How Heat Styling Tools Can Damage Your Hair
Using heat styling tools like straightening irons and curling tongs can give you the perfect sleek look or voluminous curls, but they can also cause long-term damage if not used correctly. Understanding the science behind this damage can help you make better styling choices at home to help keep your hair strong and healthy.
How does heat damage hair?
Let's jump into the deep end and explain some of the science that goes on within your hair. This is the stuff that your stylist knows but may not have explained to you in detail.
1. Hair structure: which bonds are weakened by water and heat?
Human hair is primarily composed of keratin, a fibrous protein rich in disulfide bonds (covalent bonds between sulfur atoms in cysteine amino acids). These bonds, along with hydrogen bonds and salt bonds, help maintain the shape and strength of the hair.
- Hydrogen Bonds: Weaken when hair is wet and reform when it dries (basis of temporary styling).
- Disulfide Bonds: Strong chemical bonds that determine the hair’s natural shape (wavy, curly, or straight). Excessive heat can break these bonds permanently.
- Cuticle Layer: The outermost protective layer of the hair, made of overlapping scales. When damaged, the hair becomes frizzy, rough, and more prone to breakage. Cuticle damage is easy to see as the hair lacks any shine.
2. How Heat Causes Hair Damage
- Breaks Hydrogen Bonds (Temporary Change) – Heat temporarily weakens hydrogen bonds, allowing hair to be reshaped (straightened or curled). Frequent use weakens hair structure over time.
- Breaks Disulfide Bonds (Permanent Damage) – High temperatures (above 180°C) can permanently break disulfide bonds, leading to weak and brittle strands.
- Damages the Cuticle Layer – High heat lifts the protective cuticle layer, exposing the inner cortex and leading to increased porosity, frizz, and split ends.
- Moisture Loss & Bubble Hair Effect – When heat is applied too quickly on damp hair, water inside the shaft turns to steam, creating tiny bubbles inside the hair fibre, making it fragile and prone to breakage. You can hear the bubble effect when it happens and you can also be burnt by the resulting steam.
- Oxidation & Colour Fading – High temperatures degrade natural melanin and lipids in the hair, causing colour-treated hair to fade faster and appear dull. In some cases, very delicate colours such as 'brights or 'toners' can be visibly erased before your eyes with excessive heat styling!
Heat-Safe Styling: How to Minimise Damage
1. Always, always, always use a Heat Protectant
Heat protectants form a thin barrier around your hair, reducing moisture loss and preventing direct heat damage. We recommend using:
- REF Heat Protection Spray – Lightweight and non-greasy, perfect for everyday use.
- Innoluxe Elixir V3 – Strengthens disulfide bonds while providing thermal protection.
How to Use:
- Apply to dry or damp hair before styling.
- Comb through for even distribution.
- Blow dry completely and then use your preferred hot tool to finish the styling.
2. What temperature is safe? Is 180°C too hot?
- Fine/Damaged Hair: 120°C–150°C
- Normal Hair: 150°C–180°C
- Thick/Coarse Hair: 180°C–200°C
Never exceed 200°C as this can cause irreversible keratin damage.
3. Ensure Hair is Completely Dry Before Styling
Using a straightener or curling tong on wet hair can lead to severe bubble hair damage. Always use a hairdryer first, preferably with a low to medium heat setting.
4. Choose High-Quality Styling Tools
Using tools with ceramic or tourmaline plates can help distribute heat more evenly, reducing the risk of hot spots.
Recommended Tools:
- Straightener: GHD Platinum+ Styler – Ensures even heating.
- Curler: Dyson 'Airwrap' – Uses low heat, preventing excessive damage.
5. How often can you heat style without long-term damage?
- Heat styling should be limited to 2-3 times per week to allow hair recovery time.
- Try heatless styling techniques like braiding damp hair for waves or using foam rollers for curls.
6. Strengthen Hair with Treatments
Using protein and moisture-rich treatments can help repair heat damage and reinforce keratin structure. Both INNOluxe and REF have an extensive range of options to choose from.
Best Treatments for Heat-Damaged Hair:
- REF Ultimate Repair Masque – Provides deep moisture to repair for your hair.
- Innoluxe Elixir V3 – Strengthens disulfide bonds, preventing breakage.
Leave-In Conditioners:
- REF Leave-In Treatment – Lightweight, ideal for fine to normal hair.
- Innoluxe Platinum – Designed for colour-treated or severely damaged hair.
7. Lock in Moisture and Shine
Applying lightweight oils after styling helps maintain shine and protect against environmental damage.
Recommended Oils:
- REF Shine Elixir – Provides UV and heat protection with a glossy finish.
- REF Leave In Serum – Strengthens and seals the cuticle.
Best Heat-Safe Products Based on Your Hair Type
1. Fine or Thin Hair
🔹 Concerns: Prone to heat damage, lacks volume, gets weighed down easily.
✅ Best Products:
- Heat Protectant: REF Heat Protection Spray
- Leave-In Conditioner: REF Leave-In Treatment
- Strengthening Treatment: Innoluxe Elixir V3
2. Thick or Coarse Hair
🔹 Concerns: Takes longer to style, needs high heat but is prone to dryness.
✅ Best Products:
- Heat Protectant: Innoluxe Elixir V3
- Leave-In Conditioner: REF Intense Hydrate Masque
- Styling Tool: Dyson Corrale Straightener (Handles thick hair well)
3. Curly or Wavy Hair
🔹 Concerns: Frizz, dehydration, heat causing curl pattern loss.
✅ Best Products:
- Heat Protectant: REF Heat Protection Spray
- Leave-In Conditioner: Innoluxe Platinum
- Curl Styling Tool: GHD Curve Classic Curl
4. Colour-Treated or Damaged Hair
🔹 Concerns: Prone to breakage, fading, and extreme dryness.
✅ Best Products:
- Heat Protectant: Redken Acidic Bonding Concentrate
- Leave-In Conditioner: Innoluxe Platinum
- Repair Mask: REF Ultimate Repair Mask
Final Thoughts
Heat styling doesn’t have to mean damaging your hair. By using heat protectants like REF Heat Protection Spray or Innoluxe Elixir V3, choosing the right temperature, and limiting frequency, you can maintain healthy, shiny, and resilient hair. Incorporate deep conditioning and strengthening treatments into your routine to keep your hair strong and vibrant.
Would you like personalised product recommendations based on your hair type? Let us know!
Heat styling questions, answered
Which bonds in the hair are weakened or broken by water or thermal heat?
Hydrogen bonds. They weaken when hair is wet or heated and reform as it cools and dries, which is exactly how a blow-dry or straightener holds a shape temporarily. Disulfide bonds are much stronger and hold hair's natural texture; sustained heat above roughly 180°C can break them permanently.
Is 180°C too hot for hair?
Treat 180°C as a ceiling rather than a starting point. Above it, disulfide bonds begin to break permanently. Fine, colour-treated or already damaged hair should sit lower, around 150–170°C, and always with a heat protectant.
How often can you heat style without long-term damage?
Two to three times a week gives hair recovery time between services. Heatless methods such as braiding damp hair or foam rollers fill the gap without adding thermal stress.
Are heat styling tools safe on colour-treated or chemically processed hair?
They can be, at lower temperatures. Colour-treated and chemically processed hair is more porous and has already had its bond structure disrupted, so it heats faster and tolerates less. Drop the temperature, use a protectant every time, and support it with bond or protein treatments.
Which styling products work best alongside heat tools?
A heat protectant first, every time, on every section. After that, protein and bond treatments do the repair work, and a lightweight oil or serum seals the cuticle once styling is finished.
Can the right styling tool actually improve hair condition over time?
No tool improves hair on its own. What better tools do is control temperature accurately and distribute heat evenly, so you spend less time on each section and avoid the hot spots that cause most of the damage.
