A Brazilian smoothing treatment does not degrade solely due to the passage of time. The shampoo used at home can accelerate or slow down the loss of keratin deposited on the hair fiber. The question is less about the brand and more about the formulation: the type of cleansing agents, pH, and compatibility with the salon treatment determine the longevity of the smoothing.
Classic keratin, tannin, or glyoxylic acid: the shampoo varies depending on the smoothing
Online guides treat Brazilian smoothing as a single category. The reality is different. In recent years, formulations have diversified: keratin smoothing with formaldehyde, formaldehyde-free smoothing based on glyoxylic acid, or tannin smoothing. Each of these techniques modifies the hair fiber in a distinct way, and tolerance to shampoos varies accordingly.
Related reading : What are the steps to follow for a complete home renovation?
A tannin smoothing treatment, for example, requires a sulfate-free shampoo but tolerates nourishing treatments better than a classic formaldehyde smoothing. Conversely, a glyoxylic acid treatment may be more sensitive to formulas that are too rich in heavy silicones, which weigh down the fiber without strengthening the chemical bond created by the acid.
Before buying a shampoo, the first step is to ask the hairdresser which main active ingredient was used. The answer guides you toward the right family of products and avoids compromising the result from the first wash. To find out which shampoo to use after a Brazilian smoothing, this criterion takes precedence over reading the label.
You may also like : Buying a gas auger: how to make the right choice in 2020?
| Type of smoothing | Main active ingredient | Sulfates | Nourishing treatments | Heavy silicones |
|---|---|---|---|---|
| Keratin + formaldehyde | Keratin, formaldehyde | Avoid | In moderation | Tolerated |
| Formaldehyde-free keratin (glyoxylic acid) | Glyoxylic acid | Avoid | Recommended | Avoid (weighting) |
| Tannin | Plant tannin | Avoid | Well tolerated | Tolerated sparingly |
Sulfate-free shampoo after Brazilian smoothing: what the label doesn’t always say
The mention “sulfate-free” appears on the majority of shampoos sold as a complement to smoothing treatments. This indication remains necessary, but it is not enough to guarantee the product’s compatibility with the treatment.
Sulfates (sodium lauryl sulfate, sodium laureth sulfate) are powerful surfactants that strip the keratin film deposited during smoothing. Their absence protects this protective layer. However, some “sulfate-free” shampoos compensate with other aggressive cleansing agents or a pH that is too high, which produces a comparable effect.
Ingredients to look for on the INCI list
- Mild surfactants (cocamidopropyl betaine, decyl glucoside): they cleanse without attacking the keratin layer and are suitable for all types of smoothing
- Hydrolyzed keratin or silk amino acids as a supplement: these actives strengthen the fiber between salon visits
- Light oils (argan, jojoba) rather than heavy occlusive silicones (dimethicone in high concentration), especially after a glyoxylic acid smoothing
A shampoo with a pH between 4.5 and 6 better preserves the keratin bond than an alkaline formula. The scales of the hair fiber remain closed, which maintains shine and limits frizz.
Colored hair and Brazilian smoothing: adapting the shampoo to a dual constraint
Specialized salons now recommend coloring before smoothing. The keratin treatment fixes the color by closing the scales, which prolongs the hold of the pigments. This sequence creates an additional requirement for the maintenance shampoo.
A sulfate-free shampoo designed for colored hair becomes more relevant than a simple “post-smoothing shampoo.” It must protect both the keratin deposit and the coloring pigments, two layers sensitive to stripping agents.
Formulas containing UV filters or antioxidants (vitamin E, pomegranate extract) provide additional protection against fading, especially during the summer. This point is rarely addressed in standard recommendations, while the majority of clients combine coloring and smoothing.
Washing frequency and steps after a Brazilian smoothing
The choice of shampoo does not compensate for a poor washing routine. Spacing out shampoos preserves the keratin film longer. Two to three washes per week is an appropriate rhythm for most types of smoothed hair.
Reflexes to adopt from the first shampoo
- Wait for the recommended time by the hairdresser after the treatment (usually several days) before the first wash, to allow the keratin to set
- Apply the shampoo to the scalp and let the foam run down the lengths without rubbing the hair fiber
- Rinse with lukewarm or cold water: heat opens the scales and accelerates the loss of the treatment
- Alternate with a leave-in treatment or a light conditioner to maintain hydration without overloading the fiber
A dry shampoo between washes reduces the frequency of exposure to surfactants. Formulas based on rice powder or starch absorb sebum without interacting with the keratin layer.
The first month after the treatment determines the overall duration of the smoothing. An unsuitable product used three times a week during this period can significantly reduce the hold of the result, regardless of the care applied afterward. Adapting the shampoo to the type of smoothing performed, checking the INCI list, and maintaining a moderate washing rhythm remain the three measurable parameters to act upon.