Ethanolamine

What it is

Ethanolamine is the substance that does ammonia's job in “ammonia-free” hair colours. An oxidative colour has to open the cuticle so that the dye precursors can reach the inside of the hair, and for that it needs an alkaline agent. If ammonia is left out, ethanolamine almost always takes its place.

This record is therefore the clearest evidence in the lexicon that an advertising claim and a property are two different things. “Ammonia-free” correctly describes what is absent and says nothing about what is present instead. Ethanolamine smells considerably less — it is corrosive as well, and unlike ammonia it does not evaporate.

Why

• Origin corrected, and substantially so: until 11.09.2026 the short field named a “natural ingredient derived from coconut”. That is wrong. Ethanolamine is produced industrially from ethylene oxide and ammonia; the substance has nothing to do with coconut. The mix-up probably comes from cocamide MEA — a different substance in which a fatty acid residue from coconut oil is bound to ethanolamine. The short field now reads “synthetic” in all four languages.
• Function corrected: “pH adjustment” describes the role too harmlessly. Ethanolamine does not adjust anything, it raises the pH considerably so that the fibre swells and opens. That is exactly the purpose, and exactly from it follows the strain on hair and scalp. Function and reason were reworded in all four languages.
• Why the classification reads “increased attention”: more ethanolamine is needed than ammonia for the same degree of lightening — a paper in the Journal of Cosmetic Science from 2014 states this expressly. There is a second difference on top: ammonia is volatile and largely escapes, ethanolamine stays in the hair.
• A paper in the Journal of Dermatological Science from 2012 investigated in mice which components of a hair colour trigger skin inflammation and hair loss, and arrived at hydrogen peroxide and ethanolamine. That is an animal model with three days of application to the back and is not readily transferable to a salon appointment. It appears here because it is one of the few studies that tested the components separately, not as proof of harm in humans.
• A counterweight belongs here. A doctoral thesis at the University of York from 2014 found that the differences between ethanolamine and ammonia disappear in model systems as soon as a strong chelating agent is added. Part of the observed difference may therefore not be down to the alkalising agent at all, but to metal ions that drive the decomposition of the peroxide. It is for precisely this reason that etidronic acid and tetrasodium EDTA stand alongside it in the products of this lexicon.
• Figures are now available for one of the three products. According to the Herb UK product data sheet of 16.01.2023, the OCS Colour Gel is declared at pH 9.0 to 11.0 and the matching developer at pH 1.5 to 2.5 with at most six per cent hydrogen peroxide; the mixing ratio is 1:1. A pH table from the manufacturer's training material gives 8.5 to 9.5 for the finished mixture. Ordinary permanent oxidative colours sit at 9.5 to 10.5 once mixed — this product is therefore at the lower end. Both are manufacturer statements and not measurements of our own.
• The same data sheet names an ethoxylated fatty amine at over twenty per cent as the largest component of the colour gel — a substance that is itself alkaline; the ingredient list names PEG-2 soyamine in first place. Ethanolamine does not appear in the list of components above ten per cent and therefore lies below that. In this product ethanolamine is thus not the main alkalising agent. No comparable information is available for the other two products in this record; the classification above applies to the substance and not to a single product.

When the assessment differs

• Salon staff: the substance is corrosive and can irritate the airways. Whoever mixes and applies colour daily carries the highest exposure in the room.
• Irritated or broken scalp skin: with colour the scalp is under strain anyway; an alkaline substance carries more weight there than on intact skin.
• Known contact allergy to ethanolamine: then the product is unsuitable, regardless of the classification above.
• Anyone who understands “ammonia-free” as gentler: the claim describes what is absent, not what replaced it. For advice at the chair that is the heart of this record.
• Frequent colour appointments: the exposure adds up over years, not over a single appointment.

Open questions

• Concentration in the specific product: still not available. For the OCS Colour Gel it is at least documented that it lies below ten per cent and that the substance is not the main alkalising agent there; an exact figure is missing. For the two Schwarzkopf products there is no information at all.
• The widespread claim that ethanolamine-based colours cause up to 85 per cent more fibre damage: this figure circulates in the trade press. The underlying study has not been examined here in full text. What is documented at this point is only the direction and the mechanism, not the magnitude.
• Transferability of the 2012 mouse study to use in humans: not examined and, given the design of the study, not to be expected either.
• Share of metal ions in the observed difference between ethanolamine and ammonia: open. The 2014 thesis suggests it could be considerable.
• Regulatory status: not checked; statements on use, maximum levels and workplace limits are not quoted second-hand.

Sources for this assessment

• Herb UK Ltd: Cosmetic Product Data Information Sheet, 16.01.2023, im Format der britischen Cosmetic, Toiletry and Perfumery Association — Organic Colour Systems Hair Colour (alle Nuancen) und Cream Peroxide 6 %. Herstellerunterlage, vom Betreiber bereitgestellt am 11.09.2026.
• Organic Colour Systems, pH-Tabelle aus den Schulungsunterlagen des Herstellers; nennt für die fertige Mischung pH 8,5 bis 9,5. Vom Betreiber berichtet am 11.09.2026, hier nicht im Original geprüft.
• Comparison of damage to human hair fibers caused by monoethanolamine and ammonia based hair colorants. Journal of Cosmetic Science, Band 65, Heft 1, 2014. Hält fest, dass für dieselbe Aufhellung ein höherer Anteil Ethanolamin nötig ist als Ammoniak. Begutachtete Fachzeitschrift, abgerufen am 11.09.2026.
• Hydrogen peroxide and monoethanolamine are the key causative ingredients for hair dye-induced dermatitis and hair loss. Journal of Dermatological Science, 2012. Tierversuch an Mäusen mit dreitägiger Anwendung; prüft die Bestandteile einer Haarfarbe einzeln. Begutachtete Fachzeitschrift, abgerufen am 11.09.2026.
• Smith R. A. W.: The Role of Monoethanolamine in Hair Bleaching and Dyeing — Mechanistic Insights from Model Formulations. Dissertation, University of York, 2014. Offener Zugang; findet, dass die Unterschiede zwischen Ethanolamin und Ammoniak in Modellsystemen mit starkem Komplexbildner verschwinden. Abgerufen am 11.09.2026.

Related substances

Applies to: Alkalising and pH-adjusting agents

• Aminomethyl Propanol — Formulation ingredient
• Ammonium Bicarbonate — pH buffer, alkalising
• Ammonium Hydroxide — Alkalising agent
• Citric Acid — pH regulator and chelating agent

Further substances from the same group for which a long-form assessment already exists.