A Higher Edible Dose Did Not Produce a Higher Mean Blood THC Peak in Every Group
A 50 mg edible THC dose did not produce a higher mean whole-blood THC peak than 25 mg in a small between-group study. That observation does not show reversed absorption or make blood concentration a reliable dose calculator.
Only six people received each dose
Healthy adults without recent cannabis use received brownies containing 10, 25 or 50 mg THC, with six participants per dose. Blood and oral fluid were collected repeatedly, and subjective and performance effects were assessed during the initial eight hours.
Unlike a crossover comparison, different people received the different doses. The influence of between-person absorption and metabolism therefore remained important when comparing group averages.
The mean concentration pattern was not a dosing rule
Mean maximum whole-blood THC was approximately 1 ng/mL after 10 mg, 3.5 ng/mL after 25 mg and 3.3 ng/mL after 50 mg. These small-group means do not establish that the highest dose generally yields less systemic exposure.
Subjective and cognitive effects were broadly dose-related, while associations between concentrations and cognitive measures were not consistently significant or orderly by dose. Oral-fluid parent THC peaked immediately after ingestion, consistent with local residue rather than simultaneous peak systemic exposure.
Why back-calculating dose is uncertain
The small sample and selected healthy infrequent users limit generalization. Food, formulation, co-medications and prior use can influence responses. A concentration drawn at another time also need not represent the person’s maximum.
Accordingly, one whole-blood THC value cannot identify a precise edible dose from these averages. Nor can a low result alone exclude functional effects. The study supports keeping measured concentration, administered dose and observed response distinct rather than forcing them into a single proportional conversion.
Related: Why concentrations do not establish functional impairment.
Primary research
Pharmacokinetic Profile of Oral Cannabis in Humans: Blood and Oral Fluid Disposition and Relation to Pharmacodynamic Outcomes. Journal of Analytical Toxicology (2017).
