Last week, the US government voted to impose a blanket ban on all so-called ‘intoxicating hemp’ substances, ending what has been a contentious and long-running battle to regulate the recent emergence of THC substitutes.
These substances, which include a broad and rapidly increasing array of compounds like HHC, Delta 8 THC, THCA and others, have emerged and spread across the globe far more rapidly than regulation is able to keep pace with.
While the outright ban in the US, where these substances supported a grey-market worth an estimated $30bn, has been criticised as short-sighted, their young lifespan and semi-synthetic production mean we have very little scientific understanding of their effects.
European states have also quickly moved to prohibit these substances, with the notable exception of the Czech Republic, which has made efforts to categorise, regulate and study them.
Now, the European Food Safety Authority (EFSA) has issued its first comprehensive assessment of Delta 8 tetrahydrocannabinol (Delta 8 THC or Δ8-THC), concluding that it should be regulated using the same acute reference dose as Delta 9 THC in food
However, perhaps more importantly, it highlights the severe lack of basic scientific understanding of the cannabinoid, including whether it occurs naturally at all.
While consumer safety is paramount, this early research shows that global policy is being shaped around a substance for which key toxicological, analytical, and even botanical questions remain unresolved.
A crucial first scientific step
The European Commission asked the European Food Safety Authority to conduct its first full scientific assessment of delta-8 THC in response to rising detections of the cannabinoid in hemp-derived foods and growing questions over whether existing safety limits for delta-9 THC should also apply to its isomer.
EFSA explains that ‘besides Δ9-THC, also Δ8-THC have been found in hemp-derived foods, sometimes in significant amounts’, prompting uncertainty over whether the current acute reference dose for Δ9-THC ‘is also relevant for Δ8-THC’ or whether ‘a separate Health Based Guidance Value (HBGV) for Δ8-THC needs to be derived’.
In its assessment, made on November 18, 2025, EFSA was tasked with establishing whether a new health-based guidance value (HBGV) was needed for Δ8-THC, or whether it could be categorised using the existing framework for Δ9-THC.
This new evaluation therefore serves to fill a regulatory gap created by the rapid emergence of Δ8-THC in consumer products across global markets. The panel was asked to clarify potency, toxicology and natural occurrence, and to provide updated guidance for national authorities and food operators.
Key Knowledge Gaps Highlighted By EFSA
EFSA identifies a fundamental absence of controlled human data at relevant exposure levels, stating that ‘no appropriate studies in the low-dose range (<10 mg/person) were available to identify a reference point for Δ8-THC’.
Because of this lack of information, the panel based its hazard characterisation almost entirely on read-across from Δ9-THC and a single controlled study involving healthy adults.
It also notes that standard genotoxicity assays ‘are not available’ for Δ8-THC and that evidence on developmental and reproductive toxicity is limited to a small number of animal studies with methodological constraints. It reports ‘adverse effects… observed in the reproductive system… although the studies have limitations’.
Uncertainty also extends to neurotoxicity and endocrine endpoints, prompting EFSA to recommend further assessment, including a broader update of Δ9-THC toxicology, as this underpins its evaluation of Δ8-THC.
Although the dataset is limited, EFSA concludes that Δ8-THC acts through the same biological pathways as Δ9-THC, noting that ‘the effects of Δ8-THC are likely mediated by its activity as agonist for CB1 and CB2 receptors… similar to Δ9-THC’.
Available clinical studies show ‘psychotropic, psychomotor and cognitive effects along with physiological responses such as increased heart rate’ at oral doses between 10 mg and 75 mg.
Using a single crossover study in 19 adults, EFSA found Δ8 potency to be within the same range as Δ9, concluding that ‘Δ8-THC is equally or slightly less potent than Δ9-THC’ and adopting a relative potency factor of one.
As such, the regulator confirmed that its existing acute reference dose of 1 microgram per kilogram of body weight, originally set for Δ9-THC, now applies to the sum of both cannabinoids. It states that ‘given the similarity in the effects and the mode of action… the ARfD derived for Δ9-THC can be considered applicable as a group ARfD for both compounds’.
Adverse Events Highlight Risks In Unregulated Products
EFSA’s review of international case reports includes several involving young children, with Δ8-laden gummies described as ‘food-like products such as gummies that resemble popular sweets’. These exposures produced ‘serious adverse effects, especially in children… bradypnoea, lethargy and unresponsiveness’.
While not suitable for dose-response modelling, EFSA notes that these cases demonstrate the potential severity of intoxication when Δ8-THC is present in attractive, unregulated formats.
The assessment doesn’t argue against regulation, EFSA’s role is risk assessment, not risk management. However, it does highlight how policy often precedes science in cannabinoid regulation, with bans implemented before basic questions about occurrence, safety thresholds, and long-term effects receive definitive answers.
The delta-8 situation mirrors broader challenges in cannabis policy: demands for regulatory action on novel compounds that science hasn’t yet fully characterised, detection methods that may create the substances they’re meant to measure, and safety assessments based on limited human data extrapolated from animal studies using non-oral routes of administration.
Whether policymakers will allow science to catch up to policy remains uncertain as jurisdictions worldwide continue implementing bans on compounds that regulators now acknowledge they don’t fully understand.
