Protein myths, debunked: The truth about proteins in hair care

However, this widespread use also fuels misinformation. Almost all TikTok users (98%) acknowledge its prevalence, and studies suggest up to one in five videos may contain it (2), allowing unsubstantiated hair advice to thrive as non-experts dominate content, leaving many common myths unchecked. 

To help cut through the noise, I asked two of our hair experts, Mike Hindley and Farahdia Edouard, to set the record straight and share the science behind proteins in hair care. 

 

Myth 1: Can proteins “build up” and make the hair stiff and brittle? 

Mike: "The notion that proteins inherently make hair stiff or crunchy is a misconception. At their recommended use levels, proteins do not typically cause this effect. While protein deposition on the hair fibre can increase with multiple applications, this process generally plateaus when products are used at normal application concentrations. However, if excessively high protein concentrations are used, as seen in some intensive protein treatments, then an overabundance of protein can indeed remain on and within the hair. This excess can then lead to the hair feeling rigid and brittle, both due to surface build and excessive delivery inside the fibre interfering with the balance of moisture inside the hair. When proteins are used at the correct and recommended usage levels, they can offer a multitude of benefits without compromising the natural feel of the hair. It’s all about balance, expertise, and using the right type of protein in the right way. At Croda Beauty, we provide recommended use levels for all our proteins and peptides to help formulators ensure optimal performance and achieve the right balance without compromising the natural feel of the hair.”  

Myth 2: Is vegan keratin as effective as traditional keratin? 

Farahdia: "Keratin is a protein traditionally derived from wool, so an animal source, but advancements in biotechnology have led to vegan alternatives that replicate its benefits. These bioengineered proteins use amino acid sequences that mimic natural keratin in hair, leading to bond building and improving strength without the need for animal-derived ingredients. Vegan keratin alternatives can also be plant based these are typically designed with amino acid profiles that match the most abundant amino acids found within animal-derived keratin and also replicate the performance and functional benefits.”  

Croda solutions related to keratin include:

• NEW! KeraBio K31: Biomimetic bond builder  
• Keramatch V:  Plant-derived vegan keratin 
  
  

Myth 3: Can proteins cause sensitisation? 

Mike: "The concern that proteins in hair care products frequently lead to sensitisation or allergic reactions is also largely a misconception, often stemming from general protein allergenicity in other contexts (e.g., food allergies). Sensitisation, an allergic response that develops after repeated exposure to a substance, typically involves the immune system recognising specific structural features (epitopes) on a protein. In cosmetic applications, the processing of proteins significantly alters their structure, often through hydrolysis, which breaks down large protein molecules into smaller peptides or amino acids. 

This hydrolysis significantly reduces or eliminates the allergenic potential of the original protein. Sensitisation usually occurs when the immune system recognises specific epitopes (structural features) on a protein. By breaking down the protein, these epitopes are destroyed or altered, making them unlikely to trigger an immune response. Furthermore, the skin barrier, particularly on the scalp, offers protection against large molecules. While rare individual sensitivities can occur with any ingredient, hydrolysed proteins used in hair care are designed to be non-sensitising and are considered safe for topical application. Furthermore, known allergens such as wheat (or the protein within wheat known as gluten), are restricted in Europe to an average molecular weight below 3.5kDa. This ensures the material is hydrolysed sufficiently and is therefore not recognised by the body as an allergen.”  
 

Myth 4: Do all proteins work the same way? 

Farahdia: "Not all proteins are created equal. The effect of a protein depends on its origin, molecular weight, and how it interacts with the hair structure. For example, proteins with a low molecular weight penetrate deep into the cortex to reinforce the hair from within, while others with a high molecular weight form a protective barrier on the surface. Some, like Keravis™, can even do both. Also, certain sources offer unique properties; for instance, some exhibit antioxidant capabilities (for example FibraShield™ C) which provides protection against oxidative stress. At Croda Beauty, we offer a broad portfolio of proteins for hair care, and selecting the right one requires a tailored approach based on the specific needs of the hair. Use our Product Finder to explore our key protein technologies and discover their unique features and benefits.” 

Croda peptides include: 

• Keravis™ NSP ET: Multi-action strengthening peptides  
• FibraShield™ C: Protective multi-peptide  

Myth 5: Can proteins moisturise the hair? 

Mike: "Sometimes yes, but the concept of hair moisturisation is commonly misunderstood. It’s about finding the right balance of water in the hair. While proteins themselves aren't traditional humectants, some hydrolysed proteins possess water-binding properties that help hair regulate its moisture content/level which is useful for hair types which naturally have a low water content as these hair types can be brittle and break easily. However, hair naturally absorbs water, particularly if damaged or textured, causing the cortex to swell and cuticles to lift, leading to frizz in high humidity. This is largely due to the disruption of temporary hydrogen bonds within the hair's keratin structure, which, when broken by excess water absorption, allow the hair to revert to it’s original, un-styled and often unruly shape. To counter this, certain low molecular weight proteins offer frizz protection: they penetrate the hair fibre to provide internal moisture regulation within the cortex, stabilising hydrogen bonds, as well as forming a subtle surface barrier to slow down excessive moisture entry. This combination of moisture-balancing and film-forming properties, inherent in specific protein technologies, synergistically provides effective protection against humidity-induced frizz." 

Croda beauty's solution: 

Prolevium™ SB: Hair humidity proof protein 

Final thoughts 

Proteins are essential for achieving stronger, healthier, more resilient hair. But the benefits depend on choosing the right protein and using it in the right way. Whether you're developing for bond building, longevity, strength or frizz control, understanding how proteins behave is key to unlocking their full potential in your formulations. 

Want to know more about the latest in protein and peptide technology? Our experts are here to help you explore the best solutions for your next hair innovation. 

References:

(1). https://ads.tiktok.com/business/en-GB/blog/smb-beauty

(2). https://pmc.ncbi.nlm.nih.gov/articles/PMC11150891/