The incidents both happened at the Ladywell Pharmacy, Fernbank, Livingston at 16:40 on Saturday 7 September 2013 and at 10:10 on Saturday 14 June 2014.
Police are appealing for people who can identify him to come forward.
He is white, 5ft 7ins, of medium to heavy build, with short dark coloured hair and has a Scottish accent.
Det Supt Pat Campbell, of Police Scotland, said: "These robberies have been terrifying for the staff inside the pharmacy and our officers have been making extensive enquiries to find the man responsible.
"It is of particular concern that this man appears to have targeted these premises on two separate occasions."
"The fact that a significant amount of medicine has been stolen and is in the wrong hands is an obvious concern, and we would urge anyone who may recognise the man pictured or is able to provide any information that might help our investigations to get in touch immediately."
CCTV images have been released of a man police wish to trace in connection with two robberies in West Lothian.