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Annurca apple extract (procyanidin B2)

An unlikely candidate with genuinely published human trials — a southern-Italian apple whose polyphenols push keratin synthesis.

Reviewed by Bodil Isaksson, Licensed Biomedical Scientist (Sweden)Last reviewed July 2026Supplement guide

SupplementsHair, skin & nailsReal trials, industry-linked

Most “botanical” hair actives collapse under scrutiny. The Annurca apple — a small, tart heirloom variety from Campania — is a rare exception, because a Naples pharmacology group actually ran the trials. Its draw is an unusually high content of the polyphenol procyanidin B2, which in their work raised keratin production in follicle cells and increased hair growth in people.

Key takeaways

  • The active is procyanidin B2, concentrated in Annurca apples (standardised as an Annurca polyphenol extract).
  • In a randomised trial, two months of the extract increased hair count, hair weight and keratin content versus baseline.1
  • Among the better-evidenced botanical actives here — but the trials come from a single group with commercial links to the extract.
  • Low risk; a fair trial if you want a plant-based option with actual published data.

Why this apple

Procyanidin B2 is a flavonoid found across apples, but the Annurca cultivar is exceptionally rich in it — and older work had already hinted that topical procyanidin B2 could promote hair growth. That gave the Naples group a specific, plausible molecule to test rather than a vague “apple extract”, which is part of why this line of research is more credible than most botanical hair claims.

Procyanidin B2 and keratin

In their laboratory model, the Annurca polyphenol formulation increased expression of keratins in human skin/follicle cells — the structural proteins the hair fibre is made of — alongside antioxidant effects.1 The mechanistic story (more keratin substrate and signalling in the bulb) at least matches the clinical endpoints they went on to measure, which is more than can be said for many ingredients in this space.

The Tenore trials

Tenore and colleagues (2018) reported that healthy volunteers taking the Annurca apple nutraceutical for two months showed significant increases in number of hairs, hair weight and keratin content compared with baseline.1 These are real, peer-reviewed human results — genuinely more than most competitors offer. The honest asterisk: the studies come from essentially one research group that is associated with the commercialised extract, and independent replication is thin. Encouraging, not settled.

An honest verdict

If you want a botanical with actual published trials rather than folklore, Annurca apple extract is one of the few that qualifies — worth a couple of months if the idea appeals. Just keep the industry-and-single-group caveat in mind, and hold it to the same “stop if nothing changes” rule as everything else on this list.

Bottom line: Annurca apple / procyanidin B2 has real RCT data for hair count and keratin — among the strongest botanical cases here, tempered by single-group, industry-linked evidence.

References

Adult research summary for education, not a prescription. These are food supplements, not treatments for disease.

  1. Tenore GC, Caruso D, Buonomo G, et al. Annurca apple nutraceutical formulation enhances keratin expression in a human model of skin and promotes hair growth and tropism in a randomized clinical trial. J Med Food 2018;21(1):90–103. pubmed.ncbi.nlm.nih.gov

This article summarises nutrition science for education. It is not a substitute for individual medical advice; consult a professional before starting a supplement, in pregnancy, or alongside medication.