Role of scalp health in achieving optimal hair growth and retention

Abstract

We have conducted a thorough review of the literature to assess the evidence for supporting a cause-and-effect linkage between scalp condition and resultant hair condition.Over 20 epidemiological studies have been published covering a wide range of abnormal scalp conditions in which consequent impacts to the hair have been documented. A treatment study was conducted to demonstrate not only that impaired scalp condition led to impaired hair quality but that the impacts to hair are reversible upon normalization of the scalp condition. A proposed explanation involves the impact of scalp oxidative stress, which is part of the etiology of these scalp conditions as well as normal aging, in interfering with the normal keratinization of the pre-emergent hair cuticle. This perturbed cuticle impedes normal fiber anchorage and emerges more brittle and fragile than normal cuticle leading to accelerated physical degradation, mirroring the effects of chronological aging of the hair fiber. The consequences of the rapid cuticle degradation result in hair that is more vulnerable to mechanical insults and compromised overall quality. RésuméNous avons mené un examen approfondi de la littérature médicale pour évaluer les preuves étayant un lien de cause à effet entre l'état du cuir chevelu et celui des cheveux. Plus de 20 études épidémiologiques ont été publiées, couvrant un large éventail d'affections du cuir chevelu pour lesquelles des impacts conséquents sur les cheveux ont été documentés. Une étude de traitement a été menée pour démontrer non seulement qu'une altération du cuir chevelu entraînait une altération de la qualité des cheveux, mais aussi que les impacts sur les cheveux étaient réversibles après normalisation de l'état du cuir chevelu. Une explication proposée inclut l'impact du stress oxydatif sur le cuir chevelu, qui fait partie de l'étiologie de ces affections du cuir chevelu ainsi que du vieillissement normal, en interférant avec la kératinisation normale de la cuticule du cheveu à son point d'émergence. Cette cuticule perturbée gêne l'ancrage normal des fibres et fait émerger des cuticules plus fragiles et friables que la normale, entraînant une dégradation physique accélérée, reflet des effets du vieillissement chronologique des fibres capillaires. La dégradation rapide de la cuticule rend les cheveux plus vulnérables aux agressions mécaniques et compromet leur qualité globale.

Scalp application of antioxidants improves scalp condition and reduces hair shedding in a 24‐week randomized, double‐blind, placebo‐controlled clinical trial

“…A hypothesis was that premature loss was at least partially due to asymptomatic, though non-optimal, scalp condition resulting in an environment that is not maximally supportive of normal hair fibre maturation and retention. The cause-and-effect association between scalp condition and maturation of pre-emergent hair fibre is well established based on epidemiological and treatment studies of compromised scalp conditions with specific symptomologies [18]. It is likely that these disturbed scalp conditions create an environment that perturbs normal passive fibre maturation during the two-week transit to the scalp surface impairing optimal fibre anchorage.…”

“…Reducing oxidative stress at the scalp creates a physical/chemical environment that appears to allow the pre-emergent hair fibre to mature normally [18]. While proliferation occurs in the follicular bulb, the remaining pre-emergent hair is considered to be 'dead' [19].…”

Scalp application of the antioxidant piroctone olamine reduces hair shedding in an 8‐week randomized, double‐blind, placebo‐controlled clinical study

“…As mentioned in the introduction, once hair is lost, there are few non-surgical reliable options to re-grow it [1]. Our hypothesis [2,3] is that premature hair loss is due to nonoptimal scalp condition resulting in an environment that is not maximally supportive of normal hair fibre maturation and retention. The cause-and-effect association between scalp condition and maturation of pre-emergent hair fibre is well established based on epidemiological and treatment studies of compromised scalp conditions with specific symptomologies [3].…”

“…Our hypothesis [2,3] is that premature hair loss is due to nonoptimal scalp condition resulting in an environment that is not maximally supportive of normal hair fibre maturation and retention. The cause-and-effect association between scalp condition and maturation of pre-emergent hair fibre is well established based on epidemiological and treatment studies of compromised scalp conditions with specific symptomologies [3]. It is likely that these disturbed scalp conditions create an environment that perturbs normal fibre maturation during the near two-week transit to the scalp surface impairing optimal fibre anchorage.…”

“…We have previously shown [2] that topical delivery of a mixture of materials with direct and indirect antioxidant activities can create a scalp environment that reduces premature hair loss. This is based on substantial observational and treatment data that relate a poor scalp condition to increased hair shedding and impaired normal pre-emergent hair maturation via oxidative stress [3]. Since the skin's surface natural antioxidant defences can be overwhelmed by exogenous oxidant stress [4][5][6][7], supplementing the scalp with topically applied cosmetic antioxidant materials is a rational approach to shielding the skin from oxidative stress so that it can naturally restore normalcy and reduce premature hair loss.…”