What oxygen therapy is
Oxygen therapy can be given at different concentrations. Normal air contains around 21% oxygen, but additional oxygen can be mixed in with air to increase this anywhere up to 100%. The extra oxygen can either come from a portable oxygen tank or a concentrator that pulls oxygen from the air and removes other gases.
Hyperbaric oxygen therapy is slightly different. This treatment involves sitting inside a sealed chamber where a high concentration of oxygen (usually 100%) is given at an increased pressure.
A rarer type of oxygen treatment is topical oxygen therapy. This involves using a special device to administer 100% pure oxygen directly to a wound or burn. With topical oxygen therapy, the amount of oxygen you breathe in doesn’t change.
How oxygen therapy works
The cells in your body need oxygen to produce energy and survive via a process known as respiration.
Oxygen is required for the most effective type of energy production known as aerobic respiration. Without enough oxygen, cells rely on anaerobic respiration - a process that produces around 15 times less energy.
Cells using anaerobic respiration function less effectively and as waste products build up, they eventually stop being able to function at all. This impaired cell function means the body’s organs stop working properly, the immune system is less effective and waste can’t be removed.
Oxygen delivery is important for healing processes within the body. It’s commonly recognized that lung function can affect tissue oxygenation, but cardiovascular health, red blood cell quality and microcirculation also impact how effectively oxygen reaches tissues.
As well as health conditions that directly affect these systems, chronic inflammation, poor nutrition, sedentary behavior and smoking can also contribute.
Regenerative thinking recognizes that inadequate oxygen delivery to tissues is a root-level problem in many chronic conditions. Damaged, inflamed, or tissues with inadequate blood supply can’t heal efficiently because cellular repair and energy production are oxygen-dependent processes.
Traditional oxygen therapy
Traditional oxygen therapy provides oxygen to the body when the lungs aren’t providing enough. This helps your cells to get the oxygen they need and function effectively again, avoiding long-term cell and organ damage.
With traditional oxygen therapy, the concentration of oxygen given depends on the oxygen saturation levels in your blood (measured by a probe clipped onto your finger). The flow of oxygen will be increased gradually until your blood oxygen saturation is within the desired range – the range will depend on which health condition you have, but it’s usually 95-100%.
In an emergency where oxygen levels are very low or delivery is impaired (such as when the heart has stopped pumping), 100% oxygen is given. However, it’s not always safe to give 100% oxygen – it can cause cell damage and toxicity if given in too high concentrations to people with normal blood oxygen levels.
Hyperbaric oxygen therapy
Hyperbaric oxygen therapy is a slightly different kind of oxygen treatment. With hyperbaric oxygen therapy, high concentrations of oxygen are given at increased pressure.
Oxygen is usually carried by the red blood cells, but increasing the pressure means that some oxygen is also dissolved directly into the blood. This increases how much total oxygen the blood can carry and increases delivery to the tissues.
Learn more in our guide to hyperbaric oxygen therapy
Topical oxygen therapy
Oxygen partial pressure is a measure of the pressure oxygen exerts on the other gases within the blood – it’s a way of measuring the concentration of oxygen. The partial pressure of oxygen within the tissues of the body is important for wound healing, and low pressure may be associated with poor wound healing (Putri et al., 2024).
Topical oxygen therapy involves applying 100% oxygen directly onto open/healing wounds and burns at normal pressure. This raises oxygen partial pressure in the damaged tissues, increasing blood vessel growth, supporting wound repair and stopping bacterial growth.
Who oxygen therapy helps
High-concentration oxygen can be useful in an emergency or acute situation where blood oxygen levels are low or delivery is impaired, such as:
An asthma attack
Pneumonia
Pulmonary embolism (a blood clot in the lungs)
Trauma to the lungs
Cardiac arrest (the heart has stopped beating)
Anaphylaxis (severe allergic reaction)
Sepsis (a severe infection affecting the whole body)
Long-term oxygen therapy can also be used for people with chronic conditions where their oxygen levels continue to be low. This includes individuals with:
Chronic obstructive pulmonary disease (swelling and damage inside the lungs, often caused by smoking)
Pulmonary fibrosis (scarring of the lungs)
Ongoing heart failure (inability of the heart the pump properly and circulate blood around the body, leading to low oxygen levels)
Hyperbaric oxygen therapy is less common in a hospital setting, but is approved by the FDA for 14 different uses (including decompression sickness relating to deep-sea diving and poorly healing wounds). It’s also provided off-label by private clinics for other health conditions, although there is usually less evidence to support these uses.
Topical oxygen therapy is FDA approved for diabetic ulcers, burns and several other types of wounds.
Common uses
Conventional medicine recommends using supplemental inhaled oxygen only in specific situations relating to low blood oxygen saturation levels. This includes acute situations, like an accident, asthma attack, altitude sickness or severe infection, and for managing health conditions that cause chronically low blood oxygen levels, like COPD or heart failure.
Hyperbaric oxygen therapy was first used to treat decompression sickness – a condition where gas bubbles form in the blood when the pressure increases rapidly as scuba divers surface too quickly. It’s also an effective treatment for non-healing diabetic foot ulcers, skin grafts and other non-healing wounds (as is topical oxygen therapy).
Oxygen therapy is also being used for an increasing number of experimental uses, but these tend to be off-label and not approved by the FDA. Some of the emerging uses of oxygen therapy include:
Hair loss treatment, acne treatment (topical oxygen)
Traumatic brain injury, stroke, PTSD, fibromyalgia, Lyme disease, autoimmune conditions (hyperbaric oxygen)
Strokes, depression, improving cognitive function in healthy people (standard oxygen therapy at lower concentrations)
Let’s explore which of these uses have a good amount of evidence behind them and the areas where evidence is lacking.
What the evidence supports
Hyperbaric oxygen therapy has a strong amount of high-quality evidence from randomized controlled trials (RCT) for its 14 FDA-approved uses (Ortega et al., 2021).
The 14 FDA-approved uses include treating:
Air or gas embolism (a bubble blocking blood flow)
Acute thermal burns
Carbon monoxide poisoning
Carbon monoxide poisoning complicated by cyanide poisoning
Central retinal artery occlusion (blocked artery in the eye)
Clostridial myositis and myonecrosis (gas gangrene)
Compromised grafts and skin flaps
Crush injury, compartment syndrome and other acute trauma with compromised blood flow
Decompression sickness
Delayed radiation injury
Enhancement of healing of selected wounds
Sudden hearing loss of unknown cause
Intracranial abscess (collection of infection within the brain)
Necrotizing soft tissue infections (causing tissue death)
Bone infections unresponsive to other treatments
Severe anemia
For off-label non-FDA approved uses, like traumatic brain injury and Alzheimer’s disease, there are some promising results from case studies and clinical trials. For example, a review of 11 RCTs found that hyperbaric oxygen therapy may improve cognitive function in people with Alzheimer’s disease (Lin et al., 2024).
Another review found a high level of evidence (including nine control trials) that hyperbaric oxygen can improve acute moderate-to-severe traumatic brain injury, although more research into specific protocols is needed (Hadanny et al., 2023).
A review article found a significant amount of evidence (from observational studies and RCTs) that topical oxygen therapy is a useful additional therapy for chronic nonhealing wounds (Putri et al., 2024). However, lack of standardization is a problem and more research into specific protocols is needed.
Where the evidence is limited
There’s very limited evidence supporting standard oxygen therapy for people with normal blood oxygen levels even during an acute illness. A study that investigated oxygen therapy for people experiencing heart attacks found that people with normal blood oxygen saturation levels were not more likely to survive when given oxygen therapy (Hofmann et al., 2017).
Some small studies have found that standard oxygen therapy may improve cognitive function in healthy people (Wang et al., 2023), mood and wellbeing in people with depression (Bloch et al., 2021) and relieve migraine/cluster headache symptoms (Bennett et al., 2015). However, larger and higher quality studies are needed into the impact of oxygen therapy on brain function.
Safety and regulations
Both hyperbaric oxygen therapy and topical oxygen therapy have specific FDA-approved uses. In some cases these therapies are used to treat other conditions, but this is done off-label.
In most cases, standard oxygen therapy isn’t routinely recommended by healthcare professionals for people with normal blood oxygen saturation levels as there isn’t enough evidence to currently support it.
All types of oxygen therapy do come with the risk of oxygen toxicity, skin/nose/airway irritation and pose a fire hazard.
The experience
Your experience of oxygen therapy will vary depending on which type of treatment you have.
Oxygen is usually given through a mask during an emergency, but may be administered through a nasal cannula for less acute or long-term use. This is usually in a hospital or nursing home, but some people receive home oxygen.
Some private health clinics may offer low-concentration standard oxygen therapy for people with normal oxygen levels as a recovery, wellness or experimental therapy. This will usually involve attending a clinic for one or multiple sessions.
Hyperbaric oxygen therapy typically involves a 60-120 minute session sitting inside a pressurized chamber where you inhale 100% oxygen via a mask or hood. The pressure will be gradually increased at the start and decreased at the end and during this time you may feel your ears pop. The number of sessions you need will depend on what you’re treating, but many protocols involve 20-40 sessions.
Topical oxygen therapy is provided at some wound care centers, podiatry offices and via certain home health care services. The process will depend on which device you use, and can involve:
Wearing a backpack generator that directs oxygen into a sealed dressing 24/7
Using a topical spray on your wound
Applying an enclosed chamber (like an inflatable boot or cast) that’s attached to an oxygen generator
Most topical treatments are used for several weeks.
Takeaway
Oxygen is key for cell function in every tissue of the body. Standard oxygen therapy can improve how much oxygen you breathe in and help with acute and ongoing lung and circulatory problems, while hyperbaric and topical oxygen therapies are FDA-approved to help with wound healing and certain other conditions.
These oxygen therapies may be used off-label for other health issues, with varying amounts of evidence behind them. Although oxygen can be useful to support wound healing and oxygen delivery to the tissues, hyperbaric and topical oxygen therapies aren’t a replacement for standard treatments and are best used as add-on therapies.
