Citrus-like, oxidizes — regulated under EU Regulation 2023/1545 (expansion of declarable fragrance allergens from 26 to 81+).
Prepared by Allergen81 Compliance Team · Last reviewed September 2026. Provided for information only — always verify against the official regulation and your responsible person's assessment.
CAS Number
99-86-5
EC Number
202-785-3
INCI Name
ALPHA-TERPINENE
Status
Declarable
Leave-on products
0.100%
= 10 mg/kg (10 ppm)
Rinse-off products
1.00%
= 100 mg/kg (100 ppm)
Alpha-Terpinene must be separately declared in the ingredient list (INCI) when its concentration in the finished product exceeds these values. Below the threshold, no separate mention is required.
Typical concentration ranges (of the oil itself, not the finished product):
Example: at 1.5% lavender oil in a leave-on cream with linalool at up to 45%, the product contains up to ~0.68% linalool — far above the 0.001% threshold, so it must be declared.
Upload your supplier PDFs and Allergen81 extracts every allergen, runs the threshold math (including pre-hapten grouping), and generates your INCI-compliant label.
Under EU Regulation 2023/1545, Alpha-Terpinene must be listed separately in the ingredient declaration (INCI) when its concentration in the finished product exceeds 0.100% in leave-on products or 1.00% in rinse-off products.
Alpha-Terpinene naturally occurs in: Lemon Oil, Tea Tree Oil. Typical concentration ranges in these oils vary — always confirm with a supplier IFRA certificate or GC/MS report.
Yes. Alpha-Terpinene is a pre-hapten: on air exposure it oxidizes to Terpinene hydroperoxides, which are stronger sensitizers. Fresh product and antioxidant-stabilized formulations reduce this risk.