Earlier this month, the Drug Enforcement Administration announced that it had busted 16 underground labs and seized 134,000 steroid tablets and pills, 8,200 liters of injectable steroid liquid (that’s 140 kegs worth), and 1,400 pounds of the raw powder from which steroids are made. In Arizona alone, four labs and 150,000 doses of all types were taken by DEA agents in an undercover operation that spanned 20 states and four foreign countries.

There are, clearly, a lot of steroids out in the world. Investigators suspect there are hundreds more labs churning out performance-enhancing drugs. According to the DEA, most of the material used to make steroids isn’t even in the U.S. – it’s in China. As big as it was, the DEA inquiry offers a view through the smallest of keyholes of this illicit business.

One reasonable inference from the amount of steroids seized might be: there must be a heck of a lot of athletes who are doping. And that’s true.

This month, the British Parliament released a previously unpublished study by the World Anti-Doping Agency that used anonymous surveys to estimate the prevalence of doping at some recent competitions. It estimated that between 29 and 34 percent of the athletes at the 2011 world championships in track and field in Daegu, South Korea used performance-enhancing drugs that season. As many as half of the competitors at the 2011 Pan-Arab Games in Doha, Qatar had recently juiced, the study found. (I was at those Pan-Arab Games, and privy to the barely noted fact that nine gold medals were stripped before the event even ended.)

Amazingly enough, world-class athletes are merely the fine layer of frost atop the iceberg’s tip when it comes to the steroid economy.

To illustrate, and speaking of ice, take Iceland. As part of this recent operation, a lab was busted there. Iceland sent five athletes total, all skiers, to the last Olympics. (Compare that to nine people who were arrested at the steroid lab.) It’s unlikely that an underground steroid economy in Iceland subsists on elite athletes alone. So who is driving this tremendous market?

One answer is non-elite athletes. In years of reporting on performance-enhancing drugs, I’ve frequently been asked why athletes in smaller sports or facing lower stakes would dope, given that there’s little money in it for them.

My answer: people like being good at sports, and anyone who has ever scheduled their life around training for a sport, no matter how big or small, would never have to ask that question.

My alma mater, Columbia University, launched a steroid probe into the football team way back in 1988, when the team had not won a game in five years. Two players admitted to steroid use as part of that internal investigation.

More than a decade later, while I was a Columbia student-athlete, two students were busted for selling steroids on campus, and one claimed he sold to an athlete.

This is a university that gives no athletic scholarships and whose greatest sports successes (post-Lou Gehrig) have come in the pool, on the track, and in the fencing hall. I happen to know about these incidents only because I went there. And still, my reporting has shown that there are nowhere near enough sub-elite athletes to account for the booming trade in illegal steroids. So, again, who is driving this market?

In my observation, the main customers for what’s being churned out of the illegal labs the DEA took down are gym-goers who want to get stronger and look different, supplemented by people in professions where physical strength is prized, such as police officers and soldiers.

For a 2008 Sports Illustrated article on steroids that I co-wrote with L. Jon Wertheim, I spent several days in England with a man named Tony Fitton. Despite not having a college degree, in the 1980s Fitton was given a faculty position at Auburn University, in the National Strength Research Center.

Fitton was already well-versed in steroid use. Years earlier, he had disrupted a study on the training effects of steroids when he began buying the treatment medication from other participants.

At Auburn, Fitton’s job consisted mostly of helping legendary strongman Bill Kazmaier train. “I didn’t even have a bloody typewriter,” Fitton told me. He was, though, a rather brilliant kitchen chemist. He scoured pharmacology and medical texts, often experimenting on himself. He once noticed that a blood pressure drug in trials was causing a peculiar side effect — it made patients’ eyebrows grow together. Fitton figured that if the drug could regrow hair, he could sell it to steroid users to help with the bald patches that sometimes develop from steroid use. Today, you know that drug as minoxidil, the active ingredient in Rogaine.

Fitton was also providing steroids to elite athletes. In the course of reporting that story, several NFL players admitted they’d been his clients — but I was surprised by what I saw when I got my hands on his old business ledger, and other documents related to his dealings. The ledger recounted about a year of his sales, and while college football and NFL players, power lifters, professional wrestlers and bodybuilders were among the buyers, the ledger was filled with a diverse smattering of customers, from gym owners to policemen and soldiers to droves of guys who just wanted to have bigger muscles.

Years later, when I met with a convicted steroid dealer in Florida who’d been selling to a chiropractor working with the Washington Capitals, he told me that police officers and military personnel were steady clients. And, while he also sold to some competitive athletes, he said that young men who wanted to change their physique comprised most of the demand. He, himself, began taking steroids after admiring Arnold Schwarzenegger carrying a tree trunk in the 1985 film Commando.

A year before that movie hit the theaters, Fitton was caught by a customs agent bringing steroids across the border from Mexico, and became the first person to be federally prosecuted for steroid smuggling. Steroids weren’t even controlled substances yet, but they did require a prescription, and he had more than 2,000 boxes worth of the steroid Dianabol in his car.

In 1997, he was arrested again — he told me his supply was coming via commercial airline pilots who picked up steroids in countries where they could be purchased legally. By that point, Fitton had been arrested for steroid distribution three times, and had jumped bail twice. He was sentenced to four months in prison, but his punishment was delayed, because a legal dietary supplement company was happy to employ him and had arranged a chance for him to advise the Green Bay Packers on strength training. The Packers declined to comment on why the team would allow Fitton any contact with their players.

Fitton, who was ultimately deported, might seem like an odd hire for a supplement company, but the supplement industry has a history of overlap with the steroid world. Patrick Arnold, the chemist who created designer steroids for BALCO, was better known in the workout world for having made muscle-building supplements, including androstenedione, the substance that first started performance-enhancing drug trouble for Cardinals slugger Mark McGwire when a reporter spotted it in his locker.

At the time, it was legally available over the counter, and after it was mentioned in relation to McGwire in the news in 1998, sales reportedly exploded by 1,000%, thanks to people at home who wanted to be as muscly as Big Mac.

Pick up any muscle mag at the grocery store, and you’ll get a sense of the target market. While many famous magazines are barely more substantial than pamphlets these days, Muscular Development, for example, can still stop a door.

Past issues of the magazine have featured Q&A’s in which an expert will give specific “how to” advice on dissolving steroids for injection, or how long particular dosages will be effective, and how to limit the possibility of liver damage. Much of the magazine is filled with advertisements for dietary supplements that are clearly attempting to evoke steroid use.

An advertisement for a website called legalsteroids.com shows products using nicknames of traditional steroids — “D-Bol” and “Winni-V” (Dianabol and Winstrol) — but with slightly altered chemical formulas from the familiar substances. Somatropin is a pharmaceutical name for human growth hormone; legalsteroids.com will sell you what it calls Somatroph HC. I asked an online customer service representative of the website how the company could make “legal steroids’’ and he said: “we’ve been able to take the effective parts of the illegal steroids and make it legal.’’ I’ve asked a company spokeswoman how, exactly, this is done but have not heard back.

It remains unclear what’s in these sorts of products. Some supplements may actually be designer steroids. Supplement makers want their products to work, and the industry is lightly regulated, so steroids have been known to show up in over-the-counter products.

The ads often depict muscle-bound men, and sometimes show photos of extremely fit and scantily clad women. An issue might feature a wide range of lifestyle advice to men, from the bizarre — don’t tattoo genitals because a medical report found (surprise!) there can be some unpleasant repercussions — to ads with the familiar tone of women’s magazine advice columns. One example gives four rules: “#1 – Respect Gym Etiquette;” “#2 — Train Hard & Listen More Than You Talk;” #3 – Let The Women Come To You (Animal Instinct 101);” and “#4 – Don’t Be Caught With the Wrong Supplements.”

The content is tailored for men who want to be stronger, feel more energetic and better about themselves as well as turn the heads of women and other men. That, of course, is a far larger portion of the male population than the number of athletes dreaming of Olympic gold.

It is also a market segment that is destined to grow as the Baby Boomers age. The number of men in their 40s who got prescriptions for testosterone more than quadrupled between 2001 and 2011, according to data published by the Journal of the American Medical Association. And guess what’s often cheaper and easier to get than prescribed, pharmaceutical grade testosterone? Chemical analogs of testosterone — that’s what steroids are — that someone sells on the black market or markets as a dietary supplement. In the course of my reporting on this subject, I’ve bought both testosterone and illicit steroids sold as supplements. The latter was quicker and cheaper to get.

Law enforcement agents and steroid peddlers I’ve spoken to over the years say there’s no end in sight to the burgeoning market for steroids. There is loads of money to be made, legal risks are minimal — steroids aren’t exactly DEA’s top priority — and there’s no shortage of people who want to look like the statuesque models they see in the magazines.