The 8 Best Hair Straightening Methods, Explained (2025)

A quick science lesson: Your hair is made up of disulfide bonds—and these bonds are what keep the hair in its natural state. When you straighten hair, you're breaking those bonds, allowing the hair to take on a new, sleek, glossy shape. "Straightening your hair can be a very fun way to dramaticallychange one’s look day to day," says stylist Raphael Roque.

There are a few different ways to straighten your hair, and they fall into two main categories: temporary and permanent. With temporary straightening methods, as long as no major heat damage occurs, the bonds will return to normal when wet, allowing you to go back to your natural look. With permanent methods, the hair will hold its new shape until you cut it off. (There's also a permanent method, a keratin treatment, that lies somewhere in the middle—butmore on that later.) To weigh your hair-straightening options, we spoke to Roque and hairstylist Tatiana Ramos. Keep reading our breakdown of each type, below.

Temporary Straightening Methods

Blowout

• What It Is: "A blowout involves using a blowdryer and typicallya round brush," says Roque. The brush adds tension to the hair, holding it taut as the blow dryer dries the hair, resulting in a smooth finish. And because it's round, it creates a big, bouncy curl. "Blowouts take anywhere from 30 min to an hour, depending on the hair length and density," says Ramos.
• Who It's For: All hair types and textures.
• Pros: You get a temporary sleep style and may find your hair easier to manage.
• Cons: Maintaining this style can lead to heat damage and your hair can easily revert when exposed to moisture or humidity.
• How Long It Lasts: The results usually last one to two days.
  

Flat Ironing

• What It Is: This is a form of straightening that usually happens on dry hair. Once hair is rough-dried with a blow dryer and a brush, Roque explains that you section the hair into small sections and go over them with a flat iron/straightener.
• Who It's For: All hair types and textures.
• Pros: If your hair is curly or textured, a flat iron will achieve the sleekest finish and lasts for days.
• Cons: Constant flat ironing can lead to hair damage like breakage, split ends, and dryness.
• How Long It Lasts: "The look lasts as long as the hair can last before looking visibly dirty or until the next wash," says Ramos.
  

Silk Press

• What It Is: A silk press is similar to flat ironing, except the prep is more intense. "A silk press involves deep washes and cleanses to the scalp and hair followed by a blow-dry and straightening the hair," says Roque. It can take 30 minutes to a few hours, depending on the density and length of your hair.
• Who's It For: Textured, curly, and coily hair types.
• Pros: Achieves silky, smooth hair without a chemical relaxer.
• Cons: A silk press can be damaging to the hair—leading to breakage and dryness.
• How Long It Lasts: With proper upkeep, a silk press can last about two weeks or until your next wash.

Roller Set

• What It Is: A roller set is an old-school method of straightening that involves less direct heat than the above options. First, the hair is rolled tautly into rollers, and then you sit under a hooded dryer until the hair is fully dry, which can take around 90. minutes. "They can help achieve volume and straightening," says Roque.
• Who's It For: All hair types and textures.
• Pros: This straightening method uses less heat and tension than most methods.
• Cons: The results offer a curly and voluminous style rather than something sleek and straight like a blowout or silk press would.
• How Long It Lasts: The results last one to three days.

Semi-Permanent

Keratin Treatment

• What It Is: "A keratin treatment is a chemical treatment that uses safe amounts of formaldehyde to help smooth the hair follicle," says Roque. You'll still need to apply the above methods to get your hair straight, and it will revert to only a smoother version of your natural texture when wet, but the treatment helps your hair retain straight styles as it will be more resistant to humidity.
• Who's It For: All hair types and textures. Since the treatment smooths the hair, those with curly, wavy, and coily hair types tend to experience the most benefits.
• Pros: Hair is smoother and will retain straight styling better. If you want to maintain your waves or curls, a keratin treatment will make your natural texture smoother and less frizzy.
• Cons: Strong chemicals and high heat are needed to perform, which can lead to damage over time.
• How Long It Lasts: Gradually, the results will wear off after four to six months.

Brazilian Blowout

• What It Is: A Brazilian blowout aims to smooth and defrizz the hair a step further than a keratin treatment. If you're longing for sleek, stick-straight hair, a Brazilian blowout is the way to go.
• Who's It For: All hair types and textures, including color-treated hair. That said, those with sleek, straight hair won't need a treatment like this.
• Pros: Unlike a keratin treatment, a Brazilian blowout can be customized to the client's specific hair type and texture.
• Cons: A Brazilian blowout contains formaldehyde, so it's important to find a licensed professional in a salon with proper ventilation to carry out the treatment.
• How Long It Lasts: Three to four months.

Permanent Straightening Methods

Relaxer

• What It Is: "A relaxer is a permanent hair straightening method to remove all curl/wave from the hair," says Ramos. It uses chemicals, like sodium hydroxide, to permanently break those disulfide bonds in the hair and keep it straight. The solution is applied to dry hair, processed, and then washed with a neutralizing shampoo to lock the straightness in place.
• Who's It For: Those with coily, textured hair.
• Pros: All texture and volume is removed. Hair is pin straight and will not revert when exposed to moisture or humidity.
• Cons: If you decide you don't want it anymore, you have to cut off the treated hair. The chemical application can lead to damage over time.
• How Long It Lasts: Around six to eight weeks.

Japanese Thermal Straightening

• What It Is: Also known as permanent re-bonding and thermal reconditioning, Japanese thermal straightening is similar to a relaxer; it breaks down and reshapes the bonds in hair to permanently remove curls and frizz. For this process, chemicals like ammonium thioglycolate are applied to wet hair. The solution sits and is then rinsed out. Your hair will be blow-dried and meticulously straightened before a neutralizing solution is applied. Then, that gets rinsed out, and the hair is blown out again.
• Who's It For: Japanese straightening works best for those with healthy, virgin hair.
• Pros: If you're looking for permanent pin-straight, sleek hair, Japanese straightening is the best treatment for achieving that.
• Cons: After a Japanese straightening your hair won't be able to hold a curl or a wave. With the combination of chemicals and heat at play, Japanese straightening can be very damaging to the hair.
• How Long It Lasts: Japanese straightening doesn't fade so the only way to remove it is to cut the hair off. That said, new hair growth will require a touch-up treatment.

Final Takeaway

If you're after a straighter hairstyle, you have plenty of options when it comes to how you can achieve that. To make the best choice, consider your hair type and goals. If you have wavy hair and prefer a sleek style sometimes, a blowout is going to be a much better option for you than Japanese thermal straightening. If you're set on a semi-permanent or permanent straightening method, make sure to find a qualified salon professional that will prioritize the health of your hair.