If your office doesn’t have a coffee machine, it’s probably because there’s a Starbucks around the corner or even in your building.

Coffee is the traditional go-to to get you up and going, and keep you alert throughout the day. As one anonymous wit puts it, coffee facilitates matters of high finance, serving as a “social binder, a warmer of tongues, a soberer of minds…[and] a foiler of sleep.”

Or as Henry Rollins puts it, what goes best with a cup of coffee is another cup. 

But is this yet another case where the stereotype is really the opposite of the reality? Does coffee really improve productivity at work, or impair it?

According to Lifehack, 46% of workers claim coffee is necessary for on-the-job productivity. And how many times have you heard colleagues apologize for some inattention with the excuse of not yet having had their morning cup of coffee? But is there any scientific evidence that coffee is actually fuels better work performance?

I Love My Java and My Java Loves Me

According to Gigaom, the caffeine in coffee does have some demonstrated beneficial effects in human physiology, including:

• Improved short-term memory and reaction times,
• Reduced stress levels, and
• Slowed decline of blood glucose levels, which increases energy levels

However, the positive effects on memory, alertness and energy are only exhibited by people who regularly drink coffee. Infrequent imbibers do not experience the same boost from a cup of coffee. These perceived behavioral improvements may be the result of preventing caffeine withdrawal (as the caffeine habit is considered highly addictive) rather than a benefit of the caffeine itself.

And while coffee is frequently touted as something that fights off sleepiness, that effect may actually be a drawback. The New Yorker reports a study in which a single, eight-ounce cup of coffee can lower sleep efficiency and quality. The result is that you remain tired even after a full eight hours of sleep. Thus, the need for the morning cup of just to get going becomes a vicious circle: because you drank coffee, you didn’t get enough rest, so you need a cup of coffee to ward off feeling tired during the day.

Related Article: Stop Wasting Time: Tips to Raise Productivity and Reduce Procrastination

It May Not Be Rational To Drink Coffee

Travis Bradberry maintains that caffeine actually kills performance rather than enhances it. Drinking coffee releases adrenaline, the source of the “flight or fight response” that suspends rational thinking in order to deal with a threat. A good way to respond to a charging tiger, but it may not help you respond to a customer email.

In the hyper-aroused state caused by imbibing coffee, you might tend to let emotions override intellect. Indeed, caffeine produces shallower breathing, which deprives the brain of oxygen needed to remain calm and rational. Fast Company also points out that too many cups of joe can result in digestive upset, heartburn and nervousness, which hardly promotes clear thinking.

On the other hand, according to The Huffington Post, coffee is a rich source for antioxidants and has numerous scientifically provide health benefits, including reducing the onset of Alzheimer’s disease, risk of liver cirrhosis, and even suicide. Healthier people are generally more productive people.

Related Article: Tomato, Tomahto: The Only Productivity Technique You’ll Ever Need

Boost Alertness and Have Your Coffee Too

Overall, there’s no definitive evidence that coffee makes you more or less productive. Regular coffee drinkers seem to experience some gains, even if it isn’t directly a result of caffeine ingestion. As noted in A Life of Productivity, coffee drinkers tend to focus on the benefits, while perhaps ignoring the potential for over-stimulation. If you’re really looking for a way to boost your general alertness, here are a few recommendations:

• Get eight hours of sleep
• Exercise regularly
• Avoid sugary drinks and snacks that temporarily elevate energy levels but are soon followed by a less stimulating crash
• Eat more vegetables, fruits and whole grains that metabolize more slowly, thus providing your body more energy over the course of the day

With a good diet and a rested body that gets regular workouts, you can enjoy a couple of cups of coffee. You don’t need coffee as an excuse to make you more productive, your lifestyle is doing that for you. Plus, you get the benefits of an indulgence or two, like a regular cup of java.