All available third-party research on maca can be found at PubMed.
A partial listing of the published research on maca is shown below:
Scientific Evidence for Effect on Sperm Count and Fertility:
Gonzales, G. F., et al. "Effect of Black maca (Lepidium meyenii) on one spermatogenic cycle in rats." Andrologia. 2006 Oct; 38(5): 166-72.
Bustos-Obregon, E., et al. "Lepidium meyenii (Maca) reduces spermatogenic damage induced by a single dose of malathion in mice." Asian J. Androl. 2005 Mar; 7(1): 71-6.
Ruiz-Luna, A.C., et al. "Lepidium meyenii (Maca) increases litter size in normal adult female mice." Reprod. Biol. Endocrinol. 2005 May; 3(1): 16.
Gonzales, C., et al. "Effect of short-term and long-term treatments with three ecotypes of Lepidium meyenii (MACA) on spermatogenesis in rats." J. Ethnopharmacol. 2006 Feb 20; 103(3): 448-54.
Gonzales, G. F., et al. "Effect of Lepidium meyenii (Maca) on spermatogenesis in male rats acutely exposed to high altitude (4340 m)." J. Endocrinol. 2004; 180(1): 87-95.
Scientific Evidence for Effect on Sperm Motility & Sperm Count:
Gonzales, G. F., et al. "Lepidium meyenii (maca) improved semen parameters in adult men." Asian J. Androl. 2001; 3(4): 301–3.
Gonzales, G. F., et al. "Effect of Lepidium meyenii (maca) roots on spermatogenesis of male rats." Asian J. Androl. 2001; 3(3): 231–33.
Scientific Evidence for Endocrine / Adrenal Actions:
Zhang, Y., et al. "Effect of ethanol extract of Lepidium meyenii Walp. on osteoporosis in ovariectomized rat." J. Ethnopharmacol. 2006 Apr; 105(1-2): 274-9.
Lopez-Fando, A., et al. “Lepidium peruvianum Chacon restores homeostasis impaired by restraint stress.” Phytother. Res. 2004; 18(6): 471-4.
Scientific Evidence for Anti-Depressant Actions:
Rubio, J., et al. "Effect of three different cultivars of Lepidium meyenii (Maca) on learning and depression in ovariectomized mice." BMC Complement. Altern. Med. 2006 Jun 23; 6:23.
Scientific Evidence for Male Sexual Performance / Enhancement Actions:
Cicero, A. F., et al. “Hexanic maca extract improves rat sexual performance more effectively than methanolic and chloroformic maca extracts.” Andrologia. 2002; 34(3): 177–79.
Cicero, A. F., et al. “Lepidium meyenii Walp. improves sexual behaviour in male rats independently from its action on spontaneous locomotor activity.” J. Ethnopharmacol. 2001; 75(2–3): 225–29.
Bogani, P., et al. “Lepidium meyenii (Maca) does not exert direct androgenic activities.” J. Ethnopharmacol. 2006 Apr; 104(3): 415-7.
Chung, F., et al. “Dose-response effects of Lepidium meyenii (Maca) aqueous extract on testicular function and weight of different organs in adult rats.” J. Ethnopharmacol. 2005 Apr; 98(1-2): 143-7.
Gonzales, G. F., et al. “Red maca (Lepidium meyenii) reduced prostate size in rats.” Reprod. Biol. Endocrinol. 2005; 3(1): 5.
Gonzales, G. F., et al. “Effect of alcoholic extract of Lepidium meyenii (Maca) on testicular function in male rats.” Asian J. Androl. 2003 Dec; 5(4): 349-52.
Gonzales, G. F., et al. “Effect of Lepidium meyenii (maca), a root with aphrodisiac and fertility-enhancing properties, on serum reproductive hormone levels in adult healthy men.” J. Endocrinol. 2003; 176(1): 163–68.
Gonzales, G. F., et al. “Effect of Lepidium meyenii (maca) on sexual desire and its absent relationship with serum testosterone levels in adult healthy men.” Andrologia. 2002; 34(6): 367–72.
Scientific Evidence for Hormonal Actions: (studies showing maca with a slight estrogenic action)
Valentova, K., et al. "The in vitro biological activity of Lepidium meyenii extracts." Cell. Biol. Toxicol. 2006 Mar; 22(2): 91-9.
