Every drugstore carries supplements containing extracts from the roots of greater burdock, or Arctium lappa. These are sold for greasy skin and acne, but according to researchers at Shandong University, the same supplements boost testosterone levels and libido.
Arctium lappa is widely used in traditional medicine: North American healers give the plant to pregnant women at the time of birth; Japanese healers use greater burdock against skin rashes, sore throats and arthritis; and in traditional Chinese medicine the roots of Arctium lappa are used to treat impotence, infertility and lack of interest in sex.
The researchers tested these sexual aspects in an animal study, using 75 male young adult rats. The researchers divided the rats into five groups. Two of these functioned as a control group: one group received nothing [Control] and the other group were given a daily oral dose of sildenafil – the active ingredient in Viagra - for a period of 15 days. The three experimental groups were given a daily dose of 300, 600 and 1200 mg of a water-based Arctium lappa extract.
Converting the dose to a human equivalent, you'd need 30-120 mg per kg bodyweight, according to the simple, conservative method. If you use the official, less conservative formula you arrive at 49-194 mg per kg bodyweight per day. So if you weigh 80 kg, you'd need 3.9 - 15.6 g per day. The conservative dose is just feasible. The over-the-counter Arctium lappa supplements contain about 425 mg extract per capsule. Is the higher dose safe? We wonder.
When the researchers placed their lab animals in the same space as sexually mature females, on days 3, 7 and 15, they observed that Arctium lappa stimulated the males' sexual activity. They had erections more often, mounted the females more often and ejaculated more often. [Table] The higher the amount of extract the rats had had, the stronger the effect was.
During the period of supplementation the testosterone level in the experimental groups rose by 40, 87 and 126 percent, respectively. The higher the Arctium lappa extract dosing, the higher the testosterone level.
When the researchers assessed penile function in the rats, they saw that the higher doses of Arctium lappa raised the Total Penile Reflex by as much as sildenafil.
The researchers are not sure exactly how the extract works. They suspect that components in Arctium lappa mimmick the hormone LH and stimulate the testes to make more testosterone.
BMC Complement Altern Med. 2012 Feb 1;12:8.