Testosterone is a prescription medication. Taking it simply as a sports supplement would be illegal.
Regarding prescribing TRT, all doctors fall into one of three categories. Some doctors acknowledge that adequate testosterone is one key to male "vitality," shall we say, and are willing to prescribe it if your endocrine blood panels show your total Test is "low-ish," according to AMA standards, provided you present with any of the typical accompanying complaints: low energy, low self-esteem, unexpectedly gaining weight, low sex drive, no lead in the pencil, etc (the more, the merrier).
The second group of doctors will prescribe TRT provided you're below the AMA threshold for "low-normal" in your age group, even if you are asymptomatic. In fact there is a medical precedent for this because Low T itself is associated with depression, diabetes, heart disease, osteoporosis and a bunch of other bad shit.
And the third group view TRT like it was nuclear waste, and won't put you on TRT, even if your blood panels show you're below the "low-normal" threshold, unless you have a connected medical condition. No lead in the pencil doesn't count because the little blue pill fixes that but has lower risk for side effect (and hence lower risk of malpractice suits).
Ideally you need to find a doctor in the first category. Some folks will recoil at the thought of "auditioning" multiple doctors because of the possibility of being connected with "doctor-shopping," which also is illegal. But doctor-shopping involves getting multiple doctors to prescribe treatment for the same condition. That's not what this is. It its your right as a medical consumer to seek out a doctor who you feel comfortable with, and who you think takes a comprehensive view of managing your health care. That's all you'd be doing.
The world is full of people who've only ever heard the myths and old wives tales about TRT, and anabolic steroids in general. I'm going to go out on a limb and guess your two nutrition store guys fall into that category. If you want the straight skinny, I'd suggest you take the time to read the
FAQ stickies at the steroid.com forum. That might well be the best repository of steroid doping knowledge available anywhere (free) on the Interwebs. The stickies are long, and very technical (lots of real 'doctor' words), and certain aspects of it are complicated, but they're very comprehensive and completely stripped of the mythology.
Yes, pharmaceutical testosterone is an anabolic steroid. In fact, it's
the original anabolic steroid. All the rest are imitations of testosterone. And pharmaceutical testosterone is chemically and molecularly identical to mother nature's. The only way to tell the difference is by measuring carbon isotope ratios with a gas chromatograph or an atomic mass spectrometer. Your body cannot tell them apart. It's no more dangerous than the stuff your body produces, however, your body does take measures to see to it that natural Test levels can only rise so high. When you surpass those levels with synthetic Test, you've sailed off the edge of the map.
TRT does tend to cause benign prostate enlargement (BPH), which can be a nuisance in older men. It also can cause the same shit it did when you were 14: zits and an erection every time the wind blows. In large enough doses, it
will shut down natural testosterone production, which could lead to testicular atrophy.
If you're going to do this, I would recommend you ask your endocrinologist about supplementing the Test with hCG (human chorionic gonadotropin). Your body is wired to only let you have just so much Test. So if you're juiced, the
HPG feedback loop will signal your 'nads to back off or stop producing the natural stuff. hCG supplementation interferes with normal function of the HPG loop, and allows the testes to continue producing at their normal rate. Which maintains normal (or at least more nearly normal) testicular function, despite the 'roids. And reduces or eliminates the need to 'cycle' on and off. It just plain makes the 'roids more effective.
And any Category A doctor also should be read on to the hCG and shouldn't have a problem with prescribing it as well (but those guys are not particularly common).