Lavender Oil (Silexan).

The standardised linalool and linalyl acetate pair acts on voltage-gated calcium channels and 5-HT1A signalling, while theanine works through glutamate handling and cortical alpha activity. The two routes are independent, so the pairing widens the effect rather than duplicating it.

Apigenin occupies the benzodiazepine site on GABA-A while the lavender terpenes reduce presynaptic calcium entry. Both lower excitatory transmission, at different points of the same synapse.

Rosmarinic acid slows GABA transaminase so more GABA persists in the synapse, while the lavender terpenes act on the presynaptic side. Raising transmitter availability and lowering release drive are different levers on the same circuit.

Passionflower flavonoids raise GABAergic tone at the receptor while the lavender preparation acts presynaptically on calcium entry. The combination works both sides of the synapse.

Magnesium acts as a physiological calcium antagonist at nerve terminals and in the NMDA channel, the same class of effect the standardised lavender terpenes have on voltage-gated calcium channels. Both damp excitatory signalling.

Crocin and safranal influence serotonin reuptake and receptor signalling, overlapping with the 5-HT1A involvement of linalool. Mood formulas pair them because the chemistry differs while the target system is shared.

Withanolides work on the cortisol axis over weeks, while the standardised lavender oil acts on nerve terminal excitability within hours. The time courses differ enough that they layer instead of overlapping.

Melatonin sets circadian timing through its own receptors, while the lavender preparation lowers arousal directly. Timing and arousal are separate levers on normal sleep onset.

The standardised oil is delivered in a softgel dispersed in neutral lipid, which stabilises the terpenes and supplies the micelle transport they need for uptake. Without a lipid carrier the volatile actives disperse poorly.

Adenosine receptor blockade raises cortical arousal, the opposite direction from what the standardised lavender oil produces. Each offsets part of the other in a shared serving.

5-HTP feeds serotonin synthesis directly while linalool acts at the 5-HT1A receptor, so supply and receptor signalling move the same system together. The additive push should be accounted for rather than assumed neutral.

Valerian constituents act on GABA-A signalling and adenosine receptors, a different entry point from lavender oil's calcium-channel modulation. Combined in an evening formula the calming effect adds up. That also means the drowsiness adds up, which is worth knowing before driving or drinking alcohol.

Glycine is an inhibitory neurotransmitter in the brainstem and spinal cord acting at its own receptor, entirely separate from the monoterpene mechanism. It also lowers core temperature slightly, which is part of normal sleep onset. Two independent routes to the same end of the day.

Supplemental GABA crosses the blood-brain barrier poorly and appears to act mostly peripherally and through vagal afferents, so it does not duplicate lavender oil's central action. The two are stacked in calm formulas on that reasoning. No combination trial has measured the pair.

Apigenin binds the benzodiazepine site of the GABA-A receptor, which is precisely the site lavender oil does not use. Pairing them gives two mechanisms rather than one repeated. Sedative load is cumulative across the formula.

Honokiol and magnolol are positive allosteric modulators at GABA-A receptors, adding a receptor-level action to a formula built on a non-GABAergic active. Evening blends use the two together. The combined sedation is the thing to account for.

Tryptophan is the substrate for serotonin and then melatonin synthesis, feeding a pathway the monoterpenes do not supply. The two therefore work at different points in the same evening. Supplying a precursor only matters where substrate is limiting.

Pyridoxal 5-phosphate is the required cofactor for the decarboxylases that make serotonin from 5-HTP and GABA from glutamate. A formula that supplies precursors without B6 is missing the enzyme's cofactor. This is settled biochemistry and applies whatever the other actives are.

Taurine is an agonist at glycine receptors and a weak one at GABA-A, and it also buffers intracellular calcium. The calcium handling overlaps with the reported monoterpene mechanism from a different direction. Read it as mechanistic overlap rather than a tested pairing.

Lecithin emulsifies a volatile oil into a softgel fill and holds the phase together on storage. It contributes dispersion and mouthfeel, not activity. The choice of sunflower over soy is an allergen decision.

St John's wort is a strong inducer of CYP3A4 and P-glycoprotein, which speeds clearance of lipophilic co-administered compounds and of many medicines. Anything relying on those routes sees lower exposure over days of co-dosing. It is one of the more consequential botanical interactions and it belongs on a formulator's checklist.

Rhodiola is used for daytime stress load and is not sedating for most people, so it tends to sit on the opposite side of a day from a calming oil. Formulas pair them as a morning and evening set. The pairing is convention rather than a measured interaction.

Bacopa acts over weeks of continuous dosing while a standardised oil is used acutely, so the two run on different clocks inside one product. Bacopa is sedating in a minority of people and adds to that side. No study has tested the combination.

Phosphatidylserine is used against cortisol response, an endocrine axis distinct from the neuronal one. In a stress formula the two cover different parts of the same complaint. The basis is separate mechanisms rather than a combination trial.