Hello and thank you for your question. It certainly can be difficult
to separate the promotional claims from the real science where herbal
remedies are involved.
Maca (Lepidium meyenii) grows only in the Andes, and is known in
English as mace, pepper grass, or pepper weed. Nutritionally, it is
high in calcium and iron.
Here's what I've been able to find on the scientific front.
One study, at least, indicates that a Lepidium variety is not
mutagenic i.e. cancer-causing:
Ruiz, R. et al., Screening of medicinal plants for induction of
somatic segregation activity in Aspergillus nidulans
However, it is chemically and pharmacologically active (lots of links
to technical papers at the following site):
Lepidium--Evidence of Activity
As you might expect in the scientific world, we know more about
Lepidum's effects on rats than we do on people. In one study, it was
concluded that both acute and chronic Maca oral administration
significantly improve sexual performance parameters in male rats.
Title: Lepidium meyenii Walp. improves sexual behaviour in male rats
independently from its action on spontaneous locomotor activity.
Source: Journal of Ethnopharmacology. 75(2-3):225-9, 2001 May.
So what effects is it likely to have on you?
The answer is clearest for men: At dosages of 1500 or 3000 mg/day
given over a period of 4 months, Maca did great things for their
"Treatment with Maca resulted in increased seminal volume, sperm count
per ejaculum, motile sperm count, and sperm motility. Serum hormone
levels were not modified with Maca treatment. Increase of sperm count
was not related to dose of Maca. CONCLUSION: Maca improved sperm
production and sperm motility."
Title: Lepidium meyenii (Maca) improved semen parameters in adult
Source: Asian Journal of Andrology. 3(4):301-3, 2001 Dec.
(sorry I don't have a web reference for this; I found it via Medline)
My conclusion for you is that thanks to its nutritional and
pharmacological properties, Lepidium can be beneficial and does not
pose much of a risk.
Dosages do not seem critical, since in the Andes it's grown as a food
source so people do eat it or use it in cooking without bad effects
(it's a distant relative of broccoli). I suggest you limit yourself
to the 1500-3000 mg/day dose that was considered appropriate in the
study cited above.
Additional info (the following is a single link):
Alternative Medicine: Expanding Medical Horizons
A Report to the National Institutes of Health
on Alternative Medical Systems and Practices
in the United States
Other Search Terms:
"maca root" scientific
I hope you find this useful. If you require any questions about my
work, I'd appreciate it if you would request an answer clarification
before you rate my answer.