The victim was discovered lying seriously injured in Commerce Street, near King George V Bridge. He was taken by ambulance to Glasgow Victoria Infirmary but died a short time later.
Following a post mortem examination, his death is now being treated as murder.
Detective Inspector Pat Campbell of Helen Street Police Office, said yesterday: "Officers are currently carrying out extensive inquiries in the area and studying CCTV footage in an effort to glean further information.
"I would appeal to anyone, who may have witnessed an incident take place, or anyone with any information to come forward."