How does stress affect hair?

Key points to remember.

Stress seems capable of disrupting the hair growth cycle by affecting the nervous and immune systems.
Acute stress situations, such as an examination period, can temporarily slow hair growth, generally without lasting consequences.
Chronic stress is often accompanied by a prolonged elevation of cortisol measurable in hair, potentially compromising hair health and making hair more brittle.
Stress may also contribute to premature ageing of hair and to hair greying, although this link remains scientifically debated.
The stress-management techniques can reduce psychological and physiological stress, with potentially beneficial effects on hair health.
Simple everyday strategies — physical activity, relaxation, leisure activities, social support — also help reduce the impact of stress on the body and hair.

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How does stress affect hair?

The stress is now recognised as a factor capable of influencing numerous tissues in the body, including the hair follicle.

Some individuals therefore observe a hair loss or a slowdown in growth after an episode of intense psychological or physical stress. These manifestations are explained by the impact of stress on the biological mechanisms that regulate the hair cycle, particularly at the level of follicular stem cells.

Indeed, several studies have shown that stress can inhibit hair growth by blocking the cell cycle of follicular stem cells. In a murine model subjected to severe stress – induced either by repeated resiniferatoxin injections or by physical restraint – the researchers observed a marked inhibition of regrowth after depilation, both in the telogen and anagen phases. Transcriptomic analysis revealed a decrease in the expression of genes involved in cell proliferation, associated with activation of the cAMP signalling pathway in Lgr5+ follicular stem cells. This response was accompanied by activation of the sympathetic nervous system and an increased release of noradrenaline, which was able to reduce cell proliferation, diminish the expression of cell cycle regulators such as cyclins D1/D2 and CDK4, and increase the proportion of cells in the G0/G1 phase, the quiescent stage of the cell cycle.

Beyond these experimental data, certain clinical studies have also explored the concrete effects of stress on hair. One study conducted among 33 female medical students thus assessed the effects of prolonged stress associated with preparing for a final examination on immunity and hair parameters. The participants were monitored at three distinct time points: before the revision period, during the exams, and after a twelve-week recovery period. The results show that perceived stress increased significantly during the exams, accompanied by a transient shift in immune balance towards a Th1-type response, as well as measurable changes in the hair growth cycle. However, these changes remained within physiological limits and subsided after the recovery period, with no lasting differences compared to the control group.

These data suggest that intense stress can temporarily disrupt hair growth via immune mechanisms, while remaining reversible — a reassuring finding for individuals experiencing hair loss during periods of high stress.

Beyond the transient effects of acute stress, prolonged exposure to chronic stress also appears to affect hair growth. A recent meta-analysis of 66 independent studies (over 10,000 participants) investigated hair cortisol concentration, a biological marker for assessing cumulative long-term stress exposure. The results show that groups exposed to chronic stress exhibit higher hair cortisol levels than others, which is likely to impair hair growth. Conversely, when the stress is in the past, hair cortisol levels no longer differ significantly, suggesting a reversible phenomenon. These data thus reinforce the idea that it is not so much the intensity of a single stress event but the duration of exposure that could have a lasting influence on hair health.

+ 22%

hair cortisol levels in groups subjected to chronic stress (meta-analysis encompassing 66 studies, totalling over 10,000 participants).

+ 43%

hair cortisol in groups subjected to chronic stress still present at the time of assessment (meta-analysis pooling 66 studies, involving over 10,000 participants).

Furthermore, stress could also accelerate hair whitening.

It should be noted that hair colour depends on the activity of melanocytes located in the hair follicle, which are responsible for producing melanin. During periods of stress, the release of neurotransmitters by the nervous system can promote the onset of oxidative stress, characterised by the accumulation of free radicals capable of damaging melanocyte DNA and impairing their function. This type of oxidative damage is more generally involved in the cellular ageing of the skin and hair. Nevertheless, while some empirical data suggest a link between stress, oxidative stress and the appearance of grey hair, direct scientific evidence remains limited to date, indicating that other factors — genetic, hormonal or environmental — also contribute to the process of hair depigmentation.

What measures can be taken to limit the effects of stress on hair?

In response to the potential effects of stress on hair, management relies above all on approaches designed to reduce psychological strain and its physiological repercussions.

Interventions such as mindfulness-based stress reduction, cognitive-behavioural therapy or hypnotherapy have demonstrated their capacity to improve mental health, reduce anxiety and, in certain cases of hair loss, promote hair regrowth. More broadly, structured stress management programmes can lead to a reduction in cortisol levels measured in hair, thereby suggesting a potential benefit for hair cycle balance.

A controlled clinical trial involving 78 pregnant women precisely assessed the effectiveness of a cognitive-behavioural stress management therapy (CBT) on hair cortisol levels. The participants were assigned to either a control group or a group that underwent eight weekly CBT sessions. Following the intervention, only the women in the CBT group showed a concurrent reduction in hair cortisol and in perceived stress, including stress related to pregnancy.

Scores avant et après l’intervention dans les principales mesures de stress. — Pre- and post-intervention scores for the principal stress measures.
Source: PERALTA-RAMIREZ R. I. & al. Effects of cognitive-behavioural therapy for stress management on stress and hair cortisol levels in pregnant women: A randomised controlled trial. Journal of Psychosomatic Research (2020).

Learning to manage stress therefore seems to be a relevant lever for preserving psychological, physical and even hair health.

Note : It is not always necessary to employ complex strategies to manage day-to-day stress more effectively. Gaining perspective on difficult situations, maintaining regular physical activity, practising meditation or breathing exercises, preserving leisure time and discussing concerns with those around you are all simple approaches that help alleviate stress. Nevertheless, when anxiety becomes overwhelming or persistent, psychological support can be useful in restoring a healthier balance to everyday life.