Despite its new-found legality at the state level, the buds you buy in medical marijuana dispensaries aren't that different than the dime bags you used to score on the street corner—they share the same wild swings in potency, chemical content, and fungal and pesticide contamination. That's very not good.

Potency is more than just measuring how much THC is present—the balance of eight common cannabinoids effectively determines the strain's effect on a patient. CBD-rich strains offer a host of antioxidant effects, THC-heavy strains stimulate appetite to counter the effects of chemotherapy, and CBN-rich strains are effective at reducing anxiety and promoting sleep. And even a small shift in the relative concentrations of these cannabinoids can change their therapeutic effects. Potency and formula consistency is crucial.

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Testing buds for mildew, mold, fungi, and a host of pesticides, herbicides, and fertilizers is equally important. You wouldn't want that shit in your salad, why on Earth would it be OK to have on your weed?

A lack of government oversight

The problem is simple: We really don't know all that much about the product that's being sold in medical marijuana and recreational cannabis dispensaries around the country.

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Most people know that the THC content in commercial cannabis has been rapidly rising for the past 40 years: On average, weed in the 70s contained about .75 percent THC by volume; by the 90s it had risen to around 4 percent; in 2010 the average jumped to around 10 percent; and today I can walk into the Green Cross and have my pick of a half dozen strains topping 20 percent. Some labs are even reporting individual strains containing more than 30 percent THC.

But thanks to the Food and Drug Administration's lack of oversight, due to the federal government's misguided War on Drugs, consumers really have no idea what they're ingesting. Specifically, we can thank the fact that cannabis is a Schedule 1 narcotic—up there with heroin and LSD—which bans federal researchers and agencies from testing or experimenting on cannabis in any way. And that includes the FDA.

"Because of the federal status of cannabis right now, those federal agencies that do all of that monitoring are not allowed to do it," Don Land, a professor of Chemistry at UC Davis, told KCBS' Mike Surgarman. "I don't buy anything that hasn't been tested. I don't buy aspirin from someone on a street corner. I go to a pharmacy," he added.

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In lieu of any federally mandated testing, states that have legalized cannabis, such as Colorado and California, now both face a similar issue: How to ensure that the product sold in dispensaries is safe to consume, free of contaminants, and offers a verifiable and relatively stable THC content within strains.

Unfortunately, as a pair of recent news reports from KUSA and KCBS have found, that doesn't actually happen too often.

A sketchy product

KCBS' Mike Sugarman purchased more than $600 worth of buds, edibles, and shatter from a dozen San Francisco and Oakland dispensaries for testing at an independent facility, Oakland's Steep Hill Labs. The lab's results were not reassuring: The potency of the tested edibles was wildly inconsistent, mold and pesticide residue on nearly half the nugs, and even worse production byproducts in the hash.

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Per Sugarman's report:

"All the edibles missed their mark," said Dr. Kymron Decesare, chief research officer at Steep Hill. He told me nothing I was taking had anything to do with what was on the label."

The one that was the worst claimed to be 100 milligrams, it was 1.3. That was the Edipure brand. That's 98.7% off. Most others were only half the strength they claimed, or a quarter. Even gummy bears and lozenges in the same pack had great variations from one piece to another.

Even more disturbing, what they found in the buds that people smoke. Mold. And pesticides. 40% of the samples couldn't be sold in Colorado or Washington where there are limits. Decesare told us mold can be dangerous: "Even if there are no microtoxins in mold, there are potentially deadly molds like penicillin or aspergillums, deadly toxins that could kill people."

And 15% of the hash oil had benzene, which is not approved for use in the human body.

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Sure, we could write this off as a byproduct of California's medical cannabis legislation and the fact that the state operates in a legal grey area regarding its use and sale. But the story should be different in Colorado, right? They've not only legalized weed entirely but also set up an extensive monitoring and quality control mechanism to protect consumers. Yeah, no. Not by a long shot, according to a recent report by Denver's KUSA.

The station's news team similarly purchased $500 worth of various weed products for independent testing and the results were just as bad. The THC content of edibles once again tested far below what was on the label (the stony equivalent of buying a bottle of single malt scotch and finding it actually contains hard pear cider), the potency of concentrates varied wildly, and despite being legal for nearly a year, the state still has not implemented any sort of test for mold, pesticide, or other contaminants.

Granted, these contaminants won't kill you outright—you're in no danger of a puff-puff-pass-cough-die situation—but they're still not things you want to be putting in your body and they're things that the federal government guards consumers against in virtually every other edible product on the market. But because of racism against Mexican immigrants in the 1930s, MMJ patients in the 21st century have to go it alone.

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Testing cannabis

Which is odd because lab testing methods for both potency and chemical contamination are already quite common.

Potency testing simply involves isolating one or all of the eight most common cannabinoids found in a plant and measuring their relative concentration. Different combinations and concentrations of these cannabinoids can greatly influences the drug's effects—CBN, for example, modulates how sleepy or couch locked you'll get—so it's pretty important for patients to understand what they're getting.

Gas Chromatography has been widely used for these potency tests for years. This system essentially vaporizes the active ingredients and blows them through a metal cylinder coated in a microscopic layer of liquid. The various vaporized chemicals will interact with the fluid for varying amounts of time, known as the retention time, which allows researchers to isolate and measure the relative concentrations of specific chemicals within a complex mass of molecules—i.e., cannabis vapor.

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This is a useful system but does have the drawback that the act of vaporizing a sample changes its physical properties which affects the precision of the test itself—not unlike trying to directly observe an electron.

To get around this issue, the cannabis industry has begun switching to a newer and more precise method, known as Ultra-High Performance Liquid Chromatography. Instead of vaporizing the material, UPLC systems rely on high-pressure solvent to deliver a sample through the testing column, which is lined with absorbent material rather than a liquid film.

The time it takes a specific cannabinol to exit the testing column counts as its retention time and because the solvent molecules employed are rarely bigger than 50 micrometers in diameter, the system is able to resolve to a much higher degree than conventional GC systems, providing a much more accurate measure of the various chemicals present. As such UPLC is the analytic choice for the FDA, United Nations, Drug Enforcement Agency and even the World Health Organization.

Human error

These systems, when used properly, can provide highly accurate and dependable analysis. But, like the rest of this industry, their use is subject to human error. Sometimes a lot of it.

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Back in 2011, the California division of the National Organization to Reform Marijuana Laws (NORML) conducted a round robin (aka "ring") experiment among ten testing labs, submitting identical samples of four bud strains and two alcohol extract concentrates to all ten. The results, were surprising.

In most cases, lab results were consistent to within 20% of each other. To some degree, the differences in results might be explained by natural variations in the of the cannabis samples used; to some degree, by differences in lab procedures. In certain cases, there were glaring discrepancies suggesting laboratory error. Three of the 10 labs performed poorly on half the tests. Particularly in the case of liquid alcohol extracts, test results were troublingly inconsistent. Nevertheless, the general results showed good agreement between most lab results involving herbal samples. Lab performance can be expected to improve in the future as the industry responds with improved standards.

The study also found that both GC and UPLC were reliable measures of potency of buds but fell short on testing concentrates. So not only does it matter how the sample is tested but also by who is doing the testing. But for consumers, that information isn't always readily available and that needs to change.

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Labs need to develop more accurate testing (like, to two decimal places) and more reliable methodologies, dispensaries and growers alike need to become more transparent in what their products contain, and both consumers and patients need to be more cognizant of what they're putting into themselves. [USA Today - KCBS - Cannlabs - Analytic 360 - NORML - Project CBD (pdf) - Weed Maps - Green Leaf Lab - Wiki 1, 2]

top image: ChameleonsEye