The ingredient, explained

Caffeine

Caffeine has been studied in a small topical combination-pad trial for the under-eye area.

AntioxidantMaskingSkin conditioning

Explore connections

Ingredient guide

What it is and what it does

1H-Purine-2‚6-dione, 3‚7-dihydro-1‚3,7-trimethyl-

About this ingredient: EU CosIng ingredient registry (via Open Beauty Facts taxonomy) ↗

Antioxidant: Limits oxidation, including deterioration of formulation ingredients. This label alone does not show a clinical antioxidant effect in skin.
Masking: Reduces or conceals the formula's underlying odour or taste.
Skin conditioning: A broad cosmetic role for maintaining skin condition. It does not identify a particular clinical benefit.

Function definitions: European Commission ingredient function definitions (SCCNFP/0299/00, pages 16 to 20) ↗

Registry functions describe possible formulation roles, not results for a finished product. A dictionary entry is not an approval or a safety assessment.

A closer look

What the research shows

Human research on a combination

Eleven women used a pad containing 3% caffeine, 1% vitamin K and an emu-oil base under the right eye, with a water pad under the left, for one hour each night over four weeks. Investigators reported improved hydration, elasticity and pigmentation measurements with the active formulation.

What this does not tell us

The trial was small and single-blind, with fixed side allocation and a water-pad control rather than a matched emulsion base. It cannot isolate caffeine or establish that a caffeine serum reduces dark circles, wrinkles or puffiness. The vitamin K and emu oil may have contributed.

Sources for this summary. PubMed 25625116 ↗

Research review checked Sep 30, 2026

Selected primary sources were reviewed for the existing research brief on 30 September 2026, with exact ingredient, route and combination limitations recorded. This was a bounded editorial review, not a systematic search.

Ingredient research is not proof that a product containing this ingredient works.