A 2009 study in Peru found Black Maca to be the best for increasing sperm count and motility as well as for boosting male libido.

A study from 2013 reported that Black Maca has a positive effect on spermatogenesis (the formation of sperm cells). 

A Swiss study from 2010 showed Black Maca to excel at protecting bone structure and preventing osteoporosis.

2 studies from China in 2006 and 2011 found Black Maca to be superior for increasing memory, concentration and learning skills.  

A UK study from 2011 found that Black Maca supported the most rapid muscle growth and endurance of all varieties of Maca.