Truth be told, smoking is a significant health problem associated with various diseases.
However, research shows that smoking may contradict popular belief regarding its effects on men’s testosterone. Instead, the habit generally thought to be “bad” for men’s reproductive health may increase testosterone levels.
RELATED: Why Is There a Steady Decrease in Testosterone Levels of Men in the U.S?
What You Don’t Know About Smoking and Testosterone
Smoking and Testosterone: What’s the Connection?
Smoking May Increase Testosterone
According to the International Journal of Andrology, there is a positive correlation between smoking status and testosterone levels in over 3,000 men. Compared to men who never smoked, smokers had 15% higher total and 13% higher free testosterone levels.
Even more surprisingly, increasing the number of cigarettes per day can simultaneously increase both total and free testosterone levels, meaning the more cigarettes smoked, the higher the effect on testosterone.
The Connection Remains Elusive
However, the reported effects of smoking on testosterone levels remain primarily conflicting. For example, many studies found that smoking may lower or cause no change in the male hormone, whereas many other studies claim otherwise.
|Study||Number of subjects||Age range (years)||Findings|
|Briggs (1973)||12||20-29||T ↓ in smokers|
|Shaarawy & Mahmoud (1982)||45||25-35||T ↓ in smokers|
|Lindholm et al. (1982)||443||30-60||T ⇆|
|Handelsman et al. (1984)||119||~31||T ⇆|
|Barrett-Connor & Khaw (1987)||590||30-79||T ⇆|
|Klaiber & Broverman (1988)||43||18-24||T ⇆|
|Attia et al. (1989)||85||18-40||T ⇆|
|Hautanen et al. (1993)||289||N/A||T ⇆|
|Harman et al. (2001)||890||22-91||T ⇆|
|Deslypere & Vermeulen (1984)||181||20-80||T ↑ in smokers|
|Vogt et al. (1986)||239||19-40||T ↑ in smokers|
|Dai et al. (1988)||121||~46||T ↑ in smokers|
|Field et al. (1994)||1241||38-70||T ↑ in smokers|
|Handa et al. (1997)||313||50-54||T ↑ in smokers|
|English et al. (2001)||50||17-60||T ↑ in smokers|
|Svartberg et al. (2003)||1563||25-84||T ↑ in smokers|
So, how much precisely does smoking increase testosterone?
To put it into perspective, the International Journal of Andrology research compared testosterone levels in smokers who had smoked for an average of 42.8 years, 11.6 cigarettes per day, to previous and never-smokers.
|Total testosterone (nmol/L)||15.5||13.5||13.6|
|Free testosterone (pmol/L)||285||248||269|
|Smoking duration (years)||42.8||26.8||N/A|
How Does Smoking Increase Testosterone?
Smoking and the SHBG Level
Sex hormone-binding globulin (SHBG) is a protein that influences the bioavailability of testosterone.
The amount of testosterone in your circulation is regulated by SHBG, which controls which tissues this hormone can access. Therefore, SHBG is crucial in transporting sex hormones’ active forms all over your body, hence known as the “carrier” of testosterone.
The International Journal of Andrology research found that smoking was positively associated with the SHBG level. However, smoking does not affect bioavailable testosterone, although SHBG levels are higher in smokers. This suggests that the rise in total testosterone levels may have been a byproduct of the elevated SHBG levels.
Smoking and the LH Level
Luteinizing hormone (LH) is a chemical released by the pituitary gland that triggers crucial processes in men’s reproductive system. This hormone signals and stimulates the testes to start producing testosterone.
The International Journal of Andrology research also found that smokers had slightly higher LH levels than never-smokers. However, compared to individuals who had given up smoking, the LH levels in smokers were lower, suggesting that giving up smoking may further increase this parameter.
Does Smoking Status Matter?
The number of cigarettes smoked per day is a crucial factor that determines the effects of smoking on testosterone.
The International Journal of Andrology’s study also examined the relationship between testosterone and the number of cigarettes smoked. The smokers were divided into four categories: 1 to 5, 6 to 10, 11 to 20, and >20 cigarettes smoked daily.
And yes, the result is as confounding as the finding telling us smoking increases testosterone. Total and free testosterone was positively correlated with the number of cigarettes smoked before and after adjustment for other factors like age.
|Number of cigarettes per day|
|Total testosterone (nmol/L)||13.7||14.2||14.9||15.9||16.5|
|Free testosterone (pmol/L)||260||267||268||288||294|
But does how long a person smokes affect their testosterone levels? The research found no association, as there is no data about the impact of smoking duration on testosterone nor SHBG levels.
RELATED: New Findings on the Safety of Short-term Testosterone Replacement Therapy Discussed
Is Increasing Testosterone by Smoking Worth It?
Testosterone Levels Decline Faster in Smokers
So you may think, after all the data shown in the International Journal of Andrology research, smoking is beneficial in increasing testosterone, which equates to boosting male reproductive health.
Not really, as another research by the American Journal of Epidemiology shows that heavy smokers who smoke up to 36.5 packs per year experience a faster decline in testosterone than non-smokers. This data means that despite the initially high levels, the sex hormone is impaired later by smoking.
Sperm Count and Quality Are Lower in Smokers
Unfortunately, an accelerated testosterone decline is not all the detrimental effects of smoking. Sperm count and quality are the more direct factors determining a man’s reproductivity. These factors, however, are also diminished by smoking.
Research by Environmental Epidemiology shows that smoking is linked to lower semen volume and total sperm count. And although smoking may increase sperm motility, which is vital in fertility because sperm need to move efficiently to reach and fertilize the eggs, smoking still contributes to the development of abnormal semen quality.
Smoking Cessation Might Have a Restorative Effect
Finally, the International Journal of Andrology found that the total testosterone level among former smokers was nearly identical to that of non-smokers, suggesting that quitting smoking may reverse the harmful effects of smoking on men’s reproductive health.
|Total testosterone (nmol/L)||13.5||13.6|
|Smoking duration (years)||26.8||N/A|
So, it’s fair enough to say that giving up smoking is a must if you want to preserve your reproductive health and embrace your parenthood. And it’s never too late to start breaking a bad habit, resist the craving for smoking, and lead a healthier life.
Some tips to reduce and resist smoking cravings include:
- Trying nicotine replacement therapy (nicotine patches or gum)
- Avoiding triggers like parties, stress, or designated smoking places
- Increasing physical activity to distract you from cravings
- Trying relaxation techniques like yoga or muscle relaxation
- Reminding yourself of the benefits of smoking cessation
Zmuda, J. et al. (1997). Longitudinal Relation Between Endogenous Testosterone and Cardiovascular Disease Risk Factors in Middle-aged Men. American Journal of Epidemiology.
Svartberg, J., Jorde, R. (2006). Endogenous Testosterone Levels and Smoking in Men. International Journal of Andrology.
Tang, Q. et al. (2019). Semen Quality and Cigarette Smoking in a Cohort of Healthy Fertile Men. Environmental Epidemiology.
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