Smelling salts release ammonia gas that triggers a sharp, involuntary inhalation reflex, jolting you into alertness within seconds. They work by irritating the sensitive membranes inside your nose, which sends an urgent signal through a major nerve in your head that activates your body’s fight-or-flight response. The effect is intense, brief, and almost impossible to ignore.
How Smelling Salts Work in Your Body
The active ingredient in smelling salts is ammonium carbonate. When exposed to air or moisture, it breaks down and releases ammonia gas. That gas dissolves on the wet surfaces inside your nose and forms a mildly caustic compound that irritates the cells lining your nasal passages.
This irritation fires up the trigeminal nerve, a large nerve that runs through your face and head. The trigeminal nerve provokes your body into taking a sudden, deep breath. That flood of oxygen raises your alertness, speeds your heart rate, and can snap you out of a faint or a daze almost immediately. Some researchers suspect that receptors in the lungs also respond to the ammonia, further driving the inhale reflex. Your eyes water, you may cough, and your breathing rate jumps. The whole cascade happens in a few seconds.
The sensation is deliberately unpleasant. Your body is reacting to a chemical irritant the same way it would react to any threat: by going on high alert. That’s the entire point.
Why Athletes Use Them
If you’ve seen powerlifters or football players crack a small capsule and inhale before a lift or a play, they’re chasing that burst of sympathetic nervous system activation. The ammonia triggers a spike in adrenaline-related stress hormones, which athletes describe as feeling “hyper-alert” or suddenly more awake. Researchers at Old Dominion University observed dilated pupils and increased breathing rates in subjects who inhaled ammonia before maximal deadlift attempts, consistent with a fight-or-flight response.
Whether that translates to measurably better performance is less clear. The stress hormones involved (epinephrine, norepinephrine) are difficult to measure in real time during exercise, so most evidence for a strength boost remains anecdotal. What’s not debatable is that the psychological effect is real: the jolt of alertness and aggression can help an athlete commit fully to a heavy lift or an explosive play.
What’s Actually Inside Them
Commercial smelling salts are simple. A typical product contains about 15% ammonium carbonate and 10% sodium carbonate. Some formulations come as crushable capsules wrapped in gauze, while others are bottled liquids. The capsule versions release a single controlled dose of ammonia when you snap them open. Bottled versions can vary in concentration and tend to be stronger, which increases the risk of irritation.
Products marketed specifically for athletic use or “energy boosting” sometimes contain higher concentrations of ammonia than traditional medical-grade inhalants. The FDA has flagged several of these products as unapproved, noting that they are not regulated the same way as over-the-counter medications.
Risks of Using Smelling Salts
The immediate side effects are the ones you’ll notice right away: burning in your nose and throat, watery eyes, and coughing. These are all caused by ammonia irritating your mucosal surfaces. At the concentrations found in a single capsule held at a safe distance, these effects are temporary and generally harmless.
The risks increase with misuse. Holding a capsule too close to your nose or inhaling directly from a concentrated bottle can cause chemical burns to the nasal lining and airway constriction. The FDA has received reports of more serious adverse events from consumers using high-concentration ammonia inhalants, including shortness of breath, seizures, migraines, vomiting, and fainting. These reports are associated primarily with unapproved products marketed for alertness and energy, not with standard medical-grade ammonia inhalants.
There’s also a specific concern around head injuries. Smelling salts were once routinely used on the sidelines to rouse athletes who had been knocked unconscious. The problem is that snapping someone awake with ammonia can mask the symptoms of a concussion or a more serious brain injury. The person appears alert and responsive, but the underlying damage hasn’t been assessed. Most major sports leagues have moved away from using smelling salts for this reason.
How to Use Them Safely
If you do use smelling salts, Poison Control recommends holding the capsule or solution 4 to 6 inches from your nose. That distance gives you the alertness jolt without delivering a concentrated blast of ammonia directly to your nasal membranes. One brief inhalation is enough. Repeated sniffs or holding the capsule closer won’t make the effect meaningfully stronger, but they will increase irritation.
Avoid using them on anyone who is unconscious from an unknown cause, especially if a head injury is possible. And avoid the high-concentration bottled products that have drawn FDA warnings. If a product is marketed as an energy booster or performance enhancer rather than a simple ammonia inhalant, it may contain concentrations that haven’t been reviewed for safety.