Neuropathic pain — supplement stack and where the evidence is real
Neuropathic pain covers a wide range of conditions (diabetic peripheral neuropathy, post-herpetic neuralgia, chemotherapy-induced peripheral neuropathy, trigeminal neuralgia, post-surgical nerve pain). The pharmaceutical first-line — gabapentinoids, duloxetine/SNRIs, TCAs, topical lidocaine and capsaicin — has the strongest evidence. Supplements have a real but narrower role, with the cleanest data for alpha-lipoic acid and acetyl-L-carnitine in diabetic peripheral neuropathy, and for methylcobalamin (B12) in B12-deficiency neuropathy.
The strongest-evidence supplement options
Alpha-lipoic acid (R-ALA or racemic)
600 mg/day oral (R-ALA preferred for bioavailability), or 600 mg IV in research/clinic settings
ALA has the cleanest neuropathic-pain trial evidence of any supplement. SYDNEY 2 trial (Ziegler 2006, 181 patients, 5 weeks) and the META-ALA meta-analysis (Mijnhout 2012) show meaningful symptom reduction (~20–30% improvement on Total Symptom Score) at 600 mg/day oral. Effect is more pronounced in early disease and with consistent dosing. Take on an empty stomach for best absorption.
Acetyl-L-Carnitine (ALCAR)
1500–3000 mg/day divided BID, 6–12 months
ALCAR has multiple RCTs in diabetic peripheral neuropathy showing reductions in pain and improvements in nerve conduction (Sima 2005 multi-centre trial). Effect sizes are modest but meaningful. Also evidence in chemotherapy-induced peripheral neuropathy prevention, though the Hershman 2013 trial in breast cancer survivors raised concerns that ALCAR may worsen taxane-induced neuropathy — avoid prophylactic ALCAR in active chemotherapy.
Methylcobalamin (Vitamin B12)
1000 mcg/day sublingual or oral; or IM injection per primary care if severe deficiency
B12 deficiency causes peripheral neuropathy (and dorsal column / lateral column degeneration). Test serum B12 and methylmalonic acid in any neuropathy workup. Repletion treats B12-deficiency neuropathy; routine supplementation in B12-replete patients does not help non-deficient neuropathy. Use methylcobalamin or hydroxocobalamin (not cyanocobalamin in active neuropathy).
Palmitoylethanolamide (PEA) — micronised or ultra-micronised
600 mg BID micronised or 600 mg/day ultra-micronised PEA, 8+ weeks
PEA is an endogenous fatty acid amide with anti-inflammatory and neuroprotective activity. Meta-analyses (Paladini 2016) show modest pain reductions in mixed neuropathic pain populations. Standardised micronised preparations (e.g., Normast) are the trial-cited forms. Reasonable adjunct; cleaner safety profile than pharmaceuticals.
Magnesium glycinate or taurate
200–400 mg elemental magnesium daily; correct deficiency if present
Magnesium modulates NMDA receptors (which sit at the centre of central sensitisation). Trials in chronic neuropathic pain and complex regional pain syndrome show modest signals; effect is more reliable when deficiency is present. Reasonable addition with low harm.
Vitamin D — if deficient
1000–2000 IU/day vitamin D3 to a 25-OH-D target of 30–50 ng/mL
Vitamin D deficiency has been linked to diabetic peripheral neuropathy severity in observational data. Causation is uncertain, but repletion is low-harm and reasonable.
Pharmaceutical and procedural interventions that outperform any supplement
- Duloxetine (SNRI) — first-line for diabetic peripheral neuropathy; FDA-approved indication.
- Gabapentin / pregabalin — first-line for post-herpetic neuralgia and many neuropathic conditions. Start low, titrate slowly to balance efficacy and sedation.
- TCAs (amitriptyline, nortriptyline) — effective for neuropathic pain; nortriptyline is generally better tolerated than amitriptyline. Use with ECG and caution in older adults.
- Topical lidocaine 5% patch — focal neuropathic pain, post-herpetic neuralgia. Low systemic effect.
- Topical capsaicin 8% patch (Qutenza, by clinician) — single-application treatment for PHN and HIV neuropathy.
- Treating the underlying cause — glycemic control in diabetes, B12 repletion, thyroid optimisation, removing offending medications. This often matters more than any analgesic.
- Physical therapy and graded activity — often underused. Movement reduces central sensitisation over time.
- Cognitive behavioural therapy — for chronic neuropathic pain, CBT reduces pain interference and improves function.
What to skip
- High-dose B6 chronically (>100 mg/day) — causes peripheral sensory neuropathy itself; the very condition you're trying to treat.
- "Nerve repair" combination products — typically sub-therapeutic blends with marketing that doesn't match evidence.
- Generic "anti-inflammatory" stacks — neuropathic pain is mechanistically different from inflammatory pain; turmeric/quercetin/etc. don't target nerve sensitisation.
- Long-term opioids for chronic non-cancer neuropathic pain — typically ineffective; risk profile dominates.
- Kava, kratom, and unregulated psychoactive botanicals for pain — hepatotoxicity (kava), opioid-receptor activity and dependence (kratom).
- Magnesium IV for "detox" — magnesium has a real role in pain modulation but not in supplement-clinic IV form for vague indications.
What to track
Use a standard pain numeric rating (0–10) plus a brief functional measure (interference with sleep, mood, daily activities). The DN4 questionnaire helps confirm neuropathic features. Reassess at 8–12 weeks of any supplement intervention. If no benefit at 12 weeks of consistent use, the supplement is not going to start working.