For all hair types: the most widespread myth in hair care

For years, hair cosmetics have repeated a seemingly unquestionable promise: shampoos and treatments “for all hair types.”

The message is appealing. It suggests simplicity, universality, and ease of choice.
However, from a biological and dermatological perspective, this statement is, at the very least, incomplete.

It is important to make an essential distinction: not all hair products interact with the same biological structure. Masks and most conditioners primarily act on the hair fiber, while shampoo is, above all, a skin-contact product.

And it is precisely on the skin, on the scalp, where true cosmetic compatibility is determined.

The most common misconception in hair care

Hair is a keratinized fiber; it is a biologically inert structure. It has no metabolism, no immunological response, and no capacity to inflame.

The scalp is a continuation of the facial skin, biologically active.

A cutaneous extension where highly dynamic structures are integrated, particularly the pilosebaceous unit, involved in key physiological processes such as:

• Sebaceous gland activity.
• Integrity of barrier function.
• Balance of the cutaneous microbiome.
• Sensory reactivity.
• Inflammatory dynamics.

Sebaceous secretion is not a direct function of the epidermal surface, but of the sebaceous gland associated with the hair follicle, whose activity is primarily modulated by hormonal and metabolic signals. Sebum is released into the follicular canal and from there contributes to the physiological environment of the scalp.

In dermatological terms, the scalp constitutes the main biological tissue exposed to cleansing systems, i.e., shampoos. However, much of the cosmetic discourse has been built around "hair type," shifting attention away from where relevant physiology actually occurs.

What could truly be considered “universal” in hair formulation

From a laboratory perspective, universality is not impossible, but it is limited.

A formula with broad compatibility that does not destabilize the scalp usually shares very specific principles:

• Non-aggressive cleansing systems.
• Low alteration of the hydrolipidic film.
• Minimization of cumulative irritant potential.
• Respect for the microbial ecosystem.
• Good tolerance with repeated use.
  

This approach completely redefines the concept of "universal."

It does not imply that a product is optimal for all needs, but rather that it represents a reduced probability of negatively interfering with the physiological balance of the scalp.

When universality loses its scientific basis

The promise of "suitable for everyone" can make sense when a product is designed to accompany: to cleanse without destabilizing, to respect the barrier, to maintain comfort.

But when a product seeks to correct something more directly, universality begins to fail. And this is constantly seen in product development: the same action that transforms one person's scalp can leave another's "on alert."

This usually occurs when more specific actions come into play, such as:

• Control of excess sebum.
• Exfoliation / keratolytic action.
• Antifungal strategies.
• Highly biologically intense active ingredients.
• Deeper cleansing and purifying protocols.

Here the key is simple: the scalp is not always in the same state.

The same active ingredient can be helpful when there is oiliness, flaking, or a "heavy" feeling, and yet be excessive when the barrier is more sensitive or the scalp is more reactive.

Because the scalp's response is neither uniform nor permanent: it changes with the season, stress, washing frequency, water, color treatments, heat use..., and its barrier function at that moment.

Environment and skin condition: variables almost never considered

We often talk about “oily hair,” “dry hair,” or “flat hair” as if they were fixed traits. As if hair had a stable and immutable identity.

In practice, what usually changes is not the fiber, but the biological environment in which it grows.

The scalp is a tissue extraordinarily sensitive to context. Its behavior can be modified with relative ease depending on daily factors:

• Seasonal and climate changes.
• Physiological stress.
• Washing frequency.
  
• Leaving it wet for too long.
• Water type.
• Cumulative cosmetic routines.
• Diet.

Something as simple as transitioning from winter to summer, varying exercise frequency, or moving cities can completely alter the perception of hair. Not because the hair has changed, but because the scalp's physiology is dynamic.

Even in the same person, sebum production, feeling of comfort, or skin reactivity can fluctuate without any structural modification in the hair fiber.

And this variability is precisely what complicates universal promises.

The question almost no one asks, and it changes everything

The market has taught us to look at the fiber: shine, frizz, volume, split ends. But science, and daily clinical experience, force us to look at the scalp first.

That's why the usual question is often:

What shampoo do I need for my hair type?

And the truly useful question is another:

What does my scalp need right now?

Because the scalp is not a neutral background: it is a living, changing tissue that responds to the season, stress, washing frequency, water, habits..., and also to what we apply to it.

When that foundation is in balance, hair usually becomes more predictable: it gets less dirty, fizzes less, feels more consistent, more beautiful. And when it's not, we try to compensate from the fiber, with more masks, more oils, more repair, without having resolved the origin.

In hair care, often the before and after doesn't start at the length. It starts at the scalp.

If you want to discover what your scalp needs right now, take our diagnostic test.

A formulation centered on biology, not labels

For years, hair cosmetics have simplified diagnosis into convenient categories:
dry hair, oily hair, fine hair, damaged hair. But real physiology rarely responds to static labels.

The scalp is a dynamic biological system, influenced by the activity of the pilosebaceous unit, the state of the skin barrier, the microbial environment, and multiple external factors. Reducing this complexity to “hair types” is not only imprecise but often leads to ill-suited routines.

In advanced formulation, the approach changes radically. It is no longer about classifying hair, but about understanding the ecosystem where it originates. It is about observing how the skin behaves, how it responds to washing, how it tolerates active ingredients, how its balance varies.

This shift in perspective is what we at Modesta Cassinello define as Scalpology.

Not as a trend, but as a development logic: a way of designing products starting from the scalp as the main target tissue, prioritizing its physiological stability before any cosmetic promise about the fiber.

From this approach, formulating does not consist of “treating hair types,” but of respecting biological systems.

• Maintaining barrier integrity.
• Minimizing cumulative irritability.
• Preserving the lipid and microbial environment.
• Allowing for sustainable routines over time.
  

Because when the scalp is in balance, the hair usually needs fewer corrections.

Conclusion: when hair care begins with the skin

For years, hair care has been built around the hair: its texture, its shape, its visible appearance. But the biological logic is different.

Hair is the result.
The scalp is the origin.

Understanding this difference completely transforms how products are formulated, chosen, and how real needs are interpreted. The biology of the scalp does not respond to static categories or universal promises, but to dynamic balances that change with the environment, habits, and the physiological state of the skin itself.

This change of perspective is the foundation of what we define as Scalpology: a way of understanding hair care that starts from living tissue, not the fiber, from physiology, not the label.

Because when the scalp is in balance, the hair usually needs fewer interventions, fewer corrections, and fewer artifices.

True hair care is not about pursuing a cosmetic ideal, but about respecting the biological system that makes it possible.

 

Each article is backed by the experience of our founder and CEO Dr. Modesta Cassinello, Doctor in Pharmacy and Diploma in Nutrition, committed to excellence in skin and hair care.