Crew is launching the website after being granted £151,000 in funding by the Scottish Government.
The site, at www.mycrew.org.uk, goes live on Friday and is aimed at reaching drug users who would not normally access traditional health services for help.
Laura Dey, Crew online support co-ordinator, said: “Crew offers information and support with a non-judgemental stance on drug use. We wanted to take that service and offer it as widely as possible.
“The risk assessment questionnaire is eight multiple choice questions about the effects that drug use might have.
“It covers areas such as health, mood and their finances and gives a risk score.”