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The short answer
A relaxer permanently changes the treated hair. Keratin-style smoothing is a broader service label whose process, longevity and ingredients vary. Ask about the exact formula, heat steps, compatibility and ventilation; neither name guarantees a damage-free result.
- Compare the actual product and service, not only the menu label.
- Some heated smoothing products can release formaldehyde; not all contain it.
- A conditioning ingredient does not prove that a chemical service repairs hair.
Ask what the service is intended to change
Professional relaxer systems are formulated for chemical straightening and include specific processing and neutralizing steps. A salon smoothing service may instead aim to reduce frizz or make styling easier. The presence of keratin in the name does not identify the whole formula.
Ask the stylist to show you the product and explain the intended result on your hair. A photograph of very straight hair is not a promise that your texture will respond the same way, especially if the picture includes blow-drying or flat-ironing.
Sources: Avlon: Affirm professional relaxer systems; FDA: Formaldehyde in hair smoothing products
Separate treated lengths from future new growth
Relaxing changes the hair that receives the treatment; new hair continues growing in its own pattern. That makes touch-up placement important. Repeatedly processing the same lengths is not a way to keep the roots straight.
Smoothing services vary, so there is no reliable universal month count to attach to the word keratin. Ask how the exact treatment wears off, what happens as roots grow and which maintenance steps are actually required. Do not treat a fading result as proof that every part of the hair has returned to its untreated condition.
Sources: Avlon: Affirm professional relaxer systems; FDA: Hair dyes and hair relaxers
Ask direct questions about ingredients and heat
FDA warns that some hair-smoothing products release formaldehyde when heated. It recommends discussing ingredients and ventilation with the salon and checking for names including formaldehyde, formalin and methylene glycol. Not every smoothing product contains or releases formaldehyde.
This warning should not be copied onto every hydroxide relaxer as though the chemistries were identical. Ask for the exact product information and safety data instead. If a stylist cannot explain the formula or precautions, that unanswered question matters more than a reassuring service name.
Plan the routine as well as the appointment
Before booking, describe your previous chemical services and any scalp or hair concerns. Ask what shampooing, styling and follow-up care the proposed system requires. Follow product-specific directions rather than a universal waiting period found online.
Also consider the time and effort you want to spend between appointments. A service that changes the styling routine may still require careful handling and regular care. Do not buy a maintenance product on the assumption that it can undo chemical damage.
Sources: FDA: Hair dyes and hair relaxers; FDA: Formaldehyde in hair smoothing products
Take a short checklist to the consultation
The best decision may be a different service, postponing treatment or using a temporary styling approach. A competent consultation should leave you knowing what is being applied and what result is realistic, without pressure to choose the strongest process.
Our relaxer guide compares specific retail and professional formats for readers who are already considering relaxing. It does not establish that relaxing is a better choice than smoothing for your hair.
| Question | What to check |
|---|---|
| What product will you use? | Record the brand, exact formula and service steps. |
| How does my hair history affect it? | Disclose relaxing, coloring, bleaching and prior smoothing. |
| What heat or ventilation is required? | Ask about the actual safety information. |
| What happens afterward? | Confirm maintenance, new-growth planning and realistic result limits. |
Sources: FDA: Hair dyes and hair relaxers; FDA: Formaldehyde in hair smoothing products
Common questions
Is keratin treatment a permanent relaxer?
Not as a general category. Keratin is used in the names of different smoothing products, so ask about the exact chemistry and intended effect.
Are all keratin treatments formaldehyde-free?
No. FDA says some smoothing products contain or release formaldehyde and others do not. Check the exact product and ask the salon about its safety information.
Can I combine the two treatments?
Do not assume they are compatible. A qualified stylist needs your treatment history and the specific product instructions before recommending another service.
PUT IT INTO PRACTICE
Compare your options
Compare kit contents, formula types and important application limits before choosing a product.
Compare five hair-relaxer formatsSources and editorial approach
ChooseRight researched the sources below to explain the topic and its practical trade-offs. Examples are illustrations, not results from our own product testing. Sources checked October 28, 2026. Artwork is AI-generated for explanation and does not document hands-on testing.