Difference between Oestrogen and Estrogen

What is the difference between Oestrogen and Estrogen?

Oestrogen as a noun is any of a group of steroids that are secreted by the ovaries and function as female sex hormones. while Estrogen as a noun is any of a group of steroids that are secreted by the ovaries and function as female sex hormones.

We hope you now know whether to use Oestrogen or Estrogen in your sentence.