What is the difference between prescribed and shop-bought CBD?
The bottle on a high-street shelf and the preparation dispensed by a pharmacy can both be called CBD, and they are not the same kind of thing at all. The difference is regulatory, and it has real consequences for what is in the bottle.
The short answer
- Shop-bought CBD is regulated as a food supplement, not as a medicine.
- Novel food authorisation covers safety, not effectiveness for any condition.
- No health claims may lawfully be made for a CBD food supplement.
- Independent testing has repeatedly found content differing from the label.
- Prescribed preparations are pharmaceutical, with specified and tested content.
Two different regulatory worlds
A product's category determines what standards it must meet, what testing is required, and what may be said about it. CBD sits in two categories at once depending on how it is sold.
| Shop-bought CBD | Prescribed preparations | |
|---|---|---|
| Legal category | Food supplement (novel food) | Medicine — licensed or unlicensed |
| Regulator | Food Standards Agency | MHRA |
| What approval covers | Safety for consumption | Quality, and for licensed products, efficacy |
| Content verified batch to batch | Not required in the same way | Yes, to pharmaceutical standards |
| Health claims permitted | No | Only within the terms of a licence |
| Clinical oversight | None | Specialist prescriber and pharmacist |
The novel food route matters here. Authorisation under it is an assessment of whether a product is safe to eat. It is not a finding that the product works for anything, and it does not permit the seller to say that it does.
What is actually in the bottle
Independent analyses of consumer CBD products in the UK and elsewhere have repeatedly found actual content differing from the label — sometimes substantially less than stated, occasionally more, and in some cases detectable THC in products sold as THC-free.
That last point has practical consequences beyond value for money. A product containing more THC than its label suggests can create difficulties with workplace testing and, in principle, with driving.
It is also worth knowing that the amounts of CBD in typical consumer products are far below those used in the trials that established the licensed medicinal use of purified cannabidiol. Comparing the two as though they were the same intervention is not reasonable.
If you are already taking shop-bought CBD
Tell your prescriber and your GP. It is a substance with real pharmacological activity and real interactions, and it belongs on your medicines list.
CBD affects the enzymes that metabolise a number of other drugs, which means it can change the levels of medicines you are taking for something else. That is true regardless of where it came from.
None of this is an argument that shop-bought CBD is dangerous or that people should not use it. It is an argument for being clear about what it is: a supplement with variable content, no permitted health claims, and no clinical oversight — which is a different proposition from a prescribed medicine.
Frequently asked questions
Is shop-bought CBD the same as prescribed CBD?
No. Shop-bought CBD is regulated as a food supplement by the Food Standards Agency, which assesses safety for consumption rather than effectiveness. Prescribed preparations are medicines regulated by the MHRA with specified, tested content.
Can CBD products make health claims?
No. A CBD food supplement may not lawfully be advertised as treating or preventing any condition. Where you see such claims, they are being made in breach of the rules.
Does shop-bought CBD contain what it says?
Not always. Independent analyses have repeatedly found content differing from the label, including detectable THC in products sold as THC-free — which can matter for workplace drug testing.
Should I tell my doctor I take CBD?
Yes. CBD affects the enzymes that metabolise several other medicines and can change their levels in your body. It belongs on your medicines list wherever you bought it.
Sources and further reading
Every factual statement on this page is drawn from the following public sources. Links open in a new tab and are not affiliated with Flora House.