A man was held in connection with dealing steroids following police raids at St Helens premises.
The 27-year-old, who has since been released on bail pending further enquiries, was arrested on suspicion of possessing anabolic steroids with intent to supply.
He was taken in for questioning following the police swoop earlier this month.
A Merseyside Police spokesman confirmed a warrant had been executed under the Misuse of Drugs Act.
A number of items were seized by officers and have been sent away for forensic analysis while the investigation continues.
A man his 30s was arrested on suspicion of dealing anabolic steroids and temazepam following a raid on a house in Clinkham Wood.
He has been released on police bail pending further enquiries.
It is the second arrest in connection with steroid dealing that has come to light in recent weeks.