Apigenin is a plant compound belonging to the flavone subclass of flavonoids, found naturally in parsley, chamomile, celery, and several other herbs and vegetables. It has gained attention for its calming effects, its ability to raise levels of a key cellular energy molecule called NAD+, and a broad range of anti-inflammatory and anticancer properties studied in labs and animals. With an oral bioavailability around 30%, it is one of the more absorbable flavonoids, which partly explains its growing popularity as a supplement.
Where Apigenin Is Found
Dried parsley is by far the richest dietary source, containing roughly 4,500 mg per 100 grams. That number sounds enormous, but you’d rarely eat more than a few grams of dried parsley in a sitting, so the practical intake from a garnish is modest. Dried chamomile flowers contain 300 to 500 mg per 100 grams, and brewed chamomile tea delivers a meaningful amount, with apigenin making up about 0.8% to 1.2% of the preparation. Celery seeds provide around 79 mg per 100 grams, vine spinach about 62 mg, and Chinese celery about 24 mg.
Other sources include fresh celery stalks, oregano, thyme, and certain citrus fruits, though in smaller concentrations. For most people, chamomile tea is the most practical whole-food route to a noticeable dose. Supplements typically deliver 50 to 100 mg per capsule, far more than you’d get from a normal serving of any single food.
How It Affects Sleep and Anxiety
Apigenin’s reputation as a calming compound traces back to chamomile tea, and the mechanism is real: it binds to the same site on brain receptors that anti-anxiety medications like benzodiazepines target. Specifically, it attaches to a spot on the receptor that normally responds to GABA, the brain’s primary calming signal. The result, in animal studies, is reduced anxiety-like behavior at doses comparable to those used for conventional drugs.
The picture is more nuanced than “natural Valium,” though. Different studies have produced conflicting profiles. Some found apigenin acted as an anxiolytic without causing sedation or muscle relaxation. Others found it was mildly sedating. Still others suggested it may partially block the receptor rather than activate it. The overall conclusion from pharmacology research is that apigenin’s interaction with GABA receptors is complex, likely involving multiple binding mechanisms and possibly other receptor systems. In practical terms, many supplement users report it helps with sleep onset, and chamomile tea has centuries of traditional use as a mild relaxant, but the strength of the effect varies considerably between individuals.
NAD+ and Cellular Aging
One of the most cited reasons people take apigenin supplements has nothing to do with sleep. Apigenin inhibits an enzyme called CD38, which is responsible for breaking down NAD+ inside cells. NAD+ is a molecule every cell needs for energy production, DNA repair, and activating longevity-related proteins called sirtuins. As you age, CD38 levels rise and NAD+ levels fall, a pattern linked to many hallmarks of aging.
In lab and animal experiments, apigenin blocks CD38 with a half-maximal inhibitory concentration of about 10 micromoles per liter. When researchers treated cells with apigenin, intracellular NAD+ levels increased in a dose-dependent manner, and the downstream effect was measurable: sirtuin activity went up, and protein acetylation (a marker that rises when sirtuins are inactive) went down. In mice, injecting apigenin decreased CD38 activity in the liver and correspondingly raised hepatic NAD+ levels. These findings, published by researchers at Mayo Clinic, positioned apigenin as a natural CD38 inhibitor with potential relevance to metabolic health and aging. Human trials confirming these NAD+-boosting effects at supplement doses are still limited, but the cellular mechanism is well established.
Anti-Inflammatory Effects
Chronic low-grade inflammation underlies conditions from heart disease to autoimmune disorders, and apigenin appears to dampen several of the molecular pathways that drive it. The most studied mechanism involves a master inflammation switch called NF-kB. Normally, when your immune cells detect a threat, NF-kB moves into the cell nucleus and turns on genes that produce inflammatory proteins. Apigenin prevents this translocation by blocking an upstream signaling step, specifically the activation of a protein kinase called Akt.
The practical result in cell studies is a suppression of several pro-inflammatory and pro-survival molecules. Apigenin also reduces levels of COX-2, the same enzyme targeted by ibuprofen and other anti-inflammatory drugs. These effects have been observed in human immune cells, not just cancer cell lines, which makes them relevant to general inflammatory conditions. Whether dietary or supplemental doses achieve sufficient tissue concentrations in humans to reproduce these effects remains an open question, but the anti-inflammatory profile is consistent across dozens of studies.
Cancer Research
Apigenin has been studied against lung, ovarian, cervical, colon, and skin cancer cells, among others. The compound triggers programmed cell death through multiple routes. It disrupts the energy balance inside mitochondria, increases reactive oxygen species that damage cancer cells, and activates enzymes called caspases that execute the cell death program. At the same time, it dials down survival signals that cancer cells rely on, including the PI3K/Akt/mTOR pathway, which many tumors hijack to keep growing.
In colon cancer cells, apigenin triggers apoptosis by blocking the STAT3 pathway and reducing levels of two key survival proteins. In lung cancer cells, it prevents NF-kB from entering the nucleus, which shuts off anti-death genes. In ovarian cancer cells, it overcame resistance to cisplatin, a common chemotherapy drug. These are promising laboratory findings, and animal studies support them, but no large human clinical trials have tested apigenin as a standalone cancer treatment. It is better understood as a compound with anticancer properties that may contribute to the protective effects of a plant-rich diet.
Hormonal Effects
Apigenin inhibits aromatase, the enzyme that converts testosterone into estrogen. This is the same enzyme targeted by prescription aromatase inhibitors used in hormone-receptor-positive breast cancer treatment. For men interested in supporting testosterone levels, this mechanism is part of the appeal, though the degree of aromatase inhibition from typical supplement doses in humans has not been well quantified. The effect is unlikely to be dramatic at common doses but may be relevant as one piece of a broader hormonal picture.
Absorption and Practical Considerations
Oral bioavailability sits around 30%, which is reasonable for a flavonoid. After you take it, apigenin reaches peak blood levels within about 30 minutes to 2.5 hours, and its elimination half-life averages roughly 2.5 hours. That relatively short half-life means it clears the body fairly quickly, which is why some people split their dose or take it specifically before bed when using it for sleep.
Most supplements on the market provide 50 mg per capsule, and popular protocols use 50 to 100 mg taken in the evening. Apigenin is absorbed through the gut and recirculated through the liver and intestinal pathways, so taking it with food may improve absorption. No serious toxicity has been reported at typical supplement doses, though high doses in animal studies can interact with thyroid hormone metabolism and potentially affect how the liver processes certain medications. If you’re taking blood thinners or drugs metabolized by the same liver enzymes, it’s worth checking for interactions.