A memorable tabloid photo from the mid-1980s shows Michael Jackson lying peacefully in a hyperbaric oxygen chamber, presumably part of the pop singer’s plan to stay young forever.

Jackson was not the only one seduced by off-label uses of this medical therapy. Over the years, health seekers have looked to hyperbaric oxygen therapy (HBOT) at spas, alternative health clinics and even at home to turn back the clock or cure what ails them. Here's what you need to know.

Approved and non-approved uses

Hyperbaric oxygen therapy was first used in the early 20th century and reappeared in the 1940s as a treatment for deep-sea divers who had decompression sickness, a painful and life-threatening condition popularized on reruns of the TV show Seahunt as “the bends.” Today the Food and Drug Administration (FDA) has approved the therapy for more than a dozen ailments, including the bends, severe heat burns, gangrene and carbon monoxide poisoning. 

Related: Carbon Monoxide: Is Your Family Protected?

If you undergo this treatment, you’ll enter a special chamber where you breathe in pure oxygen at air pressure levels one and a half to three times higher than normal. The goal: infusing the blood with enough oxygen to repair tissues and get you back to normal.

Other uses for the therapy, however, are unproven, and marketing or advertising them is illegal (the chambers are approved by the FDA only for specific purposes). Despite how the therapy is sometimes marketed to consumers by practitioners promising miracle cures for autism and just about everything else, according the FDA, the safety and effectiveness for HBOT for these conditions has not been determined:

  • Alzheimer's disease
  • Asthma
  • Bell's palsy
  • Brain injury
  • Cerebral palsy
  • Depression
  • Heart disease
  • Hepatitis
  • Migraine
  • Multiple sclerosis
  • Parkinson's disease
  • Spinal cord injury
  • Sports injury
  • Stroke

According to the American Cancer Society, "available scientific evidence does not support claims that HBOT stops the growth of cancer cells, destroys germs, improves allergy symptoms, or helps patients who have chronic fatigue syndrome, arthritis, multiple sclerosis, autism, stroke, cerebral palsy, senility, cirrhosis, or gastrointestinal ulcers."

Claims to the contrary are not only unfounded, they’re unethical, according to Dr. Jake Freiberger, an attending physician at the Center for Hyperbaric Medicine & Environmental Physiology at Duke University Medical Center in Durham, North Carolina. "Some people are desperate," he says. "They are vulnerable to being manipulated.”

It's possible that studies may one day find that HBOT can help treat some of these conditions, but right now the evidence is lacking — and undergoing the therapy is not without risks. 

According to the FDA, risks range from mild problems such as sinus pain, ear pressure and joint pain to serious health threats including paralysis and air embolism (an air bubble trapped in a blood vessel). Even when the therapy is done in a highly controlled hospital setting, some patients suffer ruptured eardrums, collapsed lungs or seizures. Such complications are more likely if a person spends more than two hours in a chamber at more than three-times normal air pressure. The hazards are magnified for people working with unqualified practitioners.

A fire and explosion hazard

Since hyperbaric chambers are oxygen-rich environments, there is also a risk of fire.

Clinics offering HBOT often use portable, low-pressure fabric units whose routine use poses a serious fire and explosion hazard, experts say. The FDA has cleared these portable fabric units only for treating altitude (mountain) sickness. However, the design of the units violates existing safety codes and fire standards, according to the National Board of Diving and Hyperbaric Medical Technology. Concentrated oxygen increases the risk of combustion, and the smallest spark can lead to disaster.

Related: How to Avoid and Treat Altitude Sickness

There have been 80 fatal fires reported worldwide involving hyperbaric oxygen therapy. Although there has not been a fire fatality involving HBOT in a hospital setting since 1967, clinics using the therapy for off-label or unorthodox uses have been implicated more recently in injuries and deaths after units caught on fire.

A four-year-old boy and his grandmother died of burns after a hyperbaric oxygen chamber they were in at an alternative health clinic in Florida exploded. The boy was being treated for cerebral palsy. In 2014, the medical director and a safety technician at the clinic pleaded guilty to manslaughter.

A 19-year-old with autism suffocated after an oxygen valve disconnected from an inflatable oxygen chamber his family had bought for home use from OxyHealth, LLC, according to a lawsuit the man’s parents brought in federal court in North Carolina. Their attorney told reporters that his mother first heard of the home chamber when Oxyhealth marketed it at an autism conference she attended.

Despite such hazards, some practitioners continue to use either hard or portable fabric chambers for off-label uses. Two Tennessee pastors were recently discovered using a portable oxygen unit to treat everything from depression to hair loss. One of them was certified to run an oxygen chamber, but he was not a medical doctor and had taken only an entry level course, news reports said.

Hospitals reduce the threat of fire in HBOT therapy by making sure that patients aren’t wearing perfume, hair spray, hair gel or other potentially flammable substance. Batteries, hearing aids, cell phones, metal pins or buttons of any kind and watches are also banned from chambers.

Related: 6 Things Not To Do in an Emergency

How to protect yourself

The best way to protect yourself against possible hazards of hyperbaric oxygen therapy? Avoid hyperbaric chambers completely unless you’re receiving treatment in a hospital for a condition that the FDA approves for the therapy.

Even if you’re being treated in a hospital setting with trained medical personnel, check in advance to be sure the doctor directing your therapy has a minimum of 40 hours’ training from the Undersea & Hyperbaric Medical Society.

And unless you’re an ailing mountain climber or someone else with altitude sickness or carbon monoxide poisoning, never use a portable fabric oxygen chamber. In any other scenario, the risks of the oxygen therapy are bound to outweigh the benefits.

Chris Woolston, M.S. is a freelance writer and editor who specializes in science, health and travel. A reformed biologist, Woolston says, he studied algae and nitrogen dynamics in Antarctic lakes before the Science Writing Program propelled him out of the lab. He is a contributing editor at Nature.com, a former staff writer for Time Inc.’s Hippocrates magazine, and co-author of Generation Extra Large (Perseus). He lives in Billings, Mt., with his wife – novelist Blythe Woolston – and their two children.