Last Updated: September 1, 2026
Permanent hair straightening treatments are a procedure of chemical hair treatment. Depending on your treatment method, naturally curly or textured hair can be altered to lie flat and lose its curl.
These treatments work for several months and usually last until new hair grows to replace the treated hair for this aim. And these processes are called permanent hair straightening.
The label “permanent hair straightening” can be used to refer to keratin treatments, Japanese thermal straightening, and “permanent” straightening processes.
Home treatments and salon treatments are popular options. This article helps you learn about the pros and cons of this type of hair treatment.
This Article Belongs to Hair Oils & Treatments.
Table of Contents
Types of treatments
Several treatments claim to soften hair, and each is based on a different chemical formula and processing method.
Some of these treatments are sold kits you can use at home, while others require salon equipment to work successfully.
Professional permanent straightening
A perm mentions a chemical process that permanently alters the hair sac. Perms are sometimes associated with making curls in hair that don’t naturally have rings, but they can also be used to straighten hair.
Perms are usually complete in a salon appointment that takes a few hours. The cost of a perm can vary contingent on your salon and hair length, and prices typically start around $50.
Stay at home
Chemical relaxer kits can purchase at pharmacies and beauty supply stores. These treatments claim to offer the same fallouts as a salon perm.
Without formal cosmetology training, it won’t be easy to use these kits efficiently. At-home perm options tend to start at about $15.
Keratin Uncurling
Keratin hairs actions and Brazilian straightening refer to a method of treating hair to a smooth texture that lasts 3-5 months.
This method may require multiple salon appointments to complete the application and typically costs upwards of $150.
If you regularly use oils as part of your hair-care routine, you may also want to learn about sesame oil for your hair and how it can be incorporated into a broader hair-care routine.
Japanese thermal straightening
Japanese heat straightening, called an acid perm, is more like a traditional “straight” perm than a keratin treatment.
This process may involve the longest time consumed in a salon chair (5-6 hours). But it also rights to last up to 6 months. It also costs the most, reaching from $200 to $800.
Hair Reattachment
Also called chemical straightening, hair straightening is a process that turns a person’s wavy hair into straight hair. The cost can vary a lot depending on the salon you go toward.
How does it Work?
All permanent hair straightening means using a similar strategy:
A chemical key is practical to your hair, and these chemicals change how your hair’s proteins are configured.
And using perms and Japanese thermal straightening procedures, a neutralizer is apply to the hair. This neutralizer allows your hair to settle into its new shape, forming new bonds between the protein molecules in your hair.
Also, it would help if you waited several hours for the chemical solution to infuse into the hair, apply the neutralizer and comb your hair.
These chemical solutions usually give off pungent odours, and in many cases, it is advisable not to wet your hair or sweat too much in the days after the treatment.
And it means you walk around inhaling the chemicals used to treat your hair and exposing everyone around you.
Side Effects
Hair breakage is a possible side effect of permanent hair straightening treatments because the chemicals used to alter the hair’s structure can weaken the strands.
Damaged hair may become more difficult to style, feel dry or brittle, and take longer to return to its natural appearance. The treated portion of the hair remains chemically altered, while newly grown hair retains its natural texture.
Chemical straightening can also cause scalp irritation, dryness, allergic reactions, or hair breakage, particularly when products are used incorrectly or too frequently.
Some hair-smoothing and straightening products may contain or release formaldehyde when heated. The U.S. Food and Drug Administration (FDA) explains that formaldehyde released during certain hair-smoothing procedures can irritate the eyes, nose, throat, lungs, and skin, and recommends checking product ingredients and ensuring appropriate salon ventilation. Learn more from the FDA about formaldehyde in hair-smoothing products.
If you are looking for additional natural hair-care options, you can also read about onion juice for hair and how it is commonly used in home hair-care routines.
