Anthony Bosch, founder of Miami drug clinic Biogenesis, fidgeted as he sat across from Scott Pelley of CBS News in a mid-January interview and began listing all the drugs he’d given to New York Yankees third baseman Alex Rodriguez. 

“Testosterone…” he began, “insulin[-like] growth factor 1, human growth hormone, and some different forms of peptides.” 

“All of them banned?” Pelley asked. 

“All of them banned,” he replied. 

Bosch had allegedly been supplying A-Rod and at least 13 other Major League Baseball players with these synthetic drugs that boost performance and muscle growth. And despite the fact that both testosterone and growth hormone are naturally occurring hormones in the human body—testosterone is a steroidal hormone that builds lean muscle, and HGH is produced in the pituitary gland, activating a receptor that signals cells for muscle growth to turn on—MLB and other sports leagues ban the use of them in a synthetic form.

Why? “The performance-enhancement aspect is really at the heart of it,” says Rick Collins, a lawyer at Collins, McDonald & Gann in Mineola, NY, and one of the foremost experts on performance-enhancing-supplement law in the country. “Testosterone 

and anabolic steroids have been linked with and inextricably interwoven with the idea of cheating.”

The substances A-Rod was allegedly taking weren’t banned only by MLB; many were flat-out illegal. Testosterone and anabolic steroids have prescription use for people with hormonal deficiencies, but both are classified as Schedule III banned drugs by the DEA, and HGH laws vary depending on the state. “[HGH] is regulated under a specific law that limits its distribution and the reasons a physician can even prescribe it,” says Collins, and testosterone possession without a script could land you in jail.

Using testosterone and steroids also has serious health risks, ranging from increased urination frequency all the way to sexual dysfunction—including the famed shrinking of the testicles, or testicular atrophy. This happens because using synthetic testosterone can shut down your body’s normal production of the hormone. Synthetic HGH overuse can cause joint pain and an imbalance of good and bad cholesterol in the body. It can also accelerate your body in ways you might not want.

“If somebody is running superphysiological levels of [testosterone] from some source [such as steroids], that sets him up for also possibly accelerating the growth of tumors in the case of someone who’s vulnerable to cancer,” says Dave Ellis, R.D., of the Collegiate and Professional Sports Dietitians Association. “There seem to be people who take testosterone to slow the symptomatic sarcopenia [loss of skeletal muscle mass] of aging.” But taking steroids can exacerbate existing heart problems, he adds.

Synthetic testosterone and HGH can’t be found at your local GNC, though what you see in supplement stores often sounds close to something like an illegal hormone—and a lot of people can’t tell the difference. However, supplements from companies like Novex Biotech and BPI Sports aren’t illegal synthetic hormones—they’re basically foods.

Dietary supplements are regulated as foods, not drugs, because “their ingredients are naturally present as components of what people eat, so they’re deemed to have inherent safety,” says Collins. “Amino acids, for example, are present in our foods. Supplement products made of these amino acids are very different from prescription-drug products like testosterone and HGH. The supplement products help spur the body to naturally produce more hormones, while the prescription drugs are synthetic versions of the hormones themselves.”

Indeed, a 2009 study in Reproductive Biology and Endocrinology showed that the amino acid D-aspartic acid (also called D-asparaginic acid), one of the main ingredients in TestroVax, enhanced the release of testosterone in the body. 

A study—first presented at the prestigious Obesity Society’s 30th Annual Scientific Meeting and later featured on The Dr. Oz Show—revealed that the specialized, patented (U.S. Pat. No. 8,551,542) oral amino acid complex contained in Growth Factor-9 is actually capable of increasing mean, serum HGH levels by 682% in both men and women of a wide age range. 

Other supps like BPI GRP-HD work in a similar way with different ingredients, utilizing natural growth-factor peptide-releasing agents and roots such as Calea ternifolia, Eucommia ulmoides, and kudzu (Dolichos lobatus) to increase growth hormone levels. Or the natural test-boosting Nugenix Free Testosterone Booster, which combines the test-boosting power of zinc and Testofen, a compound derived from the fenugreek plant that’s been clinically studied; a 2011 study in Phytotherapy Research resulted in 60 male subjects reporting increased libido and muscle strength after taking Testofen. 

“Dietary supplements don’t have active pharmaceutical ingredients in them,” says Ellis. “There are lots of regulations that the supplement industry has to follow. They’re made of ingredients that are out there on the market and assembled together, hopefully under good manufacturing practices.”

Pro baseball, in the meantime, is plagued with steroids and HGH—and the culprit might be in your neighborhood. “The evidence from the Biogenesis case is showing that the antiaging clinics seem to be, for all athletes, a destination for getting your hands on some type of compounded product,” says Ellis. That is to say, testosterone or HGH compounded into another drug or another form of delivery. “That’s a bit of another unregulated beast, the compounding industry’s production, theoretically for legitimate application through a licensed health professional like a doctor, to a patient who’s really been qualified as a candidate. And now, of course, the not-so scrutinized application of all these growth delivery systems of some kind of musculotrophic compounds seem to be cavalier in some of these environments.”

The difference between test- and HGH-boosting supps and synthetic, banned substances is stark. The supps are aimed at boosting testosterone and HGH in a safe, natural way. “The chemical difference,” as Charles E. Yesalis, Ph.D., of Penn State University puts it, “is like the difference between [drinking] orange juice and gasoline.”