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

Priya Singh
Fact-Checker: Priya Singh
This article was last updated on: May 19, 2023
Table of Contents

You’re standing in the cosmetics aisle of your favorite store, looking at the back of a bottle of a promising skin or hair product. The ingredient list is an unending parade of terms that feel more at home in a chemistry class than on a product meant to make you look and feel good. Sodium lauryl sulfate, tocopheryl acetate, hyaluronic acid – it can be a head-spinning experience trying to make sense of it all.

One of those terms that may have caught your eye is ‘Kallikrein’. Kallikrein. Even the name, derived from Greek origins, seems to exude an aura of scientific complexity that leaves many wondering, what on earth does it do?

This article aims to demystify Kallikrein, a rather intriguing ingredient that has found its way into the world of cosmetics. Over the next sections, we will delve deep into what Kallikrein is, the benefits it offers to our skin and hair, and any potential side effects it may have.

What is Kallikrein?

Kallikrein is a type of serine protease, an enzyme that plays a vital role in many biological processes. In the realm of cosmetics, it’s mainly found under its own name, Kallikrein, or occasionally referred to as “human tissue Kallikrein”.

This ingredient serves as a skin and hair conditioning agent, working by breaking down proteins in our skin and hair, which aids in the process of exfoliation and conditioning. While the exact concentration of Kallikrein can vary among products, it’s usually found as part of a broader formulation of ingredients. It’s less common to see it sold as a standalone product, mainly due to its enzymatic nature and the specific conditions it requires to function effectively.

Who Can Use Kallikrein?

Kallikrein is versatile and generally suitable for a variety of skin types. Whether you have dry, oily, sensitive, or combination skin, Kallikrein-infused products can potentially be a part of your beauty regimen. However, as with any skincare product, it’s important to pay attention to how your skin responds to it.

From a dietary perspective, Kallikrein is also suitable for both vegans and vegetarians. It is not derived from animal sources, making it an acceptable choice for those adhering to these dietary practices.

Regarding its use during pregnancy or breastfeeding, there isn’t currently any specific evidence suggesting that Kallikrein poses a risk. However, as with any cosmetic product, it’s always recommended to consult a healthcare professional if you’re pregnant or breastfeeding and considering new skincare or haircare products. This is to ensure the safety of both the mother and the child.

Kallikrein Skin Benefits

Kallikrein offers several benefits for skin health:

  • Exfoliation: Kallikrein’s protease activity helps break down proteins in the outermost layer of the skin, which encourages the natural process of skin exfoliation. This enzymatic exfoliation can help remove dead skin cells, leading to a smoother and more radiant complexion.
  • Skin Conditioning: By promoting the turnover of skin cells, Kallikrein can aid in maintaining skin softness and suppleness. The continuous renewal of skin cells can enhance the overall appearance and texture of the skin, making it look more youthful and vibrant.
  • Promotes Skin Health: By aiding in the natural process of exfoliation, Kallikrein supports the skin’s ability to renew itself. This can contribute to overall skin health, keeping it looking fresh and healthy.

It’s important to note, however, that these benefits are not permanent. Like most skincare ingredients, the beneficial effects of Kallikrein require sustained usage and are contingent upon continued application as part of a consistent skincare regimen.

Kallikrein Hair Benefits

Kallikrein also offers significant benefits for hair:

  • Improved Hair Texture: Kallikrein’s proteolytic activity can break down proteins in the hair, leading to smoother hair strands. This can result in improved hair texture and reduced frizz, making hair easier to manage and style.
  • Hair Conditioning: By working on the proteins in hair, Kallikrein can also function as a conditioner. It helps in maintaining hair moisture balance, making strands look healthier and shinier.
  • Promotes Hair Health: Similar to its benefits for the skin, Kallikrein can also promote overall hair health. By helping maintain the protein structure of hair, it can contribute to the strength and vitality of the strands.

Just like with skin, the benefits of Kallikrein for hair are not permanent. The beneficial effects must be maintained through continued and consistent usage of Kallikrein-containing products.

Kallikrein Potential Side Effects

Just as each individual’s skin is unique, so too can be the reactions to skincare ingredients. Skin types and sensitivities vary widely from person to person, and thus, so can the side effects experienced from the same product or ingredient. It’s also worth mentioning that the other ingredients in a cosmetic product can have an effect on how your skin reacts to Kallikrein. To better understand your skin and its possible reactions, it may be beneficial to find your skin type.

Potential side effects and interactions can include:

  • Irritation: As an enzyme, Kallikrein may cause skin irritation in some individuals, especially those with sensitive skin. This can manifest as redness, itching, or discomfort.
  • Allergic reactions: Though rare, some people may have an allergic reaction to Kallikrein, resulting in symptoms such as rash, hives, or swelling.

If you experience any of these side effects while using a product containing Kallikrein, discontinue use and consult a healthcare provider or dermatologist. They can help assess the situation, provide appropriate treatment if necessary, and guide you on whether it is safe for you to continue using the product.

It is important to note, however, that adverse reactions to Kallikrein are generally rare. The ingredient is typically considered safe and effective for the majority of users when used as part of a properly formulated cosmetic product.

Finally, when introducing any new product into your skincare routine, it is crucial to conduct a patch test beforehand. This process involves applying a small amount of the product to a discrete area of the skin to see if any adverse reactions occur. It can help you identify potential sensitivities and avoid potential adverse reactions. If you’re unsure how to conduct a patch test, consider referring to this handy patch-testing guide.

Comedogenic Rating

Kallikrein, given its enzymatic function and method of action, is considered to have a comedogenic rating of 0. This means that it is not likely to clog pores. Its primary role involves enzymatic activity that aids in protein breakdown and does not involve the production of oil or the blocking of skin pores, which are common causes of comedogenicity.

Given this rating, Kallikrein is generally suitable for individuals prone to acne or breakouts. However, everyone’s skin responds differently to various ingredients, so it’s always important to monitor your skin’s reaction when introducing a new product or ingredient.


Navigating the world of skincare and haircare involves a certain amount of experimentation and trial and error. Every individual’s skin and hair have their own unique needs and sensitivities, which is why what works for one person may not necessarily work for another.

Opting to use products containing Kallikrein may be due to the ingredient’s multifaceted benefits – promoting skin exfoliation and conditioning, improving hair texture, and contributing to overall skin and hair health. The combination of these benefits makes Kallikrein a versatile ingredient in cosmetic products.

Despite its proven benefits, Kallikrein is not as widely known or popular as some other ingredients in the skincare and haircare industry. This relative obscurity does not, however, detract from its potential effectiveness. Given its role and functions, it stands as a potentially valuable addition to your beauty regimen.

The time it takes to see results from Kallikrein can vary based on individual factors such as skin type, the particular product formulation, and the frequency of use. However, as with most skincare and haircare ingredients, you should generally expect to see results after several weeks of consistent use.

Summing up, Kallikrein is a potent ingredient with a range of benefits for both skin and hair. Its potential for skin exfoliation, conditioning, and overall health enhancement, coupled with its hair improvement capabilities, make it an ingredient worth considering in your beauty regimen.

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