Keratin: What Is It, Skin & Hair Benefits & Side Effects

Priya Singh
Fact-Checker: Priya Singh
This article was last updated on: May 18, 2023
Table of Contents

If you’ve ever flipped your shampoo bottle or skincare cream jar to glance at the ingredients list, you’re likely familiar with the dizzying array of chemical names, botanical extracts, and mystery terms printed in the smallest font. Even for those with a scientific background, making sense of these lists can sometimes feel like decoding a foreign language.

Amidst this cornucopia of ingredients, one that you may have stumbled upon is Keratin. The name itself, with its hard ‘K’ sound followed by a smooth, rolling ‘r’, may evoke a sense of strength and resilience. Interestingly, this phonetic interpretation isn’t too far from its actual functionality in the realm of cosmetics.

In this article, we delve deep into Keratin. We’re going to unpack its official description, understand its functions as listed by CosIng, the European Commission database for information on cosmetic substances and ingredients, explore its benefits for our skin and hair and also touch upon any potential side effects.

What is Keratin?

Keratin, also commonly referred to as hydrolyzed keratin or keratin amino acids, is a naturally occurring, fibrous protein that is integral to the structure of our skin, hair, and nails. The official CosIng description characterizes it by its high cystine content, an amino acid that adds strength and durability to the protein structure. This robustness gives keratin its protective and conditioning capabilities, primarily when used in cosmetic products.

Its general purpose within products like hair treatments and skin creams is to condition and fortify. Keratin works by adhering to the surface of skin or hair, forming a protective barrier that can help resist damage and enhance the appearance and feel of the skin or hair.

In terms of concentration, it can vary widely depending on the specific product and its intended use. Keratin can be a standalone ingredient in certain products like hair treatment masks or serums, but it is more commonly found as part of a wider formulation of ingredients in shampoos, conditioners, lotions, and creams.

Who Can Use Keratin?

Keratin’s properties make it a versatile ingredient that is suitable for all skin types, including sensitive, dry, oily, or combination skin. It’s beneficial for those looking to enhance their skin or hair’s texture and appearance, irrespective of the specific concerns or conditions.

In the context of dietary preferences and restrictions, it’s important to note that keratin is derived from vertebrates, making it unsuitable for vegans or vegetarians seeking to avoid animal-derived ingredients. For those with such preferences, plant-derived alternatives that mimic keratin’s functions are available in the market.

Regarding its use during pregnancy or breastfeeding, there’s no known contraindication for keratin. However, as with any cosmetic ingredient, it’s always a good idea to consult with a healthcare provider or dermatologist if you’re pregnant, breastfeeding, or have a specific health concern. They can provide personalized advice based on your unique situation and health history.

Keratin Skin Benefits

Keratin brings a range of benefits to the skin, thanks to its skin-conditioning function. Here are some of the key benefits:

  • Improves Skin Barrier Function: Keratin proteins help to reinforce the skin’s barrier function. They fill in the gaps in the skin cells, creating a protective layer on the skin’s surface. This barrier helps to lock in moisture, protect from environmental aggressors like pollution and UV rays, and resist damage. The skin barrier’s integrity is crucial for maintaining skin health, hydration, and overall appearance.
  • Promotes Skin Elasticity and Resilience: Keratin’s robust structure can lend resilience and elasticity to the skin. By forming a supportive layer on the skin surface, it can help maintain the skin’s structure and resistance to physical impacts, reducing the likelihood of scratches, cuts, or abrasions.
  • Enhances Skin Texture and Appearance: Keratin’s conditioning properties help improve the skin’s texture and appearance. By fortifying the skin’s surface, it can smooth rough patches and help create a more even, supple skin surface, giving the skin a healthier and more youthful appearance.

It’s important to note that while keratin can help improve the skin’s condition and appearance, these benefits are not permanent. To maintain these effects, consistent usage of products containing keratin is necessary.

Keratin Hair Benefits

Just as with skin, keratin also offers significant benefits for hair, thanks to its hair-conditioning function. Here are some notable benefits:

  • Strengthens Hair: Keratin is a primary component of hair, lending it strength and structure. When applied topically in the form of shampoos, conditioners, or hair treatments, keratin can bond to the hair’s surface, effectively ‘patching up’ damaged areas and reinforcing the hair fiber. This can result in hair that is stronger and less prone to breakage.
  • Improves Hair Appearance: Keratin treatments can smooth the hair cuticle, the outermost layer of hair that can become rough or frayed due to damage. By smoothing the cuticle, keratin can give the hair a shinier, more polished appearance.
  • Reduces Frizz: By providing a protective layer around the hair shaft, keratin can help to control frizz and make hair more manageable. This can be particularly beneficial for individuals with curly or unruly hair, who often struggle with frizz and tangling.
  • Protects Against Environmental Damage: Keratin’s protective layer can shield hair from environmental factors such as UV rays and pollution, which can weaken the hair and cause it to look dull over time.

Similar to its effects on the skin, the benefits of keratin for hair are not permanent. Consistent and sustained use of hair care products with keratin is necessary to maintain these beneficial effects.

Keratin Potential Side Effects

While cosmetic ingredients like keratin offer a plethora of benefits, it’s essential to bear in mind that side effects and reactions can vary from person to person. The variability can be attributed to a range of factors, including individual skin type, skin condition, allergies, and the specific formulation of the product used. If you are unsure of your skin type, consider consulting this guide to find your skin type.

Even though Keratin is generally considered safe, there are some potential side effects to keep in mind:

  • Allergic Reactions: Some people may be allergic to keratin. Symptoms of an allergic reaction can include redness, itching, or swelling at the site of application.
  • Skin Irritation: Though uncommon, keratin may cause skin irritation in some individuals, resulting in redness, dryness, or a burning sensation.
  • Excessive Protein Buildup: Overuse of keratin-based products, particularly on hair, can lead to excessive protein buildup, which may make the hair brittle and prone to breakage.

If you experience any of these side effects while using keratin or a product containing it, discontinue use and seek advice from a healthcare provider or dermatologist. They can help determine whether the reaction is due to keratin and suggest alternative products or treatments if necessary.

That said, adverse reactions to keratin are generally rare. Overall, keratin is a safe and effective ingredient that can offer significant benefits to skin and hair when used properly.

However, as a good skincare practice, it’s always advisable to perform a patch test before incorporating a new product into your skincare routine, even with ingredients deemed generally safe like keratin. This step is crucial to identify any potential adverse reactions in a controlled manner. Check out this comprehensive patch-testing guide to learn more about this important step.

Comedogenic Rating

Keratin, as a protein-based ingredient, has a comedogenic rating of 0. This means it’s non-comedogenic, and it is unlikely to clog pores or lead to breakouts. The reason for this low rating is due to keratin’s molecular structure and function. As a large protein molecule, it’s unlikely to penetrate deep into the pores. Instead, it works mainly on the surface of the skin or hair, providing a protective and conditioning layer.

Therefore, keratin is generally suitable for all skin types, including those prone to acne or breakouts. Its non-comedogenic nature makes it less likely to exacerbate these conditions and may actually help improve the skin’s overall texture and appearance.


Success in skincare and haircare often comes down to a journey of experimentation and trial and error. What works phenomenally for one person may not yield the same results for another, highlighting the importance of individual differences in this realm.

Products containing keratin can be a valuable addition to your skincare or haircare regimen, especially if you’re looking to strengthen your hair, improve its appearance, or fortify your skin’s barrier. Its versatile benefits, coupled with its general safety profile, make it a compelling choice among a sea of cosmetic ingredients.

Keratin has gained notable popularity in recent years, particularly in hair care products, and for good reason. Its effects on improving hair strength, reducing frizz, and adding a beautiful shine are well-documented and loved by many users. In skincare, while it might not be the most hyped ingredient, its conditioning properties and benefits to skin health and appearance are undeniable.

As with many skincare and haircare ingredients, patience is key when it comes to seeing results from keratin. Depending on the specific product and your individual characteristics, it might take several weeks to observe notable improvements.

In summary, keratin is a powerful, natural ingredient that offers numerous benefits for skin and hair. Its strength lies in its ability to condition, protect, and enhance, providing both immediate and long-term benefits. Despite the potential for minor side effects, its overall safety and efficacy make it a promising component in a variety of cosmetic products.

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