Overall, 33 out of the 41 ingredients were not effective for improving erectile dysfunction.

Six ingredients had an “A” evidence level: tongkat ali, Panax ginseng, arginine, yohimbine, Tribulus terrestris, and Pinus pinaster.

Two ingredients had a “B” evidence level: ashwagandha and saffron.

All of the supplements contained 2 to 13 ingredients (more than 5 ingredients, on average), and all of the supplements contained at least 1 ingredient without any evidence supporting its efficacy. Of the 27 supplements, 24 contained ingredients with a dose lower than the minimal amount reported to produce a beneficial effect. Furthermore, 20 of the supplements were expected to have no effect.

Arginine was the most commonly included effective ingredient (63% of supplements), but it was always included in a dose below the minimally effective amount.

Supplements for erectile dysfunction: What’s in them and do they work? Original paper