No. In the largest recent analysis, quitting at every age was linked to living longer, and the gains were largest for people who quit before 40. Earlier is better. But the data doesn't show an age at which stopping stops mattering.
People ask this from two places. Some are 26, have smoked since college, and wonder whether the damage is already done. Others are asking for a father or an uncle in his fifties or sixties. The answer points the same way for both. The size of it is what changes.
The study behind the answer
In 2024, Cho and colleagues, a team that includes Prabhat Jha, pooled four national cohorts from the United States, the United Kingdom, Norway and Canada, each linked to death records (Cho et al., NEJM Evidence, 2024). Together they followed 1.48 million adults aged 20 to 79 for 15 years, during which 122,697 people died.
After adjusting for age, education, alcohol use and obesity, people who were still smoking had 2.8 times the risk of death of never-smokers if they were women, and 2.7 times if men. Former smokers came in at 1.3. Between the ages of 40 and 79, smokers lived 12 to 13 fewer years than never-smokers.
Then the part that answers the question. Compared with carrying on, having stopped for less than three years was associated with avoiding about 5 years of life lost. Having stopped for ten years or more was associated with avoiding about 10, which brought survival close to that of people who never smoked. The authors' conclusion is that quitting at any age, but particularly in younger years, was associated with lower excess mortality, overall and from vascular, respiratory and cancer causes, and that the benefit was visible as early as three years after stopping.
If you are under 40
This is most of our readers, and the numbers here are the strongest in the study.
Among people younger than 40 who had stopped for less than three years, the excess risk of death was 95% lower in women and 90% lower in men. Excess risk means the gap between a smoker's risk and a never-smoker's. Closing nine-tenths of that gap within three years of stopping is the clearest argument in the paper against waiting.
So the honest answer to "is it too late at 25" is that you are in the age group with the best figures in the study. For this age group the real question isn't whether it's too late. It's whether "I'll quit at 30" is a plan or a postponement.
If you are 40 to 59
The benefit is smaller, and still large. Among people who had stopped for less than three years, the excess risk was 81% lower in women and 61% lower in men aged 40 to 49, and 63% and 54% lower at 50 to 59.
If you are asking for a parent who is 60 or older
The age-specific figures above stop at 59, so for older ages a second study is more useful.
A 2024 modelling study used US mortality data to estimate how many years of life smoking costs, and how many quitting recovers, at different ages (Le, Mendez and Warner, 2024). For someone who has smoked through their adult life and carries on, the average loss is 9.1 years at 35, 8.3 at 45, 7.3 at 55, 5.9 at 65 and 4.4 at 75. Quitting at those ages avoids an average loss of 8.0, 5.6, 3.4, 1.7 and 0.7 years respectively.
Those later numbers are smaller. The authors put the chance of gaining at least one full year at 23.4% for someone who quits at 65, and 14.2% at 75. Their conclusion is still that people who quit at 65 and above can meaningfully increase their life expectancy.
If your parent has a heart or lung condition, the decision about how to stop belongs with the doctor treating them. And if they take regular medication, the prescriber needs to know before they quit. Tobacco smoke, not nicotine, speeds up how the body clears some medicines, and once smoking stops that effect can start to reverse within about three days, with full reversal taking two to four weeks (NHS Specialist Pharmacy Service). Nobody should adjust a dose on their own.
What the numbers can and can't tell you
These figures get quoted without their limits, so here they are.
Both studies rest on observational data. The cohorts show association, adjusted for some confounders, not proof that quitting caused every year gained. People who quit may differ from people who don't in ways the adjustments miss. The modelling study builds on relative risks from an older US cohort and applies them to 2018 data, which makes its figures estimates rather than observations.
None of the cohorts is from India. Smoking patterns and baseline health differ here, so read the figures as the shape of the answer, not a forecast for your family.
Not everything reverses. Former smokers as a group still had higher risk than never-smokers, and emphysema, the lung tissue damage at the centre of COPD, is irreversible with the treatments available today (Torre Flores et al., 2026). We cover what does and doesn't come back in how long lungs take to heal after quitting. Plenty does start early, though, and the first days and weeks are where it begins.
Too late, or too early?
Our view, not the studies': if you are in your twenties, "too late" is probably the wrong worry. The belief worth checking is the opposite one, that there is plenty of time. It is one of the beliefs smokers carry without having chosen them, and it is the one these numbers argue against most directly. The best figures above belong to people who quit before 40, and "later" has a habit of arriving closer to 40 than planned.
Cutting down instead isn't a halfway house either. On the largest pooled analysis of light smoking, even one cigarette a day was associated with a substantial share of the excess heart disease risk seen at twenty a day (is one cigarette a day bad).
And if you have tried before and gone back, that is the usual pattern. What a single slip does and doesn't mean is in smoked one cigarette after quitting.
Where Nicoxit comes in
Nicoxit is 31 modules over seven days, about 40 minutes a day, then it's done. The first instruction is: don't quit yet. You keep smoking during the programme, because the work is on why you reach for a cigarette, and no willpower is required for that. It's grounded in acceptance rather than suppression, mindful noticing, if-then planning and identity change.
It covers cigarettes, vapes, hookah and IQOS. Afterwards Nicoxit tracks days free, money saved and health recovery milestones from 20 minutes to a year, without a streak that punishes you for slipping.
Not medical advice.
References
- Cho, E. R., Brill, I. K., Gram, I. T., Brown, P. E., & Jha, P. (2024). Smoking cessation and short- and longer-term mortality. NEJM Evidence, 3(3), EVIDoa2300272. https://doi.org/10.1056/EVIDoa2300272
- Le, T. T. T., Mendez, D., & Warner, K. E. (2024). The benefits of quitting smoking at different ages. American Journal of Preventive Medicine, 67(5), 684–688. https://doi.org/10.1016/j.amepre.2024.06.020
- Torre Flores, L. P., Jalink, P. J., Fuentes-Mateos, R., Erasmus, M., van Oorschot, M. E., Gan, T., Hoffmann, R., Zwaginga, J. J., Brandsma, C. A., Nawijn, M., Chen, L., Homkar, N., Prakash, J., Hiemstra, P. S., Van der Does, A. M., Leijten, J., Gosens, R., & Heijink, I. (2026). Defective alveolar regeneration in emphysema: Identifying dysfunctional cellular crosstalk and novel therapeutic opportunities for tissue repair. European Respiratory Review, 35(181), 260090. https://doi.org/10.1183/16000617.0090-2026
- NHS Specialist Pharmacy Service (2023). Considering drug interactions with smoking. https://sps.nhs.uk/articles/considering-drug-interactions-with-smoking/
Frequently asked questions
Is it too late to quit smoking after 10 or 20 years?
No. In a study of 1.48 million adults, quitting at every age was associated with longer survival, and the benefit was visible within three years of stopping. People who stayed quit for ten years or more had survival close to never-smokers.
What is the best age to quit smoking?
As early as possible. In the largest recent analysis, the gains in survival were greatest for people who quit before 40, and among people under 40 who had stopped for less than three years, the excess risk of death was 90 to 95% lower.
Is it too late to quit smoking at 50, 60 or 65?
No. A 2024 modelling study estimated that quitting at 55 avoids an average of 3.4 lost years, at 65 about 1.7 years, and at 75 about 0.7 years. The gains are smaller with age, and the authors still describe them as meaningful.
How soon after quitting do the benefits show up?
In the 2024 cohort analysis, lower excess risk of death was visible as early as three years after stopping, in every age group with figures reported. The gain grew with time: about 5 years of life for under three years quit, about 10 for ten years or more.
Does quitting undo all the damage?
Not all of it. Former smokers as a group still had somewhat higher risk of death than never-smokers, and emphysema is irreversible with current treatments. Both studies favour stopping earlier.
