Guanine

What is Guanine?

Guanine is a naturally occurring purine base, chemically known as 2-amino-6-oxo-1,6-dihydropurine with the formula C5H5N5O, found in DNA and RNA of living organisms. In cosmetics, it is obtained through purification from natural sources like fish scales or via synthetic production. Primarily featured in makeup categories such as eyeshadows, lip products, nail polishes, and some creams, guanine functions by diffracting light across its platelet-like crystals to produce a shimmering, iridescent effect resembling pearls. This optical property creates visual depth and glow. It also serves as an opacifier, scattering light to reduce transparency in formulations, yielding a smooth, creamy appearance that masks imperfections and ensures batch consistency without altering texture.

Comedogenic Rating 0/5 Low risk of clogging pores
EWG Safety Rating 1 View on EWG →
PubChem View on PubChem →

Roles in Formulation

This ingredient serves the following purposes in cosmetic formulations:

Colorant
Provides or corrects color using dyes or pigments, helping achieve a consistent shade and visual appearance across batches and throughout wear.
Opacifying agent
Makes a formula less transparent to create a creamy, opaque look; can also help visually mask suspended particles and improve aesthetic uniformity.

Benefits

Provides lustrous pearlescent sheen for enhanced visual appeal in products.

Improves opacity to create uniform, creamy textures.

Supports consistent coloring and appearance across formulations.

Who It's For

A quick guide for who this ingredient may suit (and who should be cautious).

Who May Benefit Who Should Avoid
Individuals seeking shimmering effects in eye, lip, or nail cosmetics.
People with rare allergies to purine compounds.
Users preferring products with smooth, non-transparent finishes.
Individuals experiencing irritation from pearlescent pigments.
Those desiring reliable color uniformity in makeup.
Users sensitive to fish-derived ingredients, if not synthetic.

Safety Notes

  • Recognized as low hazard in cosmetic safety assessments.
  • Non-comedogenic, unlikely to clog pores.

Frequently Asked Questions about Guanine

What is guanine in cosmetics?

A purine-derived pigment that creates pearlescent shimmer by light refraction.

Is guanine safe for skin?

Assessed as low hazard with minimal irritation potential in formulations.

Does guanine clog pores?

Non-comedogenic, rated zero for pore-clogging risk.