How to Identify & Repair Heat Damaged Hair

A swipe of the flat iron, a fluff of the blow dryer, a twist of the curler—for many, heat styling is an everyday routine. But over time, that heat can be too much to handle. How do you know when hair switches from styled to crisped?

Heat damage is all too common. If you suspect that daily blowouts are leaving your hair lifeless, then you’re probably right. However, there’s still hope. To reclaim your hair health, let’s explore the top signs and tips for how to fix heat damaged hair including the use of heat protectant spray

Heat Damage 101: What is It?

Between chlorine and coloring, it can sometimes feel like everything hurts your hair. But what makes heat damage especially harmful?

Healthy hair relies on its keratin protein fibers, which form every hair’s outer cuticle. When keratin fibers break down, the hair cuticle degrades and releases moisture, leading to a damaged state. Unfortunately, heat and keratin don’t always get along. Temperatures over 280 degrees Fahrenheit (and even lower) can instantly deform up to 85% of hair’s keratin fibers.,, 

When left alone, hair usually avoids high temperatures. However, when hair meets heat, it can be damaging. The following common heat tools and outdoor conditions can affect your hair:

  • Flat irons
  • Curling irons
  • Blow dryers
  • High UV light (sunlight) exposure

The bad news? Once your keratin fibers malform, they typically can’t fully return to a healthy state. 

The good news? You can nurture and protect damaged hair, as well as prevent future heat damage. Let’s dive into the top signs and solutions for heat damaged hair.

Common Signs of Heat Damaged Hair

A person using a curling iron to curl their dark hair.

There’s nothing like a fresh, bouncy blowout. However, that heat could end up leaving your hair duller than it started. 

Heat leaves a trail of visible damage, from dullness to split ends. Suspect those curling sessions are leaving your hair lifeless? What does heat damaged hair look like in reality? Keep an eye out for these signs:

  • Split ends and breakage – Heat dissembles the very structure of hair cuticles, breaking apart their precious keratin content. Once that happens, your hair is left weak and vulnerable. This can lead to increased split ends and hair breakage, two common signs of heat damage.
  • Changed color  – Whether dyed or natural, hair pigment can oxidize and fade under high heat. Check if your hair color has noticeably changed after routine heat use. Additionally, little white nodules on the ends of your hair signal irreversible heat damage. These white dots are the result of heat quickly and intensively deforming hair proteins.
  • High porosity – This one’s a little harder to see. However, you might notice high hair porosity after you shower. Due to heat damage, hair cuticles become more porous and absorb extra moisture. On the flip side, high porosity can make your hair cuticles lose moisture more easily, leading to frizz.
  • New and rough textures – Snarly knots, stringy strands, and a dry feel can all result from heat damage, typically due to moisture loss. Also, high temperatures can alter hair’s natural curl pattern. One study showed that the repeated use of a flat iron prevented the restoration of a regular curl texture, even after the curly hair was washed.

Other Causes of Hair Damage

Today, heat damage is all too common. Aside from heat damage, make sure you don’t have other damaging hair practices. These problematic hair habits can lead to similar damage symptoms as heat:

  • Rough brushing
  • Brushing wet hair
  • Tight ponytails or hairstyles
  • Overwashing
  • Coarse pillowcases
  • Constant dyeing, bleaching, or chemical treatments

How to Repair Heat Damaged Hair

Let’s say you’ve been waving the curling rod frequently. Before you know it, your hair is starting to lose shine and strength. 

Is the damage done?

Unfortunately, hair strands are a bit like eggshells. Once heat “cracks” the protein-rich outer cuticle, you can’t fully put it back together. However, you can protect, nourish, and even eliminate heat damaged hair. With the right treatment, even the most fried follicles can eventually recover.

Use an Ultra-Moisturizing Product

Hair loves moisture—it’s the key to a healthy and strong cuticle. Heat damage leaves hair shafts susceptible to moisture loss, making it the perfect time for a hydrating boost.

Depending on your hair type and routine, you can choose a few ways to up the moisture. Consider these hydrating products to soothe rough texture and frizz from heat damage:

  • Sulfate-free shampoo and conditioner – A common shampoo ingredient, sulfates use a negative (anionic) charge to cleanse sebum from your scalp. Unfortunately, this can strip your hair’s natural moisture, leaving behind extra frizz. When healing heat damage, stick with sulfate-free shampoo and conditioner.
  • Deep or leave-in conditioners – Your hair strands are complex, layered structures. To enrich them fully, moisturizing products need time to penetrate these layers. That’s where deep or leave-in hair treatments can help. These products sit on hair anywhere from 15 minutes to your next shower, allowing ingredients to moisturize the entire hair follicle (a must for damaged hair). 
  • Sealant oils – Moisturizing hair requires adding and sealing in moisture. The best products for locking in moisture content are sealant oils like meadowfoam seed oil. These lightweight options can seal cuticle gaps, moisturize outer breakage, and protect remaining inner moisture.

Emphasize Protein

It makes sense—if heat degenerates your vital hair proteins, then your damage control should try to supplement this protein loss.

Protein treatments can’t repair all damaged keratin bonds. However, certain protein-rich formulas can coat or heal some keratin degeneration.,, Try leave-in conditioners with proven bonding agents like:

  • Keratin K31
  • Feather keratin hydrolysates
  • Bis-aminopropyl diglycol dimaleate
  • Biotin
  • Amino acids

Want maximum protein penetration? Try an overnight hair mask like the PhD Night Cap Overnight Perfector. You can turn back the clock in your sleep.

Reduce Your Use of Heat (and Chemicals)

We know, it’s tough. But if you can, try limiting the amount of hot tools you use. The more heat you use, the worse any damage and hair breakage will become. Try limiting your use of blow dryers, curling irons, and flat irons while healing heat-damaged hair. 

Similarly, stay away from harsh chemical treatments during this time. Heat leaves hair cuticles vulnerable and weak, so you could further damage hair health with treatments like:

  • Perms
  • Relaxers
  • Texturizing treatments (i.e. Brazilian blowouts) 
  • Coloring

Get a Haircut

The best solution for how to repair heat damaged hair? Cut it.

Hair ends usually bear the brunt of heat damage, since they lie farthest from your scalp’s soothing hair oils. To prevent split ends and breakage from traveling up the hair shaft, schedule that salon appointment. A small (or big) trim can eliminate fried ends, cutting off the most vulnerable spots.

Pro Tips for Preventing Heat Damage

Gray product bottle with a white cap and white text.

Don’t toss your beloved flat iron in the trash just yet. You can learn how to protect hair from heat damage in several ways.

You can still (gently) use heat and keep your hair healthy with the right care. To keep fried ends at bay, try these tips to prevent future heat damage:

  • Air dry – It’s obvious but true. To stop heat damage, drop the hot tools. However, it’s not easy to adopt air drying. Start with techniques like microfiber towel wrapping, braids, finger wrapping, and “plopping” (creating a loose bun at the top of your head). Additionally, leave-in hair styling cream can help form the dry hairstyle you want. 
  • Use heat protectantsDoes heat protectant work? Research shows that sprays with polymers or hydrolyzed wheat protein can partially block heat’s keratin degeneration (although not fully)., Before using any hot tools, apply a quality heat protectant spray beforehand. 
  • Lower the temperature – Heat damage runs on a gradient. The lower the temperature, the less damage you’ll probably create. Any hot tools running below 280 degrees Fahrenheit could significantly reduce hair cuticle damage.
  • Keep a distance – Most hair dryers have zero direct temperature control. However, you can reduce their heat damage by maintaining a safe distance from the dryer itself. For blow drying, one study showed that constant movement and a 5-inch minimum distance from hair can help prevent heat damage.
  • Rinse on cold – If you’re trying to be extra careful, watch the hot water in your shower. Rinsing on high heat can leave your hair cuticle raised or “open”, making it vulnerable to damage. Instead, rinse with cold water to “close” your hair cuticles.

Give Hair a New Life with Living Proof

Whether you’ve racked up days or years of heat damage, your hair can still spring back. Use these healing tips to restore the strong, shiny, and healthy locks that you deserve.

Another way to restore hair life? Take a look at Living Proof.

Our scientist-designed, stylist-approved products boost and preserve hair health. Keep heat at bay with our heat protectant sprays, heal breakage overnight with a hair mask, and check out our other hair products online for healthy hair. No matter how damaged your hair is, Living Proof can return it to a happier place. Explore our hair repair products today.

Sources:

American Academy of Dermatology. 10 Hair Care Habits That Can Damage Your Hair.  https://www.aad.org/public/everyday-care/hair-scalp-care/hair/habits-that-damage-hair

Hiroshima University. Scientists shine new light on heat-damaged hair. https://phys.org/news/2021-01-scientists-heat-damaged-hair.html

NIH. Effects of heat treatment on hair structure. https://pubmed.ncbi.nlm.nih.gov/19467113/

NIH. Effect of mineral oil, sunflower oil, and coconut oil on prevention of hair damage. https://pubmed.ncbi.nlm.nih.gov/12715094/

NIH. Hair Cosmetics: An Overview. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4387693/

NIH. Hair Shaft Damage from Heat and Drying Time of Hair Dryer. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3229938/

NIH. Health improvement of human hair and their reshaping using recombinant keratin K31. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6218806/

NIH. Modification of wheat gluten for improvement of binding capacity with keratin in hair. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5830729/

NIH. Structural investigation on damaged hair keratin treated with α,β-unsaturated Michael acceptors used as repairing agents. https://pubmed.ncbi.nlm.nih.gov/33279560/

NIH. The effect of various cosmetic pretreatments on protecting hair from thermal damage by hot flat ironing. https://pubmed.ncbi.nlm.nih.gov/21635854/

Purdue University. Integrating Design Methodology, Thermal Sciences, and Customer Needs to Address Challenges in the Hair Care Industry. https://engineering.purdue.edu/reidlab/pdf/2015_IDETC_Hahn%20et%20al.pdf

Healthline. How to Treat Heat-Damaged Hair Without Cutting It https://www.healthline.com/health/beauty-skin-care/heat-damaged-hair#treatment