Smelling salts are ammonia-based inhalants that produce a sharp, pungent gas designed to trigger a rapid jolt of alertness. They’ve been used for centuries to revive people who have fainted, and today they’re most commonly seen in sports like powerlifting, hockey, and football, where athletes crack open a capsule before a big effort. The active ingredient is simple: ammonia, which irritates the nasal passages and forces the body into a sudden “wake-up” response.
What’s Actually in Them
Traditional smelling salts are preparations of ammonium carbonate mixed with perfume or essential oils. When exposed to air, the compound releases ammonia gas, which is what produces that unmistakable sharp smell. Most commercially available versions sold online are even simpler: dilute ammonia dissolved in a mixture of water and ethanol. They come in small crushable capsules, squeeze ampules, or small bottles.
How They Work in the Body
The moment ammonia gas reaches the inside of your nose, it irritates the mucous membranes lining the nasal cavity. This triggers a nerve called the trigeminal nerve, one of the major sensory nerves in your face. That nerve fires a signal to the brain’s breathing and cardiovascular control centers, which respond by ramping up your breathing rate and heart rate through the sympathetic nervous system, the same system responsible for your fight-or-flight response.
The result is a sudden, involuntary gasp followed by a spike in alertness. Your eyes may water, your head snaps back, and you feel a rush of wakefulness. The entire response happens in seconds. Ammonia is detectable in air at concentrations as low as 5 parts per million, so even a brief whiff from a capsule held at arm’s length delivers a noticeable stimulus.
Why Athletes Use Them
Walk through a powerlifting meet or an NHL locker room and you’ll see smelling salts everywhere. Players and lifters describe the effect as an “awareness wakeup” or “a little jolt” that helps them feel locked in before a heavy lift or shift on the ice. The appeal is psychological as much as physical: research published in Sports Health found that the performance-enhancing effect of ammonia inhalation correlated with a subjective increase in perceived alertness and “psyched-up energy,” suggesting the benefit comes from heightened psychological arousal rather than any actual change in muscle function or cardiovascular output.
That distinction matters. The same research found no measurable performance benefit for short bursts of maximal effort, even though athletes reported feeling more energized and believed they performed better. In other words, smelling salts make you feel ready to go, but they don’t make your muscles stronger or faster. For sports where mental focus and aggression matter, that psychological edge may still be worth something. For pure physical output in a single rep or sprint, the evidence says they don’t help.
The Traditional Medical Use
Before smelling salts became a locker room staple, they were a first-aid tool. For someone who had fainted or felt faint, a capsule held about four inches from the nostrils would trigger that sharp inhalation reflex and help restore consciousness. The ammonia essentially forces the body to gasp, which increases oxygen flow to the brain.
This use has become far less common in modern medical settings. The practice of reviving an unconscious person with smelling salts can actually mask the reason they passed out in the first place. If someone faints because of a head injury, cardiac problem, or low blood sugar, waking them with ammonia doesn’t address the underlying cause and could delay proper assessment.
Safety Risks and Side Effects
At the concentrations found in a single capsule held at the recommended distance, smelling salts are generally tolerated without lasting harm. The body can handle ammonia concentrations up to about 100 ppm in air for several hours without tissue damage. But the margin between “unpleasant but harmless” and “genuinely dangerous” narrows quickly as concentration increases. At 300 ppm, ammonia becomes immediately harmful to health. At 1,700 ppm, it can cause spasms of the vocal cords, severe coughing, and swelling in the throat. Concentrations above 2,500 ppm can be fatal within 30 minutes.
These extreme exposures aren’t typical from a single smelling salt capsule used correctly. The real risks come from misuse: holding the capsule too close to the nose, inhaling deeply and repeatedly, or using concentrated products not designed for inhalation. Product instructions recommend holding the capsule 10 to 15 centimeters (about 4 to 6 inches) from the nose.
People with asthma face an additional concern. The trigeminal nerve stimulation caused by ammonia can trigger a reflex that constricts the airways, potentially worsening breathing in someone already prone to bronchospasm. Research on trigeminal sensitivity to ammonia has shown that nasal stimulation alone can be sufficient to induce asthma symptoms in susceptible people.
FDA Warnings on Newer Products
In August 2024, the FDA issued a warning about a wave of inhalant products marketed for “alertness” and “energy boosting” that primarily contain ammonia. These are not the traditional medical ammonia ampules found in first-aid kits. They’re consumer products sold online, often with aggressive branding aimed at athletes and gym-goers. The FDA stated that manufacturers had not demonstrated these products to be safe or effective for their intended uses.
The agency reported receiving adverse event reports including shortness of breath, seizures, migraines, vomiting, diarrhea, and fainting from consumers who used these products. The FDA warned that it may pursue legal action, including product seizure, against companies that fail to correct violations. Traditional aromatic ammonia spirit, the kind found in pharmacy first-aid sections, remains available as an over-the-counter product with established usage guidelines. The concern is specifically about unregulated, high-concentration products being marketed as performance enhancers without any safety review.
How to Use Them Safely
If you choose to use smelling salts, the key variable is distance. Hold the capsule or bottle about four to six inches from your nose and let the vapor drift toward you rather than jamming it directly under your nostrils. One brief inhalation is enough to trigger the alertness response. There’s no benefit to repeated deep sniffs, and doing so only increases your exposure to ammonia gas without adding any extra “jolt.”
Avoid using them if you have asthma or other reactive airway conditions. Don’t use them on someone who is unconscious without knowing why they lost consciousness, since the underlying cause matters far more than waking them up quickly. And be cautious with unbranded or heavily concentrated products purchased online, particularly those flagged in the FDA’s 2024 warning. A standard medical-grade ammonia ampule from a pharmacy is a more predictable and lower-risk option than an unregulated product with no listed concentration.