. >> reporter: amy brittain with "the star ledger" of newark discovered a startling case. 248 policeicers and firefighters from 53 agencies tied to a jersey city physician giving out questionable prescriptions. in his first interview since the scandal, jersey city police chief thomas comey says his officers were using testosterone to bulk up. >> when we looked at it, what we determined was, there was a health concern for these officers. we are sanctioned by this government to carry a weapon and potentially use deadly force so you'd like to make sure that that isn't impacted by a potential increase in aggression. >> reporter: his department is far from alone. we found police departments nationwide which have begun a new series of drug tests. no longer just for marijuana and cocaine, but for testosterone ratios and a variety of steroids. amy brittain found a common theme among officers. >> we found that there was almost a sense of a need to feel stronger, faster, to have a better sex drive, to feel better about yourself. >> reporter: testosterone is naturally occurring hormone which di

a amy brittain found a common theme. >> there was a need to feel stronger, faster, to feel better aboutrself. >> reporter: testosterone is naturally occurring, which diminishes with age. but researchers we spoke to say normal testosterone levels fall into an incredibly vague thousands-point scale. in many cases, doctors are putting enthusiastic patients near the top end of the scale. a hormone level that may feel good, but with uncertain long-term effects. in san francisco, dr. karron power is a believer in testosterone. >> atom by atom, it matches what your body would have made on its own. >> reporter: doctors say the bad press is unfair, but in a strange way, also driving and in. >> so, in that way, the press that the athletes shine on testosterone drives men into the clinic for various other reasons. >> reporter: the new england journal of medicine finds only about 2% of men over 40 should be getting any boost at all. it's a statistic that some t users strongly disagree with. >> you know, why not feel as good as you could possibly feel? i think this is quite as simple as that. at som