Metformin hcl and male sexual drive

I would like to know if there is any relationship between this drug, metformin HCL, and the male sex drive. I started taking two medications at about the same time, metformin HCL and Lisinopril and wonder if either of these two medications can reduce the male sexual drive. I have noticed a considerable reduction since I started this medication about 3 months ago. Is one of them the culprit? is there some other drug that could be subsitutited?

Thank you,

R