We have good news for lovers of America’s two favorite mood-altering substances, caffeine and marijuana: Caffeine may enhance a pot smoker’s high.
The downside is that caffeine may also increase the chance of becoming addicted to cannabis.
While there hasn’t been a lot of research about how caffeine mixes with marijuana, Internet commenters have strong, sometimes contradictory opinions about using the two mind-altering substances together.
A Reddit user says in r/Drugs, in the thread Caffeine & Weed are perfect :
After years of smoking I’ve found that caffeine and weed are a perfect mix. If i get nicely stoned then drink a strong cup of coffee the effects mix so perfectly. I get all the benefits of being high without feeling drowsy on the come down. I’ve never met anyone else who likes this combination, most swear it almost “sober them up” but I haven’t found this. Am I alone on this ?
The very next commenter, GolgiApparatus1, had a very different perspective that many Redditors agreed with:
One way ticket to Anxiety-Ville for me.
GolgiApparatus1 had 219 points on his comment, which means 219 more people gave it an upvote than the number who gave it a downvote. (For example, if 100 people liked his comment and 10 didn’t, it would have 90 points.) So, many commenters on Reddit agree with Mr. Apparatus.
But what does the science say? Psychology Today published an article  that asked the question, “Does coffee enhance marijuana?” It said a study in the Journal of Neuroscience, conducted by researchers from the National Institutes of Health,
... has finally provided a definitive answer: Yes, No, and it depends. I realize that sounds confusing, but their discovery does provide some fascinating insights into the workings of the brain and why humans find coffee and marijuana so enjoyable. Their euphoric effects may be related to each other.
The Psychology Today article, written by an author and medical researcher, says another research article, in the scientific journal Molecular Nutrition and Food Research, concluded “coffee’s addictive properties also involve the brain’s marijuana-like neurotransmitter system.”
Hot black silken elixir
The article concludes that “high doses of coffee makes us feel so good because it is able to tap into virtually every reward system our brain has evolved. Hidden within that hot black silken elixir is a chemical that has taken over your brain by mimicking the actions of marijuana. Go ahead and have another cup; I’m going to.”
Coffee is mildly addictive. That said, it’s not like a narcotic addiction that can ruin people’s health and lives. According to our blog How Much Caffeine Is Safe For Adults, it's OK to have about 300 to 400 mg of caffeine per day—about the same amount in 2 or 3 cups of coffee or 8 to 10 Viter Energy Mints .
Caffeine can cause dependency. It may cause more dependency than marijuana. More than 25 percent of people who take caffeine regularly have a dependence on the world's most popular substance, says Healthline .
The National Institute of Drug Abuse says  only about 9 percent of non-regular users become addicted to marijuana. But about 30 percent have a problem with marijuana, a concept called marijuana use disorder, the NIDA says.
About 85 percent of Americans use caffeine, and about 22 percent, or 55 million, smoke marijuana.
Caffeine may intensify marijuana high
When caffeine and marijuana are taken together, though, it can enhance the addictive effects of marijuana, says MedicalDaily.com :
According to a recent study published in The Journal of Neuroscience, drinking large amounts of coffee may enhance your high and increase the likelihood of marijuana addiction.
Marijuana and caffeine are America’s favorite drugs. In the U.S., 85 percent of the population consumes at least one caffeinated beverage per day, according to a ... study published in the journal Food and Chemical Toxicology.
But is it safe to mix the two? Again, not much research has been done on mixing caffeine and herb. Outside magazine published an article titled “A Primer on Mixing Caffeine and Marijuana” that says :
There’s not a lot of scientific research on what happens when you cross marijuana with any drug, says Jordan Tishler, a Harvard-trained physician who now specializes in cannabis-based medicine. From an anecdotal standpoint, he says, the caffeine-and-marijuana combination is probably fine. He’s never heard of a scenario where someone had a ghastly reaction after consuming both substances—which makes sense, based on how they work in the body.
News reports say there are now more marijuana dispensaries in Colorado than there are Starbucks or McDonald’s restaurants. And in Denmark, cafes have served weed and coffee together for years.
So maybe somebody better start studying the two drugs’ interactions soon.
Professor says marijuana and coffee are good for you.
Beware potatoes, not pot
Apparently, a coffee/marijuana buzz can be more healthful than getting high and then getting the munchies. DEA Administrative Law Judge Francis Young said in 1988 :
In strict medical terms marijuana is far safer than many foods we commonly consume. For example, eating 10 raw potatoes can result in a toxic response. By comparison, it is physically impossible to eat enough marijuana to induce death. Marijuana in its natural form is one of the safest therapeutically active substances known to man. By any measure of rational analysis marijuana can be safely used within the supervised routine of medical care.
And studies have shown that moderate amounts of caffeine do not harm people. Even in amounts greater than 400 mg per day the effects of caffeine are not catastrophic, though excessive use can cause headaches, shaking, anxiety, sleep loss and nausea.
The last thing you want when you’re high or sober is to have nausea, anxiety and a headache. As with most things in life, don’t overdo the coffee or energy drinks when you’re smoking.
Twitter users celebrate the intersection of coffee and weed a lot. We will leave you with an iconic image that brings the two together, from the Twitter account @OasisHemp:
Erectile dysfunction. In combination, those are two of the ugliest words known to man. But can caffeine help you get it up?
Science hasn't found the definitive answer to this question, but one study concluded that fewer men who consume caffeine have problems performing. The study said:
Caffeine intake reduced the odds of prevalent ED, especially an intake equivalent to approximately 2-3 daily cups of coffee (170-375 mg/day). This reduction was also observed among overweight/obese and hypertensive, but not among diabetic men. Yet, these associations are warranted to be investigated in prospective studies