Apigenin

apigenin

A dietary flavonoid promoted to preserve NAD⁺ by inhibiting the enzyme CD38.

TypeSupplement / dietary

The grade answers: What does the human evidence support for: CD38 inhibition / NAD⁺ support?

Grade

Limited

The grade rates evidence quality — it is not advice to take or buy.

Class: Flavonoid
Primary use: CD38 inhibition / NAD⁺ support
Evidence strength: low
Last reviewed: 2026-07-01

Bottom line

A neat theory — block the enzyme that burns through NAD⁺ — supported mainly by lab and animal work. Direct human longevity evidence is essentially absent.

What the evidence says

Apigenin is a flavonoid (parsley, chamomile, celery) studied as a CD38 inhibitor; since CD38 consumes NAD⁺ and rises with age, inhibiting it is proposed as a way to preserve NAD⁺ — a different angle from NAD⁺ precursors like NMN. The evidence is largely preclinical, with some small human work on anxiety/sleep (as in chamomile) unrelated to the NAD⁺ claim. There are no human trials showing it raises NAD⁺ or affects aging outcomes. Grade C: interesting mechanism, minimal direct human evidence, and poor bioavailability like most flavonoids.

Key studies

[1]
Apigenin as a CD38 inhibitor and NAD⁺ metabolism · preclinical
Preclinical basis for the NAD⁺-preservation idea.
Open on PubMed ↗
[2]
Apigenin pharmacology and bioavailability (review) · review
Low absorption complicates translation to humans.
Open on PubMed ↗
[3]
CD38, NAD⁺ decline and aging (review) · review
Why CD38 is a plausible NAD⁺ target.
Open on PubMed ↗

See all studies on PubMed ↗

Scoped PubMed search, not a curated bibliography: the individual PMIDs for this entry have not yet been verified one by one. For that reason it is not used to support a high grade and is awaiting review.

Mechanism

Inhibits CD38, an NAD⁺-degrading enzyme, potentially slowing NAD⁺ decline; also has general antioxidant, anti-inflammatory and mild anxiolytic flavonoid effects.

Safety

Consumed as a dietary flavonoid with good tolerability at food levels; concentrated supplement safety is less characterised, and flavonoids can interact with drug-metabolising enzymes.

Dosage context

No established human 'NAD⁺-preserving' dose; supplement products vary and bioavailability is low. Much of the interest is extrapolated from cell and animal studies.

Examples of application

Present in parsley, chamomile and celery.
As a supplement, the CD38/NAD⁺ rationale is largely preclinical.
One to watch rather than bank on; absorption is low.

From the field

Apigenin is the 'stop burning NAD⁺' counterpart to the 'add more NAD⁺' precursors — clever on paper, almost entirely preclinical in practice. Grade C, and one to watch rather than to bank on.

Related molecules

NMNB Nicotinamide Riboside (NR)B

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