Antioxidant

Rosmarinus Officinalis (Rosemary) Leaf Extract (12

Botanical antioxidant preservative and active from Rosmarinus officinalis (rosemary) leaves. Active constituents: carnosic acid and carnosol (diterpene phenols — primary chain-breaking antioxidants), rosmarinic acid (polyphenol — radical scavenger and anti-inflammatory), ursolic acid, and caffeic acid. Multiple antioxidant mechanisms: HAT (carnosic acid/carnosol), SET (rosmarinic acid), and chelation of pro-oxidant metal ions. ISO 16128 NI=1. Used as natural alternative to synthetic antioxidants (BHT, BHA) for product stabilisation and as anti-inflammatory skin active. Anti-microbial secondary activity (limited broad-spectrum efficacy vs synthetic preservatives).
Limited Data
Insufficient safety data available. Consider enriching this ingredient.
Details

Description

Botanical antioxidant preservative and active from Rosmarinus officinalis (rosemary) leaves. Active constituents: carnosic acid and carnosol (diterpene phenols — primary chain-breaking antioxidants), rosmarinic acid (polyphenol — radical scavenger and anti-inflammatory), ursolic acid, and caffeic acid. Multiple antioxidant mechanisms: HAT (carnosic acid/carnosol), SET (rosmarinic acid), and chelation of pro-oxidant metal ions. ISO 16128 NI=1. Used as natural alternative to synthetic antioxidants (BHT, BHA) for product stabilisation and as anti-inflammatory skin active. Anti-microbial secondary activity (limited broad-spectrum efficacy vs synthetic preservatives).

Purpose

Function

Botanical antioxidant preservative and active from Rosmarinus officinalis (rosemary) leaves. Active constituents: carnosic acid and carnosol (diterpene phenols — primary chain-breaking antioxidants), rosmarinic acid (polyphenol — radical scavenger and anti-inflammatory), ursolic acid, and caffeic acid. Multiple antioxidant mechanisms: HAT (carnosic acid/carnosol), SET (rosmarinic acid), and chelation of pro-oxidant metal ions. ISO 16128 NI=1. Used as natural alternative to synthetic antioxidants (BHT, BHA) for product stabilisation and as anti-inflammatory skin active. Anti-microbial secondary activity (limited broad-spectrum efficacy vs synthetic preservatives).
Profile

Properties

Silicone
Silicone free
Compliance

Regulatory Status

EU
Permitted
Safety
GOOD
US
Permitted
Absorptionmoderate
Sensitizationlow
MoSadequate
NOAEL100 mg/kg
ConcernLow
Verdict

Rosemary extract is a widely used natural antioxidant with genuine efficacy as a product stabiliser and anti-inflammatory skin active. ISO 16128 NI=1 — fully natural, COSMOS-approved. A comparative stability study of rosemary extract (ORE) vs BHT in raspberry seed oil nanoemulsions found both were stable at 5°C and 25°C, but ORE became pro-oxidant at 40°C while BHT remained protective. This is a temperature-dependent failure mechanism that could destroy product batches stored or used in warm climates. For any formulation using rosemary extract as primary antioxidant: mandatory accelerated stability testing at 40°C/75% RH; consider BHT/BHA or mixed tocopherol co-antioxidant for thermal protection. Efficacy as a broad-spectrum antimicrobial preservative is inferior to synthetic systems — not a standalone preservation solution.

US Note

Permitted without restriction. GRAS for food use (rosemary extract). ISO 16128 NI=1. CRITICAL STABILITY WARNING: rosemary extract (ORE) acts as a pro-oxidant at 40°C in fatty acid/oil systems (documented in raspberry seed oil nanoemulsion stability study). This is temperature-sensitive behaviour not seen with synthetic antioxidants (BHT remained stable at 40°C in the same study). Stability testing at 40°C/75% RH is mandatory for products using rosemary as primary antioxidant. MoCRA safety substantiation required.

Assessment

Ratings

Comedogenic0/5
LowHigh
Irritancy0/5
LowHigh
Reference

Identifiers

Category
Antioxidant
Updated
Apr 23, 2026

No registry identifiers available for this ingredient.