What Causes Hair to Age? 7 Signs of Ageing Hair.
Hair ageing often gets reduced to one visible change: going grey.
But colour is only part of the story. Over time, natural biological shifts combine with years of heat styling, colouring, and daily wear – leaving strands drier, finer, more fragile, and slower to grow. The routine that once worked for your hair may no longer be enough.
Our Chronologiste collection is designed to cater specifically to the changing needs of mature hair. Working across the scalp and lengths, it targets five key signs of ageing hair: dryness, dullness, brittleness, loss of strength and lack of volume.
Delve further with Kérastase to find out why hair changes with age, how to spot the tell-tale signs, and which Chronologiste products to reach for.
What causes hair to age?
Hair ageing is driven by two forces: intrinsic factors written into your biology, and extrinsic factors – everything your hair is exposed to every day. Both act on the follicle (where each strand grows) and the melanocytes, the cells that colour it – changing how your hair grows, the pigment it holds and the strength of the fibre.
The most common causes of hair ageing include:
- Age: Your hair's growth cycle slows over the years, so each strand grows for less time before it's shed. At the same time, your melanocytes make less pigment – which is what turns hair grey.
- Hormones: As oestrogen levels fall with age, hair growth can slow and density may decrease.
- UV and environmental exposure: Sunlight and pollution trigger oxidative stress, a form of cellular damage that breaks down the proteins and pigment inside each strand and weakens your hair from within.
- Cumulative damage: Years of brushing, heat styling, and colouring wear away the hair's outer surface, leaving strands weaker and prone to breakage.
7 signs of ageing hair
Hair does not age in just one way. Some people first notice thinning or a loss of volume, while others experience increased dryness, dullness, or breakage.
Below, we explore seven common signs of ageing hair, how to recognise them, and how Chronologiste can help refresh the look of your hair.
1. Dryness
As you age, your scalp produces less natural oil, which means hair holds onto less moisture. Because of this, you might notice a rough, straw-like feel or split ends creeping back not long after a trim.
To hydrate dry hair, reach for the Chronologiste Intense Regenerating Masque. Infused with hyaluronic acid, vitamin E, and abyssine – a rare ocean-derived molecule that helps protect hair from damage – this deeply moisturising hair mask helps soften dry ends, tame frizz, and impart a luminous shine.
Work it through your mid-lengths and ends once or twice a week, leave it on for five minutes, then rinse.
2. Changes in hair density or volume
Hair naturally thins with age – a shift many women notice from their 40s onwards. Individual strands grow finer and some follicles slow down, causing hair to lose its volume and density.
To keep hair looking full, reach for a gentle volumising shampoo like our Chronologiste Regenerating Shampoo. It targets the signs of ageing hair, cleansing from scalp to ends to lift build-up that weighs strands down at the root, while hyaluronic acid plumps and hydrates each fibre – for hair that feels softer, more resilient, and full of bounce.
Noticing more hair fall than usual? Follow up with our Genesis Anti Hair-Fall Fortifying Hair Serum, worked into the scalp at the end of your hair wash routine – it's specifically formulated to target hair fall linked to breakage.
3. Increased brittleness and breakage
Brittleness and breakage are another common sign of hair ageing, particularly in hair weakened by frequent colouring or heat styling. Unlike hair fall and thinning, breakage leaves behind shorter strands where the hair has snapped along the length.
If you are experiencing this, smooth our Chronologiste Regenerating Leave-In Treatment through damp lengths before styling. It provides heat protection up to 230°C and helps strengthen hair and prevent breakage throughout the day. There’s no need to rinse; simply comb through and style your hair as usual.
4. Loss of shine
Hair looks glossy and shiny when its outer layer – the cuticle – lies flat and reflects light evenly. With age, dryness, and years of heat styling, however, the cuticle can become rough and raised, scattering light and leaving hair looking dull.
Smooth a few drops of our Chronologiste L'Huile Refillable Hair Oil through your lengths to help soften the cuticle and bring back shine. Infused with the essential oil myrrh, it smooths the strands while leaving a warm, subtle fragrance. For optimal results, apply your oil to dry hair after styling, then use it to refresh your ends throughout the day.
5. More frizz and changes in porosity
Frizz is another sign of ageing hair. As porosity changes with age, the cuticle lifts more readily, so the fibre draws in and releases moisture unevenly. Years of heat, colour, and daily exposure add up, and strands may begin to feel coarser and harder to manage.
When frizz sets in, apply our Overnight Youth Serum to wet or damp hair before bed. It saturates the hair fibre overnight, so the cuticle settles instead of staying open. This leaves you with lengths that are visibly smoother and easier to manage by morning – with tests showing 66% less frizz after a single use1. It’s ideal to pack in your bag when travelling to hot, humid climates where hair absorbs moisture from the air, swelling the fibre and leaving it more prone to frizz.
1Instrumental test after 1 use of Overnight Youth Serum
6. Slower growth
Every hair grows during its anagen (growth) phase, and with age this phase gets shorter. The effect is twofold: strands spend less time actively growing before they rest and shed, and new hairs tend to come in with a finer diameter. So, hair can seem to grow more slowly and look thinner than it used to.
To support hair growth, apply our Chronologiste Longevity Potion directly to your scalp. Infused with 3% Pro-Xylane™ and ochrophyta algae, it delivers intensive cellular care by strengthening the scalp's moisture barrier – the surface layer that holds hydration in and keeps daily stressors out. This creates an optimal environment for growth and supports stronger, fuller-looking hair.
7. Greying and pigment changes
One of the most recognisable signs of hair ageing is, of course, grey hair. It's a completely natural process and not one you can prevent: as melanin production slows, new strands grow in without their original pigment, moving through silver, grey, and white.
Our Blond Absolu Bain Ultra-Violet Purple Shampoo is a toning wash that neutralises unwanted warm tones, leaving grey and white hair looking brighter and cooler. Use it in place of your regular shampoo once or twice a week, leaving it on for a few minutes before rinsing to let the violet pigments do their work.
With the right hair care routine, you can help address the signs of hair ageing and keep your hair looking its best at every age. Next, discover how real women have used the Chronologiste range to achieve timeless-looking hair.
