Article updated in April 2026

Hair loss is one of the most frequent reasons for consultation in our clinics, both in Madrid and Mexico City. In many cases, patients report having noticed an increase in hair loss during periods of stress, but also after stages of insufficient rest or sleep disturbances.

Although the focus has traditionally been on stress, recent years have shown that sleep quality and circadian rhythm can also play a relevant role in hair health.

Table of Contents

1. How much hair is normal to lose per day?
2. Why does hair fall out?
3. Stress and hair loss: what happens in the body
4. Sleep, circadian rhythm, and hair loss
5. Does it influence androgenetic alopecia?
6. Frequently Asked Questions
7. When to consult a specialist
8. Conclusion

1. How much hair is normal to lose per day?

In a healthy person, it is normal to lose up to 100 hairs per day as part of the natural cycle of the hair follicle. This hair will be replaced by a new one, maintaining the capillary balance.

The problem arises when this cycle is altered and the loss exceeds the regeneration capacity.

2. Why does hair fall out?

Alopecia is a multifactorial condition, meaning it is usually due to a combination of different factors:

• Genetic
• Hormonal
• Nutritional
• Inflammatory
• Environmental

Within the latter, stress and sleep alterations play an increasingly relevant role in clinical practice.

3. Stress and hair loss: what happens in the body

Stress can influence hair health through various mechanisms:

• Increased cortisol levels
• Higher systemic inflammation
• Alteration of the immune system
• Changes in the hair follicle cycle

As a consequence, telogen effluvium may appear, in which a greater number of follicles prematurely enter the shedding phase.

In diseases such as alopecia areata, stress can also:

• Promote inflammation
• Alter the regulation of the autoimmune response
• Modify the activity of the hair follicle

4. Sleep, circadian rhythm, and hair loss

In addition to stress, sleep quality has been identified as a relevant factor in the regulation of the hair cycle.

The hair follicle is influenced by the so-called circadian rhythm, a biological system that regulates multiple functions of the body throughout the day, including growth and regeneration processes.

When there is a sleep disturbance—whether due to insomnia, insufficient rest, or changes in schedules—alterations in this balance can occur.

From a biological perspective, it has been observed that these alterations can:

• Modify the circadian rhythm of the hair follicle
• Alter the expression of genes related to the “biological clock,” such as the PER3 gene
• Delay the entry into the anagen phase (growth phase)
• Promote staying in the telogen phase (resting and shedding phase)

From a clinical point of view, this can translate into greater hair loss or a progressive decrease in hair density, especially in patients with a prior predisposition.

Furthermore, some conditions associated with sleep disturbance, such as obstructive sleep apnea (OSA), have been linked to a higher risk of developing androgenetic alopecia.

As with stress, sleep does not usually act as the sole cause, but rather as a factor that can trigger or aggravate existing hair processes.

5. Does it influence androgenetic alopecia?

Yes, although indirectly.

In androgenetic alopecia (the most common in men and women), the following has been observed:

• Lower expression of the PER3 gene
• Longer duration of the follicle in the telogen phase
• Possible acceleration of the miniaturization process

This suggests that factors such as sleep can influence the evolution of this pathology, especially when a genetic predisposition exists.

6. Frequently Asked Questions

Does stress cause hair loss directly?
Not always directly, but it can trigger processes like telogen effluvium or make previous alopecia more evident.

Is hair loss due to stress permanent?
In most cases, no. When it is telogen effluvium, it is usually temporary and reversible.

Can poor sleep cause hair loss?
It can promote it. Poor sleep quality can alter the hair cycle and contribute to its loss.

Does improving sleep help recover hair?
In some cases, yes. Especially when there is a component of telogen effluvium or associated inflammatory factors.

Can this type of hair loss be prevented?
Partially yes, through:

• Adequate sleep hygiene
• Stress management
• Early medical evaluation

7. When to consult

If you notice:

• Higher than usual hair loss
• Decrease in density
• Changes in the thickness or quality of the hair

It is recommended to seek a specialized medical evaluation.

A proper diagnosis allows the identification of the cause and the proposal of a personalized treatment based on each case.

8. Conclusion

Stress and sleep disturbances are not the sole cause of hair loss, but they can act as triggering or aggravating factors.

Therefore, in the approach to alopecia, it is important to consider not only the hair treatment but also the general context of the patient.

This content has been developed by the medical team of the Instituto Médico del Prado and reviewed by Dr. Bonilla Juárez and Dr. Muñoz Ramírez.

If you have noticed changes in your hair or an increase in shedding during periods of stress or sleep disturbances, a proper medical evaluation can help identify the cause and guide the most appropriate management for your case.

We see patients in both Madrid and Mexico City, adapting each therapeutic approach to the characteristics and evolution of each patient.

The Instituto Médico del Prado is a clinic specialized in the diagnosis and treatment of hair pathologies. If you wish, you can request an evaluation through our usual channels.

9. Bibliography

1. Boghosian T, Mendez H, Sayegh M, et al. The intersection of sleep and hair loss: a systematic review. Dermatol Ther (Heidelb). 2026.
2. Wu Q, Li M, Xiong Y, et al. Association between sleep patterns, circadian rhythms, and hair loss in young adults. Chronobiol Int. 2025.
3. Peters EMJ, Arck PC, Paus R. Hair growth inhibition by psychoemotional stress. Exp Dermatol.
4. Paus R, Arck P. Neuroendocrine perspectives in alopecia areata. J Invest Dermatol.
5. Gupta MA, Gupta AK. Sleep-wake disorders and dermatology. Clin Dermatol.
6. Trüeb RM. Stress and hair loss: a review. J Eur Acad Dermatol Venereol.
7. Kwon O et al. Human hair growth and stress hormones. Ann Dermatol.
8. Lee S et al. Sleep apnea and androgenetic alopecia. Sleep Med.