What to Know About Hair Perms

Medically Reviewed by Poonam Sachdev on November 23, 2022
4 min read

Styling your hair is a way to showcase your individuality. Whether you have the same haircut most of your life or switch up hairstyles every month, your hair plays an important role in defining your overall style. Some people prefer to have straight hair, and others want curly hair. Curly and wavy hair comes naturally to some; for others, they require chemical hair transformations called permanent wavings.

Also known as a hair perm, these chemical treatments cause your hair to curl. Getting a hair perm can take several hours and last between three to six months. Various factors can influence the lifespan of your perm, including your scalp health, hair treatment, and overall hair growth. If you have long hair, your perm is likely to last longer than people with short hair.

When getting a hair perm, you'll spend most of the time with a chemical liquid treatment soaking your hair. Once your hair is saturated, it gets wrapped around rods and rollers. The chemical treatment makes your hair hold the curl pattern from rods and rollers.

Perms work by affecting the keratin in your hair. Keratin is a protein that makes up about 95% of your hair and forms the structure of your individual hairs. The bonds between keratin molecules are what react to the perm treatment and allow your hair to hold a new shape.

The most commonly used chemical in perms is ammonium thioglycolate. If you have thin or fragile hair, gentler perms are acid-balanced and use glyceryl monothioglycolate.

Before getting a perm, you can ask your hairdresser which chemicals are in the treatment they use. Other common ingredients include: 

  • Acrylates copolymer
  • Ammonium hydroxide
  • Ammonium thioglycolate
  • Amodimethicone
  • Cocamidopropyl betaine
  • Color additives
  • Fragrance
  • Polyquaternium-11
  • Styrene/acrylates copolymer
  • Water

Most salons will choose perm treatments with safe, tested ingredients that are unlikely to cause side effects such as scalp and eye irritation.

Today, there are three types of perms you can get. The first is a cold wave perm, also called an alkaline perm. Cold wave is a faster process that uses ammonium thioglycolate to set your perm within about 15 minutes. 

The second type, an acid-balanced perm, takes more time and needs heat. You may spend time under a hooded dryer to set the perm. Or, your hairdresser may instead use an acid-balanced perm that uses a chemical reaction to provide a self-heating perm. 

The third type of perm is an exothermic perm. It's a self-timing, self-heating perm and is considered one of the easiest perms to get.

You can also get different styles of perms depending on the amount of wave and volume you want. 

Body perm. This style of perm adds volume to thin or flat hair. If you have straight hair, this perm will give you a light wave. 

Spot perm. This plain curl perm works on specific sections of your hair. It’s good for people who want curls on the ends of their hair or around the middle. Spot perms give a more natural look.

Root perm. If you want more body in your hair, a root perm adds volume to the root. This style of perm works well for people with short hair.

The process for giving your hair permanent waves is a two-stage chemical process. The perm works on a molecular level where chemicals react with your hair's proteins and bond to form the curl. Perms work by permanently waving your hair through shape memory. Though the name suggests these waves will last forever, they're temporary. 

Perms can cause damage to your hair over time. If you don’t take care of your scalp health, you could experience hair loss. Scalp health is important because once a hair follicle gets damaged, you can't grow new hair from that follicle. 

It's important to get perms only from a trusted salon. Your hairdresser should know how to use and apply the perm chemicals properly. During the perm process, skin irritation, hair breakage, oral toxicity, and scarring alopecia can occur if the chemicals are not used correctly. 

Perms are not recommended for younger people. Studies have shown that children between 10 and 13 years old using chemical perms have a higher risk of breast cancer.

It's important to know how to care for a perm to help it last longer. The most important rule in caring for your perm is to let the curl set during the first 48 hours. 

Avoid touching your hair or getting it wet while it sets. You should also avoid heavy workouts or showering without a cap to protect your curls. 

Since perms can last up to six months, you’ll need to prepare to care for your perm differently than you would your regular hair. Once you've made it through the first two days, you should steer clear of chlorine, heat styling, and products with alcohol in them to make your perm last longer. Humidity can cause frizz, ruining your fresh new perm. 

Moisturizing is another key part of keeping your perm looking shiny and healthy as long as possible. Chemical treatments cause damage and dryness, so keeping your hair moisturized will help prevent frizz.

You'll also make your perm last longer with the right sleep routine. Make sure to sleep on your stomach or side instead of your back, which will put pressure on your permed hair. You could also use a silk cap for sleeping to help keep your hair from matting.  

With so many perm options now, you can find a perm that works best for your hair using a trusted hairdresser who only uses quality ingredients. Make sure you do your research, ask questions, and prepare to take care of your hair for the best curls possible.