5-Amino-4-Chloro-o-Cresol HCl
AKA “5-Amino-4-chloro-o-cresol hydrochloride, UNII-31J4UQW59L, Phenol, hydrochloride, 2-Methyl-4-chloro-5-aminophenol hydrochloride, hydrochloride (1:1), RefChem:101961”
Synthetic
Ingredient Facts
5-amino-4-chloro-o-cresol hcl
AKA: 5-Amino-4-chloro-o-cresol hydrochloride, UNII-31J4UQW59L, Phenol, Hydrochloride, 2-Methyl-4-chloro-5-aminophenol hydrochloride, Hydrochloride (1:1), RefChem:101961
Synthetic · Hair Dyeing · EWG: 4
Synthetic
Synthetic
Clean
A synthetic color additive that helps hair dyes develop vibrant, long-lasting color. Used in professional and at-home hair coloring formulas.
Formula
C7H9Cl2NO
Mol. Weight
194.06
CAS #
110102-85-7
Form
Powder
See origin →
Functions
Hair Dyeing
Colors Hair
Traditional Use
Hydrochloride salt form of a synthetic hair colorant precursor created for improved stability and solubility in hair dye formulations during the 1950s-1970s development of modern permanent color systems.
Skin Types
●all-skin-types
Best For
General
Melanin-Rich Skin
Suitable
Pregnancy & Breastfeeding Safe
No
EWG
4
CIR
Safe w/Qualifications
Pregnancy
No
CIR Safety Findings
Not a Sensitizer
medical-approval
all-shades-safe
Concentration Guide
Dermal absorption: 1%. Source: CIR Safety Assessment (CIR Seq 877).
Regulatory Agencies
2-Amino-4-nitrophenol.
IARC monographs on the evaluation of carcinogenic risks to humans, 1993
2-Amino-5-nitrophenol.
IARC monographs on the evaluation of carcinogenic risks to humans, 1993
4-amino-2-nitrophenol.
IARC monographs on the evaluation of the carcinogenic risk of chemicals to man, 1978
Polyphenols: skin photoprotection and inhibition of photocarcinogenesis.
Afaq F, Katiyar SK
Mini reviews in medicinal chemistry, 2011
Polyphenols: skin photoprotection and inhibition of photocarcinogenesis.
Afaq F, Katiyar SK
Mini reviews in medicinal chemistry, 2011
Potential skin anti-aging effects of main phenolic compounds, tremulacin and tremuloidin from Salix chaenomeloides leaves on TNF-α-stimulated human de
Ahn SY, Kim KA, Lee S, Kim KH
Chemico-biological interactions, 2024
Efficacy of a topical polyphenol-based formulation in palmoplantar psoriasis: an observational study.
Amato S, Dattola A, Bennardo L, Tolone M, Nisticò SP
Dermatology reports, 2025
Efficacy of a topical polyphenol-based formulation in palmoplantar psoriasis: an observational study.
Amato S, Dattola A, Bennardo L, Tolone M, Nisticò SP
Dermatology reports, 2025
Final report on the safety assessment of amino nitrophenols as used in hair dyes.
Burnett CL, Bergfeld WF, Belsito DV, Klaassen CD, Marks JG Jr et al.
International journal of toxicology, 2009
Final report on the safety assessment of amino nitrophenols as used in hair dyes.
Burnett CL, Bergfeld WF, Belsito DV, Klaassen CD, Marks JG Jr et al.
International journal of toxicology, 2009
Final report on the safety assessment of amino nitrophenols as used in hair dyes.
Burnett CL, Bergfeld WF, Belsito DV, Klaassen CD, Marks JG Jr et al.
International journal of toxicology, 2009
Final Amended Report on the Safety Assessment of p-Methylaminophenol Sulfate and p-Methylaminophenol
Cosmetic Ingredient Review (CIR) Expert Panel
International Journal of Toxicology
Final Report on the Safety Assessment of 2-Amino-6-Chloro-4-Nitrophenol and 2-Amino-6-Chloro-4-Nitrophenol Hydrochloride
Cosmetic Ingredient Review (CIR) Expert Panel
International Journal of Toxicology
Final Report on the Safety Assessment of 2-Methyl-5-Hydroxyethylaminophenol
Cosmetic Ingredient Review (CIR) Expert Panel
International Journal of Toxicology
Final Report on the Safety Assessment of 2,4-Diaminophenol and 2,4-Diaminophenol Dihydrochloride
Cosmetic Ingredient Review (CIR) Expert Panel
International Journal of Toxicology
Final Report on the Safety Assessment of 2,4-Diaminophenoxyethanol Dihydrochloride
Cosmetic Ingredient Review (CIR) Expert Panel
International Journal of Toxicology
Final Report on the Safety Assessment of 6-Amino-m-Cresol, 6-Amino-o-Cresol, 4-Amino-m-Cresol, 5-Amino-4-Chloro-o-Cresol, 5-Amino-6-Chloro-o-Cresol and 4-Chloro-2-Aminophenol
Cosmetic Ingredient Review (CIR) Expert Panel
International Journal of Toxicology
Final Report on the Safety Assessment of Amino Nitrophenols Used in Hair Dyes
Cosmetic Ingredient Review (CIR) Expert Panel
International Journal of Toxicology
Final Report on the Safety Assessment of Chlorhexidine/Chlorhexidine Diacetate/Chlorhexidine Dihydrochloride/Chlorhexidine Digluconate
Cosmetic Ingredient Review (CIR) Expert Panel
International Journal of Toxicology
Final Report on the Safety Assessment of N-Phenyl-p-Phenylenediamine, N-Phenyl-p-Phenylenediamine Hydrochloride, and N-Phenyl-p-Phenylenediamine Sulfate
Cosmetic Ingredient Review (CIR) Expert Panel
International Journal of Toxicology
Final Report on the Safety Assessment of p-Aminophenol, m-Aminophenol, and o-Aminophenol
Cosmetic Ingredient Review (CIR) Expert Panel
International Journal of Toxicology
Final Report on the Safety Assessment of p-Methylaminophenol Sulfate
Cosmetic Ingredient Review (CIR) Expert Panel
International Journal of Toxicology
Final Report on the Safety Assessment of Zinc Phenolsulfonate
Cosmetic Ingredient Review (CIR) Expert Panel
International Journal of Toxicology
Final Report: Amended Safety Assessment of 4-Chloro-2-Aminophenol as Used in Cosmetics
Cosmetic Ingredient Review (CIR) Expert Panel
International Journal of Toxicology
Final Report: Amended Safety Assessment of 5-Amino-4-Chloro-o-Cresol and 5-Amino-4-Chloro-o-Cresol HCl as Used in Cosmetics
Cosmetic Ingredient Review (CIR) Expert Panel
International Journal of Toxicology
Final Report: Safety Assessment of Sodium Benzotriazolyl Butylphenol Sulfonate as Used in Cosmetics
Cosmetic Ingredient Review (CIR) Expert Panel
International Journal of Toxicology
Final Report: Safety Assessment of Tetrabromophenol Blue as Used in Cosmetics
Cosmetic Ingredient Review (CIR) Expert Panel
International Journal of Toxicology
Note Regarding the Safety Assessment of Chlorhexidine, Chlorhexidine Diacetate, Chlorhexidine Digluconate, and Chlorhexidine Dihydrochloride
Cosmetic Ingredient Review (CIR) Expert Panel
International Journal of Toxicology
Safety Assessment of Polyaminopropyl Biguanide (polyhexamethylene biguanide hydrochloride) as Used in Cosmetics
Cosmetic Ingredient Review (CIR) Expert Panel
International Journal of Toxicology
Zinc Phenolsulfonate
Cosmetic Ingredient Review (CIR) Expert Panel
International Journal of Toxicology
2-Amino-6-Chloro-4-Nitrophenol
European Commission
EU Cosmetic Ingredient Database (CosIng)
2-Methyl-5-Hydroxyethylaminophenol
European Commission
EU Cosmetic Ingredient Database (CosIng)
3-Nitro-p-Hydroxyethylaminophenol
European Commission
EU Cosmetic Ingredient Database (CosIng)
4-Amino-3-Nitrophenol
European Commission
EU Cosmetic Ingredient Database (CosIng)
4-Hydroxypropylamino-3-Nitrophenol
European Commission
EU Cosmetic Ingredient Database (CosIng)
5-Amino-4-Chloro-o-Cresol HCl
European Commission
EU Cosmetic Ingredient Database (CosIng)
Chlorhexidine Dihydrochloride
European Commission
EU Cosmetic Ingredient Database (CosIng)
Sodium Benzotriazolyl Butylphenol Sulfonate
European Commission
EU Cosmetic Ingredient Database (CosIng)
TEA-Hydrochloride
European Commission
EU Cosmetic Ingredient Database (CosIng)
Zinc Phenolsulfonate
European Commission
EU Cosmetic Ingredient Database (CosIng)
Safety and efficacy of l-histidine monohydrochloride monohydrate produced using Corynebacterium glutamicum KCCM 80179 for all animal species.
EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP), Bampidis V, Azimonti G, de Lourdes Bastos M, Christensen H et al.
EFSA journal. European Food Safety Authority, 2019
Safety and efficacy of l-lysine monohydrochloride and concentrated liquid l-lysine (base) produced by fermentation with Corynebacterium glutamicum KCC
EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP), Bampidis V, Azimonti G, Bastos ML, Christensen H et al.
EFSA journal. European Food Safety Authority, 2020
2-Amino-5-Nitrophenol
Environmental Working Group (EWG)
EWG Skin Deep Cosmetics Database
2-Amino-6-Chloro-4-Nitrophenol
Environmental Working Group (EWG)
EWG Skin Deep Cosmetics Database
2-Methyl-5-Hydroxyethylaminophenol
Environmental Working Group (EWG)
EWG Skin Deep Cosmetics Database
3-Nitro-p-Hydroxyethylaminophenol
Environmental Working Group (EWG)
EWG Skin Deep Cosmetics Database
4-Amino-3-Nitrophenol
Environmental Working Group (EWG)
EWG Skin Deep Cosmetics Database
4-Hydroxypropylamino-3-Nitrophenol
Environmental Working Group (EWG)
EWG Skin Deep Cosmetics Database
Chlorhexidine Dihydrochloride
Environmental Working Group (EWG)
EWG Skin Deep Cosmetics Database
Sodium Benzotriazolyl Butylphenol Sulfonate
Environmental Working Group (EWG)
EWG Skin Deep Cosmetics Database
Zinc Phenolsulfonate
Environmental Working Group (EWG)
EWG Skin Deep Cosmetics Database
2-Amno-6-Chloro-4-Nitrophenol.
Fiume MM
International journal of toxicology, 2017
Novel Bioactive Multifunctional Polyphenols: A Chemo-Enzymatic Approach.
Flourat AL, Thiébault E, Martinez A, Brunissen F, Dosso A et al.
Chemistry (Weinheim an der Bergstrasse, Germany), 2026
Transdermal delivery of ondansetron hydrochloride: effects of vehicles and penetration enhancers.
Gwak HS, Oh IS, Chun IK
Drug development and industrial pharmacy, 2004
2-Amino-1,2-bis(4-methoxyphenol) ethanol and its salts
Health Canada
Health Canada Cosmetic Ingredient Hotlist
2-Amino-4-nitrophenol
Health Canada
Health Canada Cosmetic Ingredient Hotlist
2-Amino-5-nitrophenol
Health Canada
Health Canada Cosmetic Ingredient Hotlist
4-Amino-2-nitrophenol
Health Canada
Health Canada Cosmetic Ingredient Hotlist
4-Benzyloxyphenol
Health Canada
Health Canada Cosmetic Ingredient Hotlist
4-Ethoxyphenol
Health Canada
Health Canada Cosmetic Ingredient Hotlist
4-tert-Butylphenol
Health Canada
Health Canada Cosmetic Ingredient Hotlist
4,4'-Isopropylidenediphenol
Health Canada
Health Canada Cosmetic Ingredient Hotlist
Chrysoidine citrate hydrochloride
Health Canada
Health Canada Cosmetic Ingredient Hotlist
Dinitrophenol isomers
Health Canada
Health Canada Cosmetic Ingredient Hotlist
Diphenoxylate hydrochloride
Health Canada
Health Canada Cosmetic Ingredient Hotlist
Phenol
Health Canada
Health Canada Cosmetic Ingredient Hotlist
Phenolphthalein
Health Canada
Health Canada Cosmetic Ingredient Hotlist
Safety Assessment of Polyaminopropyl Biguanide (Polyhexamethylene Biguanide Hydrochloride) as Used in Cosmetics.
Johnson W Jr, Boyer I, Zhu J, Bergfeld WF, Belsito DV et al.
International journal of toxicology, 2020
Occupational allergic contact dermatitis caused by epoxy diacrylate in ultraviolet-light-cured paint, and bisphenol A in dental composite resin.
Jolanki R, Kanerva L, Estlander T
Contact dermatitis, 1995
Effects of antioxidant polyphenols on TNF-alpha-related diseases.
Kawaguchi K, Matsumoto T, Kumazawa Y
Current topics in medicinal chemistry, 2011
Effects of antioxidant polyphenols on TNF-alpha-related diseases.
Kawaguchi K, Matsumoto T, Kumazawa Y
Current topics in medicinal chemistry, 2011
Effects of antioxidant polyphenols on TNF-alpha-related diseases.
Kawaguchi K, Matsumoto T, Kumazawa Y
Current topics in medicinal chemistry, 2011
Antioxidant effects of phenolic compounds in through the distillation of Lonicera japonica & Chenpi extract and anti-inflammation on skin keratinocyte
Kim HH, Jeong SH, Park MY, Bhosale PB, Abusaliya A et al.
Scientific reports, 2023
Antioxidant effects of phenolic compounds in through the distillation of Lonicera japonica & Chenpi extract and anti-inflammation on skin keratinocyte
Kim HH, Jeong SH, Park MY, Bhosale PB, Abusaliya A et al.
Scientific reports, 2023
Antioxidant effects of phenolic compounds in through the distillation of Lonicera japonica & Chenpi extract and anti-inflammation on skin keratinocyte
Kim HH, Jeong SH, Park MY, Bhosale PB, Abusaliya A et al.
Scientific reports, 2023
Antioxidant effects of phenolic compounds in through the distillation of Lonicera japonica & Chenpi extract and anti-inflammation on skin keratinocyte
Kim HH, Jeong SH, Park MY, Bhosale PB, Abusaliya A et al.
Scientific reports, 2023
Analytical Method Development and Dermal Absorption of 4-Amino-3-Nitrophenol (4A3NP), a Hair Dye Ingredient under the Oxidative or Non-Oxidative Condi
Kim HY, Kim YJ, Lee JD, Kim HR, Seo DW
Toxics, 2024
Molecular modeling and phenoloxidase inhibitory activity of arbutin and arbutin undecylenic acid ester.
Masyita A, Salim E, Asri RM, Nainu F, Hori A et al.
Biochemical and biophysical research communications, 2021
Sargassum horneri extract containing polyphenol alleviates DNCB-induced atopic dermatitis in NC/Nga mice through restoring skin barrier function.
Mihindukulasooriya SP, Dinh DTT, Herath KHINM, Kim HJ, Han EJ et al.
Histology and histopathology, 2022
Microwave-Assisted Extraction of Phenolic Compounds and Antioxidants for Cosmetic Applications Using Polyol-Based Technology.
Myat Win S, Saelee M, Myo H, Khat-Udomkiri N
Journal of visualized experiments : JoVE, 2024
Microwave-Assisted Extraction of Phenolic Compounds and Antioxidants for Cosmetic Applications Using Polyol-Based Technology.
Myat Win S, Saelee M, Myo H, Khat-Udomkiri N
Journal of visualized experiments : JoVE, 2024
Allergic contact dermatitis due to nonylphenol ethoxylate (nonoxynol-6).
Nethercott JR, Lawrence MJ
Contact dermatitis, 1984
Lingonberry (Vaccinium vitis-idaea L.) Fruit Phenolic Bio...
Pirjo Pärnänen, Sari Niikko, Hanna Lähteenmäki, Ismo T Räisänen, Taina Tervahartiala, Timo Sorsa + 1 more
Microorganisms, 2024
Phenolic Composition and Biological Properties of Wild and Commercial Dog Rose Fruits and Leaves.
Polumackanycz M, Kaszuba M, Konopacka A, Marzec-Wróblewska U, Wesolowski M et al.
Molecules (Basel, Switzerland), 2020
Antioxidant capacity, phenolic content, and profiling of phenolic compounds in the seeds, skin, and pulp of Vitis rotundifolia (Muscadine Grapes) As d
Sandhu AK, Gu L
Journal of agricultural and food chemistry, 2010
Phenolic-enriched maple syrup extract protects human keratinocytes against hydrogen peroxide and methylglyoxal induced cytotoxicity.
Sheng J, Liu C, Petrovas S, Wan Y, Chen HD et al.
Dermatologic therapy, 2020
Chlorhexidine Dihydrochloride Shows Anti-tumor Effects in Desmoid Tumors and Colorectal Cancer.
Shin H, Kim Y, Lee Y, Kim J, Ryu YC et al.
Anticancer research, 2024
Allergy to 3-nitro-p-hydroxyethylaminophenol and 4-amino-3-nitrophenol in a hair dye.
Søsted H, Menné T
Contact dermatitis, 2005
Protective Role of Phenolic Compounds from Whole Cardamom (Elettaria cardamomum (L.) Maton) against LPS-Induced Inflammation in Colon and Macrophage C
Sreedharan S, Nair V, Cisneros-Zevallos L
Nutrients, 2023
Antioxidant screening and phenolic content of ethanol extracts of selected Baja California Peninsula macroalgae.
Tenorio-Rodriguez PA, Murillo-Álvarez JI, Campa-Cordova ÁI, Angulo C
Journal of food science and technology, 2017
Zinc Phenolsulfonate.
Tucker R, Bergfeld WF, Belsito DV, Cohen DE, Klaassen CD et al.
International journal of toxicology, 2024
Severe contact urticarial syndrome due to oxidative hair dye containing para-aminophenol and sodium-methyl-oleoyl-taurate.
Uehara S, Inomata N, Suzuki A, Matsuura M, Aihara M
The Journal of dermatology, 2014
Extraction of Polyphenols and Vitamins Using Biodegradable ATPS Based on Ethyl Lactate.
Velho P, Marques L, Macedo EA
Molecules (Basel, Switzerland), 2022
Profiling and quantification of phenolic compounds in Camellia seed oils: Natural tea polyphenols in vegetable oil.
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Food research international (Ottawa, Ont.), 2017
Profiling and quantification of phenolic compounds in Camellia seed oils: Natural tea polyphenols in vegetable oil.
Wang X, Zeng Q, Del Mar Contreras M, Wang L
Food research international (Ottawa, Ont.), 2017
Formulation of Propolis Phenolic Acids Containing Microemulsions and Their Biopharmaceutical Characterization.
Žilius M, Ramanauskienė K, Juškaitė V, Briedis V
Evidence-based complementary and alternative medicine : eCAM, 2016
Verified Feb 2026
Data: PubChem · CosIng · EWG · CIR