Ingredient guide

Dioic Acid

dioic acid

SafeModerate evidenceActive

In short

Dioic acid is a long-chain dicarboxylic acid used to improve the look of uneven tone and visible oiliness. Studies show it can gradually refine pigmentation and surface shine.

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Works for

Tone · Pores

Skin type

Oily

Best used

Morning

What it is

C18 alpha-omega dicarboxylic acid acting as a PPAR-gamma modulator; clinical studies report incremental improvement in surface pigmentation and seborrhoea over 8-12 weeks at 2% in leave-on systems; distinct from azelaic acid in chain length and mechanism.

Also found as

octadecenedioic acidoleic diacid

1,10-Decanediol

Pores

10-Hydroxydecanoic Acid

Pores · Texture

3-O-Cetyl Ascorbic Acid

Tone · Texture

4-Methoxysalicylic Acid (4-MSA)

Tone

Where to find it

SkinCeuticals Discoloration Defense

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Common questions

What does dioic acid do for skin?

It helps reduce the look of uneven pigmentation and can minimise visible oil buildup, giving a more balanced appearance.

Is dioic acid good for oily or combination skin?

Yes, it’s often chosen for its ability to reduce visible shine and refine the look of pores.

How is dioic acid used in routines?

It usually appears in leave-on serums for tone and clarity. You use it as you would any targeted brightening step.

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Personal guidance only · For clinical concerns, see a dermatologist.

Ingredients