David, a Brown University teaching assistant and doctoral student, is feeling pretty pokey tonight. He’s counting on the two fat, butterfly-bearing pills he ingested earlier this evening — leftovers from yesterday — to kick in and lift his exhaustion. For now, slouched over a Guinness at the Sligo Pub in Davis Square, he yawns languidly while talking about ephedrine (he and many others pronounce it ef-ah-drin, but doctors pronounce it eh-fed-rin). Self-assured and bright, David says he once used ephedrine regularly over a period of three years: “I used it a lot when I was working late on the [undergraduate] school paper. When I’d take it, I’d wear this bandanna around my head to let people know that I was in ‘ephedrine mode.’”

“Ephedrine mode” made David a fiend for nicotine, but it also gave him, like many other users, a crucial boost under stress. “It’s a well-known secret among grad students that ephedrine helps a lot if you’re tired and you have to teach,” he confides. He begins to share his “favorite ephedrine story,” laughing about a conference where he had to speak unexpectedly. But before he can finish, he gets completely distracted and forgets about the tale altogether.

David says he’s never incurred any ill effects from ephedrine use — aside from slight next-day burnout — and until yesterday, he hadn’t popped herbal E in probably six months. But inspired by his experience this weekend, tomorrow he’ll purchase a 60-count bottle of 25 mg doses from the Davis Square Store 24. And tomorrow night, before plodding back to Providence on Monday, he and a pal will piggyback it onto Xanax and head out for pints at the Burren.

David isn’t the only person around who both refuels on ephedrine and does it for kicks. He’s just one of the few willing to talk about it.

DAVID EXEMPLIFIES the two major types of casual ephedrine user: high-wired fireballs who swap it for coffee, and frivolous thrill-seekers seeking a cheap high. But many people also use ephedrine’s herbal source, a Chinese herb often billed as “ma huang,” to lose weight and gain muscle. Besides workhorses repossessing hours from the sandman, high-school kids weaseling for accessible intoxicants, ragged rig drivers with too many highways to travel, and frivolous college students foraging for a fix, ephedrine eaters also include middle-aged women looking to lose their love handles, bodybuilders pumping barbells, asthmatics trying to loosen their lungs, tank-topped gym bunnies staving off fat grams, and hard-playing athletes squeezing their bodies for energy spurts.

Ephedrine not only serves a variety of purposes; it is legal, it’s available, and it packs more bang for the buck than most other drugs. But its relationship with the medical world and the FDA is volatile. Some doctors call it a stealth catalyst for heart trouble, and some say regular use can be highly addictive. Others claim that ephedrine is perfectly safe when consumed responsibly.

But the controversy surrounding herbal E is rendered more or less invisible when the drug is routinely found selling beside Pokémon trading cards and stainless-steel cookware on, say, a Web site out of Ohio (www.mtenutrition.com). Spit at a shelf in GNC and probably a third of the time your saliva will hit an ephedra-based product: Xenadrine, Metabolife, Ripped Fuel, Metabolift, Stacker 2, Thermo-Max. Rows of ephedrine pills marketed for asthmatics also line the back counters of many local convenience stores and gas stations: Mini Tabs, Ephedra Super Caps, White Crosses, and Black Crosses.

Behind the pseudonyms, some basic facts help to put ephedrine into context. Considered a performance-enhancing drug, it’s banned from the Olympics: not only have athletes been stripped of honors after testing positive for it, but so have racehorses at Suffolk Downs. But perhaps more damning is the fact that ephedrine and its chemical cousin pseudoephedrine (an active ingredient in Sudafed and many other decongestants) are both are used in the manufacture of methamphetamine (also known as crank, crystal meth, or speed). Underground meth labs buy large quantities of over-the-counter ephedrine and pseudoephedrine, which are critical ingredients in the homemade drug.

These outward signs of the drug’s potency have given rise to a small but growing anti-ephedrine movement. Within the past five or six years, the brouhaha over ephedrine and its potential dangers has grown from a dull roar to a shrill scream. Since it is a central-nervous-system stimulant, ephedrine constricts blood vessels, raises blood pressure, and increases heart rate — all of which could lead to heart attack, stroke, and death, especially in people with undiagnosed circulatory problems. Since 1994, the FDA has reportedly received complaints of more than 900 adverse reactions to ephedra-based products, and more than 40 deaths. As a result, hundreds of lawsuits are pending against companies producing ephedra-based products, and entire law firms specialize in ephedra-related personal-injury suits. Yet manufacturers, as well as an ephedrine-defending brain trust called the Ephedra Education Council, reject these charges, claiming, among other things, that they’re based on scrappy science or that alleged victims suffered from pre-existing health conditions. And although these “experts” have mostly gotten their way, this past February a state jury in Alaska awarded $13.3 million to an ephedrine-related-stroke victim. It was the first such ruling ever.

Still, although the FDA has held public hearings on ephedra, the laws haven’t changed much; with only a few varying state restrictions, ephedrine is generally legal and widely available. And as the mainstream press has focused on the jai alai match between the FDA, the DEA, the alleged victims and their lawyers, the Ephedra Education Council, and manufacturers such as Metabolife, attention has slipped away from the folks who are munching on ephedrine — especially the ones treating it like legal speed.

WHAT’S STRANGE about ephedrine is that, despite mounting regulatory battles, courtroom warfare, and its availability on countless store shelves, the drug flies below the radar of general public scrutiny. It doesn’t have a “scene,” like cocaine and disco or ecstasy and raves, and it doesn’t have much in the way of mainstream PR. Unlike the taurine-and-caffeine-laced Red Bull, ephedrine doesn’t have an illustrated mascot, a sleek red-and-blue design, or a self-incriminating tagline about how it “gives you wings.” And unlike the much the more potent MDMA (“ecstasy” or “E”), ephedrine isn’t accompanied by “it makes your pores orgasm” hype, a starring role in films like Go and Groove, or Spin magazine’s suggestion that it might be the new beer.

Still, it’s been name-checked in pop culture, and that makes the ephedrine phenomenon’s relatively low visibility even more strange. Stoner-rock savants Queens of the Stone Age, a band whose most recent disc Rated R opens with the lyrics “Nicotine, Valium, Vicodin, marijuana, ecstasy, and alcohol,” rhymes “ephedrine” with “where the hell ya been” in a song on their first record called “How To Handle a Rope.” Über-rock writer Lester Bangs (recently immortalized in Almost Famous), a hard-living scribe who considered Romilar cough suppressant the nectar of the gods, is described in Jim DeRogatis’s biography Let It Blurt as speeding on the “ephedrine-coated wicks inside plastic nasal inhalers.” And Eminem slips in several doses of ephedrine on The Slim Shady LP. (“Tired of having skinny friends hooked on crack and Mini Thins,” he laments.)

Part of the reason for ephedrine’s low profile may be that even those who do gobble it up aren’t sure how to classify it. Seasoned drug users lump it together with other substances stored in the medicine cabinet, like aspirin, Romilar, and Vicodin, viewing it as a cheap, lowbrow high — the word “scrounging” comes to mind. Bring up ephedrine with twentysomething acquaintances, and many are likely to respond, “I haven’t done that stuff since high school.” Those who have access to more potent drugs — primarily ecstasy or speed — just snicker at the mention of herbal ecstasy. Joanna, a Boston College junior who regularly rolls on E, derides herbal ecstasy as “so lame” compared to the real thing. “It’s like taking St. John’s wort instead of Prozac or cocaine,” she says.

Yet ephedrine’s adrenaline rush is similar enough to the effects of MDMA that dealers to try to pass it off as E. According to statistics kept by Dancesafe, a Berkeley-based collective that tests E pills at raves and through the mail, ephedrine is found in a small percentage of tabs masquerading as pure MDMA. And this past November, the Boston Herald reported that four high-school girls in Keene, New Hampshire, suffered heart palpitations after taking ephedrine, thinking it was ecstasy.

But even those who know what they’re taking and don’t scorn it are hesitant to go on record. When I asked various acquaintances in their mid 20s to discuss their experiences with ephedrine — people who have pulled all-nighters with it, extolled it as “the wonder drug,” or taken it before clubbing or going to a rock show — they grew shy and chagrined. “Oh, I don’t really bother with that stuff anymore” and “I feel sketchy enough doing it; it’d be weird to talk about it” were common refrains.

A similar thing happened to Amanda Gruber, associate chief substance-abuse researcher at McLean Hospital, when she published a paper on the widespread use of ephedrine by bodybuilders. “After I wrote the paper, I had a lot of news people who wanted me to find them ephedrine users to interview,” she says by phone from Belmont. “And I couldn’t find any. My good friends wouldn’t even be interviewed in a shadow, because they hadn’t told their friends.”

Ephedrine occupies an awkward position: it’s a recreational high that’s sort of embarrassing — and sort of feared, even by those who scarf the drug strictly for the buzz. Pages and pages of testimony on the Web praise it, but the enthusiasm is almost always tempered by advice. One account, describing how 13 tablets caused muscle cramping, wisely cautions, “Ephedrine might be fun, but don’t do too much of it”; another newsgroup declaration lauds ephedrine’s potential for intensifying psychedelic trips, but cautions, “The trick is to take it only TWICE PER WEEK, and not every day. Taken every day, it stops working its magic.” And last week, my 24-year-old roommate, who supervises a bookstore in Cambridge, brought up the topic of ephedrine with a co-worker. The co-worker’s response? “That shit will fuck you up. [Pause] I was on it yesterday.”

WILL FUCK you up” isn’t one of the disclaimers on the baby-blue label of a 60-count bottle of Two-Way MaxBrand, a bronchodilator and expectorant sold over the counter at a handful of Boston-area convenience stores. Instead, Two-Way MaxBrand’s fine print cautions, “Some users of this product may experience nervousness, tremor, sleeplessness, nausea, and loss of appetite.”

Such warnings are primarily intended to shield the manufacturer’s backside from litigious kicks. On the other hand, none of these over-the-counter bottles are daring enough to announce that the product’s selling point — its 25 mg of ephedrine — is a pocket rocket launcher.

Some users may also experience:

Amphetamine-like rushes. Mild euphoria. Stamina to stay awake all night. “It was as though I had taken about 8 grams of speed!” writes James from Brighton, England, in an online chronicle of his first experience with herbal ecstasy. “My body was running at a thousand Volts!”

Nerve endings that ooze. Tingling skin. Erotic body chills. Masturbatory urges. “I do remember feeling a little horny during the experience, especially as I was starting to peak,” James recalls. “It was definitely a different type of eroticism than MDMA — less deep, less still. It definitely made me tingle all over.”

Creative spurts. Rigid focus. Slightly fuzzy vision. Robin, a 19-year-old who has used ephedrine twice, once for studying and once because she “simply wanted to experience it,” says it hit her “like caffeine, but a little more awareness-based.” She adds: “I wanted to think about things and be more objective.”

Decreased inhibitions. Accentuated self-assurance. Loquaciousness. Eric, a 20-year-old from Canada who gushed about ephedrine in a drug-related newsgroup, reports in an email, “It gets my heart beating and I feel more awake. I get quite a buzz when I take it on an empty stomach right before eating. I have also found that I talk a lot more on it — especially in a social setting.”

Eric swallowed ephedrine for the first time last spring, after several rounds of dope and booze: “I’ve been able to drink more than two jugs of beer while on ephedrine and still walk home.” Like Eric, many experimental partiers use ephedrine as a cocktail mixer. For some puffers, ephedrine counteracts marijuana-induced drowsiness and paranoia. With caffeine, the heart-racing jolt has been described as “a triple whammy.” For those doused with the blurry warmth of alcohol, ephedrine’s boosts and bursts increase lucidity. One posting on an online clearinghouse of drug experiences reports: “I have heard that people do ephedrine with alcohol and some of them feel like they would be rolling [on ecstasy] or on amphetamines. So I thought I [would] try [it], and it was good!!! I loved it, now every time we have a drink I pop in about 2-3 pills. Makes me feel like I’m on amphetamines or coke.” The writer closes with, “Perfect :)”

PERFECT” PROBABLY isn’t the word 38-year-old Tom would choose to sum up his experiences with ephedrine. “I got into ephedrine in a backwards kind of way,” he writes in an email. The Washington, DC, resident had started taking meth, both to study and to work extra hours; later, he resorted to Mini Thins when meth wasn’t within reach. About the energy surge he received from ephedrine, he writes, “I felt like I was capable of doing many things at once: I often fed my six-month-old son while typing chapters of my dissertation all at the same time!”

More disturbing, though, are the other tasks he undertook under the influence: “I was the person who balanced the load for cargo aircraft at a major airport. I was responsible for loading the aircraft with over 80,000 lbs. of cargo. I was also the person responsible if the plane crashed because it was loaded improperly.” With a palpable sense of bitter irony, he adds, “Nothing like showing up for work with three hours of sleep within four or five days.”

Though Tom still trolls the drug-related Web sites and newsgroups, he says he’s quit both substances — for two good reasons. “One, I completed my PhD and didn’t need to ‘burn the candle’ to stay awake,” he says. “The other was that I became extremely irritable toward my wife. In the end, my irritability was the thing that caused the end of our marriage, a short prison term (because of my irritability, not because of drug use), and the loss of a great job.” Also, he adds, “After eighteen-plus months without using, I’m still seeing a psychologist for depression.”

That’s one of the major pitfalls of any amphetamine-like substance — regular use can build tolerance, which, in turn, can lead to withdrawal when use is stopped, which can lead to depression. Tom’s certainly not the only one to face bouts of depression and/or addiction. In national health-advice columns, ephedrine-related inquiries intermittently peek out, anonymous voices wondering about the possible dangers of depression and addiction. Take, for example, one letter written to the syndicated column “The People’s Pharmacy”:

My boyfriend has been abusing a drug called Mini Thin Pseudo for over two years. He has all of the symptoms listed on the warning label as reasons to discontinue use: nervousness, loss of appetite, insomnia and dizziness. He takes more than the recommended dose because he is afraid of becoming overweight again as he was in childhood.

On weekends when he doesn’t take the pills he sleeps most of the time, his appetite doubles and he eats a lot to quell his hunger pangs. He tried to quit, but only succeeded for a week. During that time, he complained of being sleepy all day on the job.

“I’ve been contacted by a number of women who were taking ephedrine and became hypomanic and psychotic and were hospitalized,” says McLean Hospital’s Gruber. “They wanted to know if ephedrine could do this. And it can — it’s just like an amphetamine-induced psychosis.”

Barbara Michel has heard troubling stories too. An anti-ephedrine crusader since ephedrine was listed on her son’s death certificate, she founded the nonprofit organization HEAT (Halt Ephedrine Abuse Today) and maintains an informal Web survey on ephedrine. Within the past two years, Michel has received approximately 800 responses from users, with 50 percent describing depressive-like states, mammoth hangovers (“Some nights when I take too much ephedrine, the next day my heart will feel like it was scraped on asphalt,” one daily feeder told me), and signs of addiction.

Although ephedrine is described as “nonaddictive” in most encyclopedias, Gruber contends that it is an addictive substance. “At McLean we’ve definitely had people come in and detox from ephedrine,” she says. “I think there’s a large danger of becoming addicted. Many women that I’ve talked to have tried many times to stop using it and can’t. They just can’t stand not feeling good, even for one more day.”

Ephedrine is not only addictive, according to Gruber. She says it can also increase risk of heart attack, stroke, kidney failure, and death. But how common are these side effects? “Death, strokes, and kidney failure certainly aren’t common, but they can happen. What I try to tell people is that they probably know a lot of people who are taking it. And those people seem fine. But some number of those people are going to have really bad things happen — heart attacks, strokes, and getting psychotic. But many more will become addicted and have a tough time getting off of it.”

If commentary like this moves the FDA to issue regulations restricting access to ephedrine (the official word is that it’s an “ongoing decision,” that they’re “still evaluating” cases), it would probably reduce the number and types of people at risk. Most pimple-faced kids, amped-up undergrads, adrenaline junkies, speed freaks, tractor-trailer captains, and Xanax mixers would realize that over-the-counter doesn’t necessarily mean safe.

On the other hand, if ephedrine became illegal or available only by prescription, it would probably be considered a hell of a lot cooler among the drug cognoscenti. Jeff, an 18-year-old daily ephedra feeder who takes the herbal supplements for weight loss, observes, “If it were made illegal it’d go into the zone of amphetamines, where people start mainlining it and then it becomes truly dangerous.”

True enough. But that threat won’t change minds like Barbara Michel’s. “Our kids are dropping like flies from this stuff,” she says with passion. “People need to know that what they’re taking is legal speed.” Apparently, many already do.

Camille Dodero can be reached at cdodero[a]phx.com.