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Limited evidenceGeneral health

Corydalis

Corydalis yanhusuo is a genuinely interesting analgesic herb: its alkaloids act on dopamine receptors and produce real pain relief in animal models without opioid tolerance. What is missing is decent human trial evidence, and it carries sedative and drug-interaction risks that most labels ignore.

What the science says

  • Relieves pain through a non-opioid mechanism Limited evidence

    A 2014 Current Biology study isolated dehydrocorybulbine (DHCB) from Corydalis yanhusuo and showed it reduced inflammatory and neuropathic pain behaviour in rodents via dopamine D2 receptor antagonism, notably without the tolerance seen with morphine over repeated dosing. This is preclinical work in mice; no adequately powered, placebo-controlled human pain trial has confirmed it.

  • Acts as a sedative and sleep aid Limited evidence

    L-tetrahydropalmatine (l-THP), the best-characterised Corydalis alkaloid, is a dopamine D1/D2 antagonist with clear sedative and anxiolytic effects in animals and is sold in China at roughly 30-120 mg for sleep and pain. Human data are mostly small, unblinded Chinese-language studies, and the same dopamine blockade that sedates can, with chronic use, produce drug-induced parkinsonism.

  • Safe because it is a traditional herb Limited evidence

    Tetrahydropalmatine-containing preparations have a documented hepatotoxicity signal: Jin Bu Huan tablets, standardised to l-THP, caused acute hepatitis in adults and children in the 1990s and prompted an FDA advisory. Reviews of THP pharmacology also report inhibition of CYP1A2, CYP2D6 and CYP3A activity, meaning meaningful interaction potential with common prescription drugs.

Dosage & safety

Studied doseTraditional decoctions use 3-9 g/day of dried rhizome, usually vinegar-processed. Western extracts are commonly sold at 500-1,000 mg/day of a 10:1 concentrate, rarely standardised to any alkaloid. Chinese studies of isolated l-THP have used roughly 30-120 mg/day. Because alkaloid content varies enormously between products, dose on the label tells you little about dose delivered.
SafetySedation, dizziness and lowered blood pressure are common; do not combine with alcohol, benzodiazepines, opioids or other sedatives, and do not drive after dosing. Hepatotoxicity has been reported with l-THP-containing products (Jin Bu Huan), so avoid with liver disease and stop at any sign of jaundice or dark urine. Dopamine antagonism means it should be avoided by people with Parkinson's disease, on antipsychotics, or with a movement-disorder history. CYP inhibition creates interaction risk with many prescription medicines. Avoid in pregnancy and breastfeeding.

Scientific references

Where to buy

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