Research & Sources

Where the milestones come from.

ClariLung's 30+ health milestones aren't invented. They're drawn from decades of public-health research by the CDC, NHS, American Lung Association, NIDA, and WHO. This page explains our sources and what the evidence actually says.

ClariLung is not a medical device and does not provide medical advice. The health milestones shown in the app are general wellness information based on established public-health research. They are not a substitute for guidance from a qualified healthcare professional. If you have concerns about your health or withdrawal symptoms, please speak with a doctor.

Our Sources

Established public-health authorities.

ClariLung cites organizations — not individual studies. We reference well-established, verifiable bodies of research from the world's leading public-health institutions. We do not fabricate paper titles, author names, DOIs, or study URLs.

Centers for Disease Control and Prevention (CDC)

The CDC's Office on Smoking and Health publishes comprehensive data on cessation benefits, chemical exposure, and long-term cardiovascular and respiratory recovery. ClariLung draws on their published cessation timeline research.

National Health Service (NHS)

The NHS publishes detailed timelines of what happens to the body after stopping smoking, used in public smoking-cessation programs across the United Kingdom. These timelines inform several of ClariLung's early milestones.

American Lung Association

The ALA's research and advocacy work covers both tobacco and cannabis cessation. Their published health-benefit timelines for quitting smoking and vaping are directly referenced in ClariLung's milestone data.

National Institute on Drug Abuse (NIDA)

NIDA publishes research on cannabis use disorder, THC clearance timelines, and cognitive recovery. ClariLung's weed-specific milestones draw on this body of work.

World Health Organization (WHO)

WHO reports on global tobacco use, health outcomes, and cessation effectiveness inform the broader context of ClariLung's health claims and risk-reduction framing.

The Complete Timeline

30+ milestones. Every substance.

What happens to your body when you quit — across all four substances ClariLung supports. Timeline items are labeled with the substance(s) they apply to.

20 minutes
Cigarettes
Blood pressure and pulse normalize
Within 20 minutes of your last cigarette, blood pressure and heart rate begin returning to normal ranges.
1 hour
Vaping, Weed
Heart rate stabilizing
Heart rate — elevated by nicotine and THC stimulation — begins returning to baseline.
8 hours
Vaping, Cigarettes, Cigars
Carbon monoxide clears, oxygen rises
Carbon monoxide from combustion drops by half or more. Blood oxygen levels return to normal. The body's tissues begin receiving full oxygen supply again.
24 hours
Vaping, Cigarettes, Weed, Cigars
Nicotine clearing; cardiac risk begins to drop
Nicotine levels fall significantly within 24 hours. For cigarette smokers, heart attack risk begins decreasing. THC's acute effects clear for cannabis users.
48 hours
Vaping, Cigarettes, Cigars
Taste and smell returning
Nicotine damages nerve endings that enable smell and taste. At 48 hours those nerve endings begin regrowing. Many people notice taste and smell sharpening.
72 hours
Vaping, Cigarettes, Weed
Bronchial tubes relax; nicotine fully cleared
Bronchial tubes relax and widen, making breathing physically easier. By 72 hours, nicotine is essentially gone from the bloodstream — physical withdrawal peaks and then begins to subside.
1 week
Vaping, Cigars, Weed
One week free
Nicotine receptors in the brain begin returning to normal density. Withdrawal symptoms typically peak and start declining. Appetite often normalizes for cannabis users.
2 weeks
Vaping, Cigarettes, Weed
Circulation improving; lung function rising
Blood flow improves throughout the body. Walking and exercise become easier. Irritability from withdrawal fades. Emotional regulation often improves for cannabis users.
1 month
All substances
Cilia recovering; infection risk falling
Cilia — tiny hair-like structures in the airways that sweep out mucus and debris — begin regrowing. Lung function often measurably improves. THC is mostly cleared from fat cells.
3 months
All substances
Significant respiratory improvement
Lung function often improves notably for cigarette smokers by three months. Coughing and shortness of breath tend to decrease. Sleep patterns often normalize for cannabis users. Circulation is typically significantly better.
6 months
All substances
Airways healing; chronic cough resolving
Airway inflammation drops substantially. Chronic cough tends to ease significantly for many users. Energy levels are often noticeably higher. Throat and esophageal healing is underway for cigar smokers.
1 year
All substances
Heart disease risk halved; oral cancer risk falls
Coronary heart disease risk drops to about half of an active smoker's (per public-health data). Oral cancer risk significantly reduced for cigar smokers. Many cannabis users report sustained improvements in sleep, memory, and focus.
5 years
Cigarettes
Stroke risk approaches a non-smoker's
After five smoke-free years, stroke risk approaches the level of someone who has never smoked (per public-health data).

Sources: Centers for Disease Control and Prevention (CDC) · National Health Service (NHS) · American Lung Association · National Institute on Drug Abuse (NIDA) · World Health Organization (WHO)
ClariLung is not a medical device. These milestones are general wellness information, not medical advice.

How we use the research

Science-backed. Substance-specific. Honest.

We don't extrapolate

Each milestone shown in ClariLung is drawn from established cessation research. We do not extend claims beyond what the public-health consensus supports. When the evidence covers cigarette smokers specifically, we label it that way.

Substance-specific where the evidence is

Vaping, cigarettes, weed, and cigars each have different chemical profiles and different recovery timelines. Where the research is substance-specific — like THC clearance times or oral cancer risk reduction — we apply it to the right substance. We don't mix them.

No fabricated citations

We cite organizations, not specific papers. We do not manufacture paper titles, author names, DOIs, or study links. If you want to read the research, go to cdc.gov, nhs.uk, lung.org, nida.nih.gov, or who.int and search for smoking cessation.

Not a medical device

ClariLung is a wellness and behavior-change application. It does not diagnose, treat, or cure any condition. It does not replace a doctor. For serious medical concerns or if withdrawal symptoms are severe, please speak with a healthcare professional.

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