White oval pill with Z on one side & # 70 on other what is it please?

Z 70
Pill imprint Z 70 has been identified as Metformin hydrochloride 500 mg.

Metformin is used in the treatment of diabetes, type 2; polycystic ovary syndrome; insulin resistance syndrome; female infertility and belongs to the drug class non-sulfonylureas. There is no proven risk in humans during pregnancy.

Metformin 500 mg is not subject to the Controlled Substances Act.