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Ep 13: Is Your Haircare Routine Weighing You Down?

Updated: Jan 16

In this episode of Beauty by the Beaker, we're diving into the science of haircare! We discuss identifying your hair type, and the importance that plays on an ideal haircare routine. We're answering questions about the effectiveness of heat protectants for styling, and rosemary oil for hair growth. Check out the episode for a discussion on salon ‘grade’ versus drugstore haircare products, and a reminder of the importance of personal preference in hair care routines.


Are Heat Protectants a Scam?


You may have heard a stylist or creator say that heat protectants are a scam—or even that they cause more damage than using heat alone. To understand where this claim comes from (and whether it’s true), we need to look at how hair is structured, how heat damages hair, and what heat protectants actually do.


Hair is made primarily of a protein called keratin. Keratin is held together by different types of bonds, but two are especially important when it comes to heat styling.


Hydrogen bonds are weak and break easily. They break every time your hair gets wet or is exposed to heat. When the hair cools or dries, these bonds reform, which is why heat styling is usually temporary and why hair returns to its natural texture after washing.

Breaking hydrogen bonds is reversible, but only up to a point. If heat is too high or applied repeatedly, the damage can become permanent.


Disulfide bonds are much stronger and help give hair its long-term strength and shape. Once these bonds break, they do not naturally reform. High heat (roughly 302–428°F) can break disulfide bonds through a process called thermal denaturation, permanently altering the hair’s structure.

This same process is intentionally used in keratin straightening treatments, which rely on heat and chemicals to break and reset these bonds.

When disulfide bonds are damaged, hair becomes weaker, drier, more brittle, and more prone to split ends and breakage.


Most heat styling tools operate within ranges that overlap with known damage thresholds.

  • Flat irons and curling irons typically range from 194°F to 338°F

  • When hair reaches temperatures above 266°F, several damaging processes begin:

    • Keratin proteins start to break down

    • Hair pigments can change

    • Hydrogen bonds break more aggressively

    • The hair fiber weakens over time


If hair contains any water when heat is applied, the water can rapidly turn into steam. Steam expands as it forms, and as it escapes the hair fiber, it can:

  • Crack and fray the cuticle

  • Create internal structural damage

  • Increase brittleness and roughness


What Heat Protectants Actually Do


Heat protectants do not make hair “heat-proof,” but they reduce the amount of damage caused by heat.


Heat protectants work mainly by forming a thin film on the surface of the hair. This film:

  • Slows down heat transfer

  • Helps distribute heat more evenly

  • Reduces hot spots

  • Lowers friction between the hair and the styling tool


A 1998 study examined three ingredients commonly used in heat protection:

  • PVP/DMAPA Acrylates Copolymer

  • Quaternium-70

  • Hydrolyzed Wheat Protein


Each ingredient was used at under 1% concentration. All three resulted in 10–20% less heat damage when hair was exposed to a curling iron. The protective effect was attributed to surface film formation.


Silicones and silicone quaternary compounds work especially well because they:

  • Form stable, smooth films

  • Spread heat evenly along the hair shaft

  • Reduce moisture loss

  • Reduce friction during styling

These are among the most effective heat-protective ingredients available.


Heat protectants generally reduce damage by up to about 50% at best. They cannot fully prevent damage, especially with high temperatures or frequent heat styling. Using less heat and styling less often still matters.


Oil-Based Heat Protectants: What to Know


Oil-based heat protectants are not automatically bad, but they require more caution.


Every oil has a smoke point, which is the temperature at which it begins to break down and smoke. When this happens:

  • The oil becomes unstable

  • Protective coverage becomes uneven

  • Heat protection drops significantly

If your hot tool is hotter than the smoke points of the oils in your product, those oils may provide little to no protection.


As oils heat up, some components boil off faster than others. This creates a patchy, uneven film, which reduces protection.


When heated oils react with oxygen, they oxidize. Oxidized oils:

  • Lose lubricity, increasing drag

  • Increase friction between hair and tool

  • Can produce smelly, sticky byproducts

  • Can make hair look dull


Oxidation can generate free radicals, unstable molecules that damage keratin proteins. In hair, this can:

  • Roughen the cuticle

  • Weaken the cortex

  • Increase long-term damage


Hair does not literally fry like food. However, if oils scorch and lose their protective function, they can leave hair hotter, drier, and more brittle than if a stable film-forming protectant had been used. This is largely due to increased friction and uneven heat exposure.


What to Look for in a Heat Protectant


The effectiveness of a heat protectant depends on formulation, not price.


  • Silicones (such as dimethicone or amodimethicone)

  • Silicone quaternary compounds

These ingredients are especially good at spreading heat evenly and reducing moisture loss.


Other helpful ingredients include:

  • Film-forming polymers (such as acrylates or PVP-based polymers)

  • Cationic conditioning agents

  • Certain proteins that help coat the hair surface


More expensive products are not automatically better. What matters is:

  • Ingredient choice

  • Ingredient concentration

  • Overall formula design


In this episode, we also chatted about whether or not rosemary water helps to grow the hair, and also our thoughts on salon vs drugstore haircare. Check out the episode for more information!


Bibliography


  1. Wong M. Hair frizz science: water and hydrogen bonds. Lab Muffin Beauty Science. November 29, 2019. Accessed May 21, 2025. https://labmuffin.com/hair-frizz-science-water-hydrogen-bonds/ 

  2. Wong M. How do heat protectant hair products work?. Lab Muffin Beauty Science. April 17, 2016. Accessed April 12, 2025. https://labmuffin.com/how-do-heat-protectant-hair-products-work/ 

  3. Wong M. How does hair straightening (and perming) work?. Lab Muffin Beauty Science. June 7, 2013. Accessed April 22, 2025. https://labmuffin.com/how-does-hair-straightening-and-perming-work/ 

  4. The Beauty Brains Podcast, episode 380 “Patented Ingredients, porosity, Quats & More”. November 28, 2024.

  5. The Beauty Brains Podcast, Episode 346 – “Beauty Devices, Korean Skin Care & More”. November 26, 2023.

  6. Choe E, Min DB. Chemistry of deep-fat frying oils. J Food Sci. 2007 Jun;72(5):R77-86. doi: 10.1111/j.1750-3841.2007.00352.x. PMID: 17995742.

  7. https://www.curlynikki.com/smoke-points-why-oil-doesnt-work-as.html?utm

  8. Lab Muffin Beauty Science. (2024, November 15). Rosemary oil vs minoxidil: what the study really says [Video]. YouTube. https://youtu.be/SW2NCv_vF2Q

  9. The Beauty Brains. (2024, November 15). Episode 327 - Salon hair care, cationic skin care, collagen threads and more [Audio podcast episode]. Spotify. https://open.spotify.com/episode/3Cbjt0OW1TGx3RDZBhjbVg

  10. The Beauty Brains. (2024, October 20). Curology questions – Salon conditioners and bar soap shampoo – episode 178 [Audio podcast episode]. Spotify. https://open.spotify.com/episode/7u94wQIx1gJ4pE0j9D9OmR

  11. Lab Muffin Beauty Science. (2025, March 18). Professional vs drugstore hair products? [Video]. YouTube. https://www.youtube.com/watch?v=TV6fm6W9A_0

  12. Wong M. How Do Different Types of Hair Dye Work? The Science. Lab Muffin Beauty Science. April 21, 2019. Accessed May 30, 2025. https://labmuffin.com/how-does-hair-dye-work/

  13. Kibbelaar, H. (@sciencemeetscosmetics). (2022, January 10). Great news: you can stop worrying about your hair porosity… [Instagram post]. https://www.instagram.com/p/CZhS6HUqdAE/

  14. Kibbelaar, H. (@sciencemeetscosmetics). (2024, November 26). Hair porosity is about damage. [Video]. Instagram. https://www.instagram.com/reel/DC1oI6pucOO/

  15. Hessefort, Y., Holland, B. T., & Cloud, R. W. (2008). True porosity measurement of hair: a new way to study hair damage mechanisms. Journal of Cosmetic Science, 59(4), 303–315. https://pubmed.ncbi.nlm.nih.gov/18818850/

  16. Lab Muffin Beauty Science [@labmuffinbeautyscience]. (2024, December 15). The hair strand test for porosity doesn't actually tell you... [Video]. Instagram. https://www.instagram.com/reel/DDal877T9D1/


 
 
 

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