Table 1 Summary of randomised clinical trials with maca for sexual function

Zenico (2009) [21] Italy

50 mild ED

36 (SDs, 5)

(50/0)

n.r.

(A) Maca (pulverised dehydrated maca roots directly imported from Peruvian Andes, tablets, 2400 mg/d, 1200 mg/d, 2 daily for 12 weeks, n = 25), no follow-up

(B) Placebo tablets (2400 mg/d, 1200 mg/d, 2 daily for 12 weeks, n = 25)

IIEF-5

Intergroup: MD,

1.10 [0.61, 1.59],

P < 0.001

n.r.

Within group:

(A) P < 0.05,

(B) P < 0.05

Brooks (2003) [22] Australia

16 healthy postmenopausal women with moderate severity of menopausal symptoms

(A) Maca (company commercial product, dried maca powder, 3500 mg/d, daily for 6 weeks, n = 14), 6 weeks follow-up

(B) Placebo (refined white rice flour, 3500 mg/d, daily for 6 weeks, n = 14)

Sexual dysfunction (GCS)

Intergroup: MD,

0.70 [0.08, 1.32], P < 0.05

n.r.

54 (SDs, 11)

(0/16)

>12 months amenorrhea

Within group:

(A) P < 0.05,

(B) NS

Gonzales (2002) [23] Peru

57 adult healthy men

21-56

(57/0)

N/A

(A) Maca (company commercial product, gelatinised maca, 1500 mg/d; 500 mg/d, 3 tablets, daily for 12 weeks, n = 30), no follow-up

(C) Placebo tablets (n.r., daily for 12 weeks, n = 12)

Self-perception on sexual desire

Intergroup: MD,

0.51 [-0.35, 1.37], NS at 4 weeks; MD, 1.64 [1.07, 2.21], P < 0.008 at 8 weeks; MD, 1.64 [1.07, 2.21], P < 0.006 at 12 weeks

n.r.

(B) Maca (company commercial product, gelatinised maca, 3000 mg/d; 500 mg/d, 6 tablets, daily for 12 weeks, n = 15), no follow-up

Within group:

(A) P < 0.05 at 4, 8, and 12 weeks,

(B) NS at 4, 8, and 12 weeks

Stone (2009) [24] UK

8 experienced and endurance trained male (cyclists)

(A) Maca (company commercial product, gelatinised maca, 2000 mg/d for 2 weeks, n = 8), no follow-up

(B) Placebo capsules (Arabic gum, n = 8)

Sexual Desire Inventory

Intergroup: MD,

6.38 [-11.32, 24.08], NS

n.r.

30 (SDs, 7)

8/0

N/A

Cross-over (1 week washout period)

Within group:

(A) P = 0.01,

(B) P = 0.90