What Do We Know About Hair Growth Induced by Wounding and Its Therapeutic Applications?

August 2023 in “ Dermatologic Surgery ”

Wipawan Vathananai, Francisco Jiménez

wound healing hair follicle growth microneedling fractional laser scalp threading androgenetic alopecia female pattern hair loss hypertrichosis hair cycle signaling pathways hair follicle proliferation hair shaft thickening male pattern baldness female pattern baldness excessive hair growth

Studysummary This study reviewed evidence suggesting that certain types of wounds might stimulate localized hair growth in humans, noting anecdotal reports and mixed efficacy of treatments like microneedling and lasers for androgenetic alopecia, but emphasized that further research is needed. Our plain-language summary of this paper — not a Tressless recommendation.

The article explores the relationship between wound healing and hair follicle growth, and the potential of wound-induced procedures to stimulate hair growth. Hair growth after wounding in humans is thought to be due to the activation of existing hair follicles, changes in the hair cycle, or activation of signaling pathways that increase hair follicle proliferation and hair shaft thickening. The article reviews the use of microneedling, fractional laser, and scalp threading as hair growth therapies for male androgenetic alopecia and female pattern hair loss. The largest study mentioned involved 117 patients with a history of bone fractures, with 34.2% reporting localized hypertrichosis (excessive hair growth). However, the efficacy and safety of these procedures as treatments for androgenetic alopecia are not yet fully established due to a lack of high-quality evidence. The article concludes that further randomized controlled studies with larger patient numbers and more appropriate objective outcome measurements are needed.

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This study found that among Chinese males with male androgenic alopecia, combination therapy using topical minoxidil and nano-microneedle-assisted fibroblast growth factor significantly improved hair density, diameter, and follicular unit density over 16 weeks, outperforming individual treatments.

Randomized Trial of Electrodynamic Microneedling Combined with 5% Minoxidil Topical Solution for Treating Androgenetic Alopecia in Chinese Males and Molecular Mechanistic Study of the Involvement of the Wnt/β-Catenin Signaling Pathway

research Randomized Trial of Electrodynamic Microneedling Combined with 5% Minoxidil Topical Solution for Treating Androgenetic Alopecia in Chinese Males and Molecular Mechanistic Study of the Involvement of the Wnt/β-Catenin Signaling Pathway

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This study found that combining microneedling with 5% minoxidil improved hair growth in Chinese men with androgenetic alopecia, possibly through activating the Wnt/β-catenin signaling pathway.

research Monofilament Threads in Treatment of Female Hair Loss

4 citations , October 2019 in “Journal of Dermatological Treatment”

This study reported that injecting monofilament threads into the scalp significantly improved hair count and hair mass index in women with female pattern hair loss, with most participants noticing substantial improvements in hair characteristics compared to a placebo.

research Deciphering the Molecular Morphology of the Human Hair Cycle: Wnt Signalling During the Telogen–Anagen Transformation

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This study found that Wnt signalling agonists increase and antagonists decrease in human scalp follicles from telogen to early-anagen, with differences from the mouse model suggesting targeted interventions for hair growth disorders.

research Effects of CO2 Fractional Laser on Hair Growth in C57BL/6 Mice and Potential Underlying Mechanisms

3 citations , March 2019 in “Chinese Medical Journal”

In this study using mice, fractional CO2 laser therapy promoted hair regrowth by inducing moderate inflammation, enhancing VEGF-mediated angiogenesis, and activating the Wnt10b signaling pathway.

research The Effect of the Fractional Carbon Dioxide Laser on Improving Minoxidil Delivery for the Treatment of Androgenetic Alopecia

6 citations , January 2019 in “Journal of lasers in medical sciences”

This study found that using a fractional CO2 laser in combination with minoxidil significantly increased hair count and thickness in Egyptian men with androgenetic alopecia.

Efficacy of 1,550-nm Erbium-Glass Fractional Laser Treatment and Its Effect on the Expression of Insulin-Like Growth Factor 1 and Wnt/β-Catenin in Androgenetic Alopecia

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10 citations , August 2018 in “Dermatologic Surgery”

This study found that 1,550-nm Er:Glass fractional laser treatment increased hair density and shaft diameter in patients with androgenetic alopecia, but did not up-regulate Wnt10A and IGF-1 mRNA expression.

research A Bald Statement: Current Approaches to Manipulate Miniaturization Focus Only on Promoting Hair Growth

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research Therapeutic Efficacy and Safety of a 1927-nm Fractionated Thulium Laser on Pattern Hair Loss: An Evaluator-Blinded, Split-Scalp Study

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research Never Too Old to Regenerate? Wound-Induced Hair Follicle Neogenesis After Secondary Intention Healing in a Geriatric Patient

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This case report describes an 80-year-old patient whose scalp wound healed by secondary intention, with unexpected hair regrowth observed at 180 days, suggesting hair neogenesis is possible even in older adults.

research Minoxidil Induction of VEGF Is Mediated by Inhibition of HIF-Prolyl Hydroxylase

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This study found that millimolar concentrations of minoxidil in the skin induced VEGF production through HIF-1 stabilization by inhibiting PHD-2, implying a molecular mechanism for hair growth promotion.

Randomized Trial of Electrodynamic Microneedle Combined with 5% Minoxidil Topical Solution for the Treatment of Chinese Male Androgenetic Alopecia

research Randomized Trial of Electrodynamic Microneedle Combined with 5% Minoxidil Topical Solution for the Treatment of Chinese Male Androgenetic Alopecia

28 citations , October 2017 in “Journal of Cosmetic and Laser Therapy”

This study found that combining microneedle treatments with 5% minoxidil topical solution led to the greatest increase in hair density among Chinese men with androgenetic alopecia.

research Scalp Threading with Polydioxanone Monofilament Threads: A Novel, Effective, and Safe Modality for Hair Restoration

11 citations , May 2017 in “Journal of The European Academy of Dermatology and Venereology”

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research Gold Thread Implantation Promotes Hair Growth in Humans and Mice

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This study observed that gold thread implantation increased hair regrowth in both human patients and mice, suggesting it could be an effective hair regrowth treatment, although further studies are needed to understand its mechanisms and safety.

research Repeated Microneedle Stimulation Induces Enhanced Hair Growth in a Murine Model

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This study found that repeated microneedle stimulation in mice promoted hair growth and increased the expression of hair-growth-related genes, suggesting potential therapeutic uses for alopecia.

research The Success of Thread-Embedding Therapy in Generating Hair Regrowth in Mice Points to Its Possible Effect in Humans

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research Enhancing Hair Follicle Regeneration by Nonablative Fractional Laser: Assessment of Irradiation Parameters and Tissue Response

16 citations , April 2015 in “Lasers in Surgery and Medicine”

In this study, the researchers found that the effectiveness of a 1,550-nm fractional laser in promoting hair growth in mice depends on the specific combination of beam energy and density, with inappropriate settings potentially causing ulcers or hair follicle injury.