Ammonia inhalants, commonly known as smelling salts, are chemical preparations used as respiratory stimulants to increase alertness and consciousness. Traditionally, they were used to revive individuals who had experienced syncope, or fainting. The substance works by delivering a powerful, pungent sensory jolt that triggers an involuntary physiological reaction. The active ingredients are typically contained in small, breakable glass ampules wrapped in cotton or in modern plastic capsules or bottles.
The Chemical Composition and Function
The primary active compound in traditional smelling salts is ammonium carbonate, which releases ammonia gas (\(\text{NH}_3\)) when mixed with water. Modern versions often contain a dilute solution of ammonia mixed with water and ethanol, sometimes including essential oils for scent. When inhaled, the ammonia gas acts as a severe irritant to the mucous membranes lining the nose and lungs.
This irritation triggers a protective, involuntary reflex centered on the trigeminal nerve (Cranial Nerve V). The trigeminal nerve senses the chemical irritant and sends an immediate signal to the brainstem. This signal provokes an automatic, sharp inhalation reflex and rapidly activates the sympathetic nervous system, often called the “fight-or-flight” response.
The physiological response includes an increase in heart rate and an elevation in cerebral blood flow velocity. This sudden activation of the sympathetic nervous system is responsible for the feeling of heightened alertness and arousal. The effect is a temporary, chemically-induced jolt designed to overcome unconsciousness or extreme fatigue.
Common Uses and Misapplications
The original and medically recognized purpose of ammonia inhalants is reviving a person who has fainted due to temporary cerebral hypoxia (lack of oxygen to the brain). The intense respiratory stimulation helps restore oxygen flow to the brain, often reversing the unconscious state. The product is intended as an immediate, temporary intervention, not a treatment for the underlying cause of fainting.
In contemporary culture, the most common use is non-medical, particularly among athletes in powerlifting, strongman competitions, and contact sports like hockey and football. Athletes use the inhalants immediately before a maximal effort lift or high-impact moment to achieve a sudden boost in arousal and focus. This use is based on the subjective feeling of an adrenaline spike and increased wakefulness, which is perceived to enhance performance.
Misapplication occurs when the product is used habitually for mild fatigue or to mask the symptoms of a serious injury. Using ammonia inhalants to “wake up” an athlete after a head injury is particularly dangerous. The momentary arousal can mask the signs of a concussion, potentially leading the athlete to return to play and risk further, more severe brain injury.
Acute Safety Hazards and Proper Usage
Inhaling ammonia gas, a caustic substance, presents several acute safety hazards, particularly with repeated or improper use. The gas reacts with moisture in the nasal and respiratory passages to form ammonium hydroxide, a strong alkali. Exposure can cause chemical burns to the delicate membranes of the nose, throat, and eyes.
Severe exposure can lead to swelling in the voice box, known as laryngeal edema, which may obstruct the airway. Overuse or holding the product too close to the face increases the risk of damage to the nasal mucosa.
A specific risk in athletic settings involves the involuntary withdrawal reflex triggered by the inhalation. If an athlete uses the inhalant immediately before a heavy lift, the sudden head and neck movement caused by the gasp reflex could potentially exacerbate a spinal or neck injury under maximal load. To minimize localized irritation, guidelines suggest holding the inhalant at least four to six inches away from the nostrils during use.
Availability and Purchasing Options
Ammonia inhalants are generally classified under regulatory categories that permit them to be sold over-the-counter (OTC) in the United States. Historically, they were approved as respiratory stimulants for treating fainting. However, the Food and Drug Administration (FDA) has issued warnings regarding unapproved inhalant products marketed specifically for energy and alertness, particularly those sold to athletes.
Despite these regulatory challenges, the products remain widely available to the public. They can be found in various retail settings, including the first-aid section of general pharmacies, sometimes behind the counter, and in sporting goods stores. Online retailers, including major e-commerce platforms and specialized supplement websites, are a primary source for modern, athletic-focused products.
These products are sold in two main formats: the traditional glass ampule wrapped in gauze, which is crushed to release the gas, and modern plastic capsules or bottles containing the ammonia mixture. The latter format is often promoted to powerlifters and other strength athletes, sometimes marketed under brand names that emphasize strength or aggression.