuropathy
- EFSA Journal 2011;9(6):2202 — health claims for alpha-lipoic acid (nerve system, insulin sensitivity)
- Diabetes UK — Herbal and food supplements
- Great Britain nutrition and health claims (NHC) register
- PubMed PMID 17065669
- PubMed PMID 21775755
- PubMed PMID 38205823
- PubMed PMID 37630823
- PubMed PMID 38295879
- PubMed PMID 22331979