How does THC correlate with intoxication?

Does a milligram of THC in flower have the same effect as a milligram in an edible?

Yes, supposes the London, England, Mayor’s report. No, say Connecticut and the Marijuana Policy Group.

Yes, supposes the London Mayor’s report, as it aims for “a standard measure of one unit of THC, which would apply irrespective of method of administration and product (i.e. across cannabis flower/bud, resin, concentrated extracts and dabs, vape oils and edibles).” https://www.london.gov.uk/programmes-strategies/mayors-office-policing-and-crime-mopac/mopac-governance-and-decision-making/london-drugs-commission at 8.131. (You don’t have to click and click and “prove you are human” to see the copy at https://newrevenue.org/2025/07/14/london-mayors-report-on-cannabis/.)

No, says Connecticut, with differential tax rates for flower, edibles, and other products:

“Cannabis plant materials: Six hundred twenty-five-thousandths of one cent ($0.00625) per milligram of total THC, as reflected on the product labe

“Cannabis edible products: Two and seventy-five-hundredths cents ($0.0275) per milligram of total THC, as reflected on the product label; and

“Cannabis, other than cannabis plant material or cannabis edible products: Nine-tenths of one cent ($0.009) per milligram of total THC, as reflected on the product label.”

https://portal.ct.gov/drs/taxes/cannabis/cannabis-tax#calculation

The Connecticut tax rationale  comes from a 2015 study by Adam Orens at Marijuana Policy Group for Colorado, http://hermes.cde.state.co.us/drupal/islandora/object/co:29996/datastream/OBJ/view, which states, among other things:  “For concentrates, between 3.10 and 5.50 grams of concentrate are equivalent to an ounce of flower marijuana.”

London report, full paragraph:

8.131 We were pleased to hear about work currently underway in the UK to develop a standard measure of one unit of THC, which would apply irrespective of method of administration and product (i.e. across cannabis flower/bud, resin, concentrated extracts and dabs, vape oils and edibles). This could in future support education and guidance about the number of units, or milligrams, of THC, which is generally sufficient for an intoxicating effect but poses less risk of adverse side effects.