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. 2025 Jul 1;15(1):20822.
doi: 10.1038/s41598-025-03854-3.

Accuracy of labeled THC potency across flower and concentrate cannabis products

Gregory Giordano  1 , Colin P Brook  2 , Marco Ortiz Torres  3 , Grace MacDonald  3 , Carillon J Skrzynski  4 , Jonathon K Lisano  3 , Duncan I Mackie  2 , L Cinnamon Bidwell  4   3
Affiliations

Accuracy of labeled THC potency across flower and concentrate cannabis products

Gregory Giordano et al. Sci Rep. .

Abstract

High total tetrahydrocannabinol (THC) cannabis products are quickly gaining market share across the U.S., but it is unknown whether labeled cannabinoid content accurately reflects true product potency. This study aimed to assess discrepancies between labeled and observed THC content in flower and concentrate products. A representative sample of 277 cannabis flower (n = 178) and concentrate (n = 99) products were purchased from 52 Colorado dispensaries and analyzed for THC content. Products were classified as accurately labeled if observed THC was within ± 15% of labeled THC, and comparative analysis tested observed versus labeled THC content. Labeling accuracy for THC content depended on product type (X2(2, n = 277) = 47.44, p < 0.001), with 96.0% of concentrate products being within ± 15% of labeled THC content compared to 56.7% of flower products. Observed THC potency was significantly lower than labeled potency in both flower (U = 18,971, p = 0.001) and concentrate (U = 6095, p = 0.003) products. Nearly all tested concentrate products met the accuracy threshold for THC content, whereas flower products frequently did not. Both product types had lower observed THC content compared to labeled values. Independent and blinded verification of product labels and testing procedures is needed to protect consumers and patients and ensure rigorous testing standards that apply across various types of cannabis products.

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Conflict of interest statement

Declarations. Competing interests: D.I.M. and C.B. were employees of MedPharm Holdings (dba Bud & Mary’s) during the study period. MedPharm Holdings is a U.S. Drug Enforcement Administration (DEA) and State of Colorado licensed cannabis research company and a bulk manufacturer of cannabis products for the Colorado adult-use marketplace. MedPharm Holdings has no stake in any products tests in this study. G.G., M.O.T., G.M., C.S., J.L., and L.C.B. declare no competing interests.

Figures

Fig. 1
Fig. 1
Heat map of cannabis product purchase locations. Flower and concentrate products were purchased from 52 recreational dispensaries across Colorado to be representative of current sale locations.
Fig. 2
Fig. 2
Distribution of labeled (a) and observed (.) THC by product type.
Fig. 3
Fig. 3
Percent difference between labeled and observed THC by product type.
See this image and copyright information in PMC

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