CBN (cannabinol) can potentially show up on a drug test, but it depends on several factors. Although CBN is non-psychoactive, it is a byproduct of THC, the compound responsible for the "high" associated with cannabis. Because of its close chemical relationship with THC, some drug tests, especially urine tests, can mistake CBN for THC and cause a false positive.
Most standard drug tests, such as immunoassay urine tests, are designed to detect THC or its metabolites, like THC-COOH. Research has shown that CBN can sometimes trigger these tests due to cross-reactivity, even if no THC is present in the product. The likelihood of a false positive can increase if you're using CBN frequently or in high doses, or if the CBN product contains trace amounts of THC. However, more precise tests like gas chromatography-mass spectrometry (GC-MS) can differentiate between CBN and THC, reducing the chances of a false positive​(VRB Labs)​(Cibdol).
If you're concerned about drug testing and CBN, it's best to choose products labeled as "THC-free" or use pure CBN isolates, which reduce the risk of contamination with THC​ (Earthy Now).
