Glossary
30 terms that come up in quitting nicotine, defined.
A glossary of the terms used across these guides — clinical (nAChR, FEV1, cotinine), behavioral (cold turkey, taper, conditioned response), and Nixd-specific (SOS toolkit, RLS). Where a term has its own page, it links to it.
Acute withdrawal
The first 1–4 weeks after quitting nicotine, when physical symptoms peak and resolve. Distinct from longer-term behavioral cravings, which can persist 90+ days.
See more →Anhedonia
Reduced ability to feel pleasure. A common symptom of nicotine withdrawal, peaking days 3–7 and resolving over 1–4 weeks. Driven by dopamine system recalibration as the brain adjusts to functioning without nicotine input.
Box breathing
Paced breathing technique: 4 seconds in, 4 hold, 4 out, 4 hold. Activates the parasympathetic nervous system via vagal stimulation. Used in Nixd's SOS toolkit for acute craving spikes.
See more →Cilia
Microscopic hair-like structures lining the airways. They beat in coordinated waves to clear mucus and debris from the lungs. Chronic vaping suppresses cilia function. Within 1–9 months of quitting, cilia regrow and resume normal beating.
See more →Cold turkey
Quitting nicotine by stopping completely on day one, with no gradual reduction. Has slightly higher 6-month abstinence rates than tapering in randomized trials (~18% vs ~14% for cigarette smokers, Lindson-Hawley 2016 Cochrane).
See more →Conditioned response
Behavioral reflex where a context (driving, after meals, breaks) automatically triggers nicotine seeking, separate from physical withdrawal. Behavioral conditioning takes 60–90 days to fade after the physical addiction resolves.
Cotinine
The primary metabolite of nicotine. Stays in the body 3–4 days after the last hit, longer than nicotine itself (~2 hour half-life). Used in clinical drug tests because it's more reliable than direct nicotine measurement.
Disposable vape
A single-use vaping device pre-filled with e-liquid and a built-in battery. Examples: Elf Bar, Geek Bar, Lost Mary, Hyde, Vuse. Typically 5% nicotine, 5,000–15,000 puffs per device.
Dopamine reset
Recalibration of the dopamine reward system after chronic nicotine use. Around days 25–45, food, exercise, and natural rewards become more vivid as the brain reduces its expectation of nicotine input. Many ex-users describe a 'colors come back' moment in this window.
EVALI
E-cigarette or Vaping product use-Associated Lung Injury. Severe acute lung damage emerging from the 2019 outbreak. Most cases were traced to vitamin E acetate in illicit THC vape cartridges. Rarer in regulated nicotine vapes but documented.
FEV1
Forced Expiratory Volume in 1 second. The standard pulmonary function test measurement — how much air you can blow out in the first second of a forced exhale. Decreases with chronic vaping and recovers measurably within 2–4 weeks of quitting.
Half-life (nicotine)
Time for blood nicotine to fall to half its peak. Roughly 2 hours. By 12 hours after the last hit, blood nicotine is essentially gone — but receptor adaptation takes weeks to reverse.
JUUL
Pod-based vape system, dominant in the US 2017–2020. 5% nicotine pods (~40mg per pod, comparable to a pack of cigarettes). Owned by JUUL Labs. Subject to extensive FDA regulation and litigation.
See more →Lindson-Hawley 2016
Cochrane systematic review pooling 51 randomized trials of cigarette cessation, comparing abrupt cessation (cold turkey) to gradual reduction. Found cold turkey produced modestly higher 6-month abstinence rates. The canonical reference for the cold-turkey-vs-taper question.
Neuroplasticity
The brain's ability to reorganize itself by forming new neural connections. Central to nicotine cessation: receptor downregulation, dopamine recalibration, and behavioral rewiring all rely on neuroplastic change. Mostly complete by day 90.
Nicotine pouch
Small, oral tobacco-free pouch containing synthetic nicotine. Held in the lip for 30–60 minutes. Brands: Zyn, On!, Velo, Lucy, Lyft. Typical strengths: 2–14mg per pouch.
See more →Nicotinic acetylcholine receptor (nAChR)
The receptor nicotine binds to in the brain. Chronic nicotine causes upregulation — your brain builds more receptors to compensate. When you quit, those extra receptors fire without input, producing acute withdrawal. Downregulation completes over 4–8 weeks.
NRT
Nicotine Replacement Therapy. FDA-approved cessation aids — patches, gum, lozenges, inhalers, nasal spray — that deliver controlled doses of nicotine without the harmful delivery method (combustion, vape aerosol). Reduces acute withdrawal severity by roughly half in randomized trials.
See more →Pod system (vape)
Refillable or pre-filled pod-based vape device. Examples: JUUL (closed pods), refillable systems like SMOK, Innokin. Distinct from disposables (built-in battery, no refilling) and box mods (advanced, customizable).
Propylene glycol (PG)
One of the two primary base liquids in vape juice (the other is vegetable glycerin / VG). PG is hygroscopic — it pulls moisture out of tissue, contributing to dry throat and mild dehydration in vapers. Heated PG produces formaldehyde and acetaldehyde at varying levels.
Receptor upregulation
The brain's adaptation to chronic nicotine — building more nicotinic receptors to compensate for constant stimulation. Reverses over 4–8 weeks of cessation. Documented in PET imaging studies (Brody, Cosgrove).
REM rebound
Increased REM sleep activity after quitting nicotine, leading to vivid dreams and sometimes sleep disruption in the first 1–2 weeks. The brain compensates for the REM suppression that nicotine produced during chronic use.
See more →RLS (Row-Level Security)
Database-level access control where each row in a table is restricted to specific users. Used in Nixd's Supabase backend so users can only read their own data. Mentioned in the Privacy Policy as the access-control mechanism.
See more →SOS toolkit
Nixd's set of 6 craving intervention tools available from a permanent in-app button: 4×4 box breathing, 5-senses grounding, 90-second movement reset, distraction game, 'not this time' guided intervention, and craving log. Built for the 3–5 minute window in which most cravings peak and pass.
See more →Streak (in cessation)
Time elapsed since the last nicotine use. Nixd tracks streaks live to the second. Used as a behavioral reinforcement mechanism. Default does not reset on slips — research shows reset-to-zero framing is a relapse trigger rather than a recovery aid.
See more →Synthetic nicotine
Lab-produced nicotine without tobacco-leaf origin. Used in most modern US-sold pouches (Zyn, On!, Velo, Lucy). Pharmacologically identical to tobacco-derived nicotine — same receptor binding, same dependency mechanism.
Taper
Gradual reduction in nicotine use to zero over a defined schedule, rather than stopping abruptly. Has lower week-1 dropout than cold turkey but slightly lower 6-month abstinence rates in randomized trials. Nixd supports taper for vapes (puff count) and pouches (count + strength).
See more →Vagal tone
Activity of the vagus nerve, the main parasympathetic ('rest and digest') signaling pathway. Box breathing and other slow-paced breathing increase vagal tone, lowering heart rate and reducing acute autonomic activation during craving spikes.
Withdrawal
The set of physical and psychological symptoms produced by stopping nicotine in a chronically using brain. Acute physical withdrawal peaks at 72 hours and resolves in 2–4 weeks. Behavioral / conditioned withdrawal can persist 60–90 days after physical withdrawal ends.
See more →Zyn
Nicotine pouch brand owned by Philip Morris International (via Swedish Match). 3mg or 6mg per pouch in the US. Largest pouch brand by sales; over $1B annual revenue.
See more →