A “standard drink” is conventionally defined as the alcohol content of 12 ounces of 5%-alcohol beer or 5 ounces of 12%-alchol wine or an ounce and half (a shot) of 40%-alcohol (80-proof) whiskey: that is, about six-tenths of an ounce of absolute alcohol.

That helps consumers think about how much they’re putting away: a drinking binge is defined as four drinks for an average-sized woman or five for an average-sized man, which (depending on pacing) is enough to get someone above the .08 that constitutes legal intoxication.

Now imagine – just hypothetically, of course – that a state wanted to design a legal distribution system for cannabis. You’d want consumers to know the relative strengths of different cannabis products consumed in different ways (smoking, vaporizing, eating, drinking, sublingul, topical).

In particular, it would be helpful to define a “serving” of edible cannabis. For example, you might want to define a “serving” as containing the same bioavailable content of THC as a single puff of a joint of some sort of “standard cannabis.”

Or, since drinking is more common than cannabis use and since a legal system might well attract some cannabis-naive users, you might want to label cannabis products in terms of their alcohol-equivalent mood-altering power (necessarily inexactly, since the two altered states are dissimilar and since THC isn’t the sole active agent in cannabis).

That would have the additional advantage of hinting that cannabis use need not always be to the point of intoxication, any more than drinking need be.

So, a technical question: how many milligrams of THC, by lung, have the equivalent mood-altering power of a standard drink?

[Originally posted at The Reality-based Community]

Mark Kleiman

Mark Kleiman is a professor of public policy at the New York University Marron Institute.