tonight on "nightline," younger, stronger, leaner. from ceos to cops, it's the performance-enhancing drug that can make men fitter, more energetic, even better in bed. but there may be a dangerous catch. why even police departments are testing their own for testosterone. chasing anaconda. massive jaws, beady eyes and 200 pounds of coiled muscle. our team ventures underwater in the remote wilds of brazil to get close, maybe too close, to the most fearsome snake on earth. and, from punk rock beginnings to 65 million albums sold -- ♪ don't want to be an american idiot ♪ >> their 18-year career has even spawned a hit broadway musical.

tonight we hang with rock kings of reinvention. the guys from green day. >> announcer: from the global sources of abc news, with terry moran, cynthia mcfadden and bill weir in new york city, this is "nightline," september 21st, 2012. >> good evening, i'm terry moran. you could call it the macho man's little helper. the latest performance-enhancing drug to sweep the nation. banned in professional sports, testosterone injections have become the magic bullet for men looking for better muscles, even a better sex life. but for some, the side effects can be dangerously unpredictable. so much so that police departments nationwide are now cracking down on their own officers. here's abc's neal karlinsky. >> reporter: chris running has bulging biceps, washboard abs, two homes and four businesses.

and still has time for walks on the beach and wine with his wife, rebecca. >> cheers. >> reporter: but he doesn't do it on his own. his secret, a little vial he injects into his leg twice a week. a tiny dose of the hormone testosterone. >> i couldn't run four companies at the pace i run without this hormone, flat-out. >> reporter: he is part of a new generation. a driven, successful man who doesn't mind shooting up to get an edge and stay young. in less than three years, he says testosterone has transformed him. stripping away 30 pounds of fat, building muscles that he never had and sharpening his mind to the point that he says he has an absolute edge over the next guy. >> successful business people want to be more successful. and i think if they knew how effective testosterone could be for them, to have even more of an edge, they would be all over it. >> reporter: "t," as it's sometimes called, has quietly

moved from the drug of shame in sports to something marketed by some doctors as a virtual fountain of youth for middle aged men. prescriptions have doubled in the last six years. >> you might have a treatable condition called low testosterone, or low "t." >> reporter: but there are possible side effects. blood clots, prostate cancer, impatience and aggressive behavior. and it's that last side effect that is setting off alarm bells in, of all places, some of the nation's largest police departments. >> it can cause you, basically, to make rash decisions. get angry. and when you're talking about someone who is carrying a gun, that's a pretty dangerous situation. >> reporter: amy brittain with "the star ledger" of newark discovered a startling case. 248 police officers 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 diminishes with age. here's the tricky part. researchers we spoke with say normal testosterone levels fall into an incredibly vague 1,000-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. >> bioidentical, which means atom by atom it matches what your body would have made on its own. >> reporter: doctors who prescribe it say the bad press is unfair, but in a strange way, also driving demand. >> 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 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. so if i have to at some point start taking growth hormone because it will help me feel better and stay, you know, more fit and perform better, whatever that might might mean at whatever age i'm at, then i'll

certainly do that. >> reporter: a performance-enhanced lifestyle, banned on the playing field, growing strong everywhere else. i'm neal karlinsky in san luis obispo, california. >> testosterone. thank you, neal karlinsky, for that. next up, our team treads the waters in the wilds of brazil searching for the biggest and most feared snake on earth, the anaconda. took it on the freeway, -drove the camry, and it was just like -- this was the car for me. [ ryan ] it has stuff that guys like, like the rims and the sleekness to the body. and, then, had the bluetooth and the navigation that diana really wanted. [ diana ] and it was an se, so it felt really grounded to the ground. [ man ] grounded to the ground? yes, yes! grounded to the ground. [ male announcer ] see their story and more at the camry effect. camry. from toyota.

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"nightline" continues from new york city with terry moran. >> the anaconda is one of the most fearsome beasts on earth. a giant snake that lives off its own incredible strength. and rose to pop culture fame as the villain of a cult classic film.

so, our team went knee deep into the remote waters of brazil to chase these snakes, aided by one man who has made it his life's work. here's abc's matt gutman. >> reporter: underwater, faced with the world's biggest and deadliest snake, the anaconda. those beady, lifeless eyes. the endless scaled form, over 200 pounds of muscle, sliding a few inches from my face. its head, the size of an anvil. it's the stuff of nightmares, horror movies and native myths. legend has it they drag off children and pets in the night. and to my horror, the legends happen to be true. why do people fear them so much? >> well, there have been records of anacondas try to get children. >> reporter: that would be a good reason. >> yeah. >> reporter: that's lawrence,

who spent months tracking the world's biggest snakes, diving with them and filming them for nat geo wild's "secret brazil" series. a peek into the untamed world of brazil's savannas. there, the dry season pushes animals to desperation. the feeding frenzies of the piranha, the cannibalism of the croc's cousin. it's a place where anacondas can bite off more than they can chew. lawrence took us on a journey to the anaconda's heartland. nearly 1,000 miles from rio to remote bonito. >> hey! bonito. welcome. >> reporter: we unloaded the boats. the stream cool and clear. i'm kind of hoping we don't find one so i don't have to go in the water. >> don't say that. come on, man. >> reporter: you get to defend yourself with that and i have this. >> no, this is not what you think. >> reporter: and our date with

an anaconda approaches. what are we looking for? >> if we see a thick branch that swims, that's the anaconda. >> reporter: we found the stream where just months before, lawrence found this monster. >> the head was giant. as thick as a dive tank. that was a dinosaur. it was a snake that when i look at it, i say, "wow." >> reporter: our local guide has tracked these waters for 50 years and seen these giant snakes decounter animals like a capybara, the world's biggest rodent at nearly 100 pounds. watch in this video. an anaconda crushes the capybara's bones and begins to swallow. but they only feed a few times a year. >> they feed off pigs, dogs, chicken. so, the natives don't like them.

>> reporter: soon enough, they spot one. >> there's a very small one. you ready? >> reporter: no, i'm not ready. this is insane. but seeing them in the brush isn't good enough. when the boat gets too close, the anaconda launches itself into the water. we follow it for a few seconds -- but with the flick of its tail, it's gone. what's your fascination? you keep coming back here. year after year. you dive with them. >> anaconda is one of the most charismatic and famous animals from here -- >> reporter: charismatic? >> oh, absolutely. you look into his eyes and he's strong. like the indigenous people, they believe they're not a snake, they're an entity. a lot of admits relating anaconda to the creation of the world. >> reporter: what about that tongue? >> yeah, sometimes it's scary, like, when it's here. >> reporter: we hop in the zodiac. >> 15-foot anaconda.

>> reporter: minutes later, we spot it. >> see the head? >> reporter: a giant, closer to 17 feet. it's now tense as we get into the water. >> even if he's under your legs, don't move. >> reporter: no matter what, don't move? >> freeze. >> reporter: the first was quick and elusive. but watch this one. all 17 feet of it slither from its snoozing place. under water, you see the giant head coming towards us. we're holding our breath this anaconda keeps coming. i reach out my hand, tiny, compared to that massive body. between them, they have 40 years plus experience filming under water. their shots are steady, calm. mine? frenzied. but the anaconda isn't.

it's calm. dissolving effortlessly through the murk. and silently, the giant disappears. i'm matt gutman for "nightline," bonito, brazil. >> wow. "secret brazil" premieres sunday, september 23rd. on "nat geo wild." thanks to matt and the anaconda. just ahead, punk heroes and lasting rock icons. we hang out with the guys of green day.

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the they've won five grammys, sold over 65 million albums, kept themselves on the cutting edge of rock for 18 years and even inspired a hit broadway musical. so, what could be next for green day? how about releasing three albums back-to-back, and going "on the town" with abc's t.j. winick. ♪ do you have the time >> reporter: from underground punk, to serious pop commentary on the state of america.

♪ welcome to a new kind of >> reporter: green day has been blazing their own musical trail for 18 years. ♪ don't want to be an american idiot ♪ >> reporter: with 65 million albums sold, it's been quite a journey for billie joe armstrong, mike dirnt and tre cool. this is sort of the quintessential rock star moment, isn't it? >> 20 minutes ago in my hotel room is probably a better story. >> reporter: we caught a ride with the trio this past saturday on their way to play new york's irving plaza. the scene of their first headline show in the city, all the way back in 1994. how do you keep it fresh? there are countless musical acts that break up because they can't stand each other anymore. >> we actually like spending time together. when we're not on stage, we're hanging out. >> reporter: once teens playing punk rock, they are now men. >> i'm all of your dads. >> reporter: all around 40, all with children.

you're all parents, right? i mean, can you still -- >> apparently. >> reporter: can you be crazy hard-charging punk rockers? is that still possible? >> i think it's good to be honest to your children, let them know who you really are and let them live life, and yeah, be real. >> my younger son is a guitar player, so, we have a good language that we can speak with each other through music. i don't think a lot of parents really have that. ♪ dear mother can you hear me >> reporter: while they may have more responsibilities now, green day continues to reinvent rock stardom. ♪ >> reporter: this tuesday, they release "uno." the first album in a trilogy. in november, two months later, they unveil "dos. in january, "tres." >> three albums. what we're doing right now is sort of the short attention span of the culture. and how things go from snooki and j-woww to all of a sudden,

insanity workouts and stuff like that. it just -- the way we look at it, we're part of that culture. we're part of having sort of attention deficit disorder. >> reporter: some might consider the staggered triple release a risky move. but for green day, it's nothing new. consider 2005's "american idiot." the rock opera turned broadway musical, now considered by many, the seminal album of the decade. ♪ calling out to idiot america >> reporter: the music was a condemnation of an ambivalent america led by george w. bush. >> we didn't know if people were going to agree with what we had to say or not. it was a bold statement and we made it. you know, it's better to regret something you have done than something you haven't done. we don't go by what the trends are, and i think that's what's created our longevity. >> reporter: on saturday, the band played with abandon for over 2 1/2 hours straight. ♪ whipping the crowd into a frenzy with a mix of old favorites and new releases.

incredibly, after all these years, all three consider this the most creative time in their careers. >> we brought everything back into what it's all about to begin with and that is writing a good song. >> reporter: name an award, and they've probably won it. including five grammys. despite all their success, green day has never lost the enjoyment or the innocence of taking the stage for the very first time. is it more difficult on some nights than others? to bring your a-game? >> as long as we get nervous before we play a show, i think that's the key that we care about what we're doing. and you want to bring everything you have and leave nothing left on the stage every night. >> reporter: for "nightline," i'm t.j. winick in new york. >> green day. thanks to t.j. thank you for watching abc news. check in for "good morning america" tomorrow morning.