Liam Colgan travelled to Hamburg with 18 friends for his brother’s stag do when he became separated from the group on a night out.
The 29-year-old from Inverness, due to be best man at his brother’s wedding in three weeks’ time, was last seen at around 1:30am on Saturday leaving a bar in the Reeperbahn area.
Hamburg Police spokesman Ulf Wundrack said: “We still hope to find him alive.
“When he was reported missing by his relatives we have taken measures to find him.
“None of these efforts has been successful so far.”
Officers have made contact with hospitals and taxi-companies, used man-trailing dogs, conducted witness interviews, published photos in newspapers, TV and online and tried to find his mobile phone.
Police Scotland has also been in contact with the Foreign and Commonwealth Office and said it will assist with inquiries in Hamburg if needed.
On Tuesday, Dundee United’s captain Willo Flood posted an appeal on the club’s Twitter feed which asked people to share the video to help find Mr Colgan.
Mr Flood said: “This is my appeal to everyone out there to help bring Liam Colgan home safe.
“Liam disappeared in Hamburg on Saturday in the early hours of the morning.
“Liam’s family have asked everyone to share this to raise awareness and bring him home safe and sound.
“Liam, if you see this get in touch buddy.”
Hamburg Police have been searching the Elbe river and canals in the city.
Search dogs have been used and hospitals checked in the search.
The Foreign Office has said it is assisting Mr Colgan’s family.