Updated October 2026
What Do Smelling Salts Do? The Honest Mechanism
What smelling salts do is simple and often misunderstood: the ammonia gas irritates your nasal passages and triggers an involuntary gasp reflex — sharp inhalation, faster breathing, a spike of alertness that fades within seconds to minutes. It is a startle response, not a strength drug, and the controlled studies below show exactly that.
How do smelling salts work, step by step?
Ammonia gas releases
Smelling salts are ammonium carbonate or ammonia solution, often cut with scents. Opening or crushing the container releases ammonia gas.
Your nasal membranes get irritated
Ammonia is a chemical irritant. It triggers the sensory nerves of the nose, lungs, and mucous membranes within a second of a sniff.
The gasp reflex fires
Your body responds involuntarily: a sharp inhalation, faster breathing, a bump in heart rate. This is a protective reflex — your nervous system reacting to a threat, not a drug being absorbed.
Arousal spikes, then fades
The result is a jolt of alertness that peaks immediately and dissipates within roughly 15 seconds to a few minutes. There is no lasting pharmacological effect — when the reflex ends, so does the feeling.
What do smelling salts smell like?
Like being slapped by a public restroom. The smell is pure ammonia — sharp, chemical, eye-watering — and describing it politely is a lost cause: NHL defenseman Brenden Dillon told Sports Illustrated they “absolutely reek,” and one r/hockeyplayers user compared it to “a cat litter box that has been left out for a month in a closed room with no ventilation” (u/Kegheimer, March 2023). That foulness is the point: the stench is the irritant that triggers the gasp reflex.
It is nothing like the menthol-camphor scent of a herbal inhaler, which reads as cold and clean rather than caustic — the two products share a format, not a smell. Side effects of the ammonia blast, including the temporary smell blindness users report, are covered in are smelling salts bad for you.
Do they actually improve performance?
The arousal is real; the performance effect mostly is not. In a 2014 study of 25 resistance-trained men, ammonia inhalants produced no significant difference in reps to failure on back squat (P = 0.403) or bench press (P = 0.422) versus a menthol placebo. A 2021 controlled trial found heart rate (P < .001), alertness (P = .009), and perceived performance (P = .036) all rose after inhalation — while measured neuromuscular performance was unchanged.
In plain terms: smelling salts make you feel ready, and feeling ready has genuine value in a max attempt. But the gasp reflex does not add newtons to the bar.
Sources: Richmond et al., JEP online, 2014 · Eur J Sport Sci, 2021 (PubMed) · FDA warning, Aug 2024
Why do athletes use them anyway?
Powerlifting and strongman
The pre-max-attempt sniff is a fixture of strength sports — the recoiling-lifter reaction video is its own genre, popularized by strength influencers like Jujimufu. The draw is the arousal ritual, not any proven strength effect (see the data below).
NFL and hockey
Sideline and locker-room ammonia caps have decades of history; Aaron Rodgers' use was among the most widely reported NFL examples. Hockey benches are famous for them — a wake-up ritual between shifts, not a performance drug.
The original job: fainting
For centuries, ammonia spirits revived people who fainted. Modern first aid has moved away from this, and sports medicine warns against using the jolt to “clear the cobwebs” after a head hit — it can mask concussion symptoms.
Full safety picture, including the FDA's 2024 adverse-event reports: are smelling salts bad for you?
What-do-they-do FAQ
What do smelling salts do?
Sniffing smelling salts releases ammonia gas that irritates the membranes of your nose and lungs, which triggers an involuntary gasp reflex: a sharp inhalation, faster breathing, a brief rise in heart rate, and a jolt of alertness. The effect is a startle response, not a stimulant drug — it peaks instantly and fades within seconds to a few minutes.
What do smelling salts smell like?
Pure ammonia: sharp, caustic, eye-watering — players describe it as everything from “absolutely reek” (NHL defenseman Brenden Dillon) to a month-old litter box. The foul smell is functional: it's the irritation that triggers the gasp reflex. It is nothing like the clean menthol-camphor scent of herbal inhalers that share the same pocket format.
What are smelling salts made of?
Traditionally ammonium carbonate (“spirit of hartshorn”); modern gym products use ammonium carbonate capsules or ammonia solution, usually mixed with fragrance. The active agent in every case is ammonia gas.
Do smelling salts make you stronger?
The controlled evidence says no. A 2014 study of 25 resistance-trained men found no significant difference in squat or bench press reps after ammonia inhalants versus placebo (P = 0.403 and 0.422), and a 2021 trial found heart rate and alertness rose while actual neuromuscular performance was unchanged. What they reliably raise is arousal and the feeling of readiness.
How long do smelling salts last?
The jolt is immediate and short: the strongest effect passes within about 15 seconds to a minute, with residual alertness fading over a few minutes. That is why athletes use them seconds before an effort, not before a game.
Are smelling salts a stimulant like caffeine?
No. Caffeine is absorbed and acts on your brain chemistry for hours. Ammonia is not absorbed in meaningful amounts — it works by irritating your airways and triggering a reflex. Once the reflex subsides, nothing keeps working.
Do smelling salts wake you up when tired?
Briefly, yes — the gasp reflex cuts through grogginess for a moment. But the FDA warned in August 2024 against ammonia inhalants marketed for alertness and energy, citing reports of seizures, breathing problems, and fainting. For a repeatable daily pick-me-up, an irritant reflex is the wrong mechanism — menthol inhalers exist for exactly that use.