What you need to know before using any hemp-derived product—including CBD, CBN, CBG, and more.

The Short Answer

Most drug tests are designed to detect THC (tetrahydrocannabinol), the intoxicating compound found in cannabis - not CBD, CBN, CBG, or other non-intoxicating cannabinoids. However, virtually all hemp-derived products carry some level of risk for a positive drug test, regardless of which cannabinoid is featured on the label. Here’s why:

Why Any Hemp Product Can Matter for Drug Testing

1. Trace THC Is Naturally Present in Hemp
   

   Hemp is cannabis that contains no more than 0.3% delta-9 THC by dry weight under the 2018 Farm Bill. That legal threshold is not zero. Every hemp plant—regardless of whether it is bred for CBD, CBN, CBG, or any other cannabinoid - naturally produces at least trace amounts of THC.

   Full-spectrum hemp extracts preserve the plant’s full range of cannabinoids, terpenes, and flavonoids, which means they also retain these trace amounts of THC. Even at levels well below the legal limit, regular use of a full-spectrum product can cause THC and its metabolites to accumulate in the body over time.
   
   

2. Broad-Spectrum and THC-Free† Products
   

   Broad-spectrum extracts are processed to remove most THC while retaining other cannabinoids. “THC-Free†” products reduce THC to below detectable limits—less than 0.01%, or 100 parts per million. Many manufacturers, including Charlotte’s Web, have also shifted toward formulating products with CBD isolate. Both broad-spectrum and isolate-based products carry significantly lower risk than full-spectrum, but “undetectable” is not the same as “absent,” and individual variation in metabolism means that no product can guarantee a negative drug test.
   
   

3. Isolate Products (e.g., CBD Isolate)
   

   Isolate products contain a single purified cannabinoid (such as CBD or CBN) and are often assumed to be completely free of THC. In practice, even highly purified isolates typically contain trace amounts of THC—often in the low parts-per-million (ppm) range. While short-term studies using pharmaceutical-grade pure CBD (such as Epidiolex®) have generally not produced positive urine drug tests, these studies only examined use over days to weeks.
   
   

   Here’s what matters for long-term users: THC is lipophilic, meaning it dissolves in and is stored by fat tissue. Even very small amounts of THC, levels so low they seem negligible on a product label, can accumulate in the body over weeks and months of daily use. As THC slowly builds up in fat stores and is gradually released back into the bloodstream, its metabolites can eventually reach concentrations detectable by a drug test. A person using an isolate product daily may not test positive at weeks or even months, but with continued use, the risk increases.
   
   

   On top of this accumulation risk, studies have documented widespread inaccuracy in product labeling: some products labeled as “CBD isolate” or “THC-free” have been found to contain more THC than expected. Because hemp-derived supplements are not regulated by the FDA, quality varies significantly between manufacturers.

   
   

4. CBN Deserves Special Attention
   

   Cannabinol (CBN) is widely marketed for sleep support. Beyond the residual-THC risk that applies to all hemp products, CBN has an additional concern: its molecular structure is similar enough to THC that it can cross-react with certain immunoassay drug screens - the rapid screening tests used in most workplace and clinical settings. This means CBN itself may trigger a presumptive positive result on an initial screen, even if no THC is present. A confirmatory test (such as LC-MS/MS) would distinguish CBN from THC, but not every testing program automatically performs confirmatory analysis.
   
   

5. Topical Products Are Not Risk-Free Either

   CBD- and cannabinoid-containing creams, lotions, balms, and patches are applied to the skin rather than ingested. Research has shown that while topical products generally do not produce positive urine drug tests. However, some products, particularly those designed to help ingredients pass more easily through the skin, may lead to detectable cannabinoid levels in oral fluid (saliva). Because oral fluid testing is becoming more common in workplace and roadside testing, people subject to this type of screening should be aware of this risk.
   
   

Factors That Affect Your Risk

Dose and frequency of use. Higher doses and more frequent use increase the amount of THC metabolites that accumulate in the body.



Product type. Full-spectrum broad-spectrum THC-Free† isolate, in terms of THC content, but none are guaranteed zero.



Individual biology. Body mass, metabolism, hydration, genetics, and fat storage all influence how quickly THC metabolites are eliminated.



Product quality and labeling accuracy. Not all products contain what their labels claim. Always look for products backed by third-party Certificates of Analysis (COAs).



Type of drug test. Urine immunoassay screening, oral fluid tests, and hair tests each have different sensitivities and detection windows.



What You Can Do

• Talk to your healthcare provider before starting any hemp product, especially if you are subject to drug testing.
• Choose reputable brands that follow FDA Current Good Manufacturing Practices (cGMP), share third-party COAs, and are transparent about THC content.
• If drug testing is a concern, consider THC-Free† or broad-spectrum options, which carry meaningfully lower risk than full-spectrum products, but understand that no hemp product can guarantee a negative test.
• Inform your employer or testing authority proactively if you are using a legal hemp product. Standard drug tests cannot distinguish between legal hemp-derived THC and illicit cannabis use.
  
  

† THC-Free means trace amounts less than 0.01% or 100 ppm.



Hemp-Derived Cannabinoid Products and Drug Testing: A Clinical Summary

An evidence-based overview for clinicians whose patients use hemp-derived products containing CBD, CBN, CBG, and other cannabinoids.



Clinical Context

Since the 2018 Agriculture Improvement Act removed hemp (≤0.3% delta-9 THC) from Schedule I, hemp-derived cannabinoid products have proliferated. Patients now use not only CBD oils and capsules but also products featuring cannabinol (CBN), cannabigerol (CBG), cannabichromene (CBC), and multi-cannabinoid blends. Many of these patients are subject to workplace, clinical, or legal drug testing.



Clinicians are increasingly asked whether these products are “safe” with respect to drug screening. The evidence summarized below, drawn largely from controlled human laboratory studies, demonstrates that the answer is nuanced and product dependent.



Full-Spectrum Hemp Products and Drug Testing

Full-spectrum hemp extracts retain the complete phytochemical profile of the plant, including legally permissible amounts of THC (<0.3%). Multiple controlled studies have now demonstrated that regular oral administration of hemp-legal doses of THC (even as low as 0.5–1.0 mg, well within what is present in commercially available products) can produce positive urine drug tests under standard federal workplace testing criteria (immunoassay screen ≥50 ng/mL THC-COOH; LC-MS/MS confirmation ≥15 ng/mL) [1].




Wolinsky et al. (2026) administered 100 mg CBD with 0, 0.5, 1.0, 2.0, 2.8, or 3.7 mg THC twice daily for 14 days to healthy adults (n=60). Positive urine drug tests were observed in at least one participant at every THC dose level during the 14-day outpatient exposure period, including in the CBD-only condition (one specimen). Positive results persisted up to one week post-washout in two participants. Blood THC concentrations were very low across all conditions, and no pharmacodynamic differences were observed between the CBD-only and THC-containing groups, confirming that these doses do not produce intoxication or impairment [1].




These controlled findings are consistent with real-world data. Ferretti et al. (2023) collected urine samples from individuals who had been using oral hemp-derived CBD extracts daily for at least 30 days (mean dose: ~31 mg CBD per dose, ~1.5 doses per day) and who reported no other cannabis or illicit drug use. Using immunoassay dipstick tests, 100% of participants screened positive at the 20 ng/mL detection criterion. LC-MS/MS confirmatory testing detected.




THC-COOH across a wide range (5.3–178 ng/mL; median 38 ng/mL), with most specimens exceeding the 15 ng/mL federal confirmatory cutoff [2].




Separately, controlled studies using pharmaceutical-grade oral CBD without THC (e.g., Epidiolex®) have consistently demonstrated that pure CBD itself does not produce positive urine drug tests at standard cutoffs and does not convert to THC in vivo [3, 4]. This distinction between pure CBD and full-spectrum hemp extracts containing trace THC is central to understanding drug testing risk across product types.




Broad-Spectrum and THC-Free Products

Zvorsky et al. (2024) conducted a 2-week open-label study of a commercially available broad-spectrum CBD product (mean daily use: 34.2 ± 16.0 mg CBD) in 20 healthy adults. Urine was analyzed via LC-MS/MS. Neither THC nor its metabolites were detectable following the 2-week use period, and no adverse events were reported [5].




This study provides reassuring preliminary evidence for products manufactured under rigorous quality controls. It is worth noting that the hemp industry, including Charlotte’s Web, has increasingly shifted from broad-spectrum formulations toward CBD isolate-based products for many SKUs. Whether formulated with broad-spectrum extract or isolate, the principle remains the same: reducing THC content to the lowest achievable level meaningfully lowers, but does not eliminate, drug testing risk. Clinicians should note that the Zvorsky study was small (n=20), unblinded, and limited to a single product, so generalization across all products and formulations is not warranted.




Pure Cannabinoid Isolate Products

Published human laboratory data using pharmaceutical-grade oral CBD (Epidiolex®) and synthetically derived oral CBD have shown that pure CBD itself does not produce positive urine drug tests at standard cutoffs over short observation periods and does not convert to THC in vivo [3, 4]. However, these studies employed acute or short-duration (days to weeks) dosing protocols and do not address the pharmacokinetic reality of chronic daily use.




Even highly purified cannabinoid isolates - whether CBD, CBN, or CBG - typically contain trace THC in the low parts-per-million (ppm) range. THC is highly lipophilic (log P ≈ 6.97) with a long terminal elimination half-life due to extensive sequestration in adipose tissue. During chronic daily administration, even ppm-level THC exposure results in slow but progressive accumulation in fat stores. THC is then gradually redistributed into the bloodstream and metabolized to 11-nor-9-carboxy-THC (THC-COOH), the primary analyte in urine immunoassay and confirmatory testing. Over a period of months of daily isolate use, urinary THC-COOH concentrations can rise above the 15 ng/mL confirmatory cutoff, even when no single dose would produce a positive result in an acute study. Clinicians should understand that a negative drug test after 2–4 weeks of isolate use does not predict continued negative results at 4–6 months.




This is particularly relevant as more manufacturers, including Charlotte’s Web, increasingly formulate products using CBD isolate, including clinic-distributed SKUs. While isolate-based products represent the lowest-risk category for drug testing, patients using them chronically should still be counseled about the accumulation potential.




Compounding this pharmacokinetic risk, retail CBD isolate products exist in an unregulated market. Bonn-Miller et al. (2017) analyzed 84 CBD products purchased online and found that only 31% were accurately labeled for CBD content, and approximately 21% contained detectable THC [6]. Spindle et al. (2022) found that 35% of topical cannabinoid products purchased at retail stores and online contained THC, including products labeled as “THC-free” [7]. Products with higher-than-declared THC content accelerate the accumulation timeline.




Additionally, Hart et al. (2022) demonstrated that 7-carboxy-cannabidiol (7-COOH-CBD), the primary urinary metabolite of CBD, can convert to THC-COOH during certain gas chromatography–mass spectrometry (GC-MS) sample preparation methods, though this artifact did not occur with liquid chromatography–tandem mass spectrometry (LC-MS/MS), which is now the predominant confirmatory method in certified laboratories [8].




There are no published controlled human studies evaluating chronic (≥3 month) use of any cannabinoid isolate product - CBD, CBN, CBG, or otherwise - with respect to drug testing outcomes. This represents a significant gap in the literature.




CBN and Immunoassay Cross-Reactivity

Kroner et al. (2020) evaluated the cross-reactivity of four cannabinoids (CBD, CBN, CBC, CBG) with two commercial urine immunoassays designed to detect THC metabolite. CBD, CBC, and CBG did not cross-react. CBN, however, demonstrated cross-reactivity with both the EMIT II Plus and Microgenics MultiGent assays [9].




For the EMIT II Plus assay, approximately 5-fold more CBN than THC-COOH was required to produce a signal equivalent to the cutoff concentration (i.e., ~250 ng/mL CBN to mimic a 50 ng/mL THC-COOH positive). For the Microgenics assay, 20-fold more was needed. Importantly, CBN also displayed an additive effect with THC metabolite in the EMIT II Plus assay, meaning that if a patient has low-level THC-COOH from hemp product use combined with CBN from a sleep product, the cumulative signal could exceed the immunoassay threshold [9].




Clinicians should be aware that patients using CBN-containing products may present with presumptive positive THC screens even in the absence of THC exposure. Confirmatory LC-MS/MS testing will distinguish CBN from THC-COOH.




Topical Cannabinoid Products

Zamarripa et al. (2024) evaluated five commercially available hemp-derived topical CBD products in healthy adults (n=46) over 17 days. No urine specimens tested positive under federal workplace drug testing criteria. However, 9 of 46 participants exhibited oral fluid THC concentrations ≥2 ng/mL, the current federal workplace oral fluid threshold [10].




This finding is clinically relevant given the increasing use of oral fluid testing in workplace and roadside settings. Patients who use topical cannabinoid products and are subject to oral fluid screening should be counseled accordingly.




Implications for Oral Fluid Testing

Vikingsson et al. (2025) characterized the oral fluid pharmacokinetic profile of orally administered CBD with low-dose THC. Even at the lowest THC dose studied (0.5 mg with 100 mg CBD), 1 of 10 participants had a positive oral fluid test (≥2 ng/mL THC) within hours of a single dose. The positive rate increased dose-dependently, reaching 8 of 10 participants at 2.8–3.7 mg THC [11].




The authors also noted that 5 samples in the CBD-only group tested positive at the 0.5-hour time point, likely due to minimal conversion of CBD to THC during the analytical process itself. This underscores the importance of laboratory methodology and cautious interpretation of results [11].




Workplace Drug Testing Limitations

Vikingsson et al. (2022) analyzed 6,000 workplace drug testing urine specimens and detected CBD metabolites (7-OH-CBD) in 3.0% of regulated and 4.2% of non-regulated specimens, confirming widespread CBD use in the tested population. The study also identified delta-8-THC-COOH in 1.3% of specimens, some at concentrations suggesting use of commercially available delta-8-THC products [12].




Critically, conventional drug testing cannot reliably distinguish between the use of legal hemp-derived products and illicit cannabis. Wolinsky et al. (2026) concluded: standard urine THC tests may return positive results from low doses that produce no intoxication or impairment. Clinicians, employers, and medical review officers should consider this when interpreting results [1].




Product Quality and Labeling Accuracy

Two landmark studies by the same research group highlight the importance of product quality:



• Bonn-Miller et al. (2017) analyzed 84 CBD products sold online and found that only 31% were accurately labeled for CBD content. Approximately 21% contained detectable THC [6].
  
• Spindle et al. (2022) purchased 105 topical cannabinoid products from retail stores and online. THC was detected in 35% of products, including 4 of 37 that were labeled as THC-free [7].

Clinicians should advise patients to source products from manufacturers that follow cGMP, provide batch-specific third-party Certificates of Analysis (COAs), and have a documented chain of custody from seed to shelf.

Clinical Recommendations

• Counsel all patients who use any hemp-derived product—regardless of cannabinoid type—that a positive THC drug test is possible.
• Advise patients subject to drug testing to consider THC-Free† or broad-spectrum products from reputable manufacturers, with the understanding that no product eliminates risk entirely.
• Be aware that CBN products carry an additional risk of immunoassay cross-reactivity beyond residual THC content. Recommend confirmatory LC-MS/MS testing when a presumptive positive may be attributable to CBN.
• Recognize that topical products, while unlikely to produce positive urine tests, may yield positive oral fluid results.
• Document hemp product use in the medical record and communicate to the patient’s employer or medical review officer when appropriate, as conventional testing cannot distinguish legal hemp use from illicit cannabis use.
• Encourage patients to request COAs for every product they use and to verify that the manufacturer follows cGMP under FDA guidelines.

References

1. Wolinsky D, Zamarripa CA, Spindle TR, et al. The acute and chronic pharmacokinetics and pharmacodynamics of oral cannabidiol with and without low doses of delta-9-tetrahydrocannabinol. J Anal Toxicol. 2026;50(1).
2. Ferretti ML, Vandrey R, Irons JG, Jackson H, Loflin MJ, Hyke T, Bonn-Miller MO. Likelihood of positive urine screens of THC-COOH after daily use of full-spectrum hemp extracts varies as a function of screening criterion used. Ther Drug Monit. 2023;45(1):126–127.
   
3. Spindle TR, Cone EJ, Kuntz D, et al.Urinary pharmacokinetic profile of cannabinoids following administration of vaporized and oral cannabidiol and vaporized CBD-dominant cannabis. J Anal Toxicol. 2020;44(2):109–125. 
4. Sholler DJ, Spindle TR, Cone EJ, et al. Urinary pharmacokinetic profile of cannabidiol (CBD), Δ9-tetrahydrocannabinol (THC) and their metabolites following oral and vaporized CBD and vaporized CBD-dominant cannabis administration. J Anal Toxicol. 2022;46(5):494–503.
5. Zvorsky I, Kulpa J, Mechtler LL, et al. Urinalysis and perceived effects following 2-week use of a commercial broad-spectrum cannabidiol product. Exp Clin Psychopharmacol. 2024;33(1):62–67.
6. Bonn-Miller MO, Loflin MJE, Thomas BF, Marcu JP, Hyke T, Vandrey R. Labeling accuracy of cannabidiol extracts sold online. JAMA. 2017;318(17):1708–1709.
7. Spindle TR, Sholler DJ, Cone EJ, et al. Cannabinoid content and label accuracy of hemp-derived topical products available online and at national retail stores. JAMA Netw Open. 2022;5(7):e2223019.
8. Hart ED, Vikingsson S, Mitchell JM, et al. Conversion of 7-carboxy-cannabidiol (7-COOH-CBD) to 11-nor-9-carboxy-tetrahydrocannabinol (THC-COOH) during sample preparation for GC-MS analysis. J Anal Toxicol. 2022;46(5):573–576.
9. Kroner GM, Johnson-Davis KL, Doyle K, McMillin GA. Cannabinol (CBN) cross-reacts with two urine immunoassays designed to detect tetrahydrocannabinol (THC) metabolite. J Appl Lab Med. 2020;5(3):569–574.
10. Zamarripa CA, Tilton HE, Lin S, et al. Pharmacokinetics and pharmacodynamics of five distinct commercially available hemp-derived topical cannabidiol products. J Anal Toxicol. 2024;48(2):81–98.
11. Vikingsson S, Zamarripa CA, Spindle TR, et al. The acute and chronic pharmacokinetic oral fluid profile of oral cannabidiol (CBD) with and without low doses of Δ9-THC in healthy human volunteers. J Anal Toxicol. 2025.
12. Vikingsson S, Winecker RE, Cone EJ, et al. Prevalence of cannabidiol, Δ9- and Δ8-tetrahydrocannabinol and metabolites in workplace drug testing urine specimens. J Anal Toxicol. 2022;46(8):866–874.




† THC-Free means trace amounts less than 0.01% or 100 ppm.



^{*These statements have not been evaluated by the Food and Drug Administration. These products are not intended to diagnose, treat, cure, or prevent any disease.}