
Professor Herb
Professor Herb Hemp Briquette Hash 3.5g, Guava Dog
The Guava Dog flavour in the Professor Herb briquette range, a 3.5g heat-pressed block of Italian hemp material infused with terpenes. Tropical guava over a green hemp base. 18+ only.
£43.49
£14.50 each
In stock. Delivered in 3 to 7 working days
- Free UK delivery over £40
- Third-party lab-tested
- Plain, discreet packaging
- Over-18s only, age-checked
- Extract
- Isolate
- Format
- Hash
- Sold as
- Pack of 3
Professor Herb Hemp Briquette Hash 3.5g Guava Dog is a heat-pressed block of Italian hemp material infused with terpenes, in a tropical guava flavour. Every shop selling it, including this one, states that it has been analysed and tested by Adact Medical, and there is a QR code on the card that opens the result. Nobody says who Adact Medical are or what is worth reading once the code opens, and both turn out to be worth knowing.
Who Adact Medical actually are
Adact Medical is a testing laboratory based in South Yorkshire, established in 2012. Alongside cannabinoid testing it does regulatory work: Novel Foods applications, cosmetics notifications, stability programmes, batch quality assurance, and a long-standing line of compliance testing for the vape trade.
The part that matters is the accreditation. Its laboratory holds UKAS ISO/IEC 17025:2017 accreditation for CBD profile testing. That standard is the international requirement for the competence of testing laboratories, and UKAS is the United Kingdom Accreditation Service, the national body recognised by government to assess against it. It is not a membership scheme, a self-declaration or a phrase a company can simply adopt.
The testing itself uses high-performance liquid chromatography, and the published panel covers sixteen cannabinoids rather than a single figure for CBD.
Adact publish a caveat of their own that is worth repeating, because it is the sort of thing companies usually leave out: their accreditation is limited to the activities described on their UKAS schedule of accreditation. In other words, accreditation covers defined work rather than acting as a blanket endorsement of everything an accredited company does. We would rather point at that limit than pretend it is absent.
After six pages spent correcting things about this range, from a flavour name that arrived in two halves to a description that calls the same material both bulk plant and sifted resin, it is a pleasure to report that the credential printed smallest on the card is the one that stands up.

The certificate holds numbers the label leaves out
This is the useful part, and it resolves something we could only half answer on another page in this range.
The compliance wording printed on these packs, and copied by every shop selling them, refers to a limit of one milligram of THC. We have set out on our Wedding Cake page why that is narrower than the rule it is describing: the exempt product route in the Misuse of Drugs Regulations 2001 turns on controlled cannabinoids counted together, and that category includes CBN and THCV as well as THC. A statement about THC alone does not address the others.
Adact's published cannabinoid panel names sixteen compounds, and both Cannabinol and Tetrahydrocannabivarin are explicitly on it, alongside CBD, CBDA, CBDV, CBDVA, CBG and the rest. So the analysis behind the QR code very likely reports all three of the figures the rule cares about, even though the front of the pack mentions only one of them.
That turns a complaint into something you can act on. If the compliance question matters to you, do not read the sentence on the card. Scan the code, find THC, THCV and CBN on the profile, and consider them together against the pack rather than individually.
Two honest limits on that. We have not seen a certificate for any particular batch of this product, so everything above describes what the laboratory publishes about its service rather than any result. And a profile reports concentrations, so getting from those to a figure for a whole container is arithmetic somebody still has to do. Our lab reports page sets out how we handle certificates generally.
| On the pack | On the published panel | |
|---|---|---|
| THC | Named in the compliance sentence | Included |
| CBN | Not mentioned | Named as Cannabinol |
| THCV | Not mentioned | Named as Tetrahydrocannabivarin |
| CBD | 175mg stated for the pack | Included, with CBDA |
| Others | None named | CBDV, CBDVA, CBG and further compounds, sixteen in total |
What a QR code on a hemp pack can and cannot tell you
A code on packaging is only as useful as what sits behind it, and there is a wide range in this trade. At one end it opens a document naming a batch, a date, a laboratory and a set of measured figures. At the other it opens a marketing page, or a single certificate that stands in for an entire product range regardless of when anything was made.
The things worth checking when one opens are straightforward. Does it name the laboratory. Does it name a batch or lot rather than just a product. Does it carry a date, and how old is that date. Does it list individual cannabinoids or only a total. And does the product on the certificate match the product in your hand, including the weight.
A certificate that fails those tests is not necessarily a sign of anything wrong, but it does mean the code is decoration rather than evidence, and you should weigh it accordingly.
On this range the underlying testing is done by an accredited laboratory, which is a better starting point than most. What we cannot tell you from here is what any individual card's code resolves to on the day you scan it, because that is a question about a batch rather than about a product.
What Guava Dog tastes like
Guava is the lead and it is a distinctive one. It is a softer, muskier tropical note than pineapple, with a slightly floral, almost perfumed edge and a sweetness that is rounder and less sharp. If you have had guava juice, that is the register: fruity but heavier than citrus, and a little unusual.
The Dog part of the name gestures at the Chemdog family, the same way OG does elsewhere in the range, and it suits the profile in that there is an earthy, faintly savoury note underneath the fruit. Against the sweeter flavours it is the most complex of the ones we stock, and the least likely to read as a sweet shop.
The hemp base sits comfortably with it. The muskiness of the guava has enough weight not to be flattened by the green, resinous character of the pressed material, so this is one of the more balanced flavours in the range rather than one where the infusion fights what is underneath.
The manufacturer's own description of it, as for every flavour we have checked, runs to four or five words. Ours does not.
| Flavour | Register | Sweetness |
|---|---|---|
| Guava Dog (this page) | Musky tropical fruit with an earthy note beneath | Moderate and rounded |
| Pineapple Express | Sharp tropical fruit | Moderate, acidic |
| Forbidden Fruit | Dark berry and stone fruit | Higher |
| Gelato | Creamy dairy dessert | High, soft |
| Bubba Gum OG | Confectionery bubblegum | Highest |
Who should choose differently
If you want something simple and immediately recognisable, guava is the least familiar flavour in the range and its musky, faintly floral quality divides people more than the sweet ones do.
If you want a concentrate, this is not one. The stated content here is 175mg in 3.5g, and the solid extracts and washed grades on our hemp and hash shelf state several times that.
If you want something usable straight from the container, a briquette is a solid block and needs breaking down first. The brand's loose Premium Hemp Blend is the same material ready to use.
If you are buying partly for the flavour and it will sit unopened for a long time, read our Gelato page first, which covers what happens to an infused aroma over time and how to slow it down.
Over-18s only. This is not a food and it is not a medicine, and nothing here should be read as suggesting otherwise.
Questions people ask
Who are Adact Medical, the laboratory named on Professor Herb packs?
A UK testing laboratory based in South Yorkshire and established in 2012. Alongside cannabinoid testing they handle Novel Foods applications, cosmetics notifications, stability programmes and batch quality assurance, and they have a long history in vape compliance testing. Their laboratory holds UKAS ISO/IEC 17025:2017 accreditation for CBD profile testing.
What does UKAS ISO 17025 accreditation actually mean?
ISO/IEC 17025 is the international standard for the competence of testing laboratories, and UKAS is the United Kingdom Accreditation Service, the national body recognised to assess laboratories against it. It is an external assessment rather than something a company can award itself. Adact also state that their accreditation is limited to the activities on their UKAS schedule, which is a useful reminder that accreditation covers defined work rather than everything a company does.
Which cannabinoids does the Professor Herb analysis cover?
The laboratory publishes a panel of sixteen, run by high-performance liquid chromatography. Named on it are CBD, CBDA, CBDV, CBDVA, CBG, Cannabinol and Tetrahydrocannabivarin among others, so it is a profile rather than a single reading for CBD. That breadth is the reason the certificate is more informative than the summary printed on the card.
Does the certificate cover the cannabinoids the pack does not mention?
On the laboratory's published panel, yes. The compliance line on these packs refers only to THC, while the UK exempt product test counts controlled cannabinoids together, meaning CBN and THCV as well. Both of those are explicitly named on the panel, so the analysis behind the QR code very likely reports all three. We have not seen a certificate for any particular batch, so that describes the published service rather than a result.
What should I look at when a QR code on a hemp pack opens?
Check that it names the laboratory, names a batch or lot rather than only a product, carries a date and that the date is recent, lists individual cannabinoids instead of one total, and describes the same product and weight you are holding. A code that fails several of those is decoration rather than evidence, which does not mean anything is wrong but does mean it proves less than it appears to.
What does Guava Dog taste like compared with the other flavours?
Guava is softer and muskier than a citrus or pineapple note, with a faintly floral edge and a rounder sweetness, and there is an earthy, slightly savoury note underneath that suits the Chemdog reference in the name. It is the most complex flavour of the ones we stock and the least likely to read as confectionery, which makes it either the most interesting or the most divisive depending on what you want.
Does an accredited laboratory guarantee the pack I receive is compliant?
No, and it is worth being clear about that. Accreditation says the laboratory is competent to perform the tests on its schedule. It says nothing on its own about any particular batch, about how a result was interpreted, or about what happened between testing and packing. It raises confidence in the measurement, which is genuinely worth something, but a certificate for the batch in your hand is the document that speaks to your pack.
Why does no shop selling this explain who tested it?
Because nearly all of them paste the manufacturer's copy without adding to it, and that copy names the laboratory without describing it. The same is true of the flavour blurbs, the packaging description and the compliance sentence, all of which appear word for word across the listings. The name has been printed on every pack in this range for years without anyone selling it saying what it signifies.
Updated July 2026
Delivery and returns
3 to 7 working days
UK delivery from the day payment clears
£3.95, free over £40
Standard delivery
14 days
To change your mind, unopened
- How long will my order take?
- Delivery takes 3 to 7 working days from the day your payment clears. Orders placed at a weekend or on a bank holiday count from the next working day.
- What does it cost?
- Standard UK delivery is £3.95, and free on orders over £40. The threshold is worked out on the order total after any discount.
- Will the packaging say what is inside?
- No. Everything ships in plain, unbranded outer packaging with no reference to CBD or to GoCBD on the outside. Only the delivery label is visible.
- Do you deliver outside the UK?
- Not at the moment. CBD import rules vary widely by country and we would rather not have your order seized. UK addresses only, including Northern Ireland.
- Can I return something?
- Yes. You have 14 days from delivery to change your mind, and another 14 days to send it back. It needs to be unopened and unused, with any seal intact.
- What if it is sealed?
- Consumables are exempt from the automatic right to return once opened, on hygiene grounds. If a seal is broken we cannot resell it, so please check the strength and flavour before you open it.
- What if it arrives damaged or wrong?
- Email a photo to orders@gocbd.co.uk within 48 hours and we will replace it or refund it in full, including the delivery you paid. That is separate from the change-of-mind window and applies whether or not the item is opened.
- Do I have to be 18?
- Yes. We sell to over-18s only and verify age at checkout. Deliveries may be age-checked on the doorstep, so someone over 18 needs to be there to take it.
The full policy is on the delivery and returns page.
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