Lab shopping happens when producers send samples to the labs that return the highest THC numbers or the fewest contaminant failures. Labs compete for clients, and in a market where higher THC sells for more, there is pressure to deliver "good" numbers. The practice, not any individual lab, is the problem GenetixBay calls out.
In practice
Jikomes and Zoorob (2018) analysed Washington State's regulatory data and found that reported THC differed systematically between testing facilities, consistent with some labs reporting higher potency than others. Schwabe et al. (2023) bought retail flower and found that most samples tested below their label claims, many by a wide margin. A Colorado study (Giordano et al. 2025) found label accuracy varied with product type. Regulators in several states have responded with standardised methods, audits and recalls.
Don't confuse with
- Measurement uncertainty: honest random variation of a point or two, not a consistent upward bias.
- Getting a second opinion: retesting at an independent accredited lab to check a result is good practice.
Myth check
House position: lab shopping and label inflation are real and documented. Criticise the practice, never named businesses. See buyer beware and Mythbusters.
