Does Brushing and Combing Stimulate Hair Growth?

Hair growth, an integral aspect of personal grooming and physical appearance, is a subject of interest for many individuals. A commonly held belief is that brushing or combing hair may stimulate hair growth. This belief is rooted in the presumption that brushing enhances scalp circulation, thereby promoting hair growth. This article aims to analyze the scientific evidence for this claim.

The idea that hair brushing promotes hair growth has been around for a long time. An advice and information handbook from 1860, called “the housewife’s reason why…”, poses the question: “Why does combing and brushing the hair promote its growth and nourishment?” And answers: “Because, by combing the hair, we free the fluid which is secreted from the roots, from those obstructions which must arise in consequence of the hair being bent in all directions, and by brushing we promote the circulation of the blood through the bulbs, and free it from those secretions, which, if allowed to remain and increase, become of serious inconvenience.” This view and similar was widely held until well into the 20^th Century, even today some people still claim hair brushing promotes hair growth, but the scientific evidence in support of the claim is very limited.

Hair growth and health are influenced by various factors, including diet, age, genetics, and overall health. Brushing or combing hair has been suggested to stimulate blood flow to the scalp, potentially leading to enhanced hair growth. This hypothesis is founded on the knowledge that blood flow in the skin provides oxygen and nutrients to hair follicles, supporting their function. However, hair fiber above the roots is essentially dead material, the cells of the hair fiber are filled with keratins the makes the hair hard, but the keratin accumulation kills the cells. As such there is no mechanism by which the dead hair can send signals back to the live roots when it is “bent in all directions”.

Brushing the scalp skin as a way to stimulate blood flow seems a more reasonable theory, at least on first inspection, though empirical research supporting it is scant. Most studies on hair growth stimulation focus on pharmacological interventions, hormonal influences, or genetic factors. Current literature on the mechanical stimulation of hair follicles by physical methods, such as brushing or combing, and its effect on hair growth, is noticeably limited. Still, it seems reasonable from direct observations that vigorous brushing can irritate the scalp skin and make it more red in color. Essentially, the physical action of repeated brushing on the scalp skin makes the blood vessels vasodilate and get larger. In principle, that could allow more nutrients to get to the hair follicles.

However, while this increased scalp blood flow may seem potentially beneficial for hair growth, the process of mechanical hair brushing may also cause physical damage. Excessive brushing can lead to hair breakage and split ends, negating any potential benefits to hair growth. Combing wet hair, often considered a way to untangle with much less breakage, could also contribute to hair damage due to the increased elasticity and fragility of wet hair. Therefore, any potential hair growth promoting benefits of brushing or combing must be considered alongside these potential drawbacks. Of the few research studies in this area, all of them say that vigorous brushing does more damage and accelerates hair shedding. Kiderman and colleagues even go as far as recommending reducing the frequency of hair brushing as a way to limit hair shedding (though the effect is likely only brief, all hair will shed at some point in time).

Brushing’s role in sebum distribution deserves a mention. Brushing or combing helps to distribute the natural oils (sebum) produced by the sebaceous oil glands that are attached to the hair follicles, protecting the hair shaft from breakage and maintaining a healthy scalp environment. In this regard, brushing or combing may contribute indirectly to hair health, particularly for people with curly hair. Sebum, naturally produced by sebaceous glands at the hair root, provides a protective coating for the hair. Proper distribution of this oil helps in maintaining hair health and preventing the appearance of dryness. Brushing assists in this distribution process, indirectly supporting hair health. However, this effect is not directly linked to hair growth stimulation.

In conclusion, while brushing and combing serve important roles in maintaining hair health and managing aesthetic appearance, current scientific literature does not support the notion that they stimulate hair growth. Hair growth is a complex biological process influenced more substantially by factors such as diet, hormonal balance, genetics, and overall health.

Future research could focus on exploring the impact of brushing and combing on scalp blood circulation and the direct effects on hair growth over time. For now though, it is prudent to approach the claim of hair growth stimulation via brushing and combing with a healthy scepticism. As always, a balanced lifestyle, good nutritional intake, and proper hair care routine are paramount for promoting hair health and growth. Remember that significant hair loss or changes in hair growth can be symptoms of underlying health conditions. Individuals experiencing such changes should consider seeking professional healthcare advice.

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