There are two type of compounding pharmacies in the US. Small compounders, 503A aren't regulated by the FDA. They're controlled by state laws, and cannot send meds across state lines. They make all kinds of unapproved meds, like peptide combinations, and can freely use EO.
Large compounding pharmacies, 503B are more like small pharma factories. They supply hospitals, doctor's offices, mail order, and other pharmacies. and are regulated by the FDA.
EO isn't banned, but it's listed as "inactive" on the FDA approved excipients list and highly discouraged. There are no FDA approved drugs still sold with EO. Even the generics for discontinued brand name drugs like Delatestryl, Test-E with EO, removed EO from their formulas.
A 503B can use EO but it's rare, and only when exactly copying an older drug that was previously approved by the FDA with EO, If they mix up some new compounded med with EO they have to prove to the FDA it's not harmful, also exposing them to being sued by anyone who has a bad reaction, so they just avoid it.