The owner of a Sydney hair salon has been charged after allegedly sexually assaulting two men earlier this year.

Detectives began to investigate in June after two men, 34 and 37, alleged that the incidents had taken place at a salon on Gardeners Road, Rosebery.

Police allege the owner of the business met each of the men on an online dating site and invited them to his business on separate occasions.

It is alleged that the men, who were not known to each other, unknowingly ingested a substance before being sexually assaulted.

The two separate incidents allegedly occurred on March 8 and May 25.

After extensive inquiries, detectives arrested a 39-year-old man at the business at about 11am on Friday.

He was taken to Mascot Police Station where he was charged with two counts of using an intoxicating substance to commit an indictable offence and two counts of sexual intercourse without consent.

The man was refused bail to appear at Bail Division Court 7 on Saturday.