Product Review: tCheck Cannabis Oil Potency Tester

We have been making our own infused butter and oils – and teaching other people how to make, use, and dose themselves – for well over six years now. We’ve even come up with a formula to calculate how much THC is theoretically in your homemade oil, but there’s never been a reasonably affordable way to actually measure it. Commercial cannabis labs are super accurate, but cost somewhere between $50 and $100 to test a single sample. So now along comes tCheck, with a nice little game changing wizardly product the size of an older iPod, for just $299.99 with no consumables or anything else to buy.

The technology behind tCheck is deceptively simple. Using a spectrometer, it was determined that all cannabinoids have a secondary peak wavelength at 320 nm, so they designed their photosensitive detection using an LED that emits light at the proper frequency, shines through the oil, and the result gets turned into an exact measurement.

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One limitation of tCheck is that it cannot tell you all the separate cannabinoids that are in your sample, only the total cannabinoids by volume (CBV, expressed as milligrams per milliliter). Yet that’s still plenty of important information, especially since most users will know precisely what they started with. Your dispensary already tells you how much THC and CBD is in your bud or concentrate, and their exact proportions, but only the tCheck can tell you how much of that actually made it into your oil.

If you’re not in a “legal area”, the tCheck might even be more valuable. You’re probably only getting THC in your bud anyway, so you really have little or no idea how strong your finished product is going to be…unless you use tCheck. We’ve already warned people what can happen if they eat too much THC in their edibles! And if you are trying out some of the “legal CBD” products (some of which are several hundred dollars per bottle), tCheck could help verify that you’re actually getting the CBD you’re paying for.

Checking Out tCheck

Unlike many high tech and cannabis startups, the people at tCheck seem to be immune to hype and wild claims about their product. For instance, they mention that their battery will last for “more than 50 tests per full charge”, though our own testing shows that 40 consecutive tests drop the battery level only 24%…which means their product claim is much more conservative than actual results.

Tcheck supplied me with a unit for review, and we’ve been working with it for several weeks now. The first thing I did was carefully attempt to load infused oil into the test chamber, using the supplied test slide and precut filter paper. Half an hour later, I realized that the filters were actually removing the oil from the test chamber by capillary action, and stopped using them. Immediately after that, I started getting valid results. tCheck has subsequently come to the same conclusion: the filters are useless, and everything works just fine without them.

The company seems quite responsive. When the unit first arrived, we noted a number of minor bugs that were fixed within days and delivered as firmware updates over WiFi.

User Friendly

It’s really simple to use the tCheck. Mine arrived partially charged and already displaying the correct date and time, so all I had to do (just once) was input the login credentials for my WiFi network on the touchscreen. The company stresses that absolutely no information is “sent back” to them via the Internet, even the name of your WiFi connection, by the way. According to a company spokesperson, “If that ever changes, we will definitely have a notification to the user and have the option to disable that function. We are VERY big on transparency and we are not interested in data farming.”

Setting up WiFi allows the tCheck to “phone home” for firmware updates, so I got into the habit of checking for them every time I used it, though you certainly don’t have to. Likewise, you must calibrate the unit before you use it (which consists of pushing the calibration button), but you don’t really have to do that every time either, because it analyzes the exact characteristics of your particular unit.

To actually perform a test, you put just two drops of test liquid into the well on the concave half of the plastic test slide (almost exactly like a microscope slide), fit the corresponding convex half on top, push the slide into the tCheck unit, and push the “Run A Test” button. The unit thinks about it for a minute, and then tells you the result as milligrams per milliliter. This is a lot more useful than a simple percentage, because it lets you calculate the actual dosage directly. For example, a #00 capsule holds just under 1 ml of liquid, a tablespoon is 15 ml, etc.

Trust, But Verify

I first tested tCheck with plain uninfused olive oil and coconut oil, as well as salad dressing (checking for false positives!). They all came out with big fat zeroes, as expected.

Then I tested it with infused olive oil and six different “flavors” of infused canna-coconut oil. This is where it got interesting. I happen to have one particular mixture of oil we call API for All-Purpose Indica, that I made in my Magical Butter Machine by combining a number of strains, and it’s very strong. In fact, capsules made from this stuff are way too strong for me generally, although perfect for Felicity when she’s trying to go to sleep. So I carefully diluted a quantity of API for my own use, and labeled it “70% API”. When I tested the API, tCheck told me it was 8.3 mg/ml THC. Testing the “70% API” got a result of 5.9 mg/ml. Divide those numbers properly, and you get 71%. That’s what I call excellent consistency!

Also for testing purposes, I did repeat tests on a single sample of oil several times, sometimes leaving the slide in place and sometimes simply pulling it out and pushing it back in, without changing the test material. The results were either exactly the same or within tCheck’s published specifications (10% accuracy).

All the other oil tests also fit our experience with those oils in terms of their relative strength, other than a single sample. That one showed up as 1 mg/ml, even though it should have been over 4 times higher by calculation, and probably twice as much as that based on how strong it is when we take it. We’re still scratching our heads over that one, though tCheck verified that our unit was working fine.

Details and Future Plans

The product was formally developed by Engineered Medical Technologies. We spent a few hours recently with Peichen Chang, their CEO, and met most of their development and support team as well. Chang explained how their patented technology enables a reasonably priced, yet consistent and accurate product. The calibration process allows the precise characteristics of the UV-B LED and photoelectric detector to be analyzed before use, and then the 310 nm wavelength light shines through exactly 0.4 mm of oil. The plastic slide itself is made of a proprietary compound, and their software does the rest of the magic. They also showed us the collection of samples they had tested at Sequoia Labs by gas chromatograph to help them calibrate the tCheck units.

The people behind tCheck are medical marijuana advocates and patients, and as dedicated and focused on “doing it right” as anyone. They’ve cooked up coded an edibles calculator, and even a Chrome extension, to help you figure out the proper doses for your edibles.

“There’s really no other medicine we take where not knowing the amount is acceptable”
– Kelly K, tCheck Sales Chef

The tCheck will work with infused olive oil, coconut oil, ghee (clarified butter), and regular cannabutter (as long as you skim off the milk solids). They’re working on methods of testing vegetable glycerin and alcohol tinctures in the future, using the current hardware and free firmware updates. Chang told us that the tCheck should soon be able to test concentrates directly, by adding precise amounts of known solvents. Once this happens, home testing of home-pressed rosin will be a reality!

For the farther future, Chang sees a way to create a more expensive, but still relatively affordable model that will be able to analyze the exact proportions of THC and CBD. And they are planning to use their own product to help research the most efficient methods and temperatures to decarb and make infused oils, which is definitely something we support!

The Bottom Line

You will want a tCheck if you are a medical marijuana patient who is serious about knowing or tracking their dosage of homemade oil, butter, or edibles

You will want a tCheck if you are a medical marijuana patient who is serious about knowing or tracking their dosage of homemade oil, butter, or edibles, or someone who is informally making them for yourself or others (such as a caretaker or cannabis chef). Perhaps a responsible entrepreneurial type in a non-legal area might benefit from this, since licensed businesses in legal states must usually get their products tested by a third-party lab. Most fully legal oil, edible, or capsule manufacturers will probably want a tCheck around just for in-house sanity checking as well.

tCheck TC1S Oil Potency Tester, $299.99 with one year limited warranty

About Old Hippie Old Hippie is a father of two boys and thankfully living in California where all this kind of thing is legal. He started smoking marijuana in 1967 in high school, experimented with mind-expanding drugs of all kinds, and then straightened out 15 or so years later to become an airplane pilot. After being diagnosed with depression in 2000, he lost his job and most of the following decade to prescription medications (such as antidepressants) which sapped his energy and will. Finally, a chance conversation with a friend led to a doctor’s recommendation for medical marijuana (MMJ). This changed his entire life, health, and outlook for the better. is his continuing story. It’s also his way to provide experienced advice on using medical marijuana effectively and responsibly, as well as advocacy, activism, and support for others. Old Hippie teaches about safe use of cannabis edibles, Canna Caps, vaporizers, dosing, and even microdosing.


Hello Old Hippie,

Any tips for a potion that will help me sleep (back pain) through the night without getting me high??

Jo Jo

For making oil, see this article. While there’s no specific “potion” for back pain, many people prefer high CBD indica strains for this condition, and if you use bud with a ratio of 8:1 CBD:THC or more, you are more likely to get relief without undue psychoactive effects.

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