Across 3 studies, 2 reported beneficial effects of Tribulus terrestris on erectile function, with one showing a statistically significant moderate effect (IIEF-5 improvement, MD 3.23). The predominant effect size is moderate among beneficial studies, though one meta-analysis found neutral small effects. Populations studied were clinical patients with erectile dysfunction, but no consistent dose or duration was reported.
Caveats: Evidence base is small (only 3 studies) — conclusions should be considered preliminary. Many of the included studies did not reach statistical significance — effect may be smaller than the predominant direction suggests.
Adverse events were recorded in 19 of 24 trials, with no significant differences between placebo and verum in placebo-controlled studies.
from: Herbal Dietary Supplements for Erectile Dysfunction: A Systematic Review and Meta-Analysissaffron and T. terrestris treatment produced mixed results
on both the IIEF-5 [MD 3.23 (95%CI 1.89, 4.58), p < 0.00001]
Korean ginseng, Pygnogenol and Prelox, Tribulus terrestris, Lepidium meyenii, L-arginine, acupuncture and lifestyle interventions were the more predominantly investigated treatments interventions for ED.