Mechanisms
The biology under the surface.
Skin conditions are downstream of biology. Each mechanism page connects upstream and downstream nodes — and the ingredients that interact with each step.
Physiology
Sebum
Lipid mixture produced by sebaceous glands; substrate for both barrier function and microbial activity.
Follicular Hyperkeratinization
Excessive keratinocyte shedding inside the follicle that contributes to comedone formation.
Transepidermal Water Loss
Water diffusing outward through the stratum corneum; rises when the barrier is disrupted.
Irritation Sensitivity
Heightened reactivity to ordinarily-tolerated stimuli; common in compromised barrier states.
Keratinocyte Turnover
The rate at which skin cells proliferate, differentiate, and shed; accelerated in psoriasis.
UV-Induced Photoaging
Cumulative UVA/UVB damage that drives oxidative stress, MMP activation, and DNA changes.
Oxidative Stress
Imbalance between reactive oxygen species and antioxidant defense; a driver of structural damage.
Hydration
Stratum corneum water content; central to texture, comfort, and barrier performance.
Structure
Skin Barrier
Stratum corneum + lipid matrix that controls water loss and limits irritant entry.
Collagen
Primary structural protein of the dermis; declines and fragments with age and UV exposure.
Elastin
Elastic dermal fibers that allow skin to recoil; degraded with cumulative photoaging.
Microbiology
Immunology
Inflammation
Innate immune response producing redness, swelling, and discomfort in affected skin.
Immune Response
Adaptive and innate immune signaling that drives inflammation and shapes chronic skin disease.
Cytokine Signaling
Cell-to-cell signaling proteins (IL-17, IL-23, TNF, IL-4/13) that orchestrate skin inflammation.
Symptoms
Flaking
Visible shedding of stratum corneum, often accelerated in seborrheic dermatitis and dandruff.
Itching
Pruritic sensation from inflammatory mediators acting on cutaneous nerves.
Redness
Visible erythema from vasodilation and inflammation in affected skin.
Itch-Scratch Cycle
A self-reinforcing loop where itch drives scratching, which damages the barrier and inflames skin.
Scaling / Plaques
Visible thickened, often silvery surface layers from accelerated, disorganized turnover.