Antonino Coppola, 23, was last seen on Thursday, 16 September leaving Bow Road Station in the direction of Mornington Grove, E3 after he told a friend he felt unwell.
Antonino left his luggage with a friend and has not been seen since.
Detectives have released three new images taken at 12:46hrs on 16 September as he walked out of Bow Road Station at the last time he was last seen.
His disappearance is out of character, and his family and friends are growing increasingly concerned for his welfare.
Antonino, who is Italian and had been living in London for the past two years, is described as 6ft tall and of slim build. When he was last seen, he was wearing a white T-shirt, black trousers and orange Nike trainers.
He is known to have links to parts of southwest London.
Detective Inspector Sian Hutchings, leading the investigation, said: “Antonino’s disappearance is completely out of character and his family and friends are desperate to hear from him.
“Over the last three weeks, we have been carrying out extensive enquiries to try and locate Antonino, including reviewing a large amount of CCTV footage and speaking to those who knew him in London.
“I would appeal directly to Antonino to get in contact so we can let them know you are safe and well. I would also ask anyone who has seen Antonino or knows where he is to get in touch.”
If you can help police find Antonino then please call police via 101 quoting reference 21MIS028497.
You can also contact the Missing People charity anonymously on 180 000.