Hydrolyzed Lac: What Is It, Cosmetic Uses, Benefits & Side Effects

Curious about this ingredient? In this article we're explaining exactly what it is and why it's used within cosmetic formulations.
Updated on: June 27, 2025
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We verify all information on this page using publicly available nomenclature standards from The Personal Care Products Council (PCPC), the European Commission's CosIng database and documentation provided directly by ingredient manufacturers. Our analysis is based on technical data from these sources to ensure accuracy and reliability.

What Is Hydrolyzed Lac?

Hydrolyzed Lac is made from cow’s milk that has been broken down into smaller pieces, mainly peptides and amino acids, through acid or enzyme treatment. By splitting the milk proteins into bite-sized fragments, chemists create an ingredient that is easier for skin to accept and less likely to feel heavy. Milk has been used in beauty rituals since ancient Egypt, but it was only in the last few decades that laboratories learned how to hydrolyze its proteins to improve texture and stability in modern formulas. Today Hydrolyzed Lac shows up in a variety of products such as lightweight moisturizers, nourishing masks, anti-aging creams, all-purpose lotions and even some soothing serums.

Hydrolyzed Lac’s Cosmetic Benefits/Uses

This milk-derived ingredient mainly serves one purpose in skin care

As an emollient Hydrolyzed Lac helps moisturize by filling tiny gaps in the skin’s surface so it feels softer and smoother. It can boost the creamy feel of a lotion, cut down on roughness and support the skin barrier which in turn reduces dryness and tightness.

Who Can Use Hydrolyzed Lac

Hydrolyzed Lac is generally suitable for normal, dry and combination skin because its main job is to soften and smooth. Oily or acne-prone skin can usually tolerate it too since the ingredient itself is lightweight, but those who break out easily from rich creams should look at the full formula to be sure the product is not overly heavy.

The ingredient is derived from cow’s milk so it is not appropriate for vegans. Lacto-ovo vegetarians may be comfortable with it since it comes from an animal by-product rather than slaughter, but this is a personal choice.

Pregnant and breastfeeding women can typically use Hydrolyzed Lac as it is applied only to the skin and is not known to penetrate deeply. This is not medical advice and anyone who is expecting or nursing should run all skincare choices past a doctor to be safe.

Hydrolyzed Lac does not make skin more sensitive to sunlight so no extra sun precautions are needed beyond a normal broad-spectrum sunscreen. Because it is milk based, people with a known dairy allergy should proceed with caution even though the proteins are broken down.

Potential Side Effects/Adverse Reactions

Reactions to Hydrolyzed Lac differ from person to person. The following are potential side effects yet most users will not run into them when the ingredient is used correctly in a well-formulated product.

  • Redness or mild irritation
  • Itching or stinging on application
  • Hives or rash in individuals with dairy allergy
  • Clogged pores in very oil-rich formulations

If any negative reaction occurs stop using the product and seek advice from a healthcare professional.

Comedogenic Rating

Rating: 1 out of 5

Hydrolyzed Lac is mostly made of water-soluble peptides and amino acids that rinse away easily and do not sit heavily on skin. Because it lacks thick oils or waxes, it has a very low chance of blocking pores. People who break out can usually use it without trouble, though the rest of the formula still matters. If the product also contains rich butters or heavy silicones, the overall pore-clogging risk will go up.

Bottom line: generally suitable for acne-prone skin.

Summary

Hydrolyzed Lac works as an emollient that smooths rough spots, softens texture and supports the skin barrier by slipping into tiny surface gaps. Its small peptide size makes it light yet effective, giving creams and lotions a silky feel without greasiness.

The ingredient is not a blockbuster like hyaluronic acid or retinol but you will find it in a fair number of moisturizers, masks and all-purpose lotions aimed at adding gentle hydration.

Safety wise Hydrolyzed Lac is well tolerated for most users. The main concerns are dairy allergy and personal beliefs around animal-derived materials. As with any new product, do a quick patch test first to make sure your skin plays nice.

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