Science: scalp, sulfates and what damages hair
SCIENCE · Hair basics and keratin · Scalp, sulfates and what damages hair · Hard water · Hair and scalp pH
1c · Scalp types: how iluvia defines them. Oily, balanced or dry: a simple wash-day test
Scalp type describes how quickly your scalp gets oily after a wash. At iluvia we use a simple test you can do at home.
| SCALP TYPE | THE WASH-DAY TEST | WHAT IT MEANS FOR YOUR ROUTINE |
|---|---|---|
| Oily | You washed today and feel you need to wash again tomorrow. | You wash more often. Choose a cleanser that clears oil and build-up, and a lightweight conditioner. |
| Balanced (also called normal) | Your scalp still feels clean on day 2. | A regular wash routine suits you. Check how it behaves when the season or your activity changes. |
| Dry | You feel you could go without a wash even on day 3 or more. | You wash less often. Choose gentler cleansing and watch for tightness. |
Your scalp type is not fixed
Sweat can change the answer. Someone with a balanced to dry scalp who works out every day may need a routine for an oily scalp, because sweat contains salt as well as water and builds up on the scalp.
So can the room you sit in. Someone with a balanced to oily scalp who is always in an air-conditioned space may go a long time between washes.
How to use the test. Judge your scalp by how it behaves in your current routine, not by a label from the past, and check again when your routine or the season changes.
This is a simple guide, not a diagnosis. If you have persistent itching, flaking, redness or pain, see a doctor or dermatologist.
Scalp questions, answered
How do I know if I have an oily, balanced or dry scalp?
Use the wash-day test. Oily: you washed today and feel you need to wash again tomorrow. Balanced: your scalp still feels clean on day 2. Dry: you feel you could go without a wash even on day 3 or more. This is iluvia's simple guide, not a diagnosis.
Can my scalp type change?
Yes. Scalp type comes from genetics, environment (water, pollution and weather), lifestyle and habits, so it can change with your routine, the season and where you live or work.
Why does sweat matter for scalp care?
Sweat contains salt as well as water. Someone with a balanced or dry scalp who works out every day may need a routine for an oily scalp because of sweat build-up.
1d · Sulfates and sulfate-free: sulfates are good cleansers. For salon hair, we choose to go without
We do not think sulfates are bad. Sulfate cleansers are effective, well-studied and have a long history of use in shampoos. The question is which cleanser suits the hair in front of you.
Where salons are different. Based on feedback from the professional salons we serve in tier 1 and tier 2 cities, we estimate that around 70% of clients arrive with hair that is coloured or treated in some way. That hair is more fragile, so a milder cleansing system is the more suitable option. This is our estimate from market feedback, not a study.
Not all sulfate-free is equal. Sulfate-free only tells you which cleanser is left out. How mild and effective a shampoo is comes from the whole blend of surfactants, their levels and the pH.
Our approach. A blend of surfactants designed to cleanse effectively while staying mild. The Hard Water Shampoo, for example, combines a betaine, an isethionate, a sarcosinate and a sulfoacetate instead of relying on one cleanser. This describes how we design the formula, not a test result.
Sulfate questions, answered
Are sulfates bad for hair?
No. Sulfate cleansers are effective, well-studied and have a long history of use in shampoos. For salon clients, many of whom arrive with coloured or treated hair, we think a sulfate-free shampoo is the more suitable choice.
Is every sulfate-free shampoo gentle?
No. Sulfate-free only tells you which cleanser is left out. How mild and effective a shampoo is depends on its whole blend of surfactants, their levels and the pH.
Why are iluvia's salon shampoos sulfate-free?
Based on feedback from the professional salons we serve in tier 1 and tier 2 cities, we estimate that around 70% of clients arrive with hair that is coloured or treated in some way. That hair is more fragile, so we use a blend of surfactants designed to cleanse effectively while staying mild.
2 · What damages hair: four everyday causes, four different mechanisms
Minerals in water. Hair takes up calcium and magnesium from tap water, mostly in the cuticle, and it can stiffen the fibre.6
Humidity. When the surface lipid layer is worn or the cuticle is damaged, hair absorbs more water and frizzes.1
Chemical services. Bleach, colour, relaxers and smoothing change the fibre, strip lipids and wash out protein.1, 7
Heat and friction. Tools, rough drying and brushing wear the cuticle over time and add to damage already there.
References
1. Gavazzoni Dias MF. Hair cosmetics: an overview. Int J Trichology. 2015;7(1):2–15. PMC4387693
6. The structural implications of water hardness metal uptake by human hair. Int J Cosmet Sci. 2011;33(5):477–482. doi:10.1111/j.1468-2494.2011.00659.x. PubMed 21923661
7. Gavazzoni Dias MF, Loures AF, Ekelem C. Hair cosmetics for the hair loss patient. Indian J Plast Surg. 2021;54(4):507–513. doi:10.1055/s-0041-1739241
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