Hair Dyes

Hair Dyes: What Really Happens Inside the Hair

Every dye works with the same basic mechanism. An alkaline medium opens the hair cuticles, the oxidizing agent removes part of the natural melanin and the dyes that enter in its place combine with each other within the cortex, so they cannot be easily washed out. The greater the change in tone, the more intense the process and the greater the need for aftercare.

The most widespread misconception concerns the so-called natural colors. A dye containing argan oil or plant extracts is still an oxidative dye. The plant components improve the feel and care, they do not replace the chemistry of the color. Truly natural are only the henna type dyes, which however do not open the tone and have a very limited palette.

Permanent, Semi-Permanent and Root Touch-Up

Permanent Dye

It contains ammonia or an alternative alkaline medium and is always combined with an oxidizing agent. It is the only category that fully covers whites and opens the natural tone. The color fades with cutting and not with washes.

Semi-Permanent and Tone on Tone

Without ammonia, with low oxidizing agent or none at all. It does not open the tone, it darkens or gives highlights, it is gradually washed out within twenty to thirty washes. A good choice if you want to try a shade or cover the first few whites.

Root Touch-Up Spray and Mascara

They temporarily cover the root between dyes and wash out with the first wash. Useful when you have missed your appointment.

Oxidizing Agent: What Do the Levels Mean?

10 vol is used for dark shades and tone on tone, 20 vol for covering whites in the same tone, 30 vol for opening one to two tones and 40 vol for greater opening. The higher the level, the more intense the hair stress.

How to Read the Shade Number

• The first digit indicates the depth: 1 black, 4 brown, 6 light blonde, 8 blonde, 10 and above very light blonde.
• The digit after the dot indicates the highlight: 0 natural, 1 ash, 3 golden or honey, 4 copper, 6 red, 7 brown or chocolate.
• PPD and PTD: the main dyes of permanent dyes, responsible for most allergic reactions.
• Without ammonia: less smell and milder process, not necessarily less allergenic action, because the dyes remain.
• Plant oils in the composition: improve the feel of the hair during and after application.
• Coverage of whites: look for the explicit indication on the packaging, because not all lines have it.

Sensitivity Test: The Step That Cannot Be Skipped

Do a test application forty-eight hours before each dye, even if you have used the same shade for years. Allergic reactions to PPD can appear suddenly, after many uneventful dyes. Apply a small amount of the ready mixture behind the ear or on the inside of the elbow, let it dry and do not rinse it off. If redness, itching, swelling or burning sensation appears, do not dye and consult a doctor. Do not use dye on irritated or injured scalp, do not dye eyebrows or eyelashes and always wear the gloves from the package. Read the entire instruction sheet before starting.

Most Requested Lines

The Korres Argan Oil Advanced Colorant dominates the category, with natural blondes and browns being the most requested shades and with a line that also includes the Korres Post-Colour mask for aftercare. The Sanotint covers three lines: Classic for full coverage, Light for a milder ammonia-free formula and Reflex for tone on tone, along with an application brush. The Apivita Nature's Hair Color has a separate color activator, so you can choose the level of oxidizing agent. The @@BioKap Nutricolor@@ offers a root cover spray to cover the roots between dyes.

Refresh Rate and Aftercare

Hair grows about a centimeter per month, so the root becomes visible in four to six weeks. In this repeat dyeing, only dye the root for the longest time and apply the color to the lengths only in the last five to ten minutes. Repeated dyeing over the entire length is the main reason why the ends darken and dull. After dyeing, wait forty-eight hours before the next wash and use a color-protecting shampoo. A hair mask per week and the special products for dyed hair keep the result alive longer.

Frequently Asked Questions

Can I dye during pregnancy?

There is no evidence of harm from occasional dyeing, but many doctors recommend avoiding it in the first trimester and preferring shades that do not touch the scalp. Discuss with your gynecologist.

How long should the dye stay on?

Exactly as the packaging says. Extra time does not give a more intense color, but increases scalp irritation.

Why doesn't the color stick to my whites?

White hairs have a more closed cuticle and less porosity. They need permanent dye with 20 vol and often a mix with natural shade from the same line.

Can I dye over henna?

It is risky for the result, because some hennas react unpredictably with the oxidizing agent. Ask for a test in a tuft from a hairdresser before proceeding.

When can I safely re-dye?

The minimum interval is four weeks. If you want a color correction earlier, prefer semi-permanent or a touch-up product instead of a second permanent dye.

The information on this page is informational and concerns cosmetic products. They do not replace the advice of a dermatologist, pharmacist or professional hairdresser. Hair dyes can cause serious allergic reactions: a 48-hour sensitivity test is essential before each application.