European Cannabis Got Stronger and Cheaper Per Milligram of THC Over a Decade | Research

The takeaway

From 2006 to 2016, cannabis resin potency in Europe more than doubled while price per milligram of THC dropped, meaning users got more THC for less money.

Policy makers, public health researchers, or anyone interested in how the European cannabis market has changed.

17.22%
Average THC in European cannabis resin by 2016, up from 8.14% in 2006

What the researchers found

Using data from 28 EU member states plus Norway and Turkey, researchers tracked three variables for both cannabis resin and herbal cannabis: potency (% THC), price (euros per gram), and value (milligrams of THC per euro).

Cannabis resin showed the most dramatic changes. Potency more than doubled from 8.14% THC in 2006 to 17.22% in 2016. Price also rose, from 8.21 to 12.27 euros per gram, but not fast enough to offset the potency increase — so the value (THC per euro) climbed from 11.0 to 16.4 mg per euro. Users were getting more THC for their money.

The timing was notable: resin potency and value were relatively flat from 2006 to 2011, then increased sharply from 2011 to 2016. Herbal cannabis potency also increased but more modestly. The net result: European cannabis markets delivered progressively more THC at progressively better value over the decade.

Why it matters

Price matters for public health. When a drug becomes more potent AND cheaper per unit of active ingredient, consumption patterns change. This study showed that European cannabis markets followed the same trajectory as alcohol markets in prior decades — products got stronger while the cost of intoxication dropped. That combination historically increases population-level harm.

The 2011 inflection point in resin potency suggests something changed in production or supply chains around that time. The researchers didn't identify the cause, but the acceleration coincided with innovations in cannabis resin production techniques.

The numbers in context

• Resin potency: 8.14% THC (2006) → 17.22% (2016)

• Resin price: €8.21/g (2006) → €12.27/g (2016)

• Resin value: 11.0 mg THC/€ (2006) → 16.4 mg THC/€ (2016)

• Herbal cannabis potency also increased, but more modestly

• Data from 30 countries over 11 years

How the study worked

Repeated cross-sectional study using data collected by the European Monitoring Centre for Drugs and Drug Addiction (EMCDDA) from 28 EU member states, Norway, and Turkey. Price adjusted for inflation using Harmonised Indices of Consumer Prices. Mixed-effects linear regression with random intercepts and slopes to account for variation across countries.

Who was studied

Data collected from 28 EU member states, Norway, and Turkey.

What this study cannot tell us

Data quality varied across 30 countries with different collection methods. Potency measurements came from seized samples and may not represent retail purchases. Cannot determine whether consumers adjusted their intake in response to potency changes. Does not cover legal market products, which emerged in some countries during this period.

How to read the evidence

Large dataset across 30 countries with rigorous statistical modeling. Strong for trend identification, limited by variation in national data collection methods.

When this study was published

Published in 2019 with data through 2016. European cannabis markets have continued evolving, particularly in countries that have since moved toward legalization.

The bigger picture

Combined with the U.S. potency data (RTHC-00039 and RTHC-00049), this study confirms that rising cannabis potency is a global phenomenon, not limited to one country or market type. The economics angle — THC getting cheaper — adds a dimension that pure potency studies miss. Public health frameworks from alcohol and tobacco research suggest that when intoxicants become simultaneously stronger and more affordable, use and harm both increase.

Replication

Not stated in abstract.

Funding

Not reported in abstract.

Conflicts of interest

Not reported in abstract.

Questions still open

What caused the sharp acceleration in resin potency after 2011?
Do consumers titrate their intake as potency rises, or do they simply consume more THC?
Would minimum pricing policies for cannabis (similar to alcohol) reduce population-level harm?

Common questions

Is cannabis getting stronger in Europe too?

Yes. Resin potency more than doubled from 8% to 17% THC between 2006 and 2016, with a sharp acceleration after 2011. Herbal cannabis also increased.

Is stronger cannabis more expensive?

Yes per gram, but no per unit of THC. The price of a milligram of THC actually dropped, meaning users got more bang for their buck.

Read the original research

Increasing potency and price of cannabis in Europe, 2006-16.

Addiction (Abingdon, England), 114(6), 1015-1023

Addiction is a well-respected journal focusing on substance use and addiction research.

View on PubMed ↗Publisher’s paper ↗

Citation

Freeman, Tom P; Groshkova, Teodora; Cunningham, Andrew; Sedefov, Roumen; Griffiths, Paul; Lynskey, Michael T. (2019). Increasing potency and price of cannabis in Europe, 2006-16.. Addiction (Abingdon, England), 114(6), 1015-1023. https://doi.org/10.1111/add.14525