Ceramide NP (Ceramide 3) Ingredient Reference Record

Aliases

• Ceramide 3 (retired pre-2014 INCI name, still used interchangeably)
• N-Stearoyl-phytosphingosine (chemical name; Sigma-Aldrich lists CAS 34354-88-6 for this specific name, conflicting with CosIng CAS 100403-19-8 - see concentration_evidence.cas_number_conflict)
• Phytoceramide (generic term for phytosphingosine-based ceramides, per US Patent 6054599)

Inci name

Ceramide NP

Formula context

Used in leave-on facial/body moisturizers, barrier creams, serums, and in rinse-off cleansers/conditioners; also in hair conditioners. Typically co-formulated with cholesterol and free fatty acids to reconstruct stratum-corneum lipid lamellae, since Ceramide NP alone does not form stable lamellae (Zettersten et al. 1997; OneRChem technical guide). Cetyl/stearyl alcohol (2-5%) is commonly added to prevent ceramide crystallization in high-load emulsions (OneRChem, secondary-media, not independently verified against a primary source). Example marketed co-formulation: CeraVe Moisturizing Lotion/Cream INCI lists Ceramide NP with Ceramide AP, Ceramide EOP, Cholesterol, and Niacinamide (INCIDecoder, community source, illustrative only). No source reviewed states one industry-standard 'ideal' active percentage for Ceramide NP beyond the CIR use-concentration survey below; vendor 'active %' marketing claims were not independently verifiable and are excluded.

Functional roles

• Skin conditioning agent (CosIng ref 85476, via COSMILE Europe and SpecialChem)
• Hair conditioning agent (COSMILE Europe: 'leaves hair easy to comb, supple, soft and shiny')
• Skin-barrier-repair lipid / stratum corneum lipid replacer (CIR 2020; Zettersten et al. 1997)

Safety references

• Cosmetic Ingredient Review (CIR) Expert Panel, 'Safety Assessment of Ceramides as Used in Cosmetics,' Final Report 2020 (Int J Toxicol, DOI 10.1177/1091581820958692, PMID 33203269) - primary-regulatory. Conclusion: Ceramide NP is safe in cosmetics under present practices of use and concentration described in the assessment. Non-irritating in rabbit ocular studies (~27-51 mg neat, reversible within 72h) and human dermal patch testing (10% in petrolatum, 44 subjects, no irritation); not sensitizing in guinea pig maximization testing up to 10% w/w.

Compatible systems

• Cholesterol + free fatty acids: required co-lipids for lamellar (stratum-corneum-mimetic) structure formation - Ceramide NP alone cannot form stable lamellae (Zettersten et al. 1997, primary-academic; OneRChem technical guide, secondary-media, mechanism description).
• Niacinamide: co-formulated in commercial barrier-repair moisturizers (e.g., CeraVe line) without reported stability conflict (INCIDecoder CeraVe listings, community source - illustrative only, not quantitative evidence).
• Cetyl alcohol / stearyl alcohol (long-chain fatty alcohols, 2-5%): used to help suspend ceramide and prevent crystallization/precipitation in emulsions (OneRChem technical guide, secondary-media).

Conflicting systems

• High-load ascorbic acid (vitamin C) systems: both ascorbic acid and ceramides are independently difficult to stabilize in emulsion; co-formulating both at high concentration is a known unresolved technical challenge, motivating a dedicated stabilization patent (US Patent 10,973,749, 'Cosmetic composition comprising vitamin C and ceramides' - primary-patent).
• Fatty-acid-dominant lipid mixtures (imbalanced ratios): in the aged-skin barrier-recovery model, fatty-acid-dominant mixtures delayed barrier recovery rather than accelerating it - not a universal 'more is better' relationship (Zettersten et al. 1997, J Am Acad Dermatol, PMID 9308554 - primary-academic).
• Formulations lacking cholesterol/FFA co-lipids: Ceramide NP used in isolation is reported unable to form the stable lamellar phase associated with barrier benefit - not a drop-in single-ingredient substitute for the full stratum-corneum lipid matrix (OneRChem technical guide - secondary-media, vendor content, not independently confirmed against a primary source this pass).

Concentration evidence

CIR Final Report 2020, Table 3 (Council survey data 2013-2015): reported maximum concentration of use for Ceramide NP is up to 0.2% in leave-on skin care and 0.0001%-0.1% in rinse-off products (primary-regulatory). Separately, the underlying CIR-reviewed toxicology studies used higher TEST concentrations, not market-use concentrations: human dermal patch test at 10% dispersion in petrolatum (44 subjects, no irritation) and guinea pig maximization sensitization testing up to 10% w/w (not sensitizing) - both primary-regulatory, CIR 2020. cas_number_conflict: CosIng/PubChem CID 57378373/SpecialChem report CAS 100403-19-8 for Ceramide NP; the CIR report also lists CAS 72968-43-5 for a related entry; Sigma-Aldrich lists CAS 34354-88-6 for N-stearoyl-phytosphingosine specifically. Presented side by side, unresolved - no authoritative cross-walk found. physiological_lipid_ratio_evidence (primary-academic, Zettersten EM, Ghadially R, Feingold KR, Crumrine D, Elias PM, J Am Acad Dermatol 1997;37(3 Pt 1):403-8, PMID 9308554): roughly equimolar ceramide:cholesterol:free-fatty-acid topical mixtures restored normal barrier recovery in young-skin models; a cholesterol-dominant 3:1:1:1 (cholesterol:ceramide:essential FFA:nonessential FFA) mixture further accelerated recovery specifically in chronologically aged mouse and human skin at 6 hours post-injury, while fatty-acid-dominant mixtures delayed recovery. Caveat: this is one aged-skin study; the commonly cited vendor claim of a '3:1:1 ceramide-dominant' ratio (e.g., EpiCeram/TriCeram marketing) was not independently confirmed against a primary source in this research pass and should not be treated as equivalent to this finding.

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