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STRATUM Skin Science
A hand breaking the surface of water, droplets suspended mid-splash against the palm.

STR/01 Skin-Science Formulation

Every active has an
address.

Retinol reaches the epidermis. Ceramides stay in the corneum, holding the barrier together. We formulate by layer, not by promise -- and show you exactly where.

STR/02 See the actual cross-section 4 layers, hover any ingredient to find its depth
Depths mapped
8
Strata modelled
4
INCI disclosed
100%

STR/02 The Section

See where it sits.

Hover any ingredient in the table below and the diagram finds its layer. The corneum is drawn thicker than it really is -- at true linear scale it would be a single invisible pixel -- but the order, and the relative proportions between layers, are real.

Illustrative cross-section, not to linear scale. Facial-skin depth ranges are typical figures, not a specific clinical measurement.

Surface Hypodermis

STR/03 Ingredient Index

Eight actives, mapped to where they actually work.

Ingredients and their typical target skin layer
Ingredient Class Target layer Depth range What it does there
Zinc Oxide / Titanium Dioxide Zinc Oxide, Titanium Dioxide Mineral UV filter Corneum 15-20 µm Sits at the surface by design -- a mineral filter scatters and absorbs UV before it reaches living cells, so it is not formulated to go any deeper.
Ceramide NP / AP / EOP Ceramide NP, Ceramide AP, Ceramide EOP Barrier lipid Corneum 15-20 µm Slots into the intercellular lipid matrix between corneocytes -- reinforcing the barrier where it sits, rather than penetrating past it.
Glycolic / Lactic Acid Glycolic Acid, Lactic Acid AHA exfoliant Corneum 15-20 µm Loosens the bonds between corneocytes at the surface, encouraging them to shed more evenly.
Hyaluronic Acid (mixed MW) Sodium Hyaluronate Humectant Epidermis 50-100 µm Higher molecular weights hold water at the surface; lower molecular weights are formulated to reach further into the viable epidermis.
Niacinamide Niacinamide Barrier + tone support Epidermis 50-100 µm Reaches the living epidermis, where it is commonly associated with supporting the skin's own lipid production.
L-Ascorbic Acid Ascorbic Acid Antioxidant Epidermis 50-100 µm An antioxidant and a cofactor the skin uses in collagen synthesis -- but unstable, so formulation and storage matter as much as concentration.
Retinol Retinol Retinoid Epidermis 50-100 µm Converted in stages to retinoic acid, which signals to cells in the epidermis and, over time, to fibroblasts in the dermis below. Introduce gradually; increases sun sensitivity.
Signal Peptides Palmitoyl Pentapeptide-4 Peptide Dermis 1.0-3.0 mm Formulated to reach the dermal-epidermal junction, where fibroblasts are thought to read them as a signal to keep producing collagen.

Depth ranges are typical facial-skin figures drawn from general dermatological consensus, not a measurement of this specific formula.

We don't sell a feeling. We publish a layer. If a customer can't find the depth an ingredient is meant to reach, we haven't finished the label.

R. Okonkwo-Reyes — Formulation Lead, Stratum Lab