Possibly, but the direct evidence is thin: in one small study, older heavy smokers built new muscle protein about 37% slower at rest than matched non-smokers1. The one training study we found saw no clear difference in muscle gained over 10 weeks4.
So the honest answer has two parts: what happens inside the muscle, and what happens when smokers actually train.
What was studied
Three kinds of study speak to this question.
Tracer studies measure the building process directly. Muscle protein synthesis is how fast muscle makes new protein. Researchers infuse a labelled amino acid (a protein building block they can trace) and take small muscle samples to see how fast it is built into new protein.
Training studies follow smokers and non-smokers through the same programme and compare what they gain.
Population studies compare muscle mass or strength in large groups of smokers and non-smokers at one point in time. These are cross-sectional: a snapshot, not a follow-up. They can show a link, but not what caused it.
| Type of study | What it measured | Example here |
|---|---|---|
| Tracer | Building rate at rest | 8 smokers vs 8 non-smokers1 |
| Training | Muscle gained over weeks | 65 army recruits, 10 weeks4 |
| Population | Strength or muscle mass | 4,249 men2; 22,515 older adults3 |
| Stopping study | Muscle function after 14 days without cigarettes | 48 smokers, 38 non-smokers5 |
In plain terms: one study looked inside the muscle, one watched people train, and the rest compared groups.
What the studies found
Inside the muscle. The tracer study compared 8 smokers (at least 20 cigarettes a day for at least 20 years) with 8 non-smokers matched for sex and age, about 65 years old, 4 men and 4 women in each group1. At rest, the smokers' muscle built protein at 0.037% per hour, against 0.059% in the non-smokers1. That is about 37% slower.
Muscle-building rate at rest, smokers vs non-smokers · % per hour
The smokers' muscle also showed about 33% higher activity of the gene for myostatin, a protein that holds back muscle growth, and about 45% higher activity of MAFbx, a gene linked to muscle protein breakdown1. Whole-body protein breakdown and inflammation markers in the blood did not differ1.
During training. In 65 male British Army recruits, average age 21, ten weeks of basic training increased lower-leg muscle area in both smokers and non-smokers4. Muscle and performance measures were similar in the two groups. Smokers had higher markers of oxidative stress and inflammation, but the authors found "no clear evidence" this held back physical adaptation over that period4.
Strength in a large group. Among 4,249 Japanese men aged 20 to 79 at health check-ups, heavier smokers (cigarettes a day times years smoked of 400 or more) had lower grip strength than lighter smokers, even after adjusting for age, height, body weight and exercise habits2. The leg-strength difference faded after the same adjustment2. Smokers were also less likely to exercise: 26.2% against 40.2% of non-smokers2.
Muscle mass with age. A meta-analysis (a study that pools many studies) of 12 studies and 22,515 older adults found smokers had an odds ratio of 1.12 for sarcopenia, the age-related loss of muscle mass (95% CI 1.03 to 1.21)3. An odds ratio of 1.0 means no difference. In men it was 1.20; in women 1.21, but the women's range crossed 1.03. The authors wrote that individual studies were "largely inconsistent"3.
Sarcopenia odds ratio, smokers vs non-smokers, older adults · odds ratio
In plain terms: the building rate was lower in older heavy smokers at rest, but young recruits who smoked still gained muscle in training.
The nuance
Two very different groups. The slower building rate came from people in their sixties who had smoked heavily for decades1. The training study was of young men, average age 214. Both findings can be true at once. A long, heavy habit may matter in ways a few years do not, though no study here tested that directly.
Rest is not training. The tracer study measured the building rate at rest, once. Nobody in it lifted, so it cannot say how smokers respond to a workout1.
Smokers differ in other ways. In the Japanese sample, smokers exercised less2. Diet, sleep and activity can all differ between groups. Population studies adjust for some of this, never all.
Strength was not lower in young smokers. In a 2021 study of 48 smokers and 38 non-smokers aged 18 to 44, maximal thigh strength did not differ between the groups5. The authors concluded that smoking "is not necessarily associated with muscle weakness"5, while noting that other studies have found lower strength in smokers5. After 14 days without cigarettes, the smokers' fatigue resistance (how much force the muscle still made at the end of two minutes of electrically triggered contractions) rose, and carbon monoxide in their blood fell from 2.26% to about 0.1%5. There was no re-tested non-smoking group, and no muscle growth was measured.
The proposed mechanism comes from the tracer study's authors: smoking slows the building process and raises the activity of genes tied to poorer muscle maintenance1. That reading has not been tested in people who lift.
For individual questions about smoking and health, a doctor is the right person to ask. This page describes studies; it does not advise starting or stopping anything.
In plain terms: the lab signal is real in older heavy smokers, but it has not been shown to slow gains in people who train.
What it means in practice
The evidence describes groups, not individuals. Read descriptively:
- The clearest signal is at rest, in older long-term smokers. The building rate was about a third lower1.
- Training still produced gains. Young smokers in basic training gained muscle area like non-smokers over 10 weeks4.
- Months or years of lifting are untested. No study we found compared muscle growth in smokers and non-smokers on a structured lifting programme.
What drives growth in any group stays the same: progressive overload, enough weekly sets per muscle and enough protein.
The studies at a glance
| Study | Who was studied | Key result | Year |
|---|---|---|---|
| Petersen et al., *Am J Physiol Endocrinol Metab*1 | 8 heavy smokers vs 8 non-smokers, about 65 years old, at rest (abstract) | Building rate 0.037 vs 0.059% per hour, about 37% lower; myostatin gene activity about 33% higher | 2007 |
| Saito et al., *J Prev Med Public Health*2 | 4,249 Japanese men aged 20 to 79, cross-sectional | Heavy smokers had lower grip strength after adjustment; leg strength difference faded | 2012 |
| Steffl et al., *Physiol Res*3 | Meta-analysis of 12 studies, 22,515 older adults | Odds ratio for sarcopenia 1.12 (95% CI 1.03 to 1.21); studies largely inconsistent | 2015 |
| Siddall et al., *Med Sci Sports Exerc*4 | 65 male army recruits, 10 weeks of basic training (abstract) | Muscle area rose in both groups; no clear difference by smoking | 2020 |
| Ajime et al., *Sci Rep*5 | 48 smokers and 38 non-smokers aged 18 to 44; 14 days without cigarettes | Strength not different from non-smokers; fatigue resistance rose after 14 days | 2021 |
| Park et al., *J Cachexia Sarcopenia Muscle*6 | 337,138 UK Biobank adults, genetic analysis (abstract) | Genetic tendency to smoke linked to slightly lower limb lean mass; no clear link to grip strength | 2023 |
Limits worth knowing
- Tiny tracer study. Eight people per group, measured once, at rest; its full text is not open, so we cite only the abstract1.
- Mostly snapshots. The population studies are cross-sectional and show association, not cause.
- One training study, one population. Young men in military training, 10 weeks, read as an abstract4.
- Different measures. Building rate, strength, muscle area and muscle mass are related but not the same thing.
- Men over-represented. The Japanese sample and the training study were men only.
- Abstract only for Petersen 2007, Siddall 2020 and Park 2023. Saito 2012, Steffl 2015 and Ajime 2021 were read in full.
Latest research
The newest study we opened is a 2023 analysis of 337,138 adults of white British ancestry in the UK Biobank6. It used Mendelian randomisation, a method that uses genetic variants linked to smoking as a natural experiment, to estimate cause rather than just association. A higher genetic tendency to smoke was linked to slightly lower limb lean mass and slower walking pace, with no clear link to grip strength6. The effects were small on the study's standardised scale, and the method rests on assumptions about how those genes act. It adds weight to a link with muscle mass in the general population. It says nothing about how smokers respond to lifting.
The short version
- In a small study at rest, older heavy smokers built muscle protein about 37% slower than non-smokers.
- Young recruits who smoked gained muscle area like non-smokers over 10 weeks of training.
- Across older adults, smoking was linked to slightly higher odds of low muscle mass, with inconsistent results.
- No study has compared months of lifting gains in smokers and non-smokers.
Educational overview only — not medical advice.
