Nitrous oxide is paralyzing people by inactivating vitamin B12. Here are 5 other risks of using the legal drug.

• Laughing gas is inactivating vitamin B12 in young people, leaving them paralyzed, experts have said.
• Vitamin B12 maintains the lining of nerves — if it doesn't work, people get nerve damage.

Laughing gas is inactivating vitamin B12 in young people and leaving them paralyzed, experts have said — and the drug has other risks too.

Laughing gas, also called nitrous oxide, is commonly used as a painkiller and anesthestic in hospitals and dentistry, and caterers use it for whipped cream. Researchers are also examining its use as an antidepressant.

But, for over 200 years, people have also used the drug recreationally, inhaling it to make them feel relaxed, euphoric, and giggly, for one to two minutes on average.

It's legal to possess the drug in most countries, but some have criminalized supplying it for recreational purposes. In the US, New York state banned its sale in 2021, partly because of the risk of abuse, and in California recreational use is a misdemeanor.

Experts have become increasingly concerned about the potential harms of nitrous oxide, particularly amid the rise of stainless steel cylinders, which typically contain 20 pounds of nitrous oxide — equivalent to 1,600 silver bullet-size capsules that people tended to use.

Cylinders came onto the market in around 2017 to "deliberately target" recreational users, according to a recent European Monitoring Centre for Drugs and Drug Addiction report.

Super size cylinders, which are sold in countries including the US, the Netherlands, and the UK are easier to use: People turn a valve to fill a balloon that they inhale the drug from, rather than having to screw a lipstick-size canister onto the end of a dispenser and awkwardly twist each time.

Here are three risks of using nitrous oxide recreationally.

Incontinence or being unable to get an erection from nerve damage

Nitrous oxide destroys nerve cells within the spinal cord by inactivating vitamin B12, which is essential for maintaining the lining of the nerves, Alastair Noyce, a professor at the Preventive Neurology Unit at the Wilson Institute of Population Health, Queen Mary, University of London, told Insider.

Symptoms range from tingling, numbness, and the sensation of the "skin crawling" to paralysis, depending on how extensive the nerve damage is.

A young couple recently told Insider that nerve damage from using nitrous oxide meant that they woke up one day feeling "numb" from the waist down, and unable to walk.

Noyce, who is also a consultant neurologist working in a London hospital in the UK, said that he's seen people needing to use a walking frame or wheelchair, and others who were incontinent or unable to get an erection, as a result of nerve damage from nitrous oxide.

People can also lose their balance because signals that tell the brain where body parts are positioned don't get transmitted properly, Noyce said.

The hospital where he works treats people — mostly in their teens and twenties — with nerve damage from nitrous oxide about once every nine days, on average according to a report. Patients are treated with vitamin B12 injections.

It's rare for people who don't use the drug often or in low quantities to get nerve damage, he said.

Psychological dependence

We don't know exactly how the drug works on the brain, and scientists don't agree on whether or not nitrous oxide is addictive.

Noyce said that the drug isn't physically addictive in the same way that drugs such as heroin are, but can cause "an element of psychological dependence."

"Patients endorse that they crave it when they're not taking it, they're irritable, they're constantly chasing the same original feeling that they got and that leads to higher and higher quantities," he said.

'Whip mouth' and lung injuries

Nitrous oxide is freezing (-104 °F to -131 °F) when it's released from canisters and capsules.

The high pressure of its release can cause lung injuries, and within seconds, it can burn the lips, nose, mouth (known as "whipmouth"), throat, vocal cords, or lungs, causing frostbite, the EMCDDA report says.

Frostbite appears to be less commonly reported than nerve damage from the drug. It's more likely to occur if people inhale the drug directly from a super-size cylinder, for example, rather than first transfering the gas into a balloon, the report says.

The burn can cause the airway to swell, which can be life threatening if it becomes impossible the breath, though deaths involving nitrous oxide are rare, according to the report.

Nitrous oxide can also burn the skin, if a canister is held between a person's thighs, it says.