SCCS Opinion Summary May 6, 2026 3 min read

1,5-Naphthalenediol: What the SCCS Concluded About Safety in Cosmetics

1,5-Naphthalenediol safety summary from SCCS/1365/10: SCCS conclusion, NOAEL, maximum concentration or conditions, and source-linked context.

1,5-Naphthalenediol is covered by SCCS/1365/10, an SCCS-family cosmetic safety opinion dated 2010-09-21. The opinion conclusion for this opinion is direct enough for a substance-specific summary: The results from a LLNA study indicate that 1,5-naphthalenediol is a moderate skin sensitiser. The SCCP is of the opinion that 1,5-Naphthalenediol as an ingredient in oxidative and non-oxidative hair dye formulations at a maximum on-head concentration of 1% does not pose a risk to the health of the consumer, apart from its sensitising potential.

Core Opinion Facts

NOAEL Values Cited in the Opinion

The no-observed-adverse-effect data below is shown only from the SCCS source fields for this opinion. It is not a calculated margin-of-safety output.

EndpointValueUnitStudy context
general systemic toxicity50mg/kg bw/dayRat, Wistar Crl:(WI) BR, oral gavage, subchronic 90-day oral toxicity
embryo/foetotoxicity and teratogenicity360mg/kg bw/daySprague-Dawley CD rats, oral gavage, prenatal developmental toxicity
maternal toxicity60mg/kg bw/daySprague-Dawley CD rats, oral gavage, prenatal developmental toxicity

Maximum Concentration or Conditions

Conditions from the Opinion

The results from a LLNA study indicate that 1,5-naphthalenediol is a moderate skin sensitiser. The SCCP is of the opinion that 1,5-Naphthalenediol as an ingredient in oxidative and non-oxidative hair dye formulations at a maximum on-head concentration of 1% does not pose a risk to the health of the consumer, apart from its sensitising potential.

How to Read This Safety Conclusion

The key point for formulators is the match between the named ingredient, the cited NOAEL, and the SCCS conclusion. A NOAEL is a study point of departure, not a standalone permission to use 1,5-Naphthalenediol at any level. The SCCS conclusion and any concentration or product-type conditions remain the controlling context for cosmetic use.

The source also matters because SCCS opinions can be ingredient-specific. The internal ingredient page for 1,5-Naphthalenediol should be treated as the substance hub, while SCCS/1365/10 is the opinion-level page for the committee record.

Practical Formulation Takeaway

For a formula review, start with the identity check: confirm the INCI name, CAS number, and opinion reference align with the material in the formula. Then compare the intended product type against the SCCS concentration or condition language above. If the formulation uses a different exposure route, product category, or concentration basis, the SCCS conclusion should not be stretched beyond what SCCS/1365/10 actually assessed.

Source