Short answer: Porosity is how readily your hair lets color in, and out again. Low porosity resists color and needs longer processing. High porosity grabs color fast, then loses it fast. Most heads carry more than one porosity at once, so roots, mid lengths and ends can finish in three different shades from one bowl.
What does hair porosity actually mean?
The cuticle, the outer layer of each strand, is built from overlapping scales. Porosity describes how tightly they lie. Flat scales keep liquid out. Lifted or broken scales let it move freely. Color is a liquid, so porosity decides how a formula behaves.
What are the three porosity levels a stylist will describe?
Low porosity means tight cuticles that resist. Normal porosity means scales that open enough to take color and close enough to hold it. High porosity means raised scales, so color enters fast and washes out fast.
Is porosity the same thing as damage?
No, and this is the most common misunderstanding we hear in the chair. Porosity can be inherited, and plenty of healthy virgin hair is naturally low porosity. Bleach, heat and sun do raise it, but high porosity is not proof of damage. It matters more in Hanoi than visitors expect, because humidity keeps the cuticle more open through the hot months and most foreign clients wash more often than at home. Both shorten the life of a color.
How do we check your porosity before anything is mixed?
What does the strand test tell us?
We apply the intended formula to a small section from an inconspicuous area, then watch how fast it lifts and how evenly the tone lands. It replaces an argument about what should happen with evidence about what does happen. At home, run your fingers up a dry strand from end to root and notice whether conditioner sits on top instead of sinking in.
What do we ask about the last twelve months?
Box dye, henna, keratin, perms, pool water and sun all change porosity, and several are invisible once hair grows out. We ask for dates, not a yes or no, because a bleach from eight months ago still sits in your mid lengths.
Why can one head have three different porosities?
Hair closest to your scalp is the youngest. Your ends may be four years old and have been through every treatment since. Roots run warmest when lifted, because scalp heat speeds things up. Ends are the most porous, where a cool toner goes muddy or a vivid goes patchy.
Decision table: your porosity and your realistic color result
| Porosity | How color behaves, and how fast it fades | What we recommend | What we avoid |
|---|---|---|---|
| Low | Resists, lift is slow, fade is slow | Longer processing, gentle heat, realistic targets | A big lift in a short appointment |
| Normal | Takes and holds as predicted | Most shades, in one or two visits | Very little, this base is forgiving |
| High | Grabs fast, finishes darker or cooler, a toner shifts in four washes | Filling first, lower developer, warmer targets | Back to back lifting, strong ash on visit one |
| Mixed | Three results from one bowl, ends fade first | Zoned application, separate timings | One formula root to tip in a single pass |
What can one visit realistically do?
Low porosity hair is patient hair. It holds a result beautifully, but getting there takes time, so expect longer processing and gentle heat rather than a stronger developer. It will not jump four or five levels in an afternoon. With a pale blonde target, plan two visits and read our guide to bleaching and toning in Hanoi.
High porosity hair is fast hair, which sounds convenient and is usually the opposite. Deposit lands darker than the swatch, toners overshoot into grey or green, and it lets go just as quickly, so a pastel on porous ends is paler after four washes. We fill first, use a lower developer and pick a target that fades gracefully.
Cool tones, warm tones and the porosity trap
Why do cool shades fade first and warm shades last?
Cool pigment molecules are smaller, so they slip out of an open cuticle sooner. On porous hair an ash result can drift warm within two weeks as the underlying gold reappears. Copper and caramel hold far longer at the same level. If you want cool on porous hair, budget for refreshes.
How does porosity interact with your skin undertone?
Your undertone tells us which shades suit you. Your porosity tells us which of them you can keep. A cool undertone with porous hair often lands best on a neutral rather than a true ash. Our guide to choosing hair color for your skin undertone covers the other half.
When will we say no, and what do we offer instead?
We will not lift hair that fails the strand test, where the section stretches and does not spring back, put very porous hair through a second full bleach in one week, or promise a true silver on ends that will not hold the toner. Instead we offer a lower target you can hold today, a staged plan across two or three visits, a service that leaves fragile ends alone, or a cut first. If your hair is in trouble, a damaged hair consultation comes before any color.
What does porosity do to your maintenance schedule?
How often will you need a toner, and when does the warranty help?
The first seventy two hours cost a porous head the most pigment, so wait two days before the first wash, use cool water and skip the pool. After that, a refresh every eight to ten weeks is typical on normal porosity and every four to six weeks on high porosity. Bleaching and coloring here carry a thirty day warranty with free adjustments, so if a cool tone drifts warm in week two, come back rather than reaching for a box dye, the most common cause of the color corrections we see.
What does it cost, and why does porosity change the quote?
Figures below come from our published price list, after the standard offer of thirty percent off for booking ahead plus ten percent for checking in.
A basic color combo including the cut runs from 480,000 VND for short hair, 600,000 VND at shoulder length and 780,000 VND past the shoulders. Fashion shades start at 1,560,000 VND, balayage and ombre from 2,280,000 VND. Bleaching is quoted separately at 1,000,000 VND standard or 1,500,000 VND VIP, and a tone lift is 500,000 VND. Root, mid lengths and ends treated differently is three applications rather than one, and where porosity splits the work across two visits, each is quoted on its own. The price guide in USD converts these.
A short checklist to bring to your appointment
List every chemical service from the last twelve months with dates, including anything done abroad. Bring two or three daylight photos of the shade you want and one you dislike. Say how often you wash, whether you swim, and how much upkeep you will do. Tell us how long you are in Vietnam, because a two visit plan only helps if you are here for both.
Frequently asked questions about hair porosity in Hanoi
Can I change my porosity?
Not permanently. Conditioning and bond support services smooth the cuticle and make hair behave as though it were less porous for a while, which genuinely improves how a color takes. The underlying structure is not rebuilt, and porosity caused by damage only leaves when that length is cut off.
Should I have a treatment before coloring?
Sometimes. A conditioning service right before a color can even out a patchy cuticle so pigment lands more consistently, but on some heads it also makes the hair more resistant and slows the lift. Your stylist decides after the strand test.
My hair has never been colored. Does porosity still matter?
Yes. Virgin hair can be naturally low porosity and resist lifting stubbornly, which surprises people who assumed untouched hair would be easiest. It also matters at the ends of long virgin hair, which have had years of sun, heat and friction.
Can I have color on the same day as a keratin treatment?
Color first, then the smoothing service, never the other way round. A keratin treatment seals the cuticle, which is exactly what you do not want immediately before you need color to go in. If you want both, we sequence them in one booking.
I am only in Hanoi for two days. What is realistic?
One appointment and one achievable shade. If your hair is dark and low porosity and you want pale blonde, two days is not enough, and we will say so when you message rather than when you arrive. A root touch up, a gloss or a warm shade are doable in one visit.
Book a color consultation in Hanoi
To have your porosity read before anything is mixed, book a consultation at Nhat Tam Hair Salon, 89 Nguyen Hy Quang, O Cho Dua, Dong Da, Hanoi. We will tell you what is reachable in one visit, what needs two, and what the upkeep costs. You can book an appointment online or message any of our four branches. Our hair color guide for Hanoi covers the wider picture.
Planning a first visit? Start with our English visitor guide.