A man drawn into the world of having sex while high on illegal drugs has described how he became a “zombie” whose life was slowly deteriorating.

Chris – whose name has been changed – told the BBC he started to take part in chemsex, short for chemical sex, which helped mask the “the shame and guilt” he said he felt growing up gay.

The Londoner said after becoming addicted to chemsex – which typically involves men who have sex with men using the drugs crystal meth, methedrone and GHB/GBL to enhance their sexual experience – he faced a “wall of silence” from helplines and others within the community.

Campaigners say support is “patchy” due to gay sex stigma and has called for this to change. The government says it is aware of the harm caused by chemsex and has issued guidance to local authorities on managing the issue.

Chris was initially offered drugs at a party, but it was not until a few months later that he then began to actively seek it out more and find people who were taking drugs.

He said at first it took away “a lot of the shame and guilt you have about growing up being gay. It’s kind of quite liberating”.

However, that quickly changed.

“No-one really speaks about it. Everyone is slightly ashamed about it. It’s all behind closed doors. It doesn’t really spill out into the real world. It’s very secretive,” he said.

Chris said his friends told him he was almost like a “zombie”.

“Slowly, your life starts to deteriorate because you are missing work on a Monday. And then your work is obviously not up to standard.

“You can’t do much until Wednesday. And then it all starts again on a Friday,” he said.

“You have to eat, you have to sleep, you have to get on with your life but all you’re really doing is looking forward to the next time you can take drugs,” he added.

“Which is to escape the horror that is your life, the misery that is your life which you’ve created but, in a way, you don’t seem to see that because all you want to do is take drugs.”

Campaigners have said chemsex among some gay men has a stigma attached that meant many were not seeking the help they needed.

Ignacio Labayen De Inza, chief executive of the London-based charity Controlling Chemsex, is calling for people to start a conversation around chemsex to help change that stigma.

He said: “Chemsex is very available but not everyone has access to reliable information.

“Not just the government but no-one is doing very much. People think there is nothing we can do because it’s going to carry on happening, but people could make sure that they set boundaries and to keep safe.”

He said there was a stigma attached to it because “we are talking about sex, we are talking about gay sex, we are talking about drugs”.

Philip Hurd, a specialist adviser at Controlling Chemsex, was involved in chemsex 12 years ago and said it took a near-death overdose for him to realise he needed to stop.

He said: “You get close to the criminal justice system, and you start doing things that are dangerous.

“And then I had a near-death overdose. The doctors said I was very lucky to survive, and I had to get my parents down from the country in their early eighties. That was the point I thought I can’t do this; I’m going to die.”

Mr Hurd, who lives in London and now volunteers at Controlling Chemsex, uses his personal experience to help others.

“I think it’s possible for a person with good psychology, sociology skills to support somebody coming out of chemsex but nothing can replace having been there knowing,” he said.

An Opinium Research poll of 2,000 people for the charity found that 76% of those surveyed were not familiar with chemsex.

Just over a third of those who identified as gay/lesbian were not familiar with the risks of chemsex, the study also found.

Veronika Carruthers, a lecturer at Portsmouth University, has been looking into the current support available across the south of England and found it was still “pretty limited” and “patchy”.

“We consider this to be a bit of a postcode lottery,” she said.

She explained that some people did not know the right services to turn to.

“Particularly if we look at it from a divide of drug counselling services and sexual health clinics, while sexual health clinics are preferred there is still an element of staff not having the appropriate knowledge of what chemsex actually is and in turn not being able to provide the most effect support,” she said.

“In regards to drug counselling services, quite often we have recovery workers who have never actually heard of chemsex and therefore they’re not able to provide any form of support and individuals often don’t feel that is the most appropriate place for them.

“As a result people don’t want to call for help or support from particular organisations over others.”

A Department of Health and Social Care spokesperson said in addition to issuing guidance to local authorities, it had boosted the Public Health Grant by almost £200m.

“Local authorities can use this to improve drug and alcohol treatment and recovery interventions, including for people involved in chemsex,” the spokesperson said.

“We continue to work with substance misuse commissioners and sexual health commissioners to improve access to support services for those who use drugs in this context.”

• Details of information and support with addiction in the UK are available at BBC Action Line.