- In 2006 the International Journal of Biomedical Science published an animal study in which maca displayed hormone-balancing effects in rats. The authors noted that maca may have potential as a safe treatment for balancing physiological symptoms of post and pre-menopausal women.
- In 2008 CNS Neuroscience & Therapeutics published a double-blind pilot study comparing low-dose and high-dose maca in 16 depressed patients with sexual dysfunction. Results showed that 3 grams of maca per day improved sexual function and libido while 1.5 grams/day had no effect.
- In 2009 the Journal of Ethnopharmacology published a crossover study in which 8 male cyclists completed a 40 km cycling time trial before and after 14 days supplementation with maca or a placebo. Results showed maca extract significantly improved sexual desire.
- In 2007 &rologia published an animal study which found that 84 days of treatment with yellow or black maca increased sperm count in male rats.