What the sun does to silver hair
The golden cast that settles in over summer has a straightforward explanation. Understanding where it comes from is usually enough to know what to do, and what to set aside.
It is the question that comes back every summer, more than any other: why does my white hair turn yellow the moment I go on holiday?
The answer fits in one sentence: what the pigment used to do for you, the fibre now handles alone.
Pigment was also a shield
Melanin colours the hair, and it does more: it absorbs part of the incoming light and protects keratin (the protein the fibre is made of) from its oxidising effect.
On a depigmented hair, light reaches the structure of the fibre directly. As it oxidises, warm reflections develop: first a faintly golden ivory, then a more definite yellow, most visible on the lengths and the ends, which are the oldest parts of the head of hair.
The sun works alongside other factors: very hard water, swimming pool water, pollution, and certain product residues.
Yellowing belongs to oxidation far more than to dirt, and that changes entirely how you should respond to it.
What genuinely helps
- Cover up, quite simply. A wide-brimmed hat during the brightest hours does more than any treatment applied afterwards.
- Rinse after swimming, with clean water, as soon as you leave the pool. Chlorine and salt keep working for as long as they stay on the fibre.
- Space out sources of heat. On an already exposed fibre, a very hot dryer and a straightening iron add a strain it happily forgoes.
- Separate cleaning from neutralising. Scrubbing harder dries, and a dry fibre holds warm reflections even better. Gentleness works better here.
And purple treatments?
The principle is optical: purple sits opposite yellow on the colour wheel. Deposited in very small quantities on the fibre, a purple pigment visually offsets the warm reflection, like a lighting correction.
It works, and it also explains the accidents you see going around: plenty of pigment, a long pause, a porous fibre, and grey turns lilac. The difficulty lies in accuracy: neutralising with precision, while preserving the hydration of a fibre already coping with a new exposure.
That is exactly the problem our formulation is working on. We will talk about it again the day it is ready.