Lactose at a glance

  • Principal sugar found in milk
  • Acts as a humectant in skin care products
  • Ruled safe as used in cosmetics
  • White or slightly yellow powder in its raw form
  • Animal-derived, so not considered vegan

Lactose description

Lactose is a disaccharide (sugar made of two molecules) and the principal sugar found in milk. When ingested, it serves as an energy source with a low glycemic index. It also aids in calcium absorption, though after infancy in humans, it becomes more difficult to metabolize, resulting in lactose intolerance for many people. Applied topically, as with other sugars, lactose serves as a humectant, a type of ingredient that attracts water to skin, giving it a plump, dewy look. Humectants serve as building block ingredients for most moisturizers. The independent Cosmetic Ingredient Review Board has ruled lactose safe to use, with no instances of irritation or sensitization, in amounts up to 2.48%. In its raw form, lactose is a white or slightly yellow powder. It’s common to see lactose in a blend with other humectants such as lactic acid and glycerin. Note that because this ingredient is typically animal-derived, it isn’t considered vegan.

Lactose references

  • Foods, May 2022, ePublication
  • International Journal of Toxicology, May/June 2019, pages 5S-38S
  • Journal of Dairy Science, November 1984, Pages 2654-2679
  • UL Prospector, Website, Accessed March 2024
  • Cosmile Europe, Website, Accessed March 2024

Peer-reviewed, substantiated scientific research is used to assess ingredients in this dictionary. Regulations regarding constraints, permitted concentration levels and availability vary by country and region.

Ingredient ratings


Proven and supported by independent studies. Outstanding active ingredient for most skin types or concerns.


Necessary to improve a formula's texture, stability, or penetration.


Generally non-irritating but may have aesthetic, stability, or other issues that limit its usefulness.


There is a likelihood of irritation. Risk increases when combined with other problematic ingredients.


May cause irritation, inflammation, dryness, etc. May offer benefit in some capability but overall, proven to do more harm than good.


We couldn't find this in our ingredient dictionary. We log all missing ingredients and make continuous updates.

Not rated

We have not yet rated this ingredient because we have not had a chance to review the research on it.