This article originally appeared on The Fix.

This is the year of the knockoff. A witch’s brew of new synthetic drugs, most of them stimulants, peddled as either bath salts or “spice” concoctions, has offered users new forms of Russian Roulette, and has irrevocably changed the face of international drug dealing. 2012 was also the year hysteria took over. Myths began to accumulate, and everywhere you looked, somebody was supposedly doing something psychotic due to the new synthetics. Who can forget Rudy Eugene, Florida’s Causeway Cannibal, the bizarre face-eating man on bath salts? The attack left law enforcement officials wondering how a drug could drive Eugene to strip off his clothes, attack a homeless man, and chew pieces of flesh from the man’s face.

Well, it wasn’t bath salts, as it turned out. But never mind. As Fix columnist Maia Szalavitz wrote: “Despite the fact that Eugene had no synthetic drugs in his system, it’s likely that his case will still be used for years as an example of what bath salts can make people do.” But drug users saw it differently. After all, how deadly could bath salts really be, hanging there on the rack beside the Slim Jims, the 5-hour energy drinks, and the caffeine tabs at the local Bag-and-Drag minimart?

By 2012, amphetamine-type stimulants, including synthetic bath salt derivatives, had become more popular worldwide than either cocaine or heroin, according to the United Nations Office on Drugs and Crime (UNODC). This international eclipsing of the plant-based “hard drugs” of the past represents a major paradigm shift in the landscape of the illegal drug trade. The stunning market growth of synthetic stimulants is not hard to understand. Bath salt drug products soared in popularity throughout 2012 due largely to the belief among users that the drugs were: 1) quasi-legal, 2) non-addictive, 3) relatively safe, and 4) invisible to drug tests.

By the end of the year, it had become clear that none of these things was still true.

To begin with, bath salts—just like Spice and other cannabis spinoffs—are no longer legal. And many of the drugs found in bath salts appear to be addictive. Some carry known health hazards. And, although it was the desire to finesse drug testing that gave a major push to this new class of recreational chemicals, major bath salt ingredients can now be detected in routine urinalysis. Researchers have teased out the main culprits in both categories of synthetics—for synthetic marijuana, it’s the JWH family of research chemicals. For stimulants, it’s the cathinones, compounds like mephedrone and MDPV, members of a family of psychoactive alkaloids that includes khat, the chewable form of speed popular in East Africa.

But the truth was, nobody really knew with certainty just what was inside those shiny foil packages. Nobody knew how much to take, or how to determine how much had been taken. Doctors didn’t know enough about the drugs to consistently diagnose an overdose. And what little testing was available for detecting synthetic stimulants was costly and questionable. The effects were wildly unpredictable. Users are serving as unwitting guinea pigs for underground designers, ingesting compounds about which little or nothing is known clinically. Violent headaches, paranoia, disturbed vision and impaired decision-making can all be effects of bath salts. But you can also catch a mild ride, and come out of the evening without a scratch. Are they safe? Yes and No. Maybe. Plenty of people have taken bath salts and lived to tell about it. But bath salt stimulants and spice-style marijuana derivatives can also sometimes be compared to “a shot of methamphetamine with a PCP chaser,” in the words of one bath salts user. And that is nobody’s idea of a fun-loving evening.

We know these things are true because 2012 was also the year that “well-funded, well-conducted studies appeared on the effects of synthetic compounds in animal models,” says David Kroll, a pharmacologist with the North Carolina Museum of Natural Sciences and the former Professor and Chair of Pharmaceutical Science at North Carolina Central University in Durham. Dr. Kroll has been following the new synthetic drug products for years, and notes that by the beginning of 2012, as users continued to turn up in ERs in significant numbers, researchers around the world were feeling pressure to find ways of discriminating between the variety of chemical products that make up the new drugs. Bath salts are not just one drug, called Super Speed, Kroll is at pains to point out. “The biggest misconception I’ve found is that synthetic marijuana and bath salts are lumped into the same category of “synthetic highs,” says Kroll. “But they contain compounds that work by very diverse mechanisms of action to cause very different psychoactive effects. We’ve got chemicals with a super-intense, super-paranoid marijuana high, we’ve cocaine-like effects, and MDMA-like empathic effects.”

Arkansas law enforcement officials recently announced that they had identified 250 different chemicals in bath salt products. Researchers have found opioids like tramadol, opioid receptor-active compounds like Kratom (Mitragyna speciosa), and oleamide, a fatty acid derivative with psychoactive properties, in packets of synthetic marijuana. Plus, almost anything that might make it more difficult for forensic labs to pry it all apart: alfalfa, comfrey leaf, passionflower, horehound, etc. Obviously, not all of these compounds have been tested for safety in humans. Banana Cream Nuke, which was purchased in an American smoke shop, and made two young girls very sick, contained 15 varieties of synthetic cannabis—but none of the herbal ingredients actually listed on the label.

Realistically, what can bath salts do to you? They won’t make you take a bite out of some stranger’s face—but they are quite capable of landing you in the emergency room. However, as with speed and cocaine, most users don’t end up in the hospital. Otherwise, the drugs would not be popular. It’s not hard to understand the allure of stimulants, designer or otherwise. Countless baby boomers and Gen Xers have sampled cocaine and methamphetamine on a recreational basis, and will have no trouble explaining the appeal: It just feels good.

For public health officials, ignorant about the new drugs, the case reports about bath salt and spice users visiting the ER set off a wave of crack-style viewing with alarm on the part of the media. This makes the job of public education all the more difficult—because some of those scare stories were true:

Walking up to the patient, you note a slender male sitting wide-eyed on the sidewalk. His skin is noticeably flushed and diaphoretic, and he appears extremely tense. You notice slight tremors in his upper body, a clenched jaw and a vacant look in his eyes…. As you begin to apply the blood pressure cuff, the patient begins violently resisting and thrashing about on the sidewalk—still handcuffed. Nothing seems to calm him, and he simultaneously bangs his head on the sidewalk and tries to kick you… and his body temperature is 103.2° F….Later in your shift, you return to the same emergency department and are informed that the patient has been admitted for rhabdomyolysis and has admitted to taking “bath salts” for the past three days.”

So says Jon Nevin, a California emergency medical technician and paramedic. And rhabdomyolysis, by the way, is the breakdown of skeletal muscle tissue, which can lead to nasty complications like kidney damage. 2012 was also the year of the first official reports of acute kidney injury due to bath salts, presumably MDPV or mephedrone. Acute kidney injury appears to be a rare but devastating side effect of these drugs. Last March, Wyoming health officials were at a loss to explain a rash of kidney pain and vomiting among teenagers in the town of Casper. Three kids were eventually hospitalized after smoking something peddled as “blueberry spice.”

Some of the victims were likely suffering overdoses of MDMA or other drugs, but last year a new twist on the cathinone molecular structure began to get serious traction in the states. To stay one jump ahead of the law, underground chemists began churning out large quantities of a different amphetamine variant with the tongue-twisting name of methylenedioxypyrovalerone, or MDPV. And what were EMTs and paramedics seeing in cases where the overdose drug could be identified as MDPV? Agitation, tachycardia, hallucinations, combative behavior, hypertension, chest pain, blurred vision—and several purported deaths. This synthetic cathinone was evidently capable of producing psychotic episodes requiring sedation. It all sounded eerily similar to the PCP overdoses of the 60s and 70s, when that dissociative veterinary anesthetic enjoyed a period of dubious notoriety.

So okay, spice and bath salts are not safe as milk. Neither are heroin and cocaine. Nothing comes risk-free. But are bath salts addictive? It only takes a couple of stern-faced pronouncements to this effect from the National Office of Drug Control Policy to set loose flaming battles over drug policy. But in this case, the evidence from animal research was not looking good by year’s end, as findings trickled out from several well-regarded university research labs.

Dr. Michael Taffe, working with the Committee on the Neurobiology of Addictive Disorders at Scripps Research Institute, has been researching these questions at his lab in La Jolla, California. “Yes,” says Taffe, referring to the cathinone compounds, “there is evidence that they are addictive.” But it’s not a simple story. Direct comparisons to methamphetamine can be misleading. “It has been shown that mephedrone is self-administered in animals at rates higher than meth,” according to Taffe. “And we’ve shown self-administration data for MDPV as well. But all we can really say is that there is evidence these drugs are self-administered in animals, just like you would expect for psychomotor stimulants.” In addition, there are indisputable hints of addictiveness at the cellular level. “Inhibiting the dopamine transporter is a classic effect of abused psychomotor stimulants like meth, perhaps the signature effect,” Taffe says, “and mephedrone and MDPV both have this action.”

So, the catch appears to be that some of these drugs are potentially addictive. The underground market lottery will determine whether any of those addictive chemicals end up in your packet.

Finally, are bath salts and spice drugs invisible to drug tests, as advertised? The answer is no, not any more. There are new drug tests out there that can detect many of the major ingredients in both bath salts and spice-style cannabis products. And that marks a major change that law enforcement hopes will cripple growth in this fast-moving industry.

“Increasingly, and especially in the U.S. military, testing firms are including these compounds in their methodology,” says Dr. Kroll. A company called RTI International is now marketing a new test kit, which makes it possible to detect a wide range of synthetically produced drugs. More drug test kit manufacturers are sure to ramp up production in the near future, but it is a costly effort. “Folks probably aren’t aware of how hard it is to develop methods to detect all of these compounds,” adds Kroll.

While bath salts originate primarily in Asia, bath salt precursor drugs are now being manufactured in Malaysia, West Africa, and Iran—places previously off the radar when it came to drug manufacture. UNODC Executive Director Yury Fedotove has written that the market for synthetic stimulants “has evolved from a cottage-type industry typified by small-scale manufacturing operations to more of a cocaine or heroin-type market with a higher level of integration and organized crime groups involved throughout the production and supply chain.“ Bath salts have become big business.

Legalization is one answer, say some observers. After all the bizarre twists and turns in the Drug War, now police are faced with arresting citizens for a bag of something they just bought openly at an incense shop down the block. But another, less drastic and arguably more sensible approach would be to ease off on formal workplace drug testing—which has not proved to be worth the money, in most cases. Less testing would mean less incentive to seek out new and untested drug products that promise users an end-run around piss testing.

In the end, one bath salts user might have an acceptable drug experience, while another might find that a few whiffs of the same synthetic stimulant will land him or her in the emergency room with a dangerously elevated heart rate and other complications. As for synthetic cannabis, a large survey by Guardian/Mixmag in England, which included the U.S., reported that drug users tended to rate the Spice/K2 drugs as “more harmful than natural weed, and less likely to deliver pleasurable highs.”

Skip the synthetics. And tell your friends.