STR/03 Ingredient Index
Every active, published.
The full list of actives we formulate with, each mapped to the layer it typically targets and the formula it appears in. Focus a row to probe its layer in the diagram below.
Surface
Hypodermis
| 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 any specific formula.