Can CBD Show Up in Hair Drug Test?

With the growing popularity of CBD products in the UK, many users are asking: can CBD show up in a hair drug test? The short answer is: CBD itself will not show up—but if your product contains even small amounts of THC, you could still test positive.

Hair drug testing is designed to detect illegal or controlled substances, not over-the-counter supplements. However, due to the way CBD is extracted and processed, there’s a risk of THC contamination—which is where the problem lies.

Here’s what you need to know about CBD, hair testing, and how to avoid unwanted surprises.

What Do Hair Drug Tests Look For?

Hair drug tests are often used to detect long-term drug use, and can pick up substances used in the past 90 days or more. The test works by analysing hair strands—usually from the scalp—for traces of drug metabolites that are carried through the bloodstream and deposited in hair as it grows.

In the UK, standard hair tests are typically used to detect:

• THC (from cannabis)

• Cocaine

• Opiates (heroin, morphine)

• Amphetamines

• Benzodiazepines

• MDMA (ecstasy)

CBD is not one of the substances tested for, and it does not produce a “high” or cause impairment, so it is not considered a controlled drug under UK law.

So, Will CBD Trigger a Positive Hair Test?

No, CBD itself won’t trigger a positive drug test, including in hair testing. But if your CBD product contains any THC, even in trace amounts, that’s where a positive result for cannabis can occur.

Many CBD products—especially those labelled as “full-spectrum”—contain a mix of cannabinoids, including low levels of THC (typically under 0.2%). While this is legal under UK regulations (as long as THC content is less than 1mg per container), repeated use over time can lead to THC building up in your system and being detectable in your hair.

What About “THC-Free” CBD Products?

Some products are marketed as “THC-free” or “broad-spectrum”, but this doesn’t always guarantee zero THC. Manufacturing standards vary, and cross-contamination can occur. Unless a product has been lab-tested and verified by a third party, there’s always a small risk it contains enough THC to appear on a sensitive drug test.

To reduce your risk:

• Look for lab-tested products with certificates of analysis

• Choose CBD isolate, which contains only CBD and no other cannabinoids

• Avoid full-spectrum CBD if you're subject to regular drug testing

• Stick with reputable UK suppliers who meet legal and safety standards

How Does Hair Testing Compare to Other Drug Tests?

As you can see, hair testing has the longest detection window, and is most likely to pick up regular THC use—even if you haven’t used cannabis for weeks.

Who Gets Hair Drug Tested?

Hair drug testing is often used in:

• Workplace drug testing, especially in safety-critical jobs

• Legal or family court cases, such as child custody or probation

• Rehab or treatment programmes

• Professional sports and athletics

If you fall into one of these categories and are using CBD, it’s essential to understand what’s in your product and whether it could pose a risk.

Final Word

CBD won’t show up in a hair drug test—but THC might, and that’s where the real concern lies. If your CBD product is contaminated or contains even legal trace amounts of THC, repeated use could lead to a failed drug test, especially with hair analysis.

To stay safe, always choose lab-tested, THC-free products, particularly if you’re subject to workplace or legal testing. When it comes to drug tests, it’s not just about what you think you’re taking—it’s about what’s actually in the bottle.