Based on traditional Chinese medicine (TCM), ma huang (ephedra) contains total alkaloids that range between 0.5-2.5%. The Korean Pharmacopoeia stipulates that ma huang should contain at least 0.7% total alkaloids, including ephedrine and pseudoephedrine. The proportion of ephedrine in the total alkaloids can vary significantly between 30-90%, depending on when the plant was harvested and its growth conditions. However, it is generally understood that ephedrine makes up approximately 70-75% of the total alkaloids.
The extraction rate of ephedrine from ma huang is higher in water than in methanol, with about 90% of ephedrine being extracted within 5 minutes (25 minutes after heating) after water begins to boil. The remaining approximately 10% stays within the residue of ma huang. The amount of ephedrine in the total extract of a prescription that includes ma huang corresponds to 73-96% of that in an extract of ma huang alone, suggesting that the presence of other medicinal herbs in the prescription may affect the amount of ephedrine extracted. Moreover, if ma huang is decocted before other herbs, the ephedrine content is about 12% higher than when all the herbs are decocted together.
If we look at the use of ma huang in prescriptions in Donguibogam, a classic book in Oriental medicine, it is generally used at a daily dose of 8-16g (accounting for 58.2% of the total) in oral medications. In more severe cases, doses can reach up to 24g per day. While there are prescriptions that use more than 24g of ma huang, these are not common for usual indications. In the Sasang typology, prescriptions like Taeeumin's Mahuang Jeongchun-tang also use up to 24g of ma huang per day.
A daily dose of 24g of ma huang would contain at least 168mg of total alkaloids, according to the minimum standard set by the Korean Pharmacopoeia. If 75% of these alkaloids were ephedrine, this would translate to at least 126mg of ephedrine. (The US FDA allows up to 150mg/day of ephedrine for medicinal use.) However, ephedrine content can often reach around 10mg/g in ma huang used domestically as a medicinal herb in Korea. Depending on the blending, decoction process, absorption, and distribution conditions, the blood concentration could differ, requiring caution. Currently, Korean doctors of Oriental medicine are obliged to use standard herbal medicines, and it is advisable to confirm the ephedrine content in ma huang in advance.
In conclusion, in traditional Chinese medicine (TCM), the maximum usage amount of ma huang (ephedra) is 24 grams per day, which is similar to the FDA-approved usage amount of ephedra in pharmaceuticals. However, in most usage scenarios, the daily dosage should be within 16 grams. Usage up to 24 grams is limited to situations where it is absolutely necessary. Importantly, this applies only to prescriptions in Korea, by Korean doctors of Oriental medicine for medical purposes. It should be clarified that this is not the allowable amount for use in health supplements or for personal intake. This does not apply in the United States, and this information should be understood purely from an academic perspective.
Reference;
A Clinical Practice Guideline for Ma-huang(Ephedra sinica) Prescription in Obesity, Hojun Kim, O.M.D., Journal of Society of Korean Medicine for Obesity Research 2007:7(2):27-37,