Smelling salts, also known as ammonia inhalants, are used to quickly rouse someone from a faint or provide a temporary burst of alertness, particularly in sports. The duration of their effect has two distinct answers: the immediate physical effect felt by the user and the overall longevity of the product inside its container. Understanding both timeframes is important for anyone considering their use. The immediate physical jolt is extremely brief, while the product’s lifespan is highly variable depending on its preparation and care.
The Physiological Duration of the Stimulant Effect
The immediate physical reaction to smelling salts is exceptionally short-lived, typically lasting no more than a few seconds up to about one minute. The inhalant’s purpose is to deliver a rapid, sharp stimulus, not a sustained one. This quick response includes a feeling of a jolt, forced, rapid inhalation, and a temporary increase in heart rate.
The body quickly regulates itself back to its normal state once the ammonia gas is removed from the nostrils. The sensation of heightened alertness ends almost immediately after exposure. The goal is to trigger a momentary sympathetic nervous system response, meaning the effects are transient.
The Chemical Mechanism Behind the Short Duration
The transient nature of the stimulant effect is directly related to its chemical mechanism of action. Smelling salts contain ammonium carbonate or a solution of ammonia dissolved in water and alcohol, which releases ammonia gas. This gas acts as a potent irritant to the mucous membranes lining the nose and lungs.
This irritation triggers the trigeminal nerve, which is responsible for sensation in the face. The stimulation causes the inhalation reflex, forcing the user to breathe in quickly and deeply. This sudden, deep breath increases oxygen flow to the brain and activates the sympathetic nervous system, leading to the brief “fight-or-flight” response. Because the physiological response is an immediate reaction to an external irritant, the effect dissipates as soon as the irritant is no longer inhaled.
Product Potency and Shelf Life
The second definition of how long smelling salts last refers to the product’s effectiveness in the container, determined by the volatility of the ammonia compounds. Smelling salts are sold in two forms: pre-activated (ready to use) or non-activated (user-activated). Non-activated salts require adding water to the powder and typically have a long, sometimes unlimited, shelf life until activation.
Once a container is opened or activated, the ammonia gas begins to escape, and the product’s potency immediately starts to degrade. The shelf life of an activated or pre-activated container generally ranges from a few weeks to three to six months, depending on usage and storage. Heat and exposure to air significantly accelerate the loss of potency because the ammonia gas evaporates quickly.
To maximize the product’s longevity, it must be stored in a cool, dry place, away from direct sunlight or extreme temperatures. The container must also be sealed tightly immediately after each use. If the salts lose their strong, signature smell, it is a sign that the ammonia gas has largely evaporated and the product needs replacement.