Buying oxygen depends on what you need it for. Medical-grade oxygen requires a prescription in the United States, and most people get it through a home medical equipment supplier after their doctor documents the need. Recreational or “canned” oxygen is available over the counter but delivers far less oxygen and isn’t suitable for treating medical conditions. Here’s how each option works and what to expect.
Why Medical Oxygen Requires a Prescription
The FDA classifies medical oxygen as a prescription device. Any oxygen equipment that delivers less than 6 liters per minute is legally required to carry a prescription label, meaning you cannot buy it without a doctor’s order. Equipment that delivers at least 6 liters per minute for a minimum of 15 minutes (totaling 90 liters) can be sold over the counter, but only when labeled for emergency use.
This distinction matters because the oxygen concentration, flow rate, and duration of use all need to match your specific condition. A prescription specifies whether you need continuous flow or pulse-dose delivery, how many liters per minute, and whether you need oxygen at rest, during sleep, during exercise, or all three.
Getting a Prescription
Your doctor will order a blood oxygen test, either a blood draw from an artery or a pulse oximetry reading. Medicare and most insurers require your oxygen saturation to be at or below 88%, or your arterial oxygen level to be at or below 55 mm Hg, for coverage to kick in. If your levels fall between 56 and 59 mm Hg, you may still qualify if you also have signs of heart strain or elevated red blood cell counts related to low oxygen.
The test must be performed “at the time of need,” meaning while you’re actually experiencing low oxygen levels. For hospital patients, this means within two days of discharge. Your doctor evaluates the results and writes a prescription that specifies your flow rate and when to use supplemental oxygen.
Choosing Your Equipment
Once you have a prescription, you’ll choose between two main types of equipment: compressed gas cylinders (tanks) and oxygen concentrators.
Oxygen Tanks
These are metal cylinders filled with compressed oxygen gas or liquid oxygen. They come in sizes ranging from small portable units you can carry in a bag to large stationary tanks for home use. The main drawback is that they run out and need to be refilled or exchanged. You’ll work with a supplier who delivers full tanks and picks up empty ones on a regular schedule. If you’re running low between deliveries, contact your supplier immediately for an extra drop-off.
Oxygen Concentrators
Concentrators are electric devices that pull oxygen from room air, filter out nitrogen, and deliver concentrated oxygen through a nasal cannula. They never run out of oxygen as long as they have power. Home units plug into a wall outlet. Portable models run on rechargeable batteries and are small enough to carry in a shoulder bag. The American Lung Association recommends choosing an FDA-approved concentrator that matches your prescription’s flow type and liter rate, and avoiding non-prescription devices sold through online ads, which often can’t deliver enough oxygen for conditions like COPD or pulmonary fibrosis.
Where to Buy
Most people get oxygen equipment through a durable medical equipment (DME) supplier. Your doctor’s office or hospital discharge team will typically recommend one, but you can choose any Medicare-approved supplier if you’re using insurance. You can also purchase portable oxygen concentrators directly from manufacturers or authorized online retailers. When buying online, the seller should ask for your prescription before shipping the device.
Look for equipment that is FDA-cleared and sold by a supplier who verifies prescriptions. Avoid any site that offers to sell you a “medical-grade” concentrator without asking for documentation.
What It Costs
Medicare covers home oxygen equipment as a rental. You pay 20% of the Medicare-approved amount after meeting your Part B deductible, and Medicare pays the rest. The rental period lasts 36 months, during which the monthly payment covers the equipment, accessories, tubing, and oxygen contents. After 36 months, the equipment becomes yours, but if you use tanks that need refills, Medicare continues to cover the cost of delivered oxygen contents (you still pay 20%).
If you’re buying a portable oxygen concentrator out of pocket, prices typically range from around $2,000 to $3,500 or more depending on the model, battery life, and flow settings. Some people buy a concentrator outright to avoid long-term rental costs or because they want a specific model for travel.
Canned Oxygen: What You Actually Get
Products like Boost Oxygen are sold over the counter at pharmacies and sporting goods stores for about $10 per 5-liter can. They advertise 95% pure oxygen and claim to help with altitude adjustment, energy, and athletic performance. These are not FDA-approved medical devices and are labeled for “recreational use only.”
The reality is more limited than the labels suggest. Each can provides roughly 100 one-second puffs. Because you’re also breathing in regular room air (which is 21% oxygen) around the edges of the nozzle, the actual oxygen concentration reaching your lungs is considerably lower than 95%. Researchers at the University of Colorado have pointed out that the brief, intermittent nature of canned oxygen makes it fundamentally different from medical oxygen therapy, where patients breathe supplemental oxygen continuously for hours. If you have a medical condition causing low blood oxygen, canned oxygen is not a substitute.
Safety Rules for Home Oxygen
Oxygen itself doesn’t burn, but it makes everything around it burn faster and hotter. Keep all oxygen equipment at least 6 feet from any heat source or open flame, including candles, gas stoves, fireplaces, space heaters, electric baseboard heaters, and wood stoves. The same 6-foot rule applies in restaurants or any public space with candles or cooking flames.
Keep flammable liquids away from your oxygen supply, including cleaning products containing alcohol, oil, or grease. Don’t use petroleum-based lotions like Vaseline on your face or upper body while using oxygen. Water-based products and aloe vera are safe alternatives. Even small electrical devices like hair dryers, electric razors, and electric toothbrushes should stay at least 6 feet away from your oxygen source when in use.
Flying With Oxygen
Airlines do not allow compressed oxygen tanks on board, but portable oxygen concentrators are permitted on all U.S. commercial flights if they meet FAA acceptance criteria. The device must be FDA-cleared, must not emit radio frequency interference, and must not generate compressed gas or contain hazardous materials beyond standard batteries.
Concentrators that meet these criteria must carry a red label stating: “The manufacturer of this POC has determined this device conforms to all applicable FAA acceptance criteria for POC carriage and use on board aircraft.” Several older models, including the Inogen One, Respironics SimplyGo, and SeQual Eclipse, were previously approved under a special federal rule and can be used on aircraft even without the red label. Contact your airline at least 48 hours before your flight to confirm their specific policies and ensure your device is accepted.