Everyone knows someone who has died. In the circles of Estonian friends who use "china white", death is a constant possibility. They know that. But that does not mean they can stop.
It's so addictive," says Marko, who has lost two friends to overdoses, and survived two himself. In Estonia, the drug - whose proper name is Fentanyl - is taking a heavy toll of young people. Nationally, drug overdoses now kill more people than road accidents.
Marko desperately wants to break his addiction. He started injecting seven years ago, aged 18.
I was young and stupid. I tried it with my friends when I was drunk and began to like it, and soon I was doing it every day," he says. He has managed to cut down, and is currently shooting up three or four times a month. But he needs a daily dose of methadone to cope with the withdrawal symptoms.
And the mental dependence is much harder to deal with.
I was away from Estonia for one-and-a-half years and didn't do drugs. But when I came back, within the first hour, I felt the temptation again - it's in my head somewhere and I can't get it out. I thought I will only try it for one time - I just wanted to feel it once more. But there's no such thing as one more time. Back among his drug-taking peers, he dreams of escape.
"I have to get away from Estonia again. That's the only solution."
Fentanyl first appeared in Estonia about 10 years ago, during a heroin shortage.
At an addiction treatment centre in the capital, Tallinn, another addict, Ragnar, explains why it has got such a grip. It can be hundreds of times more potent than heroin and, once sampled, there is no going back. People who are used to china white don't feel heroin any more. [Heroin] doesn't give any effect after china white. I found it meaningless," Ragnar says.
He has good reason to want to break his habit. I have overdosed about fifty times," he says. I don't know which kind of miracle this is. Every time I overdosed I am dead. But the emergency services came and saved my life."
According to the most recent data, Estonia's overdose mortality rate is the highest in the European Union - seven times the average.