Does Smoking Lower Testosterone?

Overview

Smoking is notoriously known as a silent killer with both passive and active smoking can lead to numerous health conditions such as lung cancer, chronic obstructive pulmonary disease (COPD), and cardiovascular disease (for example, coronary heart disease). Smoking is also an important risk factor for stroke, blindness, and deafness. The list could go on. Despite all of these detrimental effects of smoking, people continue the habit of smoking.¹ In 2020, roughly 12.5% or 30.8 million adults in the United States currently smoked cigarettes. In 2019, 1.14 billion people around the globe were current smokers.² 

Apart from the numerous chronic disease and risk factors associated with smoking, many researchers also argued that smoking could impact the testosterone levels in your body. However, some researchers suggested no relationship between smoking and testosterone level.³ Meanwhile, some also demonstrated that smoking could either lower or increase the level of testosterone.⁴ Therefore, this article will explore the link between the impact of smoking on the level of testosterone. 

Impacts of smoking on the body

As mentioned earlier in the article, smoking leads to various health conditions. So, what kind of cigarette substances create such a disastrous mess for our bodies? 

Cigarette smoke contains a high amount of free radicals. Free radicals are unstable chemicals that might potentially harm our cells. High concentrations of free radicals in the cigarette can damage your DNA, protein, and lipids.⁵ Long-term exposure to free radicals can contribute to smoking-caused disease and death.⁵

Cigarette smoke also contains a high abundance of toxins.⁵ High exposure to these toxins through repeated inhalation of cigarette smoke increases the risk of developing lung cancer.⁵ Secondhand smoke also can lead to lung cancer though the risk is much lower than that of an active smoker.⁵

Yet, people still smoke. So, why? One of the reasons is nicotine addiction.⁵ Some smokers might try to quit smoking before, but it can be challenging due addictive substance in a cigarette called nicotine.⁶ Nicotine can produce a happy feeling and lower your anxiety.⁶ 

People who want to quit smoking might suffer from withdrawal symptoms such as irritability, mood depression, anxiety, inability to socialize, increased desire to eat, and sleeplessness.⁶ Thus, it can be hard to quit smoking. 

Smoking and testosterone

Role of testosterone

Testosterone is a sex hormone responsible for male sexual development, fertility, and sperm production.⁷ It also plays a crucial role in regulating male characteristics such as hair patterns, vocal changes, and voice deepening.⁷ Testosterone also stimulates the production of skeletal muscle protein and slows down protein degradation in the skeletal muscle of humans.⁸ Furthermore, the combination of exercise and testosterone promotes muscle cell growth and improves bone health.⁸ Testosterone produces these physiological effects by binding to the androgen receptor.⁸

Females also produce testosterone, although they secrete much smaller amounts than males.⁹ In other words, testosterone is also an essential hormone for females.⁸ For example, female testosterone therapy might improve their emotional, sexual, and/or physical health.⁸ 

The abnormality related to testosterone levels can involve either over-production or under-production of testosterone.⁸ 

High testosterone

Potential causes

Potential causes of high testosterone include:⁷

1. adrenal virilization/adrenal tumours
2. ovarian or testicular tumours
3. cushing syndrome
4. the result of exogenous steroid use
5. polycystic ovarian syndrome (PCOS)

However, it is also can be due to puberty. During human puberty, there is a roughly 30-fold increase in testosterone production in boys.⁸

Symptoms

Symptoms of high testosterone in males are^9,10

1. Aggressive
2. Risk-taking behaviour

On the other hand, signs of high testosterone levels in females are

1. Clitoral enlargement
2. Menstrual irregularity
3. Acne

Complications

Higher testosterone can increase the risks of type 2 diabetes and PCOS in females but reduces the risk of type 2 diabetes in men.¹¹ Furthermore, high testosterone levels increase the risk of breast and endometrial cancers in females and prostate cancer in the male.¹¹

Low testosterone

Potential causes

Potential causes of low testosterone levels are:⁷

1. Aging
2. Certain medications
3. Chemotherapy
4. Hypothalamus-pituitary axis disorders
5. Primary hypogonadism
6. Cryptorchidism
7. Orchitis
8. Genetic disorders such as Klinefelter and Kallmann syndrome

Symptoms

A study in 2020 that investigates the effect of low testosterone in adolescents and young adults suggested that signs of low testosterone are:¹²

1. Low sexual desire and activity
2. Gynecomastia
3. Delayed sexual development
4. Small testes
5. Loss of body hair

Complications

Testosterone deficiency also can lead to erectile dysfunction, fragile bone, anemia, poor concentration, and memory as well as physical performance.¹²

How does smoking impact testosterone levels?

The relationship between smoking and testosterone levels is inconclusive and varied. An old study in 2006 investigated endogenous testosterone levels and smoking in males. Endogenous testosterone refers to the naturally occurring substances in the human body. The study suggested that for males who smoke, their testosterone levels are significantly higher than those of non-smokers.¹³ Much current study in 2013 also suggested the same result.¹⁴ 

Experts theorized that smoking could stimulate the release of gonadotropin-releasing hormone (GnRH) and LH hormone, which play a key role in testosterone secretion. As a result, it might increase the testosterone level.^15,16

On the other hand,  a study in 2013 from the International Journal of Therapeutic Applications argued that smoking lower the testosterone level, which might lead to muscle mass loss and male infertility. The study suggested that smoking might alter the ability of testosterone to bind to its receptor, reducing the level of testosterone.¹⁷

How does smoking impact sperm count and quality?

As mentioned before, smoking can lead to various ill-health conditions. However, the association between smoking and sperm quality is still uncertain and inconsistent. 

A study in 2019 demonstrated that smokers who smoked more than 20 cigarettes per day have lower sperm count and total sperm count compared to those who do not smoke. The study also shows that smoking no longer affects the sperm quality of people who are already stopped smoking.¹⁸ Some studies also failed to find a relationship between smoking and adverse impact on sperm count and sperm quality. It might be due to the selection of participants for the study.¹⁹

The researcher suggested that the adverse impact of smoking on sperm quality might be due to the nicotine in the cigarette.¹⁹

Impacts of e-cigarettes on testosterone

An E-cigarette, also known as a vape, is a device that allows you to inhale nicotine in a vapour instead of in smoke. E-cigarettes are less harmful than smoking cigarettes as they contain a much lower amount of toxicants than conventional cigarettes.²⁰ However, it doesn’t mean it can be any less dangerous. 

The expert argued that exposure to e-cigarettes (with or without nicotine) might alter your DNA, leading to a reduction in testosterone levels.²⁰ Furthermore, it can lead to low sperm count and quality. In other words, e-cigarettes can cause detrimental effects on the male reproductive system.²⁰

Smoking and prostate cancer

Smoking can increase the risk of developing prostate cancer in male. A meta-analysis in 2010 demonstrated that smokers, especially heavy smokers, have a high risk of developing prostate cancer.²¹ Recent systematic reviews in 2015 also suggested that smokers develop prostate cancer.²² However, the mechanism underlying the relationship between smoking and prostate cancer remains unclear. Some experts argued that smoking increases testosterone secretion, which might increase the risk of developing prostate cancer.¹¹ 

Carcinogens contained in cigarettes might be another culprit that increases prostate cancer risk.²¹ Therefore, further studies are needed to establish how smoking can lead to prostate cancer. 

Summary

The detrimental impact of smoking on the human body is well-known. Smoking also might alter the testosterone level, although several studies suggest different findings. Nevertheless, an abnormal amount of testosterone can lead to various ill-health conditions. 

The mechanisms surrounding the relationship between smoking and testosterone level are also unclear. Still, some experts suggested some theories that might explain the association. Smoking also negatively impacts sperm quality, which can affect male fertility. Apart from conventional cigarettes, e-cigarettes also can be harmful to the human body. Finally, the article also reviews the link between smoking and prostate cancer, as well as some of the mechanisms that explain the relationship.