Triethylene Glycol (TEG) is a clear, odorless liquid used as a humectant, solvent, and preservative enhancer in skincare products. It attracts moisture to the skin, supports hydration, and enhances the delivery of active ingredients. TEG is also empowered by mild antimicrobial benefits that particularly benefit water-based products with longer shelf lives. It has a non-greasy texture that improves product feel and stability. Unlike glycerin, Triethylene Glycol is non-comedogenic, providing the same benefits but without side effects. Common ranges of products to use Triethylene Glycol are serums, toners, body lotions, etc. It is typically used in 0.5% to 5%.

Structural Overview of Triethylene Glycol

Triethylene Glycol (TEG), chemically named 2,2'-[1,2-Ethanediylbis(oxy)]diethanol, has the molecular formula C₆H₁₄O₄. Structurally, it consists of three ethylene glycol units connected by ether bonds: HO–CH₂CH₂–O–CH₂CH₂–O–CH₂CH₂–OH. This linear dihydric alcohol is water-soluble, viscous, and hydrophilic, making it an effective humectant and solvent in skincare formulations. Its dual hydroxyl groups enhance moisture retention and compatibility with both aqueous and alcohol-based systems.

How Triethylene Glycol is Used in Skincare Products?

1. Face Serums and Toners 

Usgae: 0.5% – 2%

TEG acts as a lightweight humectant and solvent, and is thereby used in face serums and toners around 0.5 to 2%. It uplifts the efficacy of niacinamides, peptides, and similar actives without adding extra weight.

2. Moisturizers and Creams

Usage: 1% – 3%

In creams and lotions, TEG supports hydration, improves spreadability. Thus, helps dissolve water-soluble ingredients with better shelf lives..

3. Cleansers and Face Washes

Usage: 1% – 2%

In cleansing essentials, TEG helps maintain formula consistency and mild hydration through the cleansing process. The ideal percentage application is around 1-2%.

5. Eye Drops and Sensitive-Skin Formulas

Usage: 0.5% – 1%

In pharma-cosmetic or dermatologically-tested formulas, TEG is used in very low concentrations to add moisture and assist in the delivery of actives without causing stinging or irritation.

Potential Benefits of Triethylene Glycol

1. Effective Humectant for Hydration

Triethylene Glycol draws moisture from the environment into the skin, which maintains standard hydration levels. Unlike heavier moisturizers, it offers lightweight hydration without leaving a greasy or sticky residue. This makes it an ideal choice for all skin types, including oily and sensitive skin.

2. Elevates Ingredient Solubility & Delivery

As a solvent, TEG improves the solubility and dispersion of water-soluble and some oil-soluble ingredients. This allows active ingredients like vitamins, antioxidants, and preservatives to be more evenly distributed across the skin, enhancing their absorption and overall effectiveness in serums, toners, and lotions.

3. Firm Antimicrobial Activity

Triethylene Glycol exhibits mild antibacterial and antifungal properties. It enhances the efficacy of existing preservative systems, preventing microbial growth. This is especially useful in low-preservative or sensitive-skin formulations seeking to avoid harsher antimicrobial agents.

4. Improves Product Texture

TEG contributes to the silky, fluid feel of skincare formulations. It reduces tackiness, increases smoothness, and helps products spread evenly across the skin. This enhances the sensory experience, especially in lightweight gels, facial mists, and emulsions designed for daily or frequent use.

5. Stabilizes and Extends Shelf Life

Due to its water-binding and solvent capabilities, TEG helps maintain the consistency and stability of emulsions and aqueous solutions. It prevents phase separation and ingredient degradation, ensuring that the product remains effective and pleasant to use over time, even under varying storage conditions.

Possible Downsides of Triethylene Glycol

1. Possible Skin Irritation for Sensitive Skin

Although generally safe, some individuals with highly sensitive or reactive skin may experience mild irritation, redness, or dryness, especially when used in high concentrations or in combination with alcohol-based or acidic ingredients.

2. Synthetic Origin

Triethylene Glycol is synthetically derived, which may not align with the preferences of consumers seeking all-natural or organic formulations. This can limit its use in clean beauty or certified organic product lines.

3. Limited Occlusive Properties

TEG lacks potential occlusive bindings. Due to this, although hydrates well, it fails to hold moisture for long periods, leading to dry skin.

4. Environmental Persistence Concerns

Being synthetic, TEG is biodegradable but may still raise mild environmental concerns regarding water pollution or production byproducts. It’s less favored in eco-conscious formulations focused on plant-based, biodegradable alternatives.

5. Low Performance in Low Concentrations

At very low concentrations, TEG’s humectant and antimicrobial functions become less effective. It often needs to be paired with stronger preservatives or moisturizers for optimal performance in large-volume or water-heavy formulations.

Why is Triethylene Glycol Popular Among Formulators?

• Multifunctional Ingredient: A versatile compound with versatile benefits as a humectant, solvent, and preservative booster.
• Enhances Ingredient Delivery: Improves solubility of active ingredients & is quickly absorbed.
• Extends shelf life: Boosts the overall shelf life of the products.
• Lightweight and Non-Greasy: Makes it perfect for lightweight, fast-absorbing skincare formulations
• Improves Texture and Stability: Enhances smoothness and consistency with consistent emulsions
• Compatible with Most Activates: Works well with vitamins, botanical extracts, and peptides, despite varying pH levels.
• Safe and Non-Comedogenic: Suitable for sensitive, acne-prone, or oily skin
• Cost-Effective and Easy to Formulate: Affordable, easily available, and blends well into both leave-on and rinse-off products