Triethyl Citrate

Overview

Triethyl citrate (TEC) is the triester of citric acid and ethanol — both naturally occurring building blocks. The cosmetic ingredient is a clear, water-thin, almost odourless liquid with a faint citrus-adjacent smell.

In deodorants, triethyl citrate works through a different mechanism from zinc ricinoleate or aluminum salts. The molecule is slowly broken down on skin into citric acid and ethanol by skin bacteria. The released citric acid does two things:

1. Lowers the local skin pH slightly, making the underarm environment less hospitable to odour-producing bacteria
2. Inhibits the lipase enzymes that bacteria use to break sweat components into smelly fatty acids

The result is gradual odour reduction rather than the immediate odour absorption of zinc ricinoleate. Many natural deodorants combine the two for a more complete effect.

Beyond deodorant use, triethyl citrate is also used as a plasticiser in nail polishes (replacing the older phthalate-based plasticisers) and as a film former in some leave-on products.

Shelf life is 2-3 years.

What it does in a formula

• Bacterial enzyme inhibition for odour control
• Mild skin-acidifying effect in the underarm environment
• Plasticiser in nail polish (makes the dried film more flexible)
• Mild emollient feel when used at higher rates
• Fragrance solubiliser in some clear cosmetic formulations

The deodorant role is the primary use in skincare. The plasticiser role is the primary use in nail polish.

How to use

Add to the oil phase, or to the cool-down phase if your formula has heat-sensitive companions. Heat-stable to 100 C.

Usage rates by product type:

• Stick deodorants: 2-5%
• Cream deodorants: 1-3%
• Roll-on deodorants: 1-3%
• Spray deodorants: 1-3%
• Nail polish (plasticiser): 5-15%
• Underarm-area body creams: 1-3%

For natural deodorants, the most effective combination is usually triethyl citrate + zinc ricinoleate together, giving both immediate odour absorption and enzyme-based prevention.

Best for / Worst for

Best for: natural deodorant lines, aluminum-free deodorants, “nail polish without phthalates” positioning, sensitive-skin deodorants, deodorant combinations targeting both immediate and sustained odour control.

Worst for: customers expecting antiperspirant action (triethyl citrate does not block sweating), strict mass-market deodorant lines competing on antiperspirant claims, customers needing immediate strong action (it works gradually).

Common pitfalls

Confusing with citric acid. Citric acid alone in a deodorant is too acidic and will sting. Triethyl citrate releases citric acid gradually on skin and is much better tolerated.

Customer expectations on sweat reduction. Set the expectation clearly: deodorant, not antiperspirant.

Pairing. Triethyl citrate alone is moderate-strength. For best effect, pair with zinc ricinoleate or magnesium hydroxide.

Substitutes

• Zinc ricinoleate — different mechanism (odour absorption), complementary effect.
• Magnesium hydroxide — simpler natural odour control.
• Sodium bicarbonate (baking soda) — traditional, more irritation risk.
• Lactic acid esters — alternative pH-lowering deodorant actives.
• Probiotic deodorants (Lactobacillus ferment) — microbiome-based approach.