Can Plant Extracts Help Prevent Hair Loss or Promote Hair Growth? A Review Comparing Their Therapeutic Efficacies, Phytochemical Components, and Modulatory Targets
Identifier: 38792149
Study Type: Review Article (2024)
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## Abstract
This narrative review evaluates the therapeutic potential and mechanisms of plant extracts in preventing hair loss and promoting hair growth or regrowth. The authors systematically compare plant extracts based on their effects in vitro (dermal papilla cells), ex vivo (hair follicles), in vivo (animal models), and in human clinical trials. The review also summarizes key phytochemical classes (phenolics, terpenes/terpenoids, sulfur-containing compounds, fatty acids) and the signaling pathways they modulate in the hair cycle. The authors conclude that well‑selected plant extracts and their active compounds can beneficially influence hair health and represent promising candidates for targeted alopecia therapies.
“Various plant extracts increased the survival and proliferation of dermal papilla cells in vitro, enhanced cell proliferation and hair growth in hair follicles ex vivo, and promoted hair growth or regrowth in animal models in vivo.”
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## Key findings
### 1. Scope and methodology
- The authors searched PubMed, Web of Science, and Google Scholar for studies on plant extracts and hair loss/hair growth, focusing on titles containing “hair loss”, “hair growth”, or “hair regrowth” plus “extract” and plant‑related terms.
- They identified and analyzed studies that used plant extracts in dermal papilla cell assays, hair‑follicle organ culture, animal models, and human clinical trials.
- The review emphasizes comparative analysis of therapeutic efficacy, phytochemical composition, and molecular targets.
### 2. Effects on dermal papilla cells in vitro
- Many plant extracts increased viability and proliferation of human follicle dermal papilla cells (HFDPCs) using MTT/MTS/WST/resazurin assays or DNA‑synthesis markers (³H‑thymidine, BrdU, Ki‑67).
- Some extracts restored cell viability reduced by testosterone or DHT, indicating potential relevance to androgen‑driven hair loss.
- Camellia japonica extract, among others, both promoted proliferation and alleviated androgen‑induced viability decline.
### 3. Effects on hair follicles ex vivo
- Extracts from plants such as Cucumis melo, Orthosiphon stamineus, Panax ginseng, Houttuynia cordata, and Polygonum multiflorum promoted hair‑shaft elongation and/or prolonged the anagen phase in organ‑cultured hair follicles.
- Some extracts reversed testosterone‑ or DHT‑induced suppression of hair‑shaft growth and follicular cell proliferation.
### 4. Effects on hair growth in animal models
- Numerous plant extracts promoted hair growth or mitigated androgen‑induced delay in hair growth in mice and rats, often using C57BL/6 models with synchronized telogen‑phase hair.
- Extracts were typically applied topically, but some were given orally or via injection; minoxidil and finasteride frequently served as positive controls.
- Several extracts accelerated telogen‑to‑anagen conversion and increased hair density or shaft length.
### 5. Clinical evidence
- Double‑blind, randomized, placebo‑controlled trials showed that topical products containing plant extracts (e.g., Thuja occidentalis, Oryza sativa, Curcuma aeruginosa, Centipeda minima, Silybum marianum, and herbal mixtures) increased hair density or reduced hair loss in humans.
- Some plant extracts (e.g., Stryphnodendron adstringens bark, Curcuma aeruginosa in specific contexts) reduced hair growth in certain body areas, highlighting site‑ and formulation‑dependent effects.
- Oral intake of some extract formulations also improved hair parameters in clinical settings.
### 6. Phytochemical classes and active compounds
- The review categorizes active constituents into phenolic compounds (flavonoids, phenolic acids, tannins, coumarins, phenylpropanoids), terpenes/terpenoids, sulfur‑containing compounds, fatty acids, and others.
- Examples include: wedelolactone (Eclipta alba), decursin (Angelica gigas), kaempferol/quercetin/myricetin (various herbs), hydroxysafflor yellow A (Carthamus tinctorius), ginsenosides (Panax ginseng), sulforaphane (Brassica oleracea), α‑linolenic and linoleic acid (Boehmeria nipononivea, Oryza sativa).
- Many of these compounds show hair‑growth‑relevant activities such as promoting dermal papilla cell survival, enhancing VEGF expression, modulating prostaglandins, or attenuating androgen‑induced damage.
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## Mechanisms of action
### Promotion of anagen and prevention of premature telogen
- Plant extracts and their phytochemicals promote cell survival, proliferation, and cell‑cycle progression in dermal papilla cells and matrix keratinocytes, supporting anagen induction and extension.
- They upregulate growth factors such as IGF‑1, VEGF, HGF, and KGF (FGF‑7), which are central to follicle activation and anagen maintenance.
### Modulation of oxidative stress, inflammation, senescence, and apoptosis
- Many extracts alleviate oxidative stress, inflammatory responses, cellular senescence, and apoptosis in hair‑related cells and tissues.
- By reducing these stressors, plant extracts help preserve follicle function and delay degenerative changes that favor hair loss.
### Hormonal and receptor modulation
- Several extracts counteract androgen‑related damage by reducing the impact of testosterone/DHT on dermal papilla cells or modulating androgen receptor–linked pathways.
- Some phytochemicals are proposed to interfere with prostaglandin D₂ synthase or related mediators that negatively affect hair growth.
### Cell signaling pathways
- Active plant extracts and phytochemicals stimulate pro‑growth signaling via AKT/PKB, ERK, WNT, and SHH pathways, while suppressing inhibitory pathways mediated by TGF‑β and BMP.
- This dual modulation—enhancing pro‑anagen signals and dampening catagen/telogen‑promoting signals—supports hair growth and regrowth.
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## Relevance to Apple Poly products
### Poly‑GRO
This review emphasizes dermal papilla survival, anagen induction/extension, and modulation of oxidative stress, inflammation, and key growth factors (IGF‑1, VEGF, HGF, KGF). Those are the same biological categories Poly‑GRO is designed to support at the scalp level—follicle environment, cellular resilience, and growth‑phase support—within a plant‑extract–centric framework consistent with the mechanisms described in this paper.
### Apple Poly
Although this review surveys many different plants, it repeatedly highlights phenolic compounds and antioxidant, anti‑inflammatory, and signaling‑modulatory mechanisms that overlap with apple‑derived polyphenols. Apple Poly, as a concentrated polyphenol product, fits into the phytochemical profile emphasized here: phenolic‑driven support for dermal papilla viability, oxidative‑stress control, and pro‑anagen signaling, in line with the review’s focus on phenolics as key hair‑active constituents.
### Hair Growth Bundle
The Hair Growth Bundle combines the scalp‑directed, follicle‑environment focus of Poly‑GRO with the systemic polyphenol support of Apple Poly. This mirrors the multi‑level strategy described in the review: targeting dermal papilla cells, hair follicles, and broader oxidative/inflammatory pathways using plant‑derived compounds that modulate AKT, ERK, WNT, SHH, TGF‑β, and BMP signaling. Together, the products in the bundle align with the review’s conclusion that “well‑selected plant extracts and their active compounds can have beneficial effects on hair health.”
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## Conclusion
This 2024 narrative review concludes that a wide range of plant extracts can prevent hair loss or promote hair growth by acting on dermal papilla cells, hair follicles, and key signaling pathways in the hair cycle. Their effects include promoting anagen entry and duration, alleviating oxidative and inflammatory stress, modulating hormonal and receptor‑mediated damage, and engaging pro‑growth signaling cascades while suppressing inhibitory ones. The authors propose that identifying phytochemicals targeting these cellular events and pathways will facilitate the development of new, targeted therapies for alopecia.
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## Reference
Choi JY, Boo MY, Boo YC. Can Plant Extracts Help Prevent Hair Loss or Promote Hair Growth? A Review Comparing Their Therapeutic Efficacies, Phytochemical Components, and Modulatory Targets. Molecules. 2024;29(10):2288. PMID: 38792149. DOI: 10.3390/molecules29102288.
