Ingredient review
Carboxymethyl Chitosan Myristamide
INCI: CARBOXYMETHYL CHITOSAN MYRISTAMIDE
A gentle, semi-synthetic ingredient that forms a breathable film on skin to lock in moisture and provide a smooth feel.
In plain English
Carboxymethyl Chitosan Myristamide is a modified version of chitosan, which comes from the shells of shrimp and other crustaceans. It has been chemically tweaked to make it more water-friendly and to add a fatty chain (myristamide) that helps it stick to skin. In skincare, it creates a thin, flexible film that holds moisture against your skin and can help other ingredients work better. It also has mild antimicrobial properties, which can help keep products fresher longer.
Review score
Safety, usefulness, and evidence
Potentially useful with some tradeoffs
The evidence base is useful, but some claims depend heavily on the formula.
Risk flags are low for most users, though the finished product can still irritate.
- Source
- semi synthetic
- Evidence
- moderate
- Irritation
- low
- Clogging risk
- low
Quick decision guide
Useful, but context matters
Carboxymethyl Chitosan Myristamide 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 Carboxymethyl Chitosan Myristamide.
- 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
moderateThere is useful support, but formula details and claim strength still matter.
What it is
A semi-synthetic polymer derived from chitosan (from crustacean shells) that has been carboxymethylated and then attached to a myristamide (a fatty acid derivative) group. This modification improves water solubility and skin adhesion.
How it works
When applied to skin, it forms a transparent, breathable film that reduces water loss (transepidermal water loss, or TEWL — the amount of moisture that evaporates from your skin). The film also helps other active ingredients stay on the skin longer. Its positive charge allows it to bind to the negatively charged skin surface, enhancing adhesion.
Pros
Gentle moisture lock
Creates a breathable film that reduces water loss without feeling heavy or sticky, making it suitable for sensitive skin types.
Improves product feel
Adds a smooth, silky texture to formulations and helps other ingredients spread evenly, enhancing the overall user experience.
Cons and cautions
Shellfish origin concern
Derived from crustacean shells; while highly processed, those with severe shellfish allergies may want to patch test or avoid.
Limited long-term data
Most evidence comes from ingredient supplier studies; independent peer-reviewed research on long-term skin benefits is still emerging.
Best for
- People with dry or dehydrated skin looking for extra moisture retention
- Those who enjoy lightweight, film-forming textures in serums or masks
Use caution if
- Individuals with confirmed severe shellfish allergy should patch test first, as the source is crustacean shells
Usage tips
Safety summary
Carboxymethyl Chitosan Myristamide is considered safe for topical use at typical concentrations. It has low irritation and comedogenic potential. The shellfish-derived source is highly processed, but individuals with severe allergies should exercise caution.
Research notes
Research is primarily from ingredient suppliers and a few academic studies on chitosan derivatives. Evidence supports its film-forming and moisture-retention properties, but independent long-term human studies are limited.
Common label clues
- Typical concentration
- 0.5% to 2%
- Regulatory status
- Approved for use in cosmetics in the EU, US, and other major markets. No specific restrictions beyond general cosmetic safety requirements.
- Common uses
- Moisturizers, Serums, Masks, Anti-aging formulations
- Environmental note
- Derived from renewable crustacean shell waste (a byproduct of the seafood industry), making it a more sustainable choice compared to fully synthetic film formers.
Good to know
- Carboxymethyl Chitosan Myristamide is often used in 'clean beauty' formulations as a natural-derived alternative to synthetic film formers.
- It is biodegradable and generally considered eco-friendly.
Common questions
What is Carboxymethyl Chitosan Myristamide in beauty products?
Carboxymethyl Chitosan Myristamide is a modified version of chitosan, which comes from the shells of shrimp and other crustaceans. It has been chemically tweaked to make it more water-friendly and to add a fatty chain (myristamide) that helps it stick to skin. In skincare, it creates a thin, flexible film that holds moisture against your skin and can help other ingredients work better. It also has mild antimicrobial properties, which can help keep products fresher longer.
What does Carboxymethyl Chitosan Myristamide do in a beauty product?
When applied to skin, it forms a transparent, breathable film that reduces water loss (transepidermal water loss, or TEWL — the amount of moisture that evaporates from your skin). The film also helps other active ingredients stay on the skin longer. Its positive charge allows it to bind to the negatively charged skin surface, enhancing adhesion.
Is Carboxymethyl Chitosan Myristamide safe for most people?
Carboxymethyl Chitosan Myristamide is considered safe for topical use at typical concentrations. It has low irritation and comedogenic potential. The shellfish-derived source is highly processed, but individuals with severe allergies should exercise caution.
Who should be careful with Carboxymethyl Chitosan Myristamide?
Individuals with confirmed severe shellfish allergy should patch test first, as the source is crustacean shells
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.