They also urged needle and syringe programmes normally targeted at heroin users to look at how to reach out to people who inject dermal fillers such as collagen or Botox.
About 70,000 people injected anabolic steroids in England and Wales in the past year, according to the National Institute for Clinical Excellence (NICE), a government body which provides guidance on health services.
A study of 395 injectors published last week found that one in 18 had been exposed to hepatitis C, one in 11 had been exposed to hepatitis B and one in 65 has HIV.
NICE has now put new guidance out for consultation urging the establishment of needle and syringe programmes in gyms.
"Anyone who injects drugs is at risk of HIV and other blood-borne viruses, regardless of their substance of choice," said Dr Vivian Hope, an expert at Public Health England.
"Our recent research suggests that levels of HIV and hepatitis infection among men using image and performance enhancing drugs have increased since the 1990s."
She urged "easy access for those who inject image and performance enhancing drugs to voluntary confidential testing services for HIV and hepatitis, as well as to appropriate sterile injecting equipment through needle and syringe programmes".