Lysine Carboxymethyl Cysteinate



Lysine Carboxymethyl Cysteinate at a glance

  • Amino acid derivative that conditions skin and hair
  • Potent antioxidant that helps “recycle” antioxidants on skin
  • Made from specialized bonds of lysine and cysteine
  • Considered safe and non-irritating as used in cosmetics

Lysine Carboxymethyl Cysteinate description

Lysine carboxymethyl cysteinate is an amino acid derivative that has skin-conditioning and potent antioxidant properties. This ingredient is supplied as a powder, and its amino acid structure gives it strengthening properties similar to the keratin protein found in skin and hair. The amino acid structure of this ingredient also encourages skin to ramp up its natural levels of the body’s master antioxidant, glutathione. As such, it plays a role in helping skin to visibly repair signs of sun damage, in part by stabilizing other antioxidants within skin’s uppermost layers, such as vitamins C and E. Lysine carboxymethyl cysteinate is not known to irritate skin or eyes when used in amounts up to 5% in cosmetics. Generally, lower amounts (less than 1%) work well in skin care and amounts greater than 2% are used in strengthening-type hair care products. Its lack of irritancy is likely due to its amino acids occurring naturally in skin’s uppermost layers. This ingredient may be animal-derived or synthetic (Paula’s Choice Skincare uses the latter).

Lysine Carboxymethyl Cysteinate references

  • Bioactive Materials, September 2020, pages 496–509
  • Journal of Anatomy, April 2009, pages 516–559

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.


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Not rated

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