Do Over-The-Counter Portable Oxygen Concentrators Actually Work? The Results of a COPD Foundation Study

Posted on February 07, 2023   |   

This article was written by Michael W. Hess, MPH, RRT, RPFT

In 2021, our Oxygen360 team noticed that online retailers were selling machines listed as “portable oxygen concentrators (POCs).” Many POCs are a good way for many people to stay mobile and active. However, they are not a good fit for everyone. They use a type of oxygen delivery called pulse dosing to conserve oxygen. This is different than the continuous flow from a regular concentrator. They are not able to provide high liter flow rates for people who need lots of oxygen during exercise or activity. Medicare and other insurance companies are not always willing to pay for them. That means they can be very expensive to get. Finally, they should always be prescribed by a licensed health care provider.

The machines available online were different. They only cost a few hundred dollars, a fraction of what the standard models cost. They claimed that they could provide five, six, even seven liters a minute of continuous flow, far more than any other on the market. Best of all, they could be ordered without a prescription, lowering the number of paperwork hoops someone had to jump through. Their advertising was slick and professional. People in white coats were seen alongside people wearing nasal cannulas. Those with cannulas were seen living their best lives thanks to the freedom these machines seemed to provide. It seemed almost too good to be true. Looking at the fine print, there were some disclaimers that the statements had not been evaluated by the Food and Drug Administration (much like one might see on the label of a nutritional supplement). Those disclaimers meant that the machines themselves had not gone through any kind of FDA testing for safety or effectiveness. Far from being medical devices like true POCs, these machines seemed to be no more than fancy air compressors. But these were buried far down in the descriptions, easy to overlook.

The COPD Foundation immediately took action against these “noncentrators,” writing a position statement against the sale of these machines. We also created a petition so the community could also ask these retailers to stop selling them. But we also knew that to make our case more strongly, we would need evidence. We started looking at ways we could prove that these machines were making false claims and that they could be putting people at risk.


One of the COPD Foundation board members, Dr. Richard Casaburi, is a researcher at Harbor-UCLA Medical Center in California. He and his team had previously created a device that simulates metabolism in the lung. That allowed the team to measure how much oxygen would make it into the bloods, which showed how effective an oxygen device would be. Dr. Casaburi came up with a strategy to test some of the noncentrators. He and his team offered to donate their time to the project.

We then picked three machines being sold as portable oxygen concentrators from a large online retailer and had them shipped to Dr. Casaburi’s laboratory. As soon as the noncentrators arrived, some of the false marketing claims were obvious. One of them had no battery, which meant it was only portable in the sense that someone could pick it up and move it somewhere else. We also noticed that within days of ordering each machine, they disappeared from the retailer’s website. This would make it very hard for someone to follow up with customer service. We also decided to test a real POC and an oxygen tank on the simulator so that we could see what the results should be. Each piece of equipment was tested at three metabolic rates (representing low activity, medium exercise, and heavy exercise) and at each of their available settings.


The testing showed that for the most part, the noncentrators did not work as well as real oxygen equipment. The machine without a battery did raise the amount of oxygen in the lung spaces slightly on its lowest setting (about the same as one liter per minute), but higher settings showed no increase in oxygen level. One machine did not increase oxygen levels at all. The team thought it might have been broken but continued testing it because someone buying it would have no way to know. The instruction manual for that machine also said it produced only 28% pure oxygen. This is far below oxygen made by true concentrators, which is usually over 90% pure.

The third machine did actually increase oxygen levels somewhat. It delivered oxygen with a pulse dose, but at lower settings (around what someone needing one or two liters per minute would use) the team measured higher oxygen levels during the low and medium activity testing. The increase was still lower than what the true POC and oxygen tank gave, but we could not rule out that someone might benefit from this machine in some way.


We feel that two of the three oxygen devices sold online without a prescription were not at all appropriate for someone needing long-term oxygen therapy. One machine did work a little but might not be enough for someone active. To be fair, the study did have several limitations. It was done in a laboratory on a simulator. Real lungs may work differently. We also only looked at one “real” POC, so these noncentrators may be able to keep up with others. We also did not look at every machine available for sale, so some others may work better. However, we are confident the results of this study prove that people should be very cautious when it comes to buying oxygen equipment without a prescription. We also feel that health care professionals should be aware of these machines and warn their oxygen therapy patients about their risks.

We would like to thank Dr. Casaburi and his team for their efforts and expertise.


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  • Thank you for posting this article.
  • This is sooo informative @Mike Hess! We will use this article for years to come. Great job Mike and team!
  • Thanks to Dr. Casaburi, his team, and our Oxygen360 project team! Our highest priority is keeping people safe. Keep an eye out for more information about these "noncentrators" throughout the year, and if you (or someone you know) has any experience with these devices, please share your story with us!
  • Awesome! Thanks so much for this article.
  • It would have been helpful if the testing results named the brands of the POCs. I have a Rhythm p2 and scared to death it will malfunction when I get a cab next week to my breathing test appointment. The last time it showed a yellow light on the way to the facility for test and screen warned: Contact your provider! Supplier has over 100 other suppliers under an “umbrella” DME. Locations in many states and the 800 number transfers me from state-to-state. Impossible in an emergency. Anyone else have to deal with supplier/s set up by investors who have been sued already for selling non-invasive ventilators to Medicare patients when they should have given them CPAP machines for their medical needs, but the other machines were more profitable for the company and their CEOs.
    • @Rahly - as far as I am aware, the ones which are mentioned in this article are not ones from legitimate durable medical equipment suppliers. Your Rhythm P2 is manufactured by a reputable company, is FAA approved for air travel, and I do not believe that it would have been one of those which was purchased and tested for the purposes of this article. I'm not sure what you are referring to in your comment about NIV's vs. CPAP's, so can't speak to that. I do hope that you were able to reach your oxygen provider to determine the reason for the yellow light on your POC so that it doesn't happen again.
    • Rahly, go to and look for the chart on POCs. You'll find that yours is one of the ones listed. If it's one that your DME found for you, you report it to them and it's their responsibility to find a replacement for you, not yours, unless you bought it. Go to the DME you got it from and turn it in so you can get a replacement. If they won't cooperate, go to the umbrella DME and discuss conversations with CMS with your attorney and theirs. I think you'll get a response.
    • Hi, Rahly! I agree with Karen...the Rhythm P2 is manufactured by a legitimate company and is only available with a prescription. We chose to not identify the machines by brand name for a couple of reasons, not the least of which was that we felt it would be unlikely to matter. As I mentioned in the article, each of the devices we ordered would subsequently disappear from the Amazon marketplace, only to reappear later with a different name (and sometimes even a different listed manufacturer). We did not want to risk implying that a brand name that was not included might be "safe," especially when it might be the same one with a different label.

      I also agree that your DME supplier is obligated to service/replace oxygen equipment that they provide. They don't always make it easy for a variety of reasons, but it is definitely their responsibility. I'd be happy to discuss both the paper and your situation further with you if you'd like...please feel free to email me at!
  • Thanks Dr Casiburi for this important work! We really need FDA to crack down on folks selling misleading and dangerous “equipment” that just enriches the seller without helping the patients! How to get that to happen is very difficult.
    • We are working on it! Mary Kitlowski of has been doggedly pursuing FDA involvement with this and several other issues regarding portable oxygen concentrators. We had a listening session with the Center for Devices and Radiological Health a few months ago, and she has been working hard to get them to follow up. There have also been some discussions with the Federal Trade Commission to try and get these banned from importation. Stay tuned!