If your hair starts falling out in September or October, summer is probably the cause. But not in the way most people think. Here is what is actually happening, and how to stop it.
The 100-Day Delay Nobody Talks About
Hair does not respond to damage immediately. The follicle operates on its own biological clock, cycling through phases of growth, transition, and rest over a period of months. When something disrupts that cycle - and summer disrupts it more than almost anything else - the hair does not fall out straight away. It enters a resting phase called telogen. And roughly 100 days later, it sheds.
This is why September and October are the peak months for hair loss complaints across Europe, every year, without exception. The research confirms it: studies analysing Google search data across multiple countries consistently find "hair loss" searches highest in August and September, with summer the dominant triggering season. The biological explanation comes from a landmark study at the University Hospital of Zürich, which found that healthy women had the highest proportion of resting-phase hair follicles in July: exactly when summer stress peaks, with the resulting shedding following months later.
You were not imagining that your hair looked fine in August. It probably did. The bill just hadn't arrived yet.
What Summer Actually Does to Your Hair
The disruption happens through four separate mechanisms that often act at the same time.
UV radiation from the sun breaks down the protein structure of the hair shaft. But more importantly for shedding, prolonged UV exposure affects the scalp itself, altering the follicle environment and disrupting normal growth cycles. Research suggests that photoperiod changes - the shift in day length through summer may directly influence the timing of the telogen phase in humans, as they do in other mammals.
Salt water and chlorine are both alkaline. Hair's natural pH sits between 4.5 and 5.5. Extended exposure to the sea or a swimming pool raises that pH, swelling the cuticle, weakening the cortex, and making the hair far more vulnerable to mechanical stress from brushing, towel-drying, and heat styling.
Heat and dehydration reduce blood supply to the scalp. The follicle depends on adequate microcirculation for oxygen and nutrient delivery. When blood flow to the periphery is reduced, follicles are among the first structures to feel it.
Cortisol, the stress hormone, has a documented effect on the hair growth cycle. Summer, for most people, involves disrupted sleep, travel stress, dietary changes, and alcohol. Even when it feels like a holiday, the body often registers it as physiological load. Elevated cortisol can push a significant proportion of follicles into the resting phase at the same time, causing the synchronised shedding that feels so alarming when it arrives.
None of these factors operate in isolation. For most people, summer combines all four simultaneously, which is precisely why the post-summer shedding period can feel dramatic even in people who have never experienced hair loss before.
Is This Normal or Not?
Losing 50 to 100 hairs per day is within the normal range. Most people do not notice this because it happens gradually and continuously across the scalp.
Post-summer telogen effluvium is different. Because the summer triggers push a larger number of follicles into the resting phase at roughly the same time, the shedding tends to arrive in a wave. It can feel sudden, concentrated, and alarming, even though the underlying process is physiological rather than pathological.
The important distinction is this: telogen effluvium is a cycle disruption, not follicle destruction. The follicles are still present. They are resting, not dying. For most people, the shedding resolves on its own within three to six months as the growth cycle restores itself.
The risk is not the shedding itself. The risk is the window of vulnerability it creates. Follicles that are repeatedly stressed, poorly nourished, or chronically under-stimulated can begin to miniaturise over time. Each shedding cycle, if unsupported, can leave the hair slightly thinner and less resilient than before. This is why addressing post-summer shedding proactively matters, even when it feels like something that will resolve on its own.
When to See a Dermatologist
Not all hair loss is seasonal. Before assuming yours is, it is worth knowing what the red flags look like.
See a dermatologist if:
- Shedding continues for longer than six months without improvement
- Hair loss is patchy or concentrated in specific areas rather than diffuse
- The scalp is itchy, inflamed, red, or painful
- You notice a visible receding hairline or widening part
- Hair loss is accompanied by changes in nails, skin, or unexplained fatigue
These patterns suggest something beyond seasonal shedding, including conditions like androgenetic alopecia, alopecia areata, or systemic issues such as thyroid dysfunction, iron deficiency, or autoimmune disease. A proper diagnosis matters, because the treatment is completely different.
The protocol described in this article is appropriate for post-summer telogen effluvium in people with no underlying pathology. It is not a substitute for medical evaluation.
The Vital Ker Hair Loss System
Vital Ker Hair Loss is a professional Italian haircare line formulated specifically for the scalp, not just the hair. It was developed by Vitalfarco, whose laboratory focuses on trichological formulations for professional salon use. The line is free of parabens, colorants, and silicones.
The formula works through three active mechanisms working together:
Plant stem cells derived from Globularia Cordifolia act on the hair follicle directly, supporting the natural recovery of the growth cycle and helping to delay follicle ageing. This is not a surface-level ingredient - it targets the biological process that post-summer shedding disrupts.
Vitamin B complex (B3, B5, and B6) supports scalp microcirculation. Better blood flow means better nutrient and oxygen delivery to the follicle base, exactly what is depleted during a summer of heat and dehydration.
Essential oils including rosemary, sage, tea tree, mint, juniper, and lavender provide a stimulating scalp environment that complements the active ingredients rather than simply making the product pleasant to use.
The system consists of three products, each with a specific role in a complete protocol.
The Routine Bundle €25.89 (Shampoo 250 ml + Lotion, 15% saved)
The most practical way to start the protocol. The Hair Loss Routine bundle combines the shampoo and lotion as a system for 15% less than purchasing them separately, and includes enough product for a complete first treatment cycle.
Most people start here before deciding whether to add the intensive ampoules based on how their hair responds over the first four to six weeks.
A Realistic 60-Day Protocol
Week 1 to 2: Begin with the shampoo three times per week and the lotion daily. The scalp environment shifts within the first two weeks. Shedding is unlikely to reduce yet, this is normal. The active ingredients need time to work at follicle level.
Week 3 to 4: Shedding typically begins to stabilise. New hair growth may not yet be visible, but the density of shedding in the shower and on the brush should start to feel less acute.
Week 5 to 8: With consistent use, hair noticeably strengthens. Reduced breakage, better volume at the root, and improved scalp comfort are the indicators to watch.
For the acute phase of post-summer shedding, particularly if the shedding wave feels severe - adding the Intensive Lotion ampoules for the first four weeks alongside the shampoo and daily lotion delivers the most concentrated treatment the Vital Ker system offers.
The Thing Most People Get Wrong
The most common mistake is waiting to see if it gets better on its own, then acting only when the shedding becomes genuinely alarming.
By that point, several shedding cycles have passed. Each cycle of unaddressed stress on the follicle leaves a small but cumulative deficit. The hair that grows back after untreated effluvium is often finer than the hair that shed. Not dramatically so, but measurably.
The biology of hair loss responds well to early intervention and poorly to delayed action. The September wave is predictable, it recurs every year for people who spent a real summer outdoors, and the protocol to address it is straightforward.
This is not about being anxious about normal shedding. It is about understanding that the follicle is a living structure that benefits from consistent support, and that the weeks after summer are the most important window to provide it.
Three Things Worth Doing Right Now
If you are reading this in July or August, you are ahead of the problem. Start the Vital Ker routine before the shedding wave arrives, and you give the follicles a head start.
If you are reading this in September or October and the shedding has already started, begin the protocol as soon as possible. The earlier you start, the shorter and less pronounced the shedding phase will be.
Either way, the most useful next step is the same.
[Shop the Hair Loss Routine →] - Shampoo + Lotion bundle, €25.89, free delivery in Slovenia.
[Add the Intensive Lotion →] - For the acute phase, €36.75 per box of 10 ampoules.
If you are unsure whether what you are experiencing is seasonal shedding or something else, start with a dermatologist rather than a product. Prolas sells professional haircare, not medical diagnoses. The protocol above is designed for healthy adults experiencing post-summer telogen effluvium, not for the treatment of pathological hair loss conditions.