Ingredient review
Lysine Carboxymethyl Cysteinate
INCI: LYSINE CARBOXYMETHYL CYSTEINATE
A gentle amino acid derivative that may help strengthen the skin barrier and provide antioxidant support, though research is still limited.
In plain English
Lysine Carboxymethyl Cysteinate is a lab-made ingredient that combines two amino acids—lysine and cysteine—with a carboxymethyl group. In skincare, it's thought to help reinforce the skin's natural barrier and protect against environmental stress. Think of it as a building block that gives your skin a little extra armor and a shield against daily wear and tear.
Review score
Safety, usefulness, and evidence
Potentially useful with some tradeoffs
The evidence base is still emerging, so marketing claims deserve extra caution.
Risk flags are low for most users, though the finished product can still irritate.
- Source
- semi synthetic
- Evidence
- emerging
- Irritation
- low
- Clogging risk
- low
Quick decision guide
Useful, but context matters
Lysine Carboxymethyl Cysteinate is generally a lower-concern ingredient when the full formula suits your skin.
Plain-English read
Treat this as a practical screening step before you compare products that contain this ingredient.
- Step 1Start with the score, then check the irritation and clogging risk before judging Lysine Carboxymethyl Cysteinate.
- Step 2Use the "Best for" and "Use caution if" sections to match the ingredient to your skin, not just to a marketing claim.
- Step 3If a product stings, breaks you out, or worsens irritation, judge the finished formula and stop using it even if the ingredient scores well.
Score terms in plain English
Irritation risk
lowLess likely to sting, burn, or bother most users, though sensitive skin can still react.
Clogging risk
lowLess likely to feel heavy or contribute to clogged pores for most skin types.
Evidence level
emergingThe ingredient may be promising, but claims should be treated more cautiously.
What it is
A semi-synthetic compound formed by linking lysine (an essential amino acid) with carboxymethyl cysteine (a modified version of the amino acid cysteine). It is designed to be more stable and skin-friendly than using the raw amino acids alone.
How it works
It is believed to support the skin's natural antioxidant systems by providing cysteine, a precursor to glutathione—a key antioxidant in skin cells. The lysine component may help with moisture retention and barrier function. In a cosmetic product, it works as a conditioning agent that leaves skin feeling smoother and more resilient.
Pros
Gentle on skin
Low irritation and comedogenic risk makes it suitable for sensitive and acne-prone skin types.
Dual-action support
Combines barrier-strengthening and antioxidant benefits in one ingredient, simplifying your routine.
Cons and cautions
Limited research
Most evidence comes from lab studies or ingredient supplier data, not large human trials, so effectiveness is not fully proven.
Lower potency
Compared to well-studied antioxidants like vitamin C or ferulic acid, its antioxidant power is less established.
Best for
- People looking for gentle antioxidant support
- Those with dry or compromised skin barriers
Use caution if
- Individuals with known allergies to cysteine or lysine derivatives (very rare)
Usage tips
Safety summary
Considered safe for cosmetic use at typical concentrations. Low irritation and comedogenic risk. No significant safety concerns reported in available literature.
Research notes
Research is emerging, with most data coming from in vitro studies and ingredient supplier trials. Human studies are limited, but preliminary findings suggest potential benefits for barrier function and antioxidant defense.
Common label clues
- Typical concentration
- 0.1–2% in leave-on products
- Regulatory status
- Approved for cosmetic use in the EU, US, and other major markets as a skin conditioning agent. No specific restrictions beyond general cosmetic safety requirements.
- Common uses
- Anti-aging serums, Barrier repair creams, Brightening treatments
- Environmental note
- Semi-synthetic production typically has a lower environmental footprint than fully synthetic alternatives, but specific sourcing data is not publicly available.
Good to know
- This ingredient is often found in formulations targeting aging and environmental damage.
- It is not a sunscreen and does not replace SPF protection.
Common questions
What is Lysine Carboxymethyl Cysteinate in beauty products?
Lysine Carboxymethyl Cysteinate is a lab-made ingredient that combines two amino acids—lysine and cysteine—with a carboxymethyl group. In skincare, it's thought to help reinforce the skin's natural barrier and protect against environmental stress. Think of it as a building block that gives your skin a little extra armor and a shield against daily wear and tear.
What does Lysine Carboxymethyl Cysteinate do in a beauty product?
It is believed to support the skin's natural antioxidant systems by providing cysteine, a precursor to glutathione—a key antioxidant in skin cells. The lysine component may help with moisture retention and barrier function. In a cosmetic product, it works as a conditioning agent that leaves skin feeling smoother and more resilient.
Is Lysine Carboxymethyl Cysteinate safe for most people?
Considered safe for cosmetic use at typical concentrations. Low irritation and comedogenic risk. No significant safety concerns reported in available literature.
Who should be careful with Lysine Carboxymethyl Cysteinate?
Individuals with known allergies to cysteine or lysine derivatives (very rare)
Research sources
Ingredient reviews are educational and are not medical advice. Patch test new products and ask a licensed clinician about persistent irritation, allergies, pregnancy-specific questions, or diagnosed skin conditions.