Maca

“Twenty-one studies were included in the systematic review and sixteen in the meta-analysis. They revealed a large effect for all outcomes (SMD: FST = 2.26, RRT = 6.26, GST = 5.23, LA = -1.01, and BLA = -1.70)”

“The phytochemical compounds of LmW, mainly macamides, increase physical performance, showing a greater effect at higher doses (dose-response effect)”

“Randomized controlled studies with a pre- and post-test design, conducted both in vitro and in vivo in animals and humans, were included”

“The evidence … suggests unclear effects of maca on semen quality parameters in both men experiencing infertility and healthy men … the total number of RCTs and the total sample size were too small to draw firm conclusions”

“The meta-analysis also failed to show the efficacy of maca in increasing the sperm concentration compared to the placebo (weighted mean difference, 2.22, 95% confidence interval -2.94 to 7.37, p = 0.4)”

“research over the last twenty years has identified up to seventeen different colors (phenotypes) of maca. The color, hypocotyl size, growing location, cultivation, and post-harvest processing methods can have a significant effect on the … clinical application”

“Maca … serves as a dietary staple of native Peruvians, particularly in its dried hypocotyl (tuber) format at >20 g daily … used in many preparations primarily for energy, fertility, libido, and as a vitality tonic for aging”

“Daily doses used in the abovementioned studies ranged between 300 mg and >3000 mg. Still, they did not define active ingredient parameters”

“a worsening effect has been observed with maca products containing proportionally greater amounts of black maca in women with hormonally imbalanced conditions such as polycystic ovarian syndrome (PCOS) and relatively higher levels of estrogen”

“goitrogens, a class of compounds commonly found in a variety of plants, including legumes, cruciferous vegetables, and maca that are known to interfere with thyroid hormone activity”

“research differentiating the colors of maca and clinical applications remains limited”

“preclinical and clinical research has provided data that would expand maca's use into other areas of health such as menstrual cycle regulation, menopausal symptoms, osteoporosis, sperm quality, memory, mood, prostate health, and fitness optimization”

“The objective of this guideline is to highlight the substances of concern when used in HS and TM and is not meant to be an exhaustive list [maca / Lepidium meyenii not listed in Annex A or B]”

“California Gold Nutrition, Peruvian Maca, 500 mg … Force Factor, Fundamentals, Black Maca, 90 Capsules … NOW Foods, Maca, 500 mg, 250 Veg Capsules … Sunfood, Black Maca, 800 mg … Nature's Truth, Red, Yellow, Black Maca, 1,600 mg”