BLUE FIX: The Chinese version of Viagra, a drug that is used to treat erectile dysfunction.

Like any other job, this one requires hard work.

But not everyone would mind the challenge. The task: Testing fake Viagra on yourself.

That's what people working for manufacturers of fake Viagra in China are being forced to do.

They are given money to sleep with prostitutes, or they can take the pill home and test it while sleeping with their wives.

But some employees found the job "too much hard work" and quit, The Telegraph reported.

The tests helped the manufacturers decide how much genuine sildenafil (the main component in erectile dysfunction drug Viagra) they could mix with cornflour, Chinese newspaper Sanxiang Metropolis reported.

"Some workers went home to test it, but for out-of-town workers, we would arrange for them to go to massage parlours and we would give them reimbursements," one worker told the newspaper.

Originally, the drugs were made with a ratio of 1:1 of genuine medication and cornflour, but the amount of sildenafil was increased by 50 per cent after the workers reported mixed results, the newspaper said.

"The staff were very happy to test the fake medication at the beginning, but soon became annoyed when the pill-testing became too much hard work," one employee was reported to have said.

The trade in fake Viagra in China has been booming in recent years.

About 1.5 million of counterfeit sex drugs were seized in Guangdong last September, reported South China Morning Post.