I have the following table and trying to merge it:

email1@mail.com value1
email1@mail.com value2
email2@mail.com value3
email2@mail.com value4
email2@mail.com value5
email3@mail.com value6
email3@mail.com value7
How do I convert into this without using macros, just simple excel functions please.

email1@mail.com value1, value2
email2@mail.com value3, value4, value5
email3@mail.com value6,value7