Heierdal has personal experience of the subject -- a promising football goalkeeper, he started taking steroids to cope with the physical demands of the switch from the junior to senior ranks, which led to a 10-year period of abuse.
"I started injecting rather than taking pills," the 35-year-old said matter-of-factly in a telephone interview. "I was told by a guy at the gym that taking pills was more damaging for the liver, so I began injecting.
"In the beginning it was great. I got stronger and girls started to notice me."
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It did not take long, however, before the positive effects were eclipsed by the negative and he became arrogant and aggressive.
Football quickly fell by the wayside and the aggression led to a violent confrontation with a doorman at an Oslo nightclub, which accelerated his descent as he began misusing other drugs.
It was only when he found himself preparing a line of cocaine at work one day that he came to his senses and began to seek help.
Heierdal now travels around Norway talking about the risks of doping, and has noticed that the profile of those taking steroids has changed.
"When I started, the people using steroids were almost exclusively men in their twenties and thirties, but what we see now is that more and more young boys and girls are interested," he said.
"It has to do with the fixation with body image, the desire to look good...
"The youngest I have heard of was 11. He had a 16-year-old brother who went to the gym and he wanted to know if he could get hold of something to help him build muscles."
There have also been cases of amateur athletes turning to drugs, with rugby and cycling recording positive tests from relatively low-level performers in recent times.
Last year a player in the strictly amateur Irish sport of Gaelic football received a two-year ban when he tested positive for steroids.
Heierdal said these cases, added to his experience with Norwegian youths, show that steroids are no longer the preserve of muscle-bound gym goers.
"What people don't understand is that there are hundreds of types of anabolic steroids, and only some of them help to build big muscles. Others are used to burn fat and to reduce weight.
"For girls, there are substances that have the effect of giving them muscles that are not huge, but they are very well-defined."
Heierdal's decision to quit steroids meant changing his entire lifestyle.
"I had to cut a lot of people out of my life. I deleted over 200 numbers from my phone when I stopped using steroids, but I had some very good friends and a lot of family who weren't involved and they supported me.”
Heierdal has held hundreds of lectures all over Norway to help people combat the temptation to use drugs.
"It's a combination of information and knowledge," he said. "Parents need to explain that the short-term gains don't last and that the negative side-effects have consequences.
"Sure, in the beginning you put on muscle and you look good, but it doesn't last."
(Editing by Toby Davis)
