What Is Triethanolamine?
Triethanolamine - commonly abbreviated as TEA - is a tertiary amine and triol compound with the molecular formula C₆H₁₅NO₃ and a molecular weight of 149.19 g/mol. It is produced industrially by reacting ethylene oxide with ammonia, a process that simultaneously yields monoethanolamine (MEA) and diethanolamine (DEA) as co-products. At room temperature, TEA is a viscous, pale yellow to colourless liquid with a mild ammonia-like odour and is fully miscible with water.
In the cosmetics and personal care industry, TEA has been in use for over 60 years and remains one of the most versatile functional ingredients available to formulators. Its dual nature - acting as both a weak base and a surfactant precursor - makes it uniquely effective at solving formulation problems that would otherwise require two separate ingredients.
TEA carries the CAS number 102-71-6 and the molecular formula C₆H₁₅NO₃. Its appearance, density, boiling point, flash point, and full physicochemical specification are detailed on our Triethanolamine product page. This article focuses on what those properties mean in practice - how TEA behaves inside a cosmetic formula, how safe it is on skin, and how to work with it as a formulator.
What Does Triethanolamine Do in Skincare Products?
TEA performs three distinct roles in cosmetic formulations, and in many products it performs all three simultaneously.
1. pH Adjuster
The most important and most common function of TEA in skincare is pH adjustment. Healthy human skin has a slightly acidic pH of around 4.5–5.5, but many cosmetic raw materials - particularly carbomer-based gels and certain surfactant systems - produce acidic solutions that need to be raised to a skin-compatible range of 5.5–7.0 before they can be used.
TEA, being a weak base (pKa ≈ 7.76), neutralises excess acidity gently and predictably. Unlike sodium hydroxide, which can overshoot pH rapidly, TEA offers a buffered, more controllable neutralisation curve. This makes it particularly popular in gel formulations, where precise pH control directly affects viscosity.
2. Emulsifier and Emulsion Stabiliser
When TEA reacts with a fatty acid (such as stearic acid or oleic acid), it forms a triethanolamine soap - an anionic surfactant with emulsifying properties. This reaction happens in situ during formulation and is the mechanism behind many classic oil-in-water (O/W) emulsions. The resulting TEA-stearate or TEA-oleate acts as an emulsifier, lowering interfacial tension between the aqueous and oil phases and producing a stable, smooth cream or lotion.
This dual-action chemistry - neutralise the pH while simultaneously generating an emulsifier - is one of the reasons TEA became so prevalent in cosmetic formulation: a single ingredient handles two critical functions at once.
3. Solubiliser and Wetting Agent
TEA also acts as a solubiliser for certain water-insoluble active ingredients and pigments. In colour cosmetics and some sunscreen formulations, it helps disperse UV filters and inorganic pigments more evenly throughout the base, reducing the grittiness or patchiness that can occur with poorly dispersed actives. Its wetting properties also improve the spreadability of thick creams and lotions on skin.
Which Skincare Products Commonly Contain TEA?
Triethanolamine appears across a broad range of product categories. If you scan the INCI lists on your bathroom shelf, you are likely to find it under the name Triethanolamine or occasionally TEA in:
- Facial moisturisers and day creams - especially carbomer-thickened gel-cream hybrids
- Cleansers and foaming face washes - to adjust pH of surfactant blends
- Sunscreens - as a pH adjuster and to stabilise chemical UV filters
- Foundation and BB creams - to emulsify and improve pigment dispersion
- Eye creams and serums - at low concentrations for pH adjustment
- Body lotions and hand creams - particularly stearic acid-based emulsions
- Shaving gels and aftershave balms - for both emulsification and pH control
- Topical pharmaceutical preparations - including analgesic creams containing triethanolamine salicylate
Typical use concentrations in finished cosmetic products range from 0.1% to 2.5%, depending on the function. As a pH adjuster alone, concentrations below 0.5% are common. When used as an emulsifier in combination with a fatty acid, concentrations of 1–2.5% are typical.
Triethanolamine Comedogenic Rating
One question that comes up frequently among formulators working on acne-prone or sensitive skin products is whether TEA clogs pores. The short answer is: triethanolamine has a comedogenic rating of 0 to 1, depending on the source consulted, which places it in the non-comedogenic to minimally comedogenic category.
At the concentrations typically used in skincare (0.1–2.5%), TEA is considered safe for acne-prone skin. Products that cause skin issues when TEA is listed on the label are most often responding to another ingredient in the formulation, or to the product's overall pH. TEA itself does not contribute to comedone formation in clinical testing at standard use levels.
Safety Profile and Regulatory Status
The safety of triethanolamine in cosmetics has been reviewed extensively by independent regulatory and scientific bodies worldwide. The consensus across all major authorities is that TEA is safe at the concentrations used in cosmetic products, with a few important caveats related to formulation chemistry.
Cosmetic Ingredient Review (CIR) Assessment
The CIR Expert Panel, which provides safety assessments for cosmetic ingredients used in the United States, has reviewed triethanolamine multiple times. The panel concluded that TEA is safe for use in cosmetics and personal care products at concentrations up to 5% in rinse-off formulations and up to 2.5% in leave-on products, provided the finished product does not contain nitrosating agents that could react with TEA to form N-nitrosoamines.
EU Cosmetics Regulation (EC No 1223/2009)
Under EU Cosmetics Regulation, triethanolamine is a permitted ingredient subject to maximum concentration limits and conditions of use. The EU restricts TEA to a maximum of 2.5% in leave-on products and 5% in rinse-off products, and prohibits its use in formulations containing nitrosating systems - a rule that protects against the formation of carcinogenic N-nitrosamines.
The Nitrosamine Issue Explained
The main safety concern with TEA - and secondary amines in general - is its potential to react with nitrosating agents to form N-nitrosoamines, which are classified as potential carcinogens. This reaction requires the presence of both a nitrosating agent and the amine in the same formulation. Simply using TEA on its own, in a nitrosating-agent-free system, does not produce nitrosamines.
In practice, formulators working within CIR and EU guidelines avoid combining TEA with nitrite-releasing preservatives (such as 2-bromo-2-nitropropane-1,3-diol, also known as bronopol) and ensure that raw material suppliers certify their ingredients as nitrosamine-free. When these precautions are observed, TEA-based formulations have a long and well-documented safety record.
Skin Sensitisation
At standard cosmetic use levels, TEA is not considered a significant skin sensitiser. However, its alkaline nature means that high concentrations can be irritating to skin and eyes. The occupational exposure limit (OEL) for TEA in manufacturing environments is set at 5 mg/m³ TWA (8-hour), and direct contact with concentrated TEA should always be avoided without appropriate PPE. In finished cosmetic products at the concentrations described above, these concerns do not apply to the consumer.
TEA vs. Other pH Adjusters: How to Choose
Formulators often ask whether TEA can be replaced with sodium hydroxide (NaOH), arginine, or other alternative bases. The answer depends on the specific formulation system.
| Ingredient | Typical pKa | Best Use | Limitation |
|---|---|---|---|
| Triethanolamine (TEA) | 7.76 | Carbomer gels, O/W emulsions, multifunctional systems | Nitrosamine risk if combined with nitrosating agents |
| Sodium Hydroxide (NaOH) | ~13.8 | Fast neutralisation, transparent gels | Risk of overshoot; not suitable for emulsification role |
| Arginine | 10.76 | Natural/organic claims, amino acid systems | Higher cost; weaker buffering in some systems |
| AMP (Aminomethyl Propanol) | 9.69 | TEA-free formulas, cleaner label preference | Does not generate emulsification chemistry with fatty acids |
| Sodium Bicarbonate | 6.35 | Very mild pH adjustment, natural positioning | Limited buffering range; CO₂ release can affect stability |
The key advantage TEA retains over most alternatives is its ability to simultaneously neutralise carbomer and form a stable emulsifier with a fatty acid co-ingredient - a chemistry that AMP, arginine, and NaOH cannot replicate. For formulators who do not require this dual function and are working on a "clean label" brief, AMP-Ultra PC is currently the most widely used drop-in alternative.
Formulation Tips for Working with Triethanolamine
Always add TEA to your batch in small increments - typically 0.1–0.2% at a time - and measure pH between each addition. Because TEA's neutralisation is not linear across the full concentration range, adding the full calculated quantity at once can overshoot your target pH. A target finished-product pH of 6.0–6.5 is appropriate for most leave-on moisturisers.
Triethanolamine is commercially available in several grades: TEA-85 (85% active in water) and TEA-99 (99%+ anhydrous). For cosmetic use, TEA-99 is strongly preferred. The 85% grade contains approximately 15% water and can introduce unwanted dilution effects and microbial risk in water-sensitive systems. TEA-99 also produces less colour in the finished product, which matters for white or lightly tinted formulations.
Before finalising a TEA-containing formula, audit your complete ingredient list for preservatives that can act as nitrosating agents. Bronopol (2-bromo-2-nitropropane-1,3-diol), imidazolidinyl urea, and DMDM hydantoin are the most common culprits. If any of these are present, substitute with a non-nitrosating preservative system (e.g., phenoxyethanol/ethylhexylglycerin) or replace TEA with AMP.
When using TEA to form an in-situ soap emulsifier with stearic acid, both the oil and water phases should be at 70–75 °C when combined. Adding TEA to a cooled fatty acid phase will cause premature solidification before the emulsifier has fully formed. Add TEA to the water phase before combining with the oil phase, and maintain temperature throughout the homogenisation step.
TEA-neutralised carbomer gels can experience pH drift over time, particularly at elevated storage temperatures. Include accelerated stability testing (40 °C / 75% RH for 12 weeks minimum) with pH measurement at intervals of 2, 4, 8, and 12 weeks. A pH drop of more than 0.5 units during this period indicates either insufficient buffering or a reactive ingredient in the formula that is consuming the amine base.
Sourcing Triethanolamine: What Buyers Should Know
For commercial formulators and contract manufacturers sourcing TEA at scale, several practical considerations apply beyond the product specification sheet.
Purity Grades and Specifications
Industrial-grade TEA and cosmetic-grade TEA are not interchangeable. Cosmetic and pharmaceutical applications require TEA with low DEA content (typically <1%), low colour (APHA <50), and certified absence of nitrosamines in the neat substance. Always request a Certificate of Analysis (CoA) and confirm that the material meets the relevant pharmacopoeial standard - BP, USP, or EP - or a recognised cosmetic industry specification.
Storage and Handling
TEA is hygroscopic and will absorb moisture and CO₂ from the air on prolonged exposure. Store in sealed containers in a cool, dry location, away from strong acids and oxidising agents. Drum storage should use nitrogen blanketing for quantities above 200 kg to prevent surface discolouration and quality degradation. Shelf life is typically 24 months under recommended conditions.
Packaging Options
Frequently Asked Questions
Summary
Triethanolamine occupies a well-earned and enduring place in cosmetic formulation chemistry. Its ability to adjust pH, generate emulsification chemistry in situ with fatty acids, and solubilise difficult actives - all within a single ingredient - gives it a practical versatility that few alternatives can match at comparable cost. With a comedogenic rating of 0–1, a strong safety track record when used within regulatory guidelines, and availability in the high-purity TEA-99 grade, it remains a sensible choice for a broad range of skincare, personal care, and topical pharmaceutical applications.
The conditions for safe use are well understood: stay within maximum concentration limits, audit the preservative system for nitrosating agents, and source cosmetic-grade material with appropriate certification. Formulators who observe these guidelines will find TEA a reliable and effective workhorse for decades of formulation work to come.
Sinolook Chemical supplies TEA-99 cosmetic-grade triethanolamine in 25 kg, 200 kg, and 1,000 kg IBC packaging with full documentation including CoA, SDS, and REACH registration support. For pricing, availability, and technical questions:
