2-AMINO-3-HYDROXYPYRIDINE

EU conditions: (a) To be printed on the la­bel: The mixing ratio. “Hair colourants can cause severe allergic reac­tions. Read and follow instruc­tions. This product is not in­tended for use on persons under the age of 16. Temporary ‘black henna’ tattoos may increase your risk of allergy. Do not colour your hair if: — you have a rash on your face or sensitive, irri­tated and damaged scalp, — you have ever experi­enced any reaction after colouring your hair, — you have experienced a reaction to a tempor­ary b‘lack henna’ tattoo in the past.”
(b) As from 3 March 2018, to be printed on the la­bel: The mixing ratio. “This product can cause severe allergic reactions. Read and follow instruc­tions. This product is not in­tended for use on persons under the age of 16. Tem­porary ‘black henna’ tattoos may increase the risk of al­lergy. Eyelashes shall not be co­loured if the consumer: — has a rash on the face or sensitive, irritated and damaged scalp, — has experienced any re­action after colouring hair or eyelashes,— has experienced a reac­tion to a temporary ‘black henna’ tattoo in the past. For professional use only. Rinse eyes immediately if product comes into contact with them”

📊 Comedogenicity

📚 Research & Evidence

🔬 The Science

2-Amino-3-hydroxypyridine (often called A132 in research) is a synthetic compound used in oxidative hair coloring products, meaning it works by chemically reacting with hair pigment to create permanent color (Int J Toxicol, 2020). #1: Safety at standard use levels — An expert panel reviewing safety data concluded that 2-amino-3-hydroxypyridine is safe when used in typical hair dye formulations at normal concentrations (Int J Toxicol, 2020). However, this assessment focused on the ingredient’s behavior in standard indoor use. #2: Phototoxicity concern with sun exposure — When this ingredient is exposed to UV-B radiation (the type of ultraviolet light from the sun), it absorbs that energy and undergoes a chemical change, creating what researchers call a “photoproduct” within about an hour of exposure (Toxicol Appl Pharmacol, 2016).

In laboratory studies using human skin cells, this sun-activated form of the ingredient significantly reduced cell viability through multiple cell-damage pathways. #3: Mechanism of damage — The sun-activated ingredient triggers the production of reactive oxygen species (ROS)—unstable molecules that damage cells—and causes DNA damage, cell cycle disruption, and programmed cell death (apoptosis) in skin cells (Toxicol Appl Pharmacol, 2016). Researchers documented this through multiple assays including DNA damage markers and mitochondrial stress indicators. #4: Long-term concerns — The research suggests that repeated use of this dye combined with regular sunlight exposure could accumulate oxidative stress in the skin, potentially affecting hair follicle health over time, though this was observed in cell cultures rather than human studies (Toxicol Appl Pharmacol, 2016).

Importantly, the safety conclusion from the expert panel predates and does not address the phototoxicity findings. The gap between “safe in formulation” and “becomes problematic under sun exposure” remains an open question for consumer use.

💧 Skin Type Compatibility

⚠️ Don’t Combine With

🧴 Products Containing 2-AMINO-3-HYDROXYPYRIDINE

• CONAXESS TRADE NORGE AS Brillance Hårfarge 872 Intense Red
• ion Bright White Crème Toner Icy White
• CONAXESS TRADE NORGE AS Brillance Hårfarge 924 Choco Couture
• CONAXESS TRADE NORGE AS Live Urban Metallics U72 Dusty Silver
• Henkel, Schwarzkopf Palette Salon Colors 8.5
• L’OREAL NORGE AS Casting Creme Gloss 415 Marron Glace
• Henkel, Schwarzkopf Perfect Mousse Châtain Chocolat 465
• Henkel, Schwarzkopf Perfect Mousse Acajou 586
• Henkel, Palette, Saint Algue Coloration crème soin à l’huile d’argan Châtain caramel 660
• Henkel, Schwarzkopf Kératine Color 4.6 Châtain Chocolat
• Henkel, Schwarzkopf Kératine Color Châtain Clair Subtil 6.0
• Henkel, Schwarzkopf Perfect Mousse Chocolats Soufflés Brownie 365
• Henkel, Syoss, Saint-Algue Syoss Gloss Sensation Blond Miel 7-86
• Henkel, Syoss, Saint Algue Syoss Oleo Supreme 4-18 Marron Chocolat
• L’OREAL NORGE AS Casting Creme Gloss 600 Blond Fonce
• L’OREAL NORGE AS Casting Creme Gloss 510 Cool Mocha
• L’Oréal Фарба для волосся L’Oreal Paris Preference 5.0

📄 Related Research

Matched by search — not necessarily verified support for every statement above.

• Burnett CL et al. (2020). Safety Assessment of 2-Amino-3-Hydroxypyridine as Used in Cosmetics. Int J Toxicol.
• Goyal S et al. (2016). Photosensitized 2-amino-3-hydroxypyridine-induced mitochondrial apoptosis via Smac/DIABLO in human skin cells. Toxicol Appl Pharmacol.