What is Medical Oxygen and Why Do You Need a Prescription for It?

Breathing is something most people don’t think twice about—until it becomes difficult. For those with respiratory conditions, supplemental oxygen can be life-changing. However, not all oxygen is the same. Medical-grade oxygen is a specific type of oxygen that is highly regulated, requires a prescription, and is distinct from the air we breathe. Here’s what you need to know about what makes medical-grade oxygen unique and why it requires a doctor’s approval.

What Is Medical-Grade Oxygen?

Medical-grade oxygen, also known as Oxygen, USP, is oxygen that meets strict purity and safety standards set by regulatory agencies such as the FDA in the United States. The term USP stands for United States Pharmacopeia, which is a national set of guidelines that defines the quality, strength, and purity of medications and health products. For oxygen to be labeled as USP, it must be at least 99.0% pure and free from contaminants and impurities that could be harmful to those using it for medical purposes.

For oxygen concentrators, which extract and purify oxygen from ambient air, purity levels vary slightly due to the process of pressure swing adsorption (PSA). This method allows concentrators to produce oxygen at 93% ± 3% purity, which is still considered medical grade, though it does not meet the USP standard. Despite this, oxygen from concentrators is safe and effective for use in oxygen therapy and is also regulated for medical use.

Unlike industrial or welding oxygen, medical oxygen undergoes rigorous testing and quality control to ensure that it is safe for human inhalation.

Why Does Medical Oxygen Require a Prescription?

Since medical oxygen is classified as a drug by the U.S. Food and Drug Administration (FDA), it requires a prescription from a licensed healthcare provider. There are several reasons for this requirement:

Proper Dosage and Safety – Oxygen is essential for life, but too much or too little can be harmful. A prescription ensures that patients receive the correct amount tailored to their medical condition.

Underlying Health Conditions – Medical-grade oxygen is prescribed to patients with conditions such as chronic obstructive pulmonary disease (COPD), emphysema, or other respiratory disorders. A doctor must evaluate whether oxygen therapy is necessary and beneficial.

Risk of Oxygen Toxicity – Breathing in high levels of oxygen for extended periods without proper monitoring can lead to oxygen toxicity, which can damage the lungs.

Fire Hazards – Oxygen is not flammable, but it supports combustion, meaning that it can make fires burn more intensely. A prescription ensures that patients receive proper safety instructions.

How Is Medical Oxygen Different From Air?

Many people assume that air and oxygen are the same, but they are significantly different in composition and function.

While the air we breathe contains oxygen, it is diluted by nitrogen and other gases. Medical-grade oxygen, whether from tanks or concentrators, is purified and concentrated to ensure it meets standards for medical use.

Why It Matters

Understanding the differences between medical-grade oxygen and the air around us is more than just a science lesson—it’s essential for those who rely on oxygen therapy. Whether sourced from a tank as Oxygen, USP, or from a concentrator, medical oxygen must meet purity and safety guidelines to ensure it is both effective and safe. A prescription ensures that patients receive the right amount of oxygen to manage their condition properly. By using oxygen under medical supervision, individuals can improve their quality of life and breathe easier with confidence. If you or a loved one is prescribed oxygen therapy, always follow your healthcare provider’s instructions to ensure the best outcomes.

This article is for informational purposes only and does not constitute medical advice. Consult a healthcare provider for personalized recommendations regarding oxygen therapy.