Full spectrum CBD is a hemp extract that keeps the plant's other compounds: other cannabinoids, terpenes, and trace delta-9 THC. Under US law, hemp must test at or below 0.3% delta-9 THC by dry weight. A store product with that label still contains THC in milligrams. That number, not the percentage, matters for dosing and for workplace drug tests.
What the three product types are
Full spectrum CBD keeps CBD, other cannabinoids such as CBG, CBC, and CBN, terpenes, and trace THC. Broad spectrum CBD is processed to strip THC. CBD isolate is purified cannabidiol alone. Isolate has no terpenes and no other cannabinoids.
The 2018 Farm Bill defines hemp as Cannabis sativa L. with a delta-9 THC concentration of 0.3% or less on a dry weight basis. That is a limit on plant material, not on dose per serving.
THC and drug tests
A 0.3% cap does not mean zero THC. A tincture at 30 mg CBD per mL can deliver a few milligrams of delta-9 THC per dropper. Repeated use lets THC build up in the body. NIDA reports that full spectrum users can test positive on standard screens. Ask the store for the THC amount in milligrams for one serving.
What to check on the label
- CBD in milligrams per serving and per bottle.
- Delta-9 THC in milligrams per serving.
- Batch number or lot code.
- A certificate of analysis (COA) from a third-party lab.
- COA results for potency, pesticides, heavy metals, residual solvents, and microbiologicals.
- Full cannabinoid profile, not just the CBD figure.
Questions for staff at the counter
- Can I see the COA for this batch?
- How much delta-9 THC is in one serving?
- What extraction method was used, CO2, ethanol, or oil?
- Does the COA match the lot code on this bottle?
Dosing
Most tincture bottles hold 30 mL. A 1 mL dropper holds about 20 drops. Start with a low serving, note the time and the amount, and wait 2 hours before the next serving. CBD inhibits the CYP3A4 and CYP2C19 enzymes. That can raise blood levels of drugs such as clobazam and warfarin. Talk to a pharmacist if you take prescription drugs.
Rules inside the store
Most US states require an ID and age 21 and over for adult-use sales. Medical cardholders can be 18 in some states. Hemp-derived CBD sits in a gap between state and federal rules. The FDA has approved CBD as a drug in one product, Epidiolex, for two seizure types. The FDA states it is not lawful to market CBD as a dietary supplement. Ask what your state permits before you buy.
What the evidence shows
Research is limited. NCCIH reports the strongest evidence for CBD is in seizure disorders. Evidence for anxiety, pain, and sleep is weaker. Side effects include dry mouth, stomach upset, drowsiness, and changes in liver enzyme levels. The FDA has warned about liver injury at high doses.