THC vape juice: the short answer
THC vape juice is a liquid made of THC oil plus a thinner and terpenes. It goes into a cartridge or a refillable tank. A coil heats the liquid into an aerosol you inhale. Most products sold in licensed US shops are cannabis distillate thinned with propylene glycol (PG), vegetable glycerin (VG), or food-grade terpenes. Federal law lists THC as a Schedule I drug, so all legal sales run through state programs.
What goes into the liquid
- Cannabinoid base: distillate, CO2 oil, or live resin. Distillate tests at 80% to 95% THC.
- Thinner: PG, VG, or a mix. Some makers use MCT oil or PEG 400.
- Terpenes: cannabis-derived or botanical, added for flavor and aroma, at 1% to 5%.
- Flavorings and other additives: brand-specific. Labels list them in states with strict packaging rules.
Potency and dosing
Distillate alone is too thick to wick. Thinners drop the final THC number to 60% to 85%, or 600 mg to 850 mg of THC per gram. A 1 gram cartridge at 70% holds about 700 mg of THC. That is about 70 doses at 10 mg each. State rules cap a single serving at 10 mg THC and a package at 100 mg for edible-style products. Vape cartridges often sit outside those caps. Start with one 2 to 3 second draw. Inhaled THC reaches the blood in seconds, peaks at 15 to 30 minutes, and fades over 1 to 3 hours.
Risks
Vitamin E acetate
Vitamin E acetate is a thickener that some black market makers added to THC cartridges. CDC lab tests found it in lung fluid from 51 of 51 EVALI patients sampled. As of February 2020, the CDC counted 2,807 hospitalizations and 68 deaths tied to the EVALI outbreak. The CDC named vitamin E acetate a primary cause of the lung injury. Licensed state products do not use it.
Carrier oils and heat
PG and VG break down into carbonyls such as formaldehyde and acetaldehyde when coil temperatures pass about 230 C (446 F). A 2017 study in the Journal of Alternative and Complementary Medicine measured those compounds in aerosol from e-liquids at high voltage. MCT oil and other lipid carriers carry a second concern: oil in the lungs. No safe inhaled dose is set for these carriers, and health agencies advise against them.
Contaminants
Unregulated cartridges have tested positive for pesticides, heavy metals, and residual solvents. Licensed US producers must pass state lab panels for those items, plus microbials and mycotoxins. Ask for the batch test result.
Legal status in the US
THC sits on Schedule I of the Controlled Substances Act. The FDA has approved no THC vaping product. State programs allow medical use in most states and adult use in 24 states and the District of Columbia. Rules on potency caps, taxes, and possession limits differ by state. Check your state cannabis authority for current law.
Device settings
- Voltage: 2.5 V to 3.8 V. Lower settings protect terpenes and cut carbonyl output.
- Coil: ceramic or quartz. Cotton wicks clog with thick oil.
- Thread: 510 for cartridges. Pods use brand-specific magnets.
- Draw: 2 to 3 seconds. Long draws burn the coil and taste harsh.
Storage
Keep cartridges upright in a dark spot at 60 F to 70 F (15 C to 21 C). Heat thins the liquid, causes leaks, and speeds THC loss. THC oxidizes into CBN over time, which lowers potency and adds sedation. Shelf life runs about 6 to 12 months from the fill date. Cold storage slows the change but makes the oil too thick to wick until it warms.
THC vape juice vs other concentrates
Live resin and rosin cartridges hold the plant's full terpene and cannabinoid profile. They are not thinned with PG or VG, so they are not juice in the same sense. A distillate cartridge with added terpenes is the standard form of THC vape juice sold in US shops.