The Phenomenon of the Seasons: Why Does Hair Fall Out More in Autumn and Spring?

If you often notice that your hairbrush or the shower drain accumulates many more strands during autumn and spring, know that you are not alone. At Faithful Hair Clinic in Porto, our diagnostic consultations increase significantly during these times of the year. The complaint is almost always the same: "Doctor, my hair seemed under control, but now it’s falling out in clumps. What changed?"

Although popular wisdom often associates this phenomenon with "falling leaves" or temperature changes, the clinical truth is much more fascinating. There is a severe biological and evolutionary explanation for this scalp behavior.

Below, we deconstruct the science behind Seasonal Telogen Effluvium and explain what you can actually do to halt this process before it affects your hair density.

The Science of Photoperiod: Why Does Hair Fall Out More in Autumn and Spring?

To understand seasonal shedding, we need to talk about chronobiology and circadian rhythms. The main trigger for hair loss in autumn and spring is not cold or heat, but the photoperiod—the variation in the number of hours of sunlight throughout the day.

The human hair cycle is divided into three phases: Anagen (active growth), Catagen (involution), and Telogen (rest and shedding). Under normal conditions, about 85% to 90% of your hair is growing, while the rest is preparing to shed. However, seasonal transitions alter this balance.

The Autumn Peak (The Summer Effect)

Photobiology studies demonstrate that during the months of July and August, the human body increases the number of follicles in the anagen phase (growth). This is an evolutionary mechanism inherited from mammals: the body retains more hair on the top of the head to protect the scalp and brain from intense summer ultraviolet (UV) radiation.

When days begin to shorten in autumn, the production of melatonin and other regulatory hormones changes. Those follicles that were "forced" to stay alive during the summer simultaneously enter the telogen phase. About 100 to 120 days later (the time the resting phase takes), a synchronized mass shedding occurs.

The Spring Renewal

In spring, the process is reversed. The abrupt increase in sunlight hours stimulates cellular metabolism and signals the body to initiate a renewal phase. Many follicles that completed their life cycle during the winter are "pushed out" to make way for new strands. It is a molting process, similar to what happens in nature.

What Can Be Done to Counteract Seasonal Shedding?

If the shedding is strictly seasonal, your hair should recover its natural balance in about 4 to 6 weeks. However, if your hair is already suffering from a silent process of miniaturization (genetic weakening), seasonal shedding can accelerate baldness definitively.

To halt the process and ensure hair grows with maximum strength, the approach at Faithful Hair Clinic rests on three scientific pillars:

1. Metabolic Optimization and Focused Diagnosis

Before taking any "trendy" supplement, it is necessary to understand if your body has the "bricks" needed to build hair. Our Clinical Director, Dr. Cristina Sá, underscores the importance of evaluating specific blood markers:

• Ferritin and Iron: Fundamental for cellular proliferation in the hair bulb.

• Vitamin D3 and Zinc: Modulators of the follicular cycle. If these levels are low, seasonal shedding will be much more severe and long-lasting.

2. Waking Up Cells: ATP Stimulation and Vascularization

Because the hair follicle spends a massive amount of energy (ATP) to produce the strand, we need to re-establish the blood microcirculation affected by seasonal hormonal changes. At Faithful, treatments of excellence such as Hair Mesotherapy and PRP (Platelet-Rich Plasma) are our greatest allies.

The precise application of these treatments is performed by Nurse Daniela Machado, whose curriculum of over 17 years dedicated exclusively to hair health—under the supervision of the clinical director—ensures that growth factors and vitamins penetrate exactly into the follicular dermis. The follicle receives a "nutrition shock" that shortens the shedding phase and forces the start of a new, strong growth phase.

3. Validated Topical and Oral Therapy

To stop shedding at the root, our doctors, such as Dr. Leila Lieva and Dr. Caroline Alves, prescribe personalized topical lotions and/or oral formulas that act directly on the follicle's hormone receptors to prevent weakening.

The Faithful Warning: When Does It Stop Being Seasonal?

If your hair loss crosses the six-week barrier, if you notice your central part is widening, or if your scalp has started to become visible in the mirror, the problem is no longer the season. You may be facing chronic effluvium or the onset of androgenetic alopecia.

The change of season should be a period of renewal for your hair, never of permanent loss. Protecting your hair capital requires science, diagnosis, and real medical follow-up.

To better understand your situation and help protect your hair health, how long ago did you notice this sudden increase in hair loss, and have you undergone any hair treatment previously?

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