Summary
Escin seems to improve sperm density and reduces the diameter of the spermatic vein (significantly in moderate cases of varicocele). It therefore it may not just help the symptoms of varicocele, it treats the underlying cause. This is in line with findings from studies looking at the effect of escin in treating varicose veins in other parts of the body.
Human Experimental Studies - Varicocele
Human RCT: Escin improves sperm quality in male patients with varicocele-associated infertility.
https://www.ncbi.nlm.nih.gov/pubmed/19682880
Participants: 219 with varicocele associated infertility.
Groups: Three groups (1) Control - 65 men, (2) Escin - 106 men, (3) Surgery - 48 men.
Dose: In Escin group, 60mg per day - in split doses, 30mg morning, 30mg night.
Duration: 2 months.
Findings: Sperm density was significantly improved in the escin group compared to the control group, as was the diameter of the spermatic vein (significantly so in the case of moderate varicocele). However, the surgery group fared better and the results were significant. Sperm motility did improve in the escin group more than placebo, but not significantly.
Chronic Venous Insufficiency
Cochrane Review: https://www.ncbi.nlm.nih.gov/pubmed/23152216
Molecular mechanisms https://www.ncbi.nlm.nih.gov/pubmed/27727329