Why doesn't your hair always behave the same way?

You leave the house with soft, well-styled hair. Hours later, it has a different shape. Or you come back from a few days away and notice your ends tangle more, even though you have used your usual products.

Your surroundings count too. Sun, humidity and the habits that come with each season are all part of your hair's story.

A recent article we read in a professional journal looks at the relationship between climate change and hair health. Reading it invites us to think about something very everyday: how to adapt hair care to the conditions we live in.

To do it well, it helps to distinguish what happens in the fibre from what happens on the scalp.

Why your hair changes from one place to another

You apply your products as usual, but once you are out, your hair does not look the way it did at home. Humidity in the air may be part of the explanation.

Hair exchanges water with its surroundings, and this can change its shape and make a style last less time. Research confirms that humidity influences the mechanical properties of the fibre.[1]

The condition of your hair also matters. Damage can encourage frizz, but frizz can also appear in well-cared-for hair. So do not automatically assume you are caring for it badly because it frizzes.

Notice how it feels as well as how it looks: whether it is soft, whether it detangles easily or whether it is often rough and tangled. These signs help you adjust your care, although on their own they cannot tell you how much damage the fibre has.

The sun also affects the fibre

Ultraviolet radiation can damage components of the hair. Studies on hair photoageing investigate these changes and how to reduce them, although the results depend on the hair type and the exposure conditions. [2]

When you spend time outdoors, wear a hat or cap that covers your hair and scalp well. And remember: protection against the heat of a hairdryer or straightener is not the same as sun protection.

And what does climate change have to do with it?

Climate change raises the question of how to adapt our care to a changing environment. But the humidity on a particular day, or what you notice in your hair during a holiday, is not enough to attribute those changes to global warming.

For your routine, what is useful is to observe your exposure conditions: how much time you spend outdoors, what the environment is like and which habits have changed. That information, together with the condition of your scalp and your lengths, helps you choose your care.

Start by looking at roots and ends separately

You can have an oily scalp and dry mid-lengths and ends. Choosing your whole routine as if they needed the same thing can leave you dissatisfied: the roots still feel heavy and the ends do not get the care you are looking for.

Before changing products, ask yourself three questions: how does my scalp feel? How are my mid-lengths and ends? What has changed in my exposure or my habits?

Choose your wash according to your scalp

• If you need frequent cleansing or notice oily roots, H01 Frequent Use Shampoo can be the basis of your routine.
• If your scalp is normal to dry and your hair is damaged, H02 Repairing Shampoo is a better fit for that need.
• And if you are looking for a fragrance-free formula, H03 Shine and Vitality Shampoo is another option worth considering, especially if your scalp is sensitive.

H07 Sea Salt Shampoo can be added as a periodic deep cleanse when you want a feeling of extra cleanliness and lightness.

Conditioner or mask: choose according to how your hair feels

Not all hair that frizzes needs a more intensive treatment.

• If it feels soft and is not very damaged, H04 Revitalizing Conditioner may be enough to make detangling easier and provide light softness.
• If your mid-lengths and ends are rough, tangle a lot or are more damaged, H09 Nourishing Mask offers more intensive conditioning. If you have oily roots, concentrate it on the mid-lengths and ends.

Start with a moderate amount, distribute it well and adjust according to the result, especially if your hair is fine. We are looking for softness and ease of combing while keeping volume and movement.

Take care with what you do afterwards too

Detangle patiently, starting from the ends. Avoid pulling at knots or rubbing hard with the towel. If you use heated tools, add suitable protection for that use and moderate the temperature. H06 Hair Resist Conditioning Mist fits into care against the heat and friction of styling.

We cannot change the humidity outside. But we can change how we care for our hair.

Understanding how it responds to its surroundings helps you choose better, starting with how you wash it.

Find the care your roots and ends need.

1. UC San Diego: research on the structure and mechanical behaviour of hair.

2. Fan et al., Performance and Mechanism of Hydrolyzed Keratin for Hair Photoaging Prevention, Molecules 2025, 30, 1182.

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