While the science isn’t yet clear, you could join the research that’s working to understand how nicotine affects testosterone levels.

Nicotine is a highly habit-forming substance, one that can be in cigarettes and e-cigarettes, patches and gum, and more. In 2021 alone, in the United States, more than 61 million people ages 21 and older reported using tobacco or nicotine products in the past 30 days.

Nicotine is a stimulant, which means that it increases the nervous system’s activity ― affecting your brain and body. But research suggests that it may also affect testosterone, with studies showing that it can cause an increase or decrease in testosterone levels.

Below, we’ll explore what science says about the impact of nicotine on testosterone.

Research on the impact of nicotine on testosterone has shown mixed results. In some cases, studies have found that nicotine can increase testosterone levels ― while other studies have found a decrease in testosterone with nicotine use.

One 2016 research review explored the effects of nicotine on more than 13,000 men and 6,000 women. The review found that while men who smoked appeared to have higher testosterone levels than nonsmokers, there was no significant association between smoking and testosterone changes in women.

But in a small study from 2022, researchers found that baseball players who chewed nicotine gum had lower levels of salivary testosterone after 30 minutes. After participants completed a series of physical tests, these low levels returned to their typical levels.

A different 2022 study involving more than 600 Swedish men found conflicting results for oral nicotine use. In this study, researchers found that men who used chewing tobacco had a 24% lower sperm count than men who didn’t, but their testosterone levels were, on average, 14% higher.

But it’s not just cigarettes, gum, or chewing tobacco that appear to affect reproductive changes and testosterone levels.

In one study from 2020 on the impact of nicotine on testicular function in men, researchers found that e-cigarette and cigarette users had lower total sperm counts than nonusers. In addition, men who smoked cigarettes ― but not e-cigarettes ― had significantly higher testosterone levels.

Language matters

You’ll notice that the language used to share stats and other data points is pretty binary, fluctuating between the use of “male” and “female” or “men” and “women.”

Although we typically avoid language like this, specificity is key when reporting on research participants and clinical findings.

Unfortunately, the studies and surveys referenced in this article didn’t report data on, or include, participants who were transgender, nonbinary, gender nonconforming, genderqueer, agender, or genderless.

To learn more about how you fit into medical trials as a transgender person, check out this article.

Because we’re still unsure of how nicotine affects testosterone, it’s difficult to conclude how quitting smoking will affect someone’s testosterone levels.

But one small study from 2015 suggested that there may be a relationship between quitting smoking and changes in testosterone levels.

For example, one small 2012 study found conflicting evidence on quitting smoking and testosterone. According to the study results, there was no significant change in testosterone levels in participants after quitting smoking ― but there was a significant decrease in sex hormone-binding globulin (SHBG).

SHGB plays an important role in transporting hormones, such as testosterone, around the body. Given that SHGB levels decreased in the study after quitting smoking, this may be why testosterone levels fluctuate in some people before and after nicotine use.

A small 2014 study also explored the impact of quitting smoking on hormone levels in postmenopausal women. During the study, researchers measured hormone levels before the women quit smoking and at 6, 12, 24, and 48 weeks after quitting.

Results of this study found that while androgen levels ― including testosterone ― were already high before quitting, they continued to increase in the year after quitting. Once again, these studies continue to show conflicting results on the impact of nicotine on testosterone.

Nicotine withdrawal refers to the physical and emotional symptoms that a person experiences when they stop using nicotine. When someone is going through nicotine withdrawal, they can experience symptoms like:

Research on the effects of nicotine withdrawal and testosterone levels is limited, with few studies available on the topic.

Interestingly, a review from 2017 on quitting smoking suggested a potential link between lower estrogen and progesterone levels and more severe nicotine withdrawal in women. But this doesn’t necessarily suggest a relationship between nicotine withdrawal and testosterone.

Get involved!

If you want to help scientists learn more about how nicotine and smoking affect testosterone levels, check out ClinicalTrials.gov to discover ongoing trials.

Research on the effects of nicotine on testosterone has produced conflicting results. Some studies point toward nicotine causing lower testosterone levels, while others suggest that nicotine users have higher testosterone than nonusers.

More research is necessary to determine how this chemical affects sex hormones like testosterone. If you have concerns about how smoking affects your testosterone levels, it’s a good idea to talk with a doctor.