STORMING a ranch south of the city of Guadalajara, Mexican soldiers last month made one of the biggest drug busts in history. They found 15 tonnes of the banned stimulant methamphetamine, which in America retails for more than $100 per gram, seven tonnes of chemicals used to make it, and a laboratory. The manufacturers had fled.

This was the latest sign that meth, once primarily a home-cooked drug, has become a mass-produced one. Unlike cocaine and heroin, imported from the limited regions where coca and poppy are cultivated, meth can be made anywhere. In most countries the ingredients, principally ephedrine and pseudoephedrine, can be bought as medicine for colds. Cooking them is dangerous. But meth is so addictive that the risk of blowing off your hands is little deterrent: in 2010 the authorities discovered 6,768 makeshift labs in America.

These “kitchens” make kilos of the stuff, not tonnes. Producing big quantities in America has become harder, as the authorities have cracked down on bulk purchases of the ingredients. So production is shifting to big and highly efficient labs in Mexico. The cheap and potent meth they supply now provides some three quarters of the drug consumed in America. Seizures at the border rose from 1.3 tonnes in 2001 to 4.5 tonnes by the end of the decade. In 2008 the Mexican authorities identified 21 labs. In 2009 they found 191. Asia has seen the same trends. In 2010 Iran dismantled 166 meth labs, up from 33 in 2009 and two in 2008. Much of it was destined for South Korea and Japan: the habit there dates from wartime days. Half of all drug takers seeking treatment in Japan have problems with meth; in South Korea the proportion is more than 90%. The UN says Indonesia in 2009 dismantled 35 synthetic-drug labs; 25 were big ones. In South East Asia arrests related to meth more than tripled between 2004 and 2009. In Europe meth has trailed other synthetic drugs such as ecstasy, but now seems to be getting a foothold. Production is centred in the Czech Republic, where police shut down 300-400 laboratories per year. Data on people arrested in Sweden show many who admitted to taking amphetamine actually tested positive for meth. That suggests dealers may be switching one for the other: 5mg of meth would give a similar hit to 30mg of amphetamine, and it is more addictive to boot. So statistics may understate the problem. Traffickers like meth. Alejandro Hope, formerly of Mexico's spy agency and now at IMCO, a think-tank, highlights its low labour and transport costs and “vertical integration”. “With cocaine you need to deal with a large set of middlemen,” he says. Fewer border-crossings mean less of the product is seized. And at nearly $25,000 per kilo, the wholesale meth price in America is a quarter more than that of cocaine, and 25 times more than cannabis.

China and America have tightened up on internet retailers. In 2011 Canada made it illegal to possess or import anything (from chemicals to beakers) with the purpose of making meth or MDMA, the active ingredient in ecstasy. This got around traffickers' trick of importing a precursor chemical minutely altered to avoid regulation and converting it back again.

But officialdom is struggling as the criminal businesses speed up, evading regulations by adapting their behaviour: more like big firms than small ones, says Matt Nice of the International Narcotics Control Board, which enforces the UN conventions on drugs. In 2005 Mexico virtually outlawed ephedrine and pseudoephedrine. So the traffickers turned to milder ingredients and a new process. “The market gets crushed, but the bad guys retool with new chemicals, new formulas and new routes,” says Mr Nice.

Another trick is to create a subtly different end-product. On March 6th Britain's Home Office announced a possible ban on methoxetamine, a new drug based on ketamine, which is not yet classified. Methoxetamine UK, an online retailer with a swanky website, claims to pack up to 100 orders a day, offering free shipping and even tax included. It proclaims a fervent commitment to customer satisfaction. British police suspect that the same chemical killed two people last month.