Behind the counter in Norwich’s two head shops hang a variety of brightly-coloured packages. Marked ‘not for human consumption’ and sold as ‘plant food’ or ‘research chemicals’ (but with illustrations of psychedelic paraphernalia or a chemical compound on the front) it’s no secret what the products actually are. But these powders aren’t the illegal, street drugs of yore. They’re barely-legal compounds, their formulas tweaked to imitate the effects of illegal drugs like amphetamine or cocaine. Marketed with names like ‘Spellweaver’ ‘Pink Panthers’ and ‘China White’, they are mostly chemical variations on the now-banned mephedrone, itself a chemical imitation of methamphetamine.

legal highs

The inventors and suppliers of these ‘legal high’ drugs are generally laboratory-owners in South-East Asia or China, real-life Heisenbergs who operate outside of the law. As soon as one compound is banned in a country, they can get straight back to work, busily innovating to produce an equally intoxicating but unbanned drug. Legislators have been left playing a legal game of whack-a-mole. As soon as one illegal drug gets smacked down another one with a slightly different formula crops up. It has become an informal arms race between the suppliers and the enforcers.

Meanwhile these new formulae remain unlicensed and largely untested, with consumers left in a dangerous limbo. Often, two ‘legal highs’ sold in the same packaging can contain two different combinations of compounds, their proportions unregulated and varying from pack to pack. The contents of most regular illegal drugs are themselves a bit dodgy. One UK study found that the average bag of cocaine was only about 30% pure, cut with a 70% mixture of worryingly non-specific “other compounds”. But with legal highs, made up of new and largely untested chemical compounds unregulated for human consumption, there is an added worry that these chemicals could react with cutting agents or other drugs in a way hitherto unknown – and to deadly effect.

Not all ‘legal highs’, however, are quite as scary or untested. Some common party drugs also fall under the definition of legal highs. Alkyl nitrites or ‘poppers’ are bottled liquid chemicals, sold online or head shops, which produce a briefly intoxicating effect when sniffed. Nitrous oxide or ‘nitrous’ is sold at clubs in party balloons for as little as 90p a pop, and when inhaled produces a slow-motion euphoria which lasts for under a minute. It’s commonly used in midwifery to provide pain relief for women giving birth (nitrous oxide is the ‘gas’ part of the pain-relieving mixture known as ‘gas and air’), or in whipped cream chargers to mix cream industrially. Bought online in 60-packs, these are the most common source of the legal drug. Even these seemingly harmless drugs, however, can be dangerous. Alkyl nitrites are poisonous if swallowed, and inhaling too much nitrous oxide can lead to dangerous hypoxia or even death, filling your lungs and pushing out air.

Another drug is salvia. Despite bans in Australia and Italy, it remains legal in the UK. Derived from the leaves of the salvia divinorum plant and available for purchase online, the drug is similar in appearance to marijuana, but produces a more intense psychoactive experience when smoked. Users debate its harmful effects – but short of new and sweeping drugs laws, ‘legal highs’ look here to stay.