Apigenin.

Apigenin modulates GABA-A receptors to quiet nervous system activity as the body winds down, while melatonin carries the separate circadian signal that it is night. Because they act on different parts of the same wind-down process, they are often paired to support an easier transition into sleep.

Magnesium supports normal GABA signaling and occupies the NMDA receptor where it keeps excitatory tone in check, which lines up with apigenin's modulation of GABA-A receptors. The two reinforce the same relaxation response, a common reason they sit together in evening and calm formulas.

L-theanine supports GABA signaling and promotes alpha-wave activity for a calm, settled feeling, which complements apigenin's action at GABA-A receptors. Together they support relaxation and an easier wind-down without heavy sedation.

Apigenin slows CD38, one of the main enzymes that breaks down NAD+, while niacinamide supplies a precursor the body uses to rebuild NAD+ through the salvage pathway. Supporting the NAD+ pool from both the supply side and the breakdown side is why the two are discussed together for normal cellular energy metabolism.

Apigenin and its glycosides are the principal flavones of chamomile flower, so the herb is the food-matrix delivery of the same molecule. A chamomile extract adds companion flavonoids and volatile oil alongside the isolate.

Apigenin binds the benzodiazepine site of the GABA-A receptor, which changes how the receptor responds to GABA itself rather than opening the channel on its own. A modulator needs the agonist present to matter.

Luteolin differs from apigenin by a single hydroxyl and shares its flavone scaffold, its mast cell effects and its glucuronidation route. Sharing the conjugation route means each slows the other's clearance.

Both flavonoids are cleared by the same UGT and sulfotransferase enzymes, so each slows the other's conjugation and raises circulating exposure. Both also inhibit CD38, the enzyme that consumes NAD precursors.

Baicalein is another flavone ligand at the benzodiazepine site, so the two act at the same receptor region from slightly different binding profiles. They are commonly formulated together in evening blends.

Glycine is its own inhibitory neurotransmitter and also lowers core body temperature at the start of the night, a route entirely separate from GABA-A modulation. The two cover different halves of sleep onset physiology.

Passionflower's activity is attributed largely to its flavone fraction, which includes apigenin itself and related flavones such as the apigenin glycoside vitexin. Pairing stacks related ligands at the same receptor site.

Valerian's valerenic acid acts at a different GABA-A subunit region than the flavone benzodiazepine site, so the two modulate the same receptor from separate positions. They have been combined in evening formulas for a very long time.

Lemon balm rosmarinic acid slows GABA transaminase, which keeps more GABA in the synapse, while apigenin changes how the receptor answers that GABA. One raises the signal and the other tunes the response.

CD38 is a main enzyme that degrades NMN before it can be converted onward to NAD. Apigenin inhibits CD38, so more of a supplemented precursor survives to reach the salvage pathway.

NR is phosphorylated to NMN, which CD38 then consumes. Slowing CD38 with apigenin keeps the precursor pool intact for longer after a dose.

Ascorbate reduces the flavonoid radical formed when apigenin donates an electron, returning it to the active form. The recycling is the basis of long-standing flavonoid plus ascorbate formulas.

Flavones carry hydroxyl and carbonyl groups that chelate ferric iron in the gut lumen, forming complexes the divalent metal transporter cannot take up. Dosing an iron supplement and a flavone-rich product together lowers the iron actually absorbed.

Apigenin's main loss is intestinal glucuronidation, and piperine inhibits the UGT enzymes responsible. Less first-pass conjugation leaves more free flavone in plasma.

Naringenin and apigenin are both handled by intestinal UGT and SULT enzymes and by the same efflux transporters on the enterocyte. Taken together they compete for that limited conjugation capacity, which can raise the unconjugated fraction of either one. The competition is documented in intestinal models rather than in people, so this is a mechanistic note at early confidence.

Propolis carries apigenin along with chrysin, galangin and caffeic acid esters, so a propolis extract already delivers some apigenin in a plant matrix. Pairing the two means adding an isolated flavone to a source that also contains it, which matters for totalling the intake. The co-occurrence is analytical fact; whether the matrix changes absorption of the isolate has not been measured.

Oxidised flavonoid quinones are quenched by glutathione conjugation, which is one of the routes that terminates flavonoid redox cycling. Apigenin also raises Nrf2-dependent transcription of the enzymes that use glutathione. The two therefore sit on one redox loop, at the level of cell biochemistry rather than a measured clinical effect.

Apigenin inhibits CD38, the main NAD-consuming glycohydrolase outside the nucleus, which is the mechanism behind reports of raised tissue NAD in cell and rodent work. Slowing consumption is a different lever from supplying a precursor, so the two act at opposite ends of the same pool. Human NAD measurements with apigenin are not available here, so this stays a mechanism.

Caffeine clearance is almost entirely CYP1A2, and apigenin inhibits that isoform in human microsome work. Combining them could slow caffeine clearance and stretch out its effect, which cuts against an evening formula. The inhibition is well characterised at the bench and unquantified at supplement doses, so state it as a caution rather than a number.

Curcumin is glucuronidated so extensively that it saturates intestinal UGT capacity, and apigenin depends on the same enzymes for its first-pass handling. Co-dosing raises the unconjugated fraction of both, which is a pharmacokinetic interaction and not an efficacy claim. Both also converge on Nrf2-driven phase II transcription.

EGCG is both substrate and inhibitor at catechol-O-methyltransferase and occupies SULT1A1, the sulfotransferase that also handles apigenin. Running them together shifts how much of each circulates unconjugated. The kinetics come from enzyme and cell work, so the direction is clear and the magnitude in people is not.

Glutamate decarboxylase needs pyridoxal 5-phosphate to make GABA, so B6 status determines how much GABA is available to the receptors apigenin binds at the benzodiazepine site. One partner supplies the transmitter, the other modulates the receptor. That division of labour is textbook, and no combination trial has measured what it adds up to.

Apigenin's 5-hydroxy-4-keto arrangement chelates divalent copper, and flavonoid copper complexes both alter mineral solubility in the gut and can drive redox cycling of the metal. Taken in the same dose window, the flavone and the mineral affect each other's handling. This is coordination chemistry rather than a measured human absorption figure, so separating the doses is the practical point.

Zinc is bound by flavones through the same hydroxy-keto site that binds copper, which can change how much of either is absorbed when they are taken together. Zinc separately modulates GABA-A receptors, the site apigenin also engages, so there is a second point of contact at the receptor. Both strands come from bench work, hence early confidence.

Apigenin aglycone is close to insoluble in water and dissolves far better in lipid, which is why a dry capsule of pure aglycone disperses badly. A medium-chain triglyceride vehicle carries it into a dispersed state before it reaches the small intestine. The chemistry is straightforward and no human comparison against a dry powder is available here.

Phospholipids form dispersible complexes with flavonoid aglycones, which is the basis of the phytosome style of formulation. For apigenin the barrier is dissolution, so a phospholipid carrier addresses the actual limiting step. Whether a given complex delivers more than the plain aglycone has to be shown for that specific material rather than assumed.

Resveratrol is cleared almost entirely by sulfation and glucuronidation and saturates those routes at ordinary doses, and apigenin passes through the same enzymes. Co-dosing shifts the conjugated to unconjugated balance for both. Recorded at early confidence because the interaction is inferred from separate kinetic studies rather than measured together.

Silybin inhibits several UGT isoforms and efflux transporters in intestinal models, the same machinery that limits apigenin's first-pass survival. The pairing could raise apigenin exposure. No study measures the combination, so this is a mechanistic flag rather than a formulation strategy.

Withanolides act on GABAergic and hypothalamic-pituitary signalling, a separate route from a flavone at the benzodiazepine site. In one evening formula the two contribute to the same felt effect through different receptors. The point of recording it is cumulative drowsiness, stated at early confidence.

Honokiol and magnolol act as positive modulators at GABA-A, and apigenin binds the benzodiazepine site of the same receptor complex with low affinity. Two modulators at one receptor complex is a real pharmacological overlap and also a reason to expect additive drowsiness. The overlap comes from receptor binding work, not from a human combination trial.

5-HTP feeds serotonin and downstream melatonin synthesis, which has no biochemical contact with flavone binding at GABA-A. The pairing appears in night-time formulas on intent. Worth flagging for additive sedation, and not as a demonstrated synergy.