Marijuana stocks are off to a smoking-hot start in 2014 — major market weakness notwithstanding — and there are sure to be more catalysts ahead.

But that doesn’t mean investors are safe from getting smoked.

Medical marijuana stocks — which are illiquid penny stocks, subject to wild swings and even manipulation — aren’t taking off on a change in fundamentals. And that means they could fall just as far and as fast as they’ve run up this year.

A terrible start to 2014 has the S&P 500 off 5.8% on a price basis for the year-to-date, and the average stock is down about 3%. The marijuana stocks, however, have been nothing close to average.

Medical Marijuana Inc. (MJNA) is up just under 100% so far this year and — get this — MJNA stock is actually the big-time laggard in the group. Next up comes Growlife (PHOT), as PHOT stock has gained “only” 150%. Indeed, when it comes to medical marijuana stock, anything less than a three-fold gain is small beer.

MediSwipe (MWIP) has tripled, with MWIP stock up 200%. Cannabis Science (CBIS) is closing in on quadrupling, as CBIS stock gained 273%. And GreenGro Technologies (GRNH)? Brace yourself, because GRNH stock is up over 1,000% … including an 18% so far today.

Part of the euphoria in marijuana stocks no doubt stems from the successful implementation — and popularity — of legal marijuana in Colorado and Washington. But there are plenty of other, more incremental catalysts, as well.

Just look at Hemp Inc. (HEMP). HEMP stock rallied as much as 60% Tuesday on anticipation of the Senate’s approval of the farm bill that would effectively legalize the cultivation of hemp. And hemp isn’t something you even smoke. This close cousin of marijuana cannabis can be refined into a wide-range of goods, including hemp oil, rope, cloth, paper and fuel. But it doesn’t have medical or recreational uses like marijuana does.

It doesn’t matter. The change in hemp’s legal status is being taken as a sign of progress on the legalization of marijuana at the federal level. So while it’s too soon to get excited about that, the slightest hint of the possibility helps marijuana stocks. After all, nothing would cause MJNA stock, MWIP stock, PHOT stock, CBIS stock or GRNH stock to break out like the nationwide legalization of marijuana.

Marijuana Stocks Set for a Fall

The dangerous part of all this for investors in marijuana stocks? Well, it’s sort of the opposite of what happens when a stock gets cheap because of headline risk. Bad news is often overblown by the market — especially in the short term — which can create opportunities to buy a good stock at a bargain price.

The same is true in the other direction, however. Good news can make a stock wildly overpriced, and that could easily be the case now with MJNA stock, MWIP stock, PHOT stock, CBIS stock or GRNH stock. Heck, anytime any stock doubles, triples or quadruples in a month like marijuana stocks have, you have got to be concerned that it’s gotten ahead of itself.

It’s even more worrisome when the securities are illiquid penny stocks like marijuana stocks. That’s part of the reason why InvestorPlace has warned investors again and again about the dangers and pitfalls of penny stocks.

MJNA stock, MWIP stock, PHOT stock, CBIS stock and GRNH stock all look like they’ve gotten ahead of themselves. True, more good news could push them higher still … but they won’t avoid the inevitable. All it takes is some bad news or for one large player to take some profits for these marijuana stock to come crashing down.

Sorry to harsh your buzz, but the bottom line is that marijuana stocks are too high for their own good.

As of this writing, Dan Burrows did not hold a position in any of the aforementioned securities.