Does caffeine have an effect on your sex life?

Most people need a caffeine or coffee fix to get through the day. But do the effects of this daily beverage carry over into the bedroom?

In the United States, 18.4% of men aged 20 and older experience erectile dysfunction (ED). By age 40, this population increases to 44%, and by age 70 it rises to 70%. In men at any age, ED compromises quality of life. Besides the personal cost, the financial cost is high, too—if all men with ED sought out treatment, the price would be $15 billion.

Many factors can raise the risk of ED, including alcohol, smoking, sedentary lifestyle, obesity, and heart disease. But little is known about other factors that could facilitate erections, possibly including caffeine. Moreover, coffee could have erectile effects separate from caffeine itself. Let’s take a closer look.

A caffeinated nation

More than 85% of adult Americans consume some type of caffeine, mostly in the form of coffee, soda, tea, energy drinks, and so forth. Specifically, nearly two-thirds of US adults enjoy coffee, and a little more than half drink one or more glasses of soda a day. But unlike other sugar-sweetened beverages, coffee is full of antioxidants and anti-inflammatory agents.

Some experts suggest that caffeine/coffee triggers a pharmacologic cascade that results in relaxation of cavernous smooth muscle, thus helping with ED. Furthermore, coffee is rich in erection-friendly polyphenols, and can possibly pump up testosterone concentrations, enhancing blood flow to the penis.

What a jolt of java can do

Despite the popularity of caffeine and the prevalence of ED, little is known about the former’s effect on the latter. To that end, researchers undertook a study, published in PLoS One, in which they reviewed data from the National Health and Nutrition Examination Survey (NHANES) for self-reported ED and 24-hour dietary recall among 3,724 men. From these data, the researchers assessed the relationship between coffee/caffeinated beverages and ED.

Although there was no overall trend, men in the third quintile (85-170 mg/day) and fourth quintile (171-303 mg/day) of caffeine ingestion reported less ED than men in the first quintile (0-7 mg/d). In other words, drinking between 2 and 3 cups of coffee a day was linked to lower rates of ED. In particular, overweight, obese, and hypertensive men who consumed more caffeine experienced less ED than those in the lowest quintile. However, this result did not apply to those with diabetes.

In an attempt to confirm the NHANES study results, the same researchers looked at the association between coffee and ED among a much larger group—more than 20,000 men—in a study published in the American Journal of Epidemiology.

Data from the Health Professionals Follow-up Study (HPFS) resulted in an analytic sample of 21,403 men, of whom 7,298 had incident ED. The researchers asked about total, regular, and decaffeinated coffee intake, and investigated these associations among men with lifestyle factors and comorbid conditions such as obesity, hypertension, diabetes, history of smoking, and marital status.

In the end, the team found no link between regular coffee—at any level of intake—and erectile dysfunction.

“We did not find an association, either positive or negative, between total or regular coffee intake and ED,” they concluded. “None of the modifiable lifestyles factors influenced the association of coffee intake with ED.”

Surprisingly, the researchers did find a correlation between decaf coffee consumption and ED, with participants with the highest intake (4 or more cups/day) experiencing a 37% increased risk of ED.

Obviously, this result was counterintuitive, so the authors offered more detailed suggestions. First, only 0.9% of participants in the study were heavy drinkers of decaf coffee, making for a small set of people to analyze. Second, decaffeination removes polyphenols and anti-inflammatory compounds. Third, the subpopulation of heavy consumers of decaffeinated coffee also had higher rates of smoking, higher lipid levels, and higher BMI. In fact, the association between high levels of decaf coffee and ED was observed only in smokers, which suggested the possibility of residual confounding.

So, will a cup perk you up?

Although the research on the association between caffeine/coffee and ED has been limited and mixed, the more recent high-powered, prospective study points to no association. At the very least, coffee and caffeine don’t interfere with erectile function. While it would be nice to think that coffee helps with erections, it appears that a cup of joe is a no-go for your mojo.

In more general terms, the value of the two studies demonstrate the importance of following up lower-power retrospective research with higher-power prospective research.