Capsicum annuum L. · supplement
Evidence tier: moderate
A topical pepper derived agent that desensitises pain nerves, for arthritis and nerve pain in specific areas.
Capsaicin is an agonist at TRPV1, the heat and pain receptor on small sensory nerve fibres. Activating it hard and repeatedly first hurts (the burn), then exhausts the fibre: MSK describes 'selective and reversible defunctionalization of cutaneous sensory nerve endings', with depletion of substance P, the neurotransmitter those fibres use to signal pain. The nerve ending is not damaged permanently; it recovers, which is why the 8 percent patch is repeated roughly every three months. This mechanism is well established and it is one of the few in the PlantRx catalogue that is genuinely understood rather than merely proposed. It also explains the strange dosing logic: the burn is not a side effect of the treatment, it IS the treatment.
Moderate, and this is the one ingredient in the batch whose evidence is genuinely good. But the evidence belongs to a PRESCRIPTION MEDICINE, not to the cream on the shelf, and that distinction is the whole story. Topical capsaicin for neuropathic pain has been through Cochrane twice, at two different strengths, and the two reviews reach OPPOSITE conclusions. HIGH concentration (the 8 percent patch): Cochrane 2017 (Derry and colleagues, PMID 28085183) pooled eight double blind randomised trials in 2,488 patients and found that a SINGLE application produced more people with moderate or substantial pain relief than control, across postherpetic neuralgia, HIV neuropathy and painful diabetic neuropathy, with numbers needed to treat of about 10 to 12 and no excess of serious adverse effects. This is not a supplement result. The 8 percent patch is a LICENSED MEDICINE (Qutenza), FDA approved for postherpetic neuralgia in 2009 and for diabetic peripheral neuropathy of the feet in 2020, EMA approved for peripheral neuropathic pain, applied in a clinic by a healthcare professional, and it can give up to three months of relief from one application. LOW concentration (the 0.025 to 0.075 percent creams sold over the counter, which is what a PlantRx user would actually buy): Cochrane 2012 (PMID 22972149) pooled six studies in 389 participants and found INSUFFICIENT EVIDENCE to draw any firm conclusion, with substantial heterogeneity, too few data to pool the primary outcome, and skin reactions in roughly one user in every 2.5. So the honest sentence is this: capsaicin for nerve pain works, at a strength you cannot buy, applied by someone who is not you. The consumer strength cream is not proven. MSK adds that low concentration topical formulations do have support for pruritus and psoriasis, that data for chemotherapy induced neuropathy are preliminary, and that use in rheumatoid arthritis is inconclusive and for cluster headache unknown. Capsaicin is graded moderate on the strength of a Cochrane backed licensed medicine, and it is graded no higher because the effect size is modest (NNT 10 to 12) and because the formulation that carries the evidence is not the formulation people use.
TOPICAL ONLY. Never ingest the medicinal forms. Two entirely separate products: (1) The licensed high concentration 8 percent dermal patch (Qutenza), applied by a healthcare professional in a clinical setting, single application, relief lasting up to about 3 months. This is the preparation the Cochrane evidence supports and it is a prescription medicine, not a supplement. (2) Over the counter creams at 0.025 to 0.075 percent, applied several times daily; Cochrane found the evidence for these insufficient. Wash hands thoroughly after application and keep away from the eyes.
Topical 0.025% to 0.075% cream applied 3 to 4 times daily. Burning sensation reduces after 1 to 2 weeks of use.
Topical only, never ingest the medicinal forms. Wash hands thoroughly after application.
Pregnancy: caution
Breastfeeding: caution
Active compounds: capsaicin (8-methyl-N-vanillyl-6-nonenamide), capsaicinoids
Remedies using Capsaicin (Topical) · Browse by body system · Check it against what you take
*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.