Sleep
Apigenin is chamomile's main flavonoid. It inhibits the NAD+-consuming enzyme CD38 in mice and acts on GABA-A receptors in cell studies; human evidence comes from chamomile trials, and the testosterone claim has none.
Key takeaways
Most people encounter apigenin as a footnote in chamomile tea research — a mild relaxant, maybe useful for winding down before bed. That picture is accurate, but it’s also radically incomplete.
Apigenin is a flavonoid found in chamomile, parsley, celery, and several other plants. It has sedative properties. It also inhibits an enzyme called CD38 that destroys NAD+ throughout your body. It weakly suppresses aromatase, the enzyme that converts testosterone into estrogen. And it modulates GABA-A receptors in a way that is mechanistically similar to — but meaningfully different from — benzodiazepines.
Andrew Huberman has mentioned apigenin in the context of his sleep stack. Peter Attia has discussed CD38 inhibition and NAD+ longevity. What neither has fully connected, in accessible writing, is that the same compound does all of these things at once — and that the interactions matter for how and when you take it.
This article covers all of it.
Apigenin (4′,5,7-trihydroxyflavone) belongs to the flavone subclass of flavonoids. It’s the primary bioactive in chamomile (Matricaria chamomilla), where it accounts for much of the plant’s documented effects. It also occurs in significant amounts in dried parsley, dried chamomile flowers, celery seed, and artichoke leaves.
As a supplement, it’s typically sold as an isolated extract, standardized to 50–100 mg per capsule. This is considerably more concentrated than what you’d get from chamomile tea, where a standard cup delivers roughly 0.5–5 mg depending on steep time and brand.
The reason isolated apigenin is worth discussing separately from chamomile tea is dose-dependent mechanism. At tea doses, you’re mostly getting mild anxiolytic and sleep-onset effects. At 50–100 mg, you start engaging the CD38 pathway and aromatase inhibition in ways that tea simply doesn’t reach.
NAD+ (nicotinamide adenine dinucleotide) is a coenzyme involved in hundreds of metabolic processes — mitochondrial energy production, DNA repair, sirtuin activation, and more. NAD+ levels decline substantially with age, and this decline is associated with reduced mitochondrial function, slower cellular repair, and increased disease risk.
Supplementing NAD+ precursors like NMN and NR (see our NMN vs NR deep-dive) has become a major area of longevity research. But there’s a second lever often overlooked: stopping NAD+ from being consumed in the first place.
CD38 is an enzyme that breaks down NAD+ as part of its signaling function. The problem is that CD38 expression increases with age and with inflammation (both of which tend to rise together). As CD38 activity goes up, NAD+ goes down.
A landmark 2016 paper by Camacho-Pereira et al. in Cell Metabolism demonstrated that CD38 is responsible for the majority of age-related NAD+ decline in mice. Mice with CD38 knocked out maintained youthful NAD+ levels and showed improved mitochondrial function well into old age.
This suggested an obvious intervention: inhibit CD38. Apigenin emerged as one of the most effective natural CD38 inhibitors tested.
An earlier paper from the same group (Escande et al., 2013, Diabetes) tested apigenin in obese mice and found:
The mechanisms are complementary to NMN/NR: NMN and NR increase NAD+ by providing more raw material; apigenin increases NAD+ by reducing its enzymatic destruction. Whether combining a NAD+ precursor with a CD38 inhibitor adds anything in humans has not been tested.
Apigenin binds to benzodiazepine receptor sites on GABA-A receptors. GABA is the brain’s primary inhibitory neurotransmitter — when GABA-A receptors are activated, neural excitability decreases, producing anxiolytic and sedative effects.
Benzodiazepines (Valium, Xanax, Klonopin) work by the same mechanism, which explains why apigenin has similar but weaker effects. The critical difference is that benzodiazepines are full agonists at these sites — they strongly amplify GABA signaling. Apigenin binds the benzodiazepine site only weakly in laboratory studies (Viola et al., 1995), and later work questions whether it acts like a benzodiazepine there at all; its calming effect probably involves several mechanisms.
A 2009 double-blind, placebo-controlled trial (Amsterdam et al., J Clin Psychopharmacol) gave 220–1,100 mg/day of chamomile extract (1.2% apigenin) to 57 adults with generalized anxiety disorder for 8 weeks. Participants showed statistically significant reductions in Hamilton Anxiety Rating Scale scores compared to placebo, with effects sustained over 8 weeks.
For sleep specifically, a 2011 pilot RCT (Zick et al., BMC Complementary and Alternative Medicine) found no significant differences from placebo on sleep-diary measures in 34 adults with chronic insomnia (270 mg twice daily for 28 days), with modest, non-significant trends toward better daytime functioning.
A 2017 RCT in 60 elderly adults (Adib-Hajbaghery & Mousavi, Complement Ther Med) found 400 mg/day of chamomile extract improved Pittsburgh Sleep Quality Index scores versus placebo over 28 days; a 2019 meta-analysis (Hieu et al., Phytother Res) pooled such trials., with no adverse effects.
What the data shows collectively: chamomile extract modestly improved subjective sleep quality in some trials and not others; there are no trials of isolated apigenin for sleep. It is not a sedative in the way that pharmaceutical sleep aids are — it won’t force you to sleep if you’re wired. It works better when combined with proper sleep hygiene and circadian rhythm support.
These are mechanistically different and often stack well:
| Apigenin | Melatonin | |
|---|---|---|
| Mechanism | GABA-A modulation (calming) | Circadian signal (timing) |
| Primary effect | Reduces anxiety, aids sleep onset | Shifts sleep timing, mild sedation |
| Half-life | Not well characterized in humans | 40–50 min (immediate release) |
| Studied for | Sleep quality and anxiety (as chamomile extract) | Jet lag, phase shifting, sleep onset |
| Dose-response | 50–100 mg typical | 0.5–1 mg is usually enough (see dosing guide) |
| Dependency risk | Very low | Low, but can blunt endogenous production |
No trial has compared apigenin with melatonin. Mechanistically, chamomile’s calming effect suits winding down, while melatonin suits shifted sleep timing. For people who sleep fine once asleep but wake too early or have shifted rhythms, melatonin is the better fit.
Aromatase is the enzyme that converts testosterone (and other androgens) into estrogens. In men especially, excess aromatase activity — particularly in adipose tissue — can shift the testosterone-to-estrogen ratio in an unfavorable direction, contributing to lower free testosterone, reduced libido, and mood changes.
Apigenin has demonstrated aromatase inhibitory effects in cell culture studies (Jeong et al., 1999, Arch Pharm Res). Its potency in vitro was moderate — meaningful but far weaker than pharmaceutical aromatase inhibitors.
No human RCTs have directly tested apigenin for testosterone optimization. However, this mechanism partially explains why apigenin is sometimes included in testosterone support stacks alongside Tongkat Ali and Ashwagandha — it may help preserve the testosterone-to-estrogen ratio while those compounds support testosterone production directly.
The evidence here is mechanistic, not clinical — worth noting but not overstating.
Chronic low-grade inflammation (“inflammaging”) is a key driver of age-related decline. Apigenin consistently inhibits NF-κB, the master transcription factor that regulates pro-inflammatory cytokine expression (IL-1β, IL-6, TNF-α).
Multiple in vitro and animal studies have documented this effect: - Zhang et al. (2014, PLOS One): apigenin reduced LPS-induced cytokine release in macrophages via NF-κB suppression - Sung et al. (2007, Anticancer Research): apigenin inhibited NF-κB activation in human cancer cell lines - Tordera et al. (2021): animal models showed reduced neuroinflammatory markers
The anti-inflammatory evidence in humans is limited to indirect markers and chamomile-based interventions rather than isolated apigenin trials. But the mechanism is consistent and well-characterized at the molecular level.
No human trial has tested isolated apigenin at any dose. Capsules are typically sold at 50 mg; the chamomile trials above delivered only a few milligrams of apigenin a day. Talk to a clinician before use if you take medication, are pregnant, or have a hormone-sensitive condition. | Testosterone support stack | 50 mg | Any time; often in PM with other stack components | | Stacked with NMN/NR | 50 mg | Same time as NAD+ precursor is fine |
What is marketed: 50 mg capsules are the common retail size. There is no published human research on isolated apigenin at 50–100 mg, and no clinical dosing standard exists. Above 100 mg, there’s no well-studied advantage and the GABA-A effects may become more pronounced than desired.
Timing for sleep: Take 30–60 minutes before target sleep time. Whether tolerance develops with nightly use has not been studied.
Timing for CD38/NAD+ support: Time of day is less critical for the CD38 mechanism. Morning is fine if you don’t want any sedative effect during the day; evening stacks conveniently with sleep benefits.
Apigenin has moderate oral bioavailability, limited by poor water solubility and first-pass metabolism. Several strategies can improve absorption:
Chamomile preparations have a good safety record in trials; there are no published human safety studies of isolated apigenin at 50–100 mg/day, so tolerability at those doses is assumed, not shown.
Known interactions: - Blood thinners (warfarin, aspirin therapy): Apigenin may have mild antiplatelet effects. Use caution if on anticoagulants — discuss with your physician. - Benzodiazepines and sedatives: Additive GABA-A effects. Do not combine with pharmaceutical sedatives without medical guidance. - CYP1A2 substrates: Apigenin is metabolized by and mildly inhibits CYP1A2. This enzyme also processes caffeine, theophylline, and some medications. High-dose apigenin may slightly slow metabolism of these compounds. - Hormone-sensitive conditions: The aromatase inhibitory and weak estrogenic effects (apigenin can act as a weak estrogen at some receptor subtypes) mean caution is warranted for anyone with hormone-sensitive cancers or on hormone therapy.
Pregnancy and breastfeeding: Insufficient safety data. Avoid.
Not a pharmaceutical sleep aid: Do not substitute apigenin for clinically prescribed sleep or anxiety medications without physician guidance.
Most existing coverage of apigenin falls into one of two narrow boxes: chamomile tea research (underdosed, endpoints limited to anxiety) or cancer biology (in vitro studies, irrelevant doses). What’s missing from most sources:
The compound is more than a chamomile derivative. For anyone already thinking about NAD+ optimization (see NMN vs NR), adding a CD38 inhibitor is an untested idea in humans — apigenin is the most accessible candidate, but its evidence is entirely from cells and mice.
Apigenin is one of the more unusual compounds in the supplement space — a molecule with interesting laboratory mechanisms in NAD+ metabolism and hormone signalling, modest human evidence via chamomile for sleep and anxiety, and no human trials of the isolated supplement. That combination is rarer than it sounds.
This article is for general education and is not medical advice.
Sources: Camacho-Pereira et al. 2016, Cell Metab | Escande et al. 2013, Diabetes (apigenin/CD38 in mice) | Amsterdam et al. 2009, J Clin Psychopharmacol (chamomile, GAD) | Mao et al. 2016, Phytomedicine | Zick et al. 2011, BMC Complement Altern Med | Adib-Hajbaghery & Mousavi 2017, Complement Ther Med | Hieu et al. 2019, Phytother Res (meta-analysis) | Viola et al. 1995, Planta Med (GABA-A binding) | Salehi et al. 2019, Int J Mol Sci (apigenin review) | plus verified links for the aromatase and NF-κB citations or delete them
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