A traditional pain herb
Corydalis yanhusuo, known in Chinese medicine as yan hu suo, is a small flowering plant whose tuber has been used for centuries to relieve pain, including menstrual, abdominal and chest pain. The tuber is usually processed with vinegar, which is thought to increase the extraction of its alkaloids. In Western supplements it appears as dried powder or extract, sometimes standardized to its alkaloid content, sometimes not.The alkaloids
Corydalis tuber contains dozens of isoquinoline alkaloids. Three get most attention:
- Tetrahydropalmatine (l-THP). A dopamine receptor antagonist with sedative and pain-relieving effects. It was the active ingredient in Jin Bu Huan, a product discussed below.
- Dehydrocorybulbine (DHCB). Identified in 2014 as a non-opioid pain reliever acting mainly through dopamine D2 receptors [1].
- Protopine. Found in corydalis and other poppy-family plants, with a range of laboratory activities reviewed in 2021 [2].
These compounds are what make corydalis interesting as a pain herb. They are also what make the dose question important.
What the studies show
Zhang and colleagues, 2014. Working in mice, the researchers found that DHCB reduced pain in models of acute, inflammatory and neuropathic pain. Unlike morphine, repeated doses did not lead to tolerance in the neuropathic model [1]. The paper drew attention because it suggested a new class of pain reliever from a traditional herb. Rodent work after spinal cord injury. A later study linked DHCB to relief of neuropathic pain after spinal cord injury in rodents, acting through the P2X4 receptor pathway [3]. Yuan and colleagues, 2004. The main human study tested a preparation of Corydalis yanhusuo with Angelica dahurica in healthy volunteers using the cold-pressor test, in which participants hold a hand in ice water. The herbal preparation increased pain tolerance compared with placebo [4].There are no published trials of corydalis for peripheral neuropathy in people.
The liver question
In the early 1990s, Jin Bu Huan, a Chinese herbal sedative and analgesic sold in the United States, was linked to cases of acute hepatitis in adults who took it for weeks to months, and to life-threatening sedation and slowed breathing in children who swallowed tablets by accident. A case series described the clinical spectrum [5]. Jin Bu Huan contained high amounts of l-THP, the corydalis alkaloid.
NIH's LiverTox database, the federal reference on drug-induced liver injury, lists Chinese and other Asian herbal medicines as a recognized category of liver injury [6]. In 2025, a study described idiosyncratic hepatotoxicity from Corydalis yanhusuo, meaning liver injury that strikes a minority of people unpredictably, and explored possible mechanisms [7].
The risk at a modest dose is probably low for most people. But idiosyncratic means it cannot be predicted from dose alone.
What 100 mg of powder means
The NerveHoney label lists corydalis as 100 mg of powder, with no plant part and no alkaloid percentage. Dried corydalis tuber typically contains a small percentage of total alkaloids by weight, so 100 mg of powder holds only a few milligrams of alkaloids at most, and the exact amount depends on the raw material. Traditional decoctions use several grams of tuber a day.
That cuts both ways. The dose is probably too small to deliver the pain relief seen in animal studies, and probably small enough to keep the risk low for most people. What it does not do is give you a number you can check. A standardized extract with a stated alkaloid content would be more useful to a buyer, and more honest.
Who should avoid corydalis
- People with liver disease, or abnormal liver tests
- People who drink alcohol heavily, or take other medicines that strain the liver
- Anyone pregnant or breastfeeding
- People taking sedatives, as l-THP has sedative effects of its own
- Anyone with surgery coming up
Signs of liver trouble that should prompt you to stop and see a doctor include dark urine, pale stools, yellowing of the skin or eyes, unusual tiredness and pain under the right ribs. Reactions can be reported to the FDA [8].
How corydalis is prepared, and why it matters
In traditional practice, corydalis tuber is usually stir-fried with vinegar before use, a step thought to convert alkaloids into more soluble salts and increase how much ends up in the decoction. It is then boiled in water, often for half an hour or more, at several grams a day, frequently in combination with other herbs. Modern extracts are made with alcohol or water and may be standardized to total alkaloids or to tetrahydropalmatine.
A capsule of raw powder skips all of that. Without vinegar processing, decoction or standardization, the amount of alkaloid that reaches the bloodstream from 100 mg is uncertain, and likely small. That is one more reason the animal results, which used purified compounds or concentrated extracts [1], do not transfer neatly to a supplement label.
Questions readers ask about corydalis
Is corydalis an opioid? No. Its pain-relieving alkaloids act mainly on dopamine receptors, not opioid receptors, which is why researchers were interested in it [1]. Can it make you sleepy? Yes. Tetrahydropalmatine has sedative effects, and they add to those of passionflower and California poppy. Should I have liver tests? If you plan to take a corydalis product for more than a few weeks, or have any liver risk factors, asking your doctor about baseline liver tests is reasonable, given the record described above [6]. Is corydalis banned? No. It is sold legally as a supplement ingredient in the U.S.; the Jin Bu Huan problems involved a specific product with high l-THP content [5].Corydalis in other products you may take
Corydalis turns up in more places than nerve formulas. It is a common ingredient in traditional Chinese patent medicines for pain and menstrual cramps, in some sleep and relaxation blends, and occasionally in pre-workout or focus products that use tetrahydropalmatine for its calming effect. If you take any of these alongside NerveHoney, your total corydalis intake rises with no way to add it up, because few labels give alkaloid content. Read the ingredient lists of every supplement and herbal tea you use, look for corydalis, yan hu suo or tetrahydropalmatine, and keep to one source at a time.
What this means for a NerveHoney buyer
Corydalis gives NerveHoney a credible pain-relief story on paper, and a safety caveat the sales page does not mention. At 100 mg of unstandardized powder, it is unlikely to deliver much of either. If you have any liver concerns, that caveat should outweigh the potential benefit. Our side effects guide covers the other ingredients.
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Sources
- Zhang Y, Wang C, Wang L, et al. A novel analgesic isolated from a traditional Chinese medicine. Curr Biol. 2014;24(2):117-123. pubmed.ncbi.nlm.nih.gov/24388848/
- Huang W, Kong L, Cao Y, Yan L. Identification and quantification, metabolism and pharmacokinetics, pharmacological activities, and botanical preparations of protopine: a review. Molecules. 2021;27(1). pubmed.ncbi.nlm.nih.gov/35011447/
- Wang Z, et al. Role of dehydrocorybulbine in neuropathic pain after spinal cord injury mediated by P2X4 receptor. Mol Cells. 2019. pubmed.ncbi.nlm.nih.gov/30622226/
- Yuan CS, Mehendale SR, Wang CZ, et al. Effects of Corydalis yanhusuo and Angelicae dahuricae on cold pressor-induced pain in humans: a controlled trial. J Clin Pharmacol. 2004;44(11):1323-1327. pubmed.ncbi.nlm.nih.gov/15496650/
- Horowitz RS, Feldhaus K, Dart RC, Stermitz FR, Beck JJ. The clinical spectrum of Jin Bu Huan toxicity. Arch Intern Med. 1996;156(8):899-903. pubmed.ncbi.nlm.nih.gov/8774209/
- LiverTox: Clinical and Research Information on Drug-Induced Liver Injury. Chinese and other Asian herbal medicines. Bethesda (MD): National Institute of Diabetes and Digestive and Kidney Diseases; 2012-. pubmed.ncbi.nlm.nih.gov/31643904/
- Guo L, Lin L, Ling J, et al. A new discovery: Corydalis yanhusuo causes idiosyncratic hepatotoxicity and its potential mechanisms. Biomed Chromatogr. 2025;39:e70093. pubmed.ncbi.nlm.nih.gov/40277353/
- U.S. Food and Drug Administration. MedWatch: The FDA Safety Information and Adverse Event Reporting Program. www.fda.gov/safety/medwatch-fda-safety-information-and-adverse-event-reporting-program