For most of your life, oestrogen has quietly worked in your hair's favour. Scalp follicles carry oestrogen receptors, and oestrogen helps keep hairs in their active growing phase for longer. As you move through perimenopause and into menopause, ovarian oestrogen production winds down, and the balance tips.

Oestrogen's supportive effect on the follicle fades, and the androgens your body still produces have a relatively stronger influence. In follicles that are genetically sensitive, that nudges hairs towards a shorter growth cycle and a finer shaft. It is the same biology behind female pattern hair loss, brought forward by the hormonal shift, which is why the change is usually gradual and diffuse rather than sudden.

Every hair moves through a cycle: a long growth phase, a brief transition, and a resting phase before it sheds and a new one begins. Most of your scalp hair is normally growing at once, which is why healthy hair feels dense.

With lower oestrogen, the growth phase shortens and the resting phase lengthens. More hairs rest and shed together, and each new hair grows in shorter and finer. Over cycles, follicles can miniaturise - the diagrams above show this - and density falls before any single dramatic loss. Nothing topical changes the hormones, but good care protects the hair you are growing.

K18 does one thing exceptionally well: it repairs the internal bonds that give hair its strength. The patented K18PEPTIDE is small enough to reach into the cortex and reconnect the keratin chains that break through colouring, heat and everyday wear. For hair that is already becoming finer with menopause, that structural support matters more, not less - there is simply less hair to lose to breakage.

It will not change your hormones or bring back density on its own. What it does is keep the hair you are growing as strong, smooth and resilient as it can be, so it behaves better and breaks less. It is cosmetic care, not a medical treatment - and for finer hair, it earns its place.