Cannabinoid receptors and the entourage effect

The grades. Which receptors exist, and how a compound behaves at one in the laboratory, is science that can be stated with a grade. What a product does for a person is a claim, and it belongs to whoever makes it ("marketed as…," "proponents suggest…"), limits attached. From strongest to weakest: the six-rung evidence ladder. Where no verified study exists, the topic stays open as catalogue in progress. Grade chips link through to /evidence. None of it is medical, legal, or professional advice.

The targets cannabinoids act on

Start with the targets, because cannabinoids have no single "switch." They act at the two cannabinoid receptors, CB1 and CB2, and at a wider set of non-cannabinoid targets, and both the receptors and those interactions are well established. What each individual cannabinoid does at each target has to be settled study by study, and for many of the minor cannabinoids that work is still catalogue in progress.

The two cannabinoid receptors (CB1 and CB2): Established.

• CB1 sits mainly in the brain and nervous system. THC produces its intoxicating "high" as a partial agonist at CB1, which in effect switches the receptor on. In laboratory studies CBG does the reverse and acts as a CB1 competitive antagonist, blocking the receptor instead of activating it (Cascio 2010). Demonstrated · in vitro Which fits: CBG doesn't intoxicate.
• CB2 is found mostly on immune cells and in peripheral tissue, and its standing as a cannabinoid receptor is settled. CBG's specific activity at CB2 is catalogue in progress, and without a verified study CBG Atlas makes no claim about it.

Beyond the cannabinoid receptors. Several cannabinoids act further afield, and CBG makes a good worked example because two verified laboratory studies map its profile:

• 5-HT1A serotonin receptor. In vitro, CBG acts as an antagonist here (Cascio 2010), one of the things that sets its profile apart from THC's. Demonstrated · in vitro
• α2-adrenoceptor. In vitro, CBG acts as an agonist here (Cascio 2010), which makes this one of the most distinctive CBG targets among the cannabinoids. Demonstrated · in vitro ⚠ Blood-pressure caution: α2-adrenoceptors are part of the noradrenaline system that helps regulate blood pressure, so this target is why CBG Atlas flags CBG for anyone taking cardiovascular medication — consult a clinician before use.
• TRP ion channels (TRPV1, TRPV2, TRPM8). The body uses these channels to sense heat, cold and irritation. In vitro, CBG activates and then desensitizes TRPV1 and TRPV2, and it blocks TRPM8 (De Petrocellis 2011). Demonstrated · in vitro
• PPARs (peroxisome proliferator-activated receptors). Some cannabinoids are studied against this family of nuclear receptors, which is involved in metabolism. Our verified registry has no study of PPAR activity for CBG, so whether CBG engages them at all is catalogue in progress.

How far that gets you. Each of those is a laboratory (in vitro) finding: it shows how a compound behaves at a target in an assay, and an effect in a person is a different and harder thing to show. A receptor interaction is a lead. CBG's own pharmacology has been followed only as far as preclinical studies, where one found an anti-inflammatory signal in a mouse model of colitis (Borrelli 2013 · Emerging · preclinical, an animal result not established in humans) and another found antibacterial activity in vitro, including against MRSA (Appendino 2008 · Demonstrated · in vitro). Our registry also holds one small human trial of CBG, in other areas. The single-compound pharmacology is verified, then, and a proven benefit in humans is a higher bar that CBG has not cleared.

What "binding affinity" means, and why the numbers are not on this page

Readers who know the literature will notice what that list leaves out: the numbers. "Binding affinity" is a laboratory measure of how tightly a compound attaches to a target, and "potency" measures how much of it an assay needs to produce an effect. Both figures exist and both matter. On the consumer side of CBG Atlas they become words, so CBG is an "agonist," an "antagonist" or a "desensitizer" at a given target, while the numeric constants that scientists report from binding and functional assays wait in researcher-level detail.

Why hold them back? Three reasons. 1. A tight in vitro number does not equal a clinical effect. A compound can bind a receptor firmly in a dish and still do little that is measurable in a whole person, and a precise figure set next to a health topic invites exactly that kind of over-reading. 2. The numbers compare badly. Values shift with the assay, the cell system and the method, so lining up figures from different studies, or different compounds, can mislead. 3. Words give the shape without false precision. "Antagonist at CB1," "agonist at the α2-adrenoceptor" and "activates then desensitizes TRPV1" each tell you the direction of the interaction, which is what a general reader needs.

The directions carry their grade and their citations (Cascio 2010; De Petrocellis 2011 · Demonstrated · in vitro). The constants sit behind the researcher tier, and /evidence sets out the six-rung ladder behind the grades.

The entourage effect: the idea and the evidence

Now to the idea the industry markets harder than almost any other. The "entourage effect," the belief that cannabis compounds work better together than any one of them alone, is a scientific hypothesis, not an established fact. Hypothesized The marketing runs well ahead of the human evidence.

The idea. Proponents argue that cannabinoids such as CBG, CBD and THC interact with the plant's aromatic terpenes and its flavonoids, so that a whole-plant or "full-spectrum" preparation gives a greater or more balanced effect than a purified single-compound "isolate." Manufacturers routinely present the point as settled: "full-spectrum is more effective," "these compounds work in synergy." Those are third-party marketing claims, and CBG Atlas does not endorse them.

The evidence. Most of the support comes from preclinical work in cells and animals, or from theory and mechanism. Controlled human trials showing that whole-plant combinations beat matched isolated compounds are lacking, and recent systematic reviews of cannabinoid–terpene "synergy" concluded that it remains unproven and that clinical trials are needed. In our registry the synergy claim is catalogue in progress, an active research question without a verified result. Emerging / Hypothesized

What a formulator can say. Part of the story holds up, and it is worth knowing exactly which part:

• CBG is an active ingredient in its own right. In the laboratory it has a distinct receptor profile: α2-adrenoceptor agonist, 5-HT1A antagonist and CB1 competitive antagonist (Cascio 2010), plus TRPV1/TRPV2 desensitizer and TRPM8 antagonist (De Petrocellis 2011). Demonstrated · in vitro At the level of mechanism, then, "a CBG-containing formulation adds a compound that has its own receptor profile" is a true statement.
• The jump to synergy is where it stops. Nobody has shown that adding CBG produces a beneficial combined effect in a person, that it "enhances" CBD or THC, or that it makes a formulation "work better." Each of those remains not established, and every claim of potentiation, enhancement or synergy is still unverified. Single-compound pharmacology is as far as the evidence takes a formulator; the combined-effect hypothesis is not verified.
• ⚠ Blood-pressure caution: because CBG acts on α2-adrenoceptors (Cascio 2010), which help regulate blood pressure, anyone on cardiovascular medication should be cautious with CBG-containing products and consult a clinician — regardless of any "entourage" framing.

Spectrum terms are definitions. Full-spectrum = the plant's full set of compounds, trace THC included; broad-spectrum = THC removed; isolate = a single purified cannabinoid. The terms describe composition and are not an effectiveness ranking. Rank them by how well they "work" and the unproven synergy claim slips back in through the side door, so CBG Atlas does not rank them.

Terpenes and flavonoids

The same gap opens wider around the plant's other compounds. Terpenes, the aroma compounds such as myrcene, limonene and pinene, and flavonoids are widely sold as active partners in the entourage effect, yet their contribution to cannabinoid effects in people is largely unproven. Low / Hypothesized

• What is solid: terpenes and flavonoids are well characterized as the compounds that give cannabis its aroma, flavor and color, which is Established, ordinary plant chemistry.
• What is claimed ahead of the evidence: that the terpenes and flavonoids in a typical product noticeably change how a cannabinoid feels or works. Proponents and manufacturers market particular terpenes for particular "effects," calming or energizing for example, often as though the matter were settled. Much of the research behind those claims is in vitro or uses high doses in animals, far above the small amounts in most consumer products, and controlled human studies of the combined effects are lacking. Low / Hypothesized
• Flavonoids have had even less attention in this context, and their role in any "entourage" effect is catalogue in progress.

So when a terpene blend is sold on its "effect," the effect is the manufacturer's claim, nobody has demonstrated it, and CBG Atlas does not rank products or blends on it. (Not medical advice.)

Common questions