Should My Colorist Be Using Heat While Bleaching My Hair?

person with bleached blonde hair
Design by Zackary Angeline.

If you are well-versed in how heat can cause further damage to your bleached hair, you might get freaked out if your stylist wants to put you under the heat post-color. While it is a common step at the salon to speed up the color process, it's not totally necessary.

"Heat, along with bleaching, strips the natural oils and hydrators and can thin the hair—increasing the risk of breakage, splitting, and brittleness of the follicle," says dermatologist Dr. Rachel Nazarian.

While there are some healthy uses for heat during the lightening process (and your stylist should be experienced to know whats best for you), it's important to know whether or not your hair can handle it. To find out more, we asked Nazarian and two hair experts for their advice on using heat on freshly color-treated hair.

Meet the Expert

  • Gina Rivera is a hair artist and founder of Phenix Salon Suites.
  • Nicolette Rauchut is a senior hair stylist and hair extension specialist at Lrn Beauty.
  • Rachel Nazarian, MD, is a board-certified dermatologist with Schweiger Dermatology in New York City.

Keep reading to learn if your colored hair can handle the heat at the salon.

Why Is Hair Processed with Bleach?

When highlighting hair or going to a lighter color, a colorist will use bleach to strip the current color from your hair through oxidation. Normally, it's a powdered bleach mixed with 10-, 20-, 30- or 40-volume peroxide. The higher the number of the peroxide, the stronger it is.

A mixed bowl of bleach has a life of a couple of hours or more, although it may need a little refreshing. If bleach is applied well, it will stay moist up to one hour and will lift the entire time. Heat is not necessary for the bleach to do its job.

How Does Heat Affect the Bleaching Process?

If heat isn't a necessity for lightening hair, why would do colorists use it? The short answer: time. All the heat does is speed up the lightening process, but it can cause some serious damage along the way by lifting moisture.

"It is very common for your colorist to use heat during your color process; the temperature and length of time depends on your natural hair color, the condition of your hair, and the desired color outcome," says hair stylist Nicolette Rauchut. "When using high heat on colored hair, for long periods of time, the cuticle can over swell and potentially cause some damage."

You're at particular risk if your color isn't appearing light enough. If that happens, you are at risk for breakage and frizz at the top of the head after your hair is blown dry.

When Is it Okay to Apply Heat?

"Everyone's hair is different but generally it is okay to apply heat to color-treated hair in moderation," says hair artist and salon founder Gina Rivera. In general, expert colorists say that the only time to use heat during processing is on healthy, virgin, black hair, as it's hard to lift. Sometimes there's a good reason, like if you've had balayage and after 30–45 minutes the bleach is drying out in which case, five minutes or so of gentle heat is recommended.

If your colorist offers you the dryer while your hair is processing, you can request to skip it, however, Rivera says to trust your stylist. "They are typically very educated on their color lines, the manufacturer's instructions, and the color limitations," she says. Rauchut adds that, if you are concerned with your colorist using heat, simply ask for an explanation. "Your colorist will be more than willing to discuss their choice and recommendations for your hair," she said, adding that inquiring why they believe you need the heat, how long they intend to have you under, and how much breakage you should expect are worth knowing.

As for heat styling, Rivera says you can always ask your colorist and stylists for advice on how to use heat correctly. "I always tell my clients to apply a heat protectant before using their hair dryer or any type of hot tools," she says. "Always use a low setting. If your hot tools are on high, your hair can become dry and damaged. Your color can also fade faster."

Best Products for Damaged Hair

The best products for heat-damaged hair will be anything hydrating and deep-conditioning. "Stay away from over-the-counter products that contain sulfates; these can leave the hair dry, frizzy, and prone to breakage," says Rivera, who recommends incorporating a leave-in conditioner into your hair care regimen. We like the lightweight, color-safe Color Security Conditioner ($24) by Color Wow for daily use.

When you do take heat to your hair, it is essential to use a good heat protectant spray. Rauchut's pick is IGK Good Behavior 4-in-1 Prep Spray ($32) because it is formaldehyde-free and has up to 450 degree heat protection. 

All experts urge the use of a heat-protectant spray before styling with heat. "These products seal the cuticle and trap moisture, and add hydration while decreasing levels of heat that the hair is exposed to. Consider it a 'shield' from outside negative influences," says Nazarian, noting that it is important to "decrease levels of heat and minimize exposure to high heat whenever possible, but especially post-color treatments."

Byrdie Tip

Not all heat protectants are created equal so always check the label to see what degree heat the product helps guard against.

"A good hair serum can provide heat protection and helps prevent split ends," says Rauchut, who recommends Milbon Plarmia Hair Serum Oil. "It's also helpful for those who have tangly brittle hair. You can apply the serum first before brushing."

If your hair is severely damaged, it might be best to visit a professional for something in-house. "The Milbon repair in-salon treatment is applied once a month and has a patented silk protein that strengthens your hair from the inside out," says Rauchut.

The Final Takeaway

Heating your hair after coloring it is okay, but be wary of the level of heat and time spent on your hair. "Color-treated hair has already undergone styling that can weaken the follicle, and is more prone to additional damage from heat-styling tools," she says. "It's important to avoid high heat and prolong it as long as possible post-coloring."

Anyone who can still see any effects of having hair bleached, permed, or chemically straightened should avoid going under heat. Thin hair should never be put under heat, nor should hair that's consistently chemically treated. If you still don't think it's best for you, you can decline going under heat at the salon. If it's between faster processing time and healthier processing, always choose the healthier route.

FAQ
  • Is it ok to blow-dry my hair after dying it?

    Since hair is in a fragile state after a dye job, avoid blow-drying and any type of heat styling for the first few weeks post-color treatment. Instead, opt for air-drying. And if you must heat style, use a heat protectant.

  • What should I do if my colorist used heat on my bleached hair?

    The priority is getting your hair back to a healthy state. To do so, avoid anything that could damage it further (e.g. more bleach, heat styling, harsh products, etc.). Use gentle hair products that will work to hydrate and strengthen strands. Protein treatments will also help. Just don't overdo it since the right protein-moisture balance is key for a healthy head of hair.

Article Sources
Byrdie takes every opportunity to use high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial guidelines to learn more about how we keep our content accurate, reliable and trustworthy.
  1. Jeong MS, Lee CM, Jeong WJ, Kim SJ, Lee KY. Significant damage of the skin and hair following hair bleachingJ Dermatol. 2010;37(10):882-887. doi:10.1111/j.1346-8138.2010.00916.x

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