Where the other cannabinoids come from
Almost every cannabinoid in a plant comes from the same molecule. It is called CBGA, and its defining characteristic is that it does not stay: the plant consumes it to build something else.
That is why it is simultaneously central and scarce. On an ordinary flower at maturity almost none remains — a few tenths of a per cent, often less than the laboratory’s limit of quantification.
This page covers what precursor means precisely, how the plant builds and then spends it, why so little survives, what a certificate shows, and why products featuring it carry the prices they do.
⚠️ Scope. This page describes a process and what can be verified from documents. It does not describe what a product does to a person, gives no amounts, and does not replace a healthcare professional.
🔴 What precursor means
In chemistry
A substance that yields another through transformation. It is consumed in the process — unlike a catalyst, which would emerge unchanged.
Applied here
CBGA is the common starting point. Three enzymatic routes lead away from it, producing THCA, CBDA and CBCA respectively.
What this implies
The more the plant converts, the less remains. A high CBD content mechanically means the precursor was largely spent.
The shortcut to avoid
Mother molecule is a convenient and inexact image. This is not a lineage but an enzyme substrate, and the distinction matters when reading a report.
How the plant builds it
The assembly
Two building blocks from separate metabolic pathways are joined: a fatty-acid derivative and a terpene chain. The result is cannabigerolic acid.
Where it happens
In the cells of the secretory disc at the base of the glands. The product is then pushed into the pocket beneath the cuticle.
When
Early in flowering, before conversion accelerates. The peak of CBGA sits well before the usual harvest window.
What follows
Enzymes take over and transform the accumulated stock. The CBGA curve rises, peaks, then falls back toward almost nothing.
Acid and neutral
CBGA and CBG
The first is what the plant contains. The second appears when the first loses a carboxyl group, under heat or over time.
Why the distinction matters commercially
A label announcing CBG without stating the form leaves an ambiguity. On raw flower, what is present is CBGA.
The parallel with THC
The same mechanism is why total THC is calculated: delta-9-THC plus THCA multiplied by 0.877. The factor comes from the difference in molar mass.
What a good certificate does
Lists both rows separately and lets the reader add them if needed, rather than presenting a single figure with an unstated convention.
The three branches
Toward THCA
An enzyme closes a ring and produces tetrahydrocannabinolic acid. This is the route with regulatory consequences.
Toward CBDA
A different enzyme closes the molecule differently. The resulting structure is related but not identical, and it behaves differently.
Toward CBCA
A third, quieter route yields cannabichromenic acid. It appears in small quantities on many certificates.
What remains
The unconverted fraction. It is what gets measured and sold under the CBG name.
What decides the branch
Genetics
The variety determines which enzymes are produced and in what proportion. This is the dominant factor by a wide margin.
The European catalogue
Varieties listed in the common catalogue of agricultural plant species are selected to stay below the regulatory THC threshold. The THCA branch is reduced by that selection.
Crop management
It modulates total quantities without changing relative proportions. More light gives more of everything, not a different profile.
What decides nothing
Drying method or storage. They act on degradation afterwards, not on the initial distribution.
🔴 Why so little survives
The stock is spent
A mature plant has converted nearly all its CBGA. What remains is measured in tenths of a per cent.
The timing trade-off
Harvesting early retains CBGA but leaves everything else unfinished. Harvesting late gives a complete flower and almost no precursor.
The consequence for price
Obtaining a useful quantity requires either a dedicated variety or an early harvest that sacrifices yield. Both cost.
The order of magnitude
A CBG isolate commonly sells for several times the price of a CBD isolate. The difference rests entirely on this scarcity.
Varieties selected for it
The principle
Plants are selected whose conversion enzymes function poorly or not at all. The stock accumulates instead of being spent.
What that produces
Flowers testing at several per cent CBGA with very little CBD or THC. The profile is unusual and immediately recognisable on a certificate.
The regulatory advantage
A plant that does not convert produces little THCA. Staying within the threshold is easier by construction.
The drawback
These varieties are newer, fewer in the catalogue, and their availability remains irregular.
What a certificate shows
The expected rows
CBDA, CBD, THCA, delta-9-THC, CBGA, CBG, CBN, CBC. A complete report lists them all, including those below threshold.
The method
Liquid chromatography with a suitable detector. The laboratory should be accredited to ISO/IEC 17025 for the result to carry weight.
What to check first
The batch number. A certificate that does not carry the number printed on the packaging says nothing about the product in hand.
The date
A report has an age. On material that changes, a two-year-old document no longer describes the current contents.
Reading the CBGA line
The direct reading
Find the CBGA row and read the mass percentage. On an ordinary flower it will be very low or noted below the limit of quantification.
What LQ means
That the substance is not quantifiable by the method used, not that it is absent. The distinction is important and frequently misread.
The useful sum
To know the total potential, add CBGA and CBG. The first becomes the second under heat.
The ratio between them
A large acid fraction indicates material little heated and little aged. A large neutral fraction indicates the opposite.
What CBG is not
Not an improved CBD
They are distinct molecules with different structures. Neither is a superior version of the other.
Not a documented benefit
The EU Register of nutrition and health claims contains no authorised entry for cannabidiol to this day, and none for cannabigerol either.
Not a new discovery
The molecule has been described since the nineteen-sixties. What is recent is commercial interest in it, not knowledge of its existence.
Not a quality guarantee
A CBG content says nothing about pesticides, heavy metals or residual solvents. Those are other lines on the same report.
The regulatory position
Food
An ingested product falls within the scope of rules on novel foods. The authorisation question arises the same way as for cannabidiol.
Cosmetic
An applied product falls under cosmetics rules, with its own labelling obligations and product information file.
Labelling
Food information rules require an ingredient list, a net quantity and an identifiable operator. That applies here as everywhere.
What stays constant
The total THC threshold does not depend on which molecule is being marketed. A CBG-rich flower is subject to it like any other.
Why claims are a problem here
The principle
No statement of benefit may accompany a product without an authorisation entered in the European register. The absence of an entry functions as a prohibition.
What appears regardless
Circumvented phrasing, testimonials, references to studies. These are assertions rather than authorised data.
The sign that settles it
An authorisation number. Without one there is no valid claim, whatever the wording.
The defensible position
Describing a material, a content, a process and a document. Everything beyond that leaves the framework.
Price and what it reflects
Agricultural scarcity
A dedicated variety, lower yield, a narrower supply chain. Three reasons the cost rises before any processing.
Purification
Isolating a minor molecule takes more steps than isolating a major one. Each step has a cost and a loss.
What does not justify it
Simply being less common. A high price on a low content remains poor value, whatever the molecule.
The right reflex
Reduce to milligrams. A forty-euro bottle holding three hundred milligrams costs more per milligram than a sixty-euro bottle holding a thousand.
The formats available
Flower
Dedicated varieties sold like any other flower, with a batch certificate. The CBGA content is readable directly.
Oil
An extract diluted in a carrier oil. The content is stated as a percentage or in milligrams per bottle, and the two should reconcile.
Isolate
A crystalline powder of high purity. It contains one molecule, without terpenes or other cannabinoids.
Broad spectrum
An extract with the THC removed and the rest retained. The exact composition should appear on the certificate, row by row.
What separates two offers
Batch transparency
A dated certificate, specific to the lot, from an accredited laboratory, matching the number printed on the packaging.
Consistency of figures
The content on the label should appear in the report. An unexplained gap is sufficient reason to look elsewhere.
The THC line
Always check the calculated total, not just the delta-9 row. The sum is what the limit applies to.
The seller
Company name, address, contact. Without those three there is nobody to address if something is wrong.
Where the conversion curve sits
The shape
CBGA accumulates during early flowering, reaches a maximum, then falls as the enzymes consume it. By the conventional harvest window the curve is well down its descending side.
Why growers do not chase the peak
Because everything else is unfinished there. The flower has not developed, the yield is a fraction of what it will be, and the aroma profile has not formed.
What a dedicated variety changes
It flattens the descending part of the curve, because the enzymes that would consume the stock are impaired. The peak becomes a plateau that survives to harvest.
What this means at purchase
A CBGA figure of several per cent indicates a dedicated variety almost certainly. A figure of tenths indicates residual precursor on an ordinary one.
The isolate market
What is sold
A crystalline powder of high purity, produced by extracting and then purifying away everything else. It contains one molecule and nothing that came with it.
Why purification costs more here
Isolating a minor component means processing far more starting material for the same output, and each purification step carries a loss.
What the certificate should show
A purity figure, the residual solvent panel if solvents were used, and the batch number. All three, or the document is incomplete.
The comparison that matters
Price divided by milligrams of the named molecule. On isolates the arithmetic is unusually clean, because there is only one component to count.
What the minor cannabinoids share
The common position
CBG, CBN, CBC and their acid forms all appear in small quantities on ordinary flower, frequently below the limit of quantification.
Why they are marketed now
Because the market for the major cannabinoids is crowded and the minor ones are differentiable. That is a commercial reason rather than a technical one.
What is true about them
They exist, they are measurable when present in quantity, and their scarcity is genuine. All three statements are supportable.
What is not
Anything about what they do. The European register contains no authorised entry for any of them, and the absence functions as a prohibition rather than a gap.
A short glossary
CBGA
Cannabigerolic acid. The form present in the living plant and the precursor to the other cannabinoids.
CBG
Cannabigerol. The neutral form, produced when the acid loses its carboxyl group under heat or over time.
Synthase
An enzyme catalysing a transformation. Here, those directing the precursor into one of three branches.
Decarboxylation
Loss of a carboxyl group under heat, converting an acid form into a neutral one.
Limit of quantification
The threshold below which a laboratory does not report a figure. Noted LQ, it means not measurable rather than absent.
The five checks that apply to any product
The batch certificate
Request it with the number printed on the packaging. A general document for the product line does not cover this batch, and those differences are exactly what it should record.
Total THC
Delta-9-THC plus THCA multiplied by 0.877, because THCA becomes THC under heat and the limit applies to the sum, not to either value alone.
Price per milligram
A division, not an opinion. The only figure that makes two products comparable, whatever the format, process and pack size.
The claims
Without an authorisation number in the EU Register these are assertions, not data — and for cannabidiol that register contains no authorised entry to this day.
The seller’s details
Company name, address and contact. Without them there is also no counterparty to turn to if something turns out to be wrong.
How this connects to the rest
With harvest timing
The trade-off between residual CBGA and flower maturity is decided entirely there. Cutting early or late is not an aesthetic preference.
With decarboxylation
What turns CBDA into CBD turns CBGA into CBG. Same mechanism, same temperatures.
With reading a certificate
Acid and neutral rows are read together. That holds for this molecule as for every other on the same report.
With price per milligram
On scarce molecules the division changes the ranking of offers most sharply. It is correspondingly more useful.
What this is for in practice
To understand a profile
A high CBGA figure signals either a dedicated variety or an early harvest. Both have explanations.
To spot an inconsistency
A flower advertised as very high in CBD while showing substantial residual CBGA raises a question. Conversion cannot be both complete and unfinished.
To compare two oils
Add the acid and neutral forms, convert to milligrams, divide by price. The rest is presentation.
To avoid paying for novelty
A less common molecule is not thereby better. The content-to-price ratio remains the only judge.
Frequently asked questions
What is CBGA? Cannabigerolic acid, the molecule from which the plant builds most of the other cannabinoids.
Why is it called the mother molecule? It is an image. The precise term is precursor: a substance consumed in producing another.
What is the difference between CBGA and CBG? The acid and neutral forms. Conversion happens under heat or over time.
Why is so little left in a flower? Because the plant has spent it. At maturity almost the whole stock has gone toward CBDA or THCA.
Why does CBG cost more? Agricultural scarcity and longer purification. It needs either a dedicated variety or an early harvest with reduced yield.
Do CBG-rich varieties exist? Yes, selected so that the conversion enzymes function poorly. The stock accumulates instead of being spent.
What does LQ mean on the CBGA row? That the value is below the laboratory’s limit of quantification. Not measurable, not absent.
Can a benefit be claimed for CBG? No. The European register contains no authorised entry for it, any more than for cannabidiol.
How do I compare two CBG products? Add CBGA and CBG, convert to milligrams, divide by price, then check the certificate carries the batch number.
Is CBG a recent discovery? No. It has been described since the nineteen-sixties. The commercial interest is what is recent.
What we check and what we do not
We check what can be checked from documents: official registers, declared contents, certificates of analysis, arithmetic. We test no products, rank nothing, and assert no effects.
This molecule is instructive because its scarcity is real and documented, while what is said about it otherwise is not. The high price is explained by agronomy and purification. Nothing else in the commercial narrative rests on an equivalent basis.
What stays verifiable amounts to three lines on a report: the acid content, the neutral content, and the batch number tying the document to the product. The rest is story.