As more states legalize marijuana, speculation has grown about the potential for it to be the catalyst that finally reverses the years-long decline in the beer industry. Yet as Anheuser-Busch InBev (NYSE:BUD) becomes the latest brewer to partner with a marijuana producer, investors ought to step back, ignore the buzz, and ask themselves whether this is more fad than trend.

Check out all our Anheuser-Busch InBev call transcripts.

Brewers often latch onto gimmicks, like ice beer, imperials, nitros, the oxymoronic black IPAs (it's an India pale ale after all), or the new New England IPAs that are cloudy rather than clear. You can still find these beers on store shelves, but their heyday has largely come and gone.

Although marijuana-infused beer appears to be another publicity stunt that will eventually fade away to become a niche product, this time brewers are paying tens of millions of dollars -- sometimes hundreds of millions -- for the privilege.

Female and male smoking marijuana and drinking beer

The law prohibits you from getting high and catching a buzz from a single beverage. Image source: Getty Images.

Canna-beer is here

Legal weed is still a new phenomenon, and because it's not yet national it still has a mystique that makes pairing suds and buds a seemingly forbidden pleasure. While Boston Beer and distiller Brown-Forman have warned in their SEC filings for years that legalization is a threat to alcoholic beverages because of the so-called substitution effect, there have been brewers that have been offering a happy mix from the beginning.

In Colorado, where marijuana has been legal longest, Dad & Dude's Breweria has been successfully selling a cannabis-infused beer for years, and Oregon's Coalition Brewing has introduced several varieties of beer made with cannabidiol (CBD). Similarly, Heineken's Lagunitas introduced its SuperCritical limited edition ale made with terpenes, which is responsible for the cannabis plant's unique aroma and flavor, while Vermont's Long Trail Brewing made a limited run IPA-like beer made with cannabis compounds.

Although these beers were popular when introduced and enjoy a cult-like following, it's only because of their newness and the heightened attention to legal weed that they got off the ground. Marijuana is now attracting the big guns of the business, like Anheuser-Busch, which paid $50 million to partner with Tilray; Constellation Brands, which initially bought a 9.9% stake in Canopy Growth early last year for $190 million and then added another $4 billion investment later in the year; and Molson Coors (NYSE:TAP), which is forming a joint venture with Hydropothecary (NYSE:HEXO), in which the brewer will have the controlling interest as it pursues cannabis-infused beverages.

Legal implications

But it's not as if you're going to get high while having a beer. The government doesn't allow the psychoactive compounds of tetrahydrocannabinol, or THC, to be mixed with alcohol, which is why CBD and terpenes are most often used (there are over 100 cannabinoids, or the chemical compounds secreted by cannabis flowers that are found in both cannabis and hemp plants). So if you're buying a marijuana-infused beer thinking you will feel the effects from both, you're likely going to be disappointed.

The Alcohol and Tobacco Tax & Trade Bureau (TTB) has pretty strict standards about what products brewers and distillers can use in their alcoholic beverages and what the labels can say. Brewers have to submit lab analyses of their products stating whether they're using oils, seeds, or some other component of the plant; how much THC, if any, is detected; and submit a sample to be tested by the TTB. Also, no words, description, images, slang, etc. can be used "implying or referencing the presence of hemp, marijuana, any other controlled substance; or any psychoactive effects."

One or the other

Brewers, however, are starting to making non-alcoholic beers that come infused with THC, but near-beer has never been a particularly popular category, and adding psychoactive properties to it seems to be at odds with near-beer's purpose.

Yet just this month Ceria Brewing launched a non-alcoholic Belgian-style white ale infused with THC in Colorado that's sold in marijuana dispensaries, while the Molson-Hydropothecary JV will similarly seek out non-alcoholic beverages.

Although there are supposed to be certain health and wellness attributes associated with THC, it doesn't mean people will prefer to drink their weed rather than smoke it.

Craft brewers naturally led the way in experimenting with marijuana-infused beer, but now macro brewers are diving headfirst into the mix. If they hope this is what changes the discussion and direction for them, they and their investors may wake up with an overspending hangover.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.