— From the face, to the whole body. A theoretical supplement to the XPRIZE Healthspan proposal.
The stratum corneum and the specificity of facial skin, read as upstream variables that OCT-A measurement should capture.
The moment facial skin meets water — already, the body’s response is being induced.
A cleanser is applied; the physical motion that follows — depending on this combination, the skin’s and the body’s response can be entirely opposite.
And this is repeated, every single day.
The carelessness of the rinse, the temperature of the lukewarm water, the direction and pressure of contact — these accumulate, quietly, as load upon the stratum corneum, the neurovascular unit (NVU), and the capillary loops.
A composite of scientific and physical stimuli is being administered, day after day, through unexamined motions and unfounded concepts — without design.
Almost no one has noticed.
The proposer has spent thirty-eight years in clinical settings devoted to the skin.
Through that experience, one fact has come into view, unmistakably: the absence of design in the daily inputs delivered to the skin fundamentally governs the quality of the physiological signals that the skin produces.
This observation was not chosen to support a particular theory. It is a phenomenon that, over many years, has appeared again and again — preceding any hypothesis, surfacing as spontaneous reports from the participants themselves.
This work begins from that observation.
Most skin research has focused on the forearm, the back, the sole — sites where measurement is convenient. The face, entangled in the language of cosmetics, has tended to be avoided as a subject of pure scientific inquiry.
And yet, the face is not a special case in skin research. It is, rather,the region of highest information density that skin research should, by rights, be addressing.
Much of the facial tissue derives from the neural crest, with the development of the cranium, nerves, vasculature, and soft tissue tightly coupled. This is a structural foundation that does not exist in the skin of other regions.
Kaucka et al., 2016The stratum corneum of the face is thinner than that of the trunk and limbs, and its layered organization shows distinctive features.
Tagami, 2008The density of sensory receptors distributed in the facial skin overwhelms that of any other region. The skin is the largest sensory organ — but its informational density is far from uniform across the body.
The structures involved in expression, swallowing, respiration, and equilibrium converge at the face. Changes in the state of facial skin can therefore propagate to a wider range of functional systems than changes elsewhere.
The face is the only region permanently exposed, daily subjected to environmental variables — gravity, temperature, humidity, ultraviolet light, chemical compounds, mechanical contact.
The age-related changes of the stratum corneum have been reported, in fragments, throughout the dermatological literature. Read together, they begin to form a picture.
Decreased epidermal turnover and delayed corneocyte desquamation proceed simultaneously, leaving the stratum corneum thicker and more accumulated.
Tagami, 2008Analysis of 1,315 paranasal sinus CT scans revealed that miliary osteomas of facial skin appear far more often than expected as incidental findings, with prevalence increasing significantly with age.
Kim et al., 2017The epidermal basement membrane is the mechanical and informational interface between the epidermis and the underlying tissue — including nerve endings and microvasculature.
Roig-Roselló & Rousselle, 2020Human skin reflects systemic endothelial function and microvascular reactivity. Its accessibility and responsiveness give it value — and, in the same gesture, difficulty.
Cracowski & Roustit, 2020Optical coherence tomography angiography has succeeded in imaging vascular alterations specific to facial skin, in a way that was not previously accessible.
Hara et al., 2018Evidence is mounting that the epidermal cell network just beneath the stratum corneum participates in the initial processing of sensory information.
Xu, 2022Synthesizing these individual findings, the proposer puts forward, as a hypothesis, the chain stratum corneum accumulation → basement membrane flattening → dermal papilla flattening → disrupted positional integrity of capillary loops and the NVU. Each stage is a fact grounded in an independent study, but the arrows connecting the stages are not a verified causal relationship — they are the proposer's integrative hypothesis. The "variability" and "noise" observed in OCT-A microcirculation signals may also be related to this unregulated upstream stratum corneum variable.
Note: The content of each box is a fact directly stated by its individually cited source. The arrows connecting the boxes — the pathway from stratum corneum accumulation to reduced capillary loop/NVU integrity — represent the proposer’s hypothesis for integrating these findings; no cited study has verified this pathway itself.
What matters here is that the state of the stratum corneum is not a fixed attribute. It is a reversible, designable condition.
Wu et al. (2006) showed that the mechanical properties of the stratum corneum vary substantially with hydration. Between dry and hydrated states, the elastic modulus, the friction coefficient, and the deformation behavior differ greatly.
Björklund (2010) reported that water gradients are a primary regulator of mass transport across the stratum corneum. A hydrated state is not merely a condition that aids permeation — it functions as a “designable window” through which the physical properties of the stratum corneum itself can be altered, reversibly.
Kimura et al. (2020) demonstrated that tissue-scale tensional homeostasis is a basic principle that maintains the structural order of the skin.
Cleansing is the most powerful daily tool for inducing biological response — and, simultaneously, the moment when material transport into the stratum corneum is timed.
Each participant arrives at the laboratory carrying their own cleansing habits. No two of them apply the same actions, the same products, the same temperatures, the same frequencies to their skin.
And yet research treats the skin of all participants as a “comparable measurement substrate.” Does this assumption, in fact, hold?
The proposer’s view is this:
many excellent studies may be unable to express the reproducibility they would otherwise possess, because of the uncontrolled state of this upstream variable.
This is not a denial of the value of existing research. On the contrary — it is a suggestion that the latent power of those studies might be released, by designing the upstream variable.
It has been reported, again and again, that rejuvenation effects observed in animal experiments fail to reproduce in humans. Several factors already identified are said to contribute to this gap — dosing, species differences, the validity of the animal model, among others. In addition, the proposer considers a variable absent in laboratory animals and present only in humans — namely, industrialized daily inputs to the skin — worth examining as a further contributing factor. This is not a verified conclusion; it is the proposer’s hypothesis.
For thirty-eight years, the proposer has observed that following a redesign of the cleansing protocol, participants repeatedly report subjective changes related to the microcirculation — facial color, the sensation of skin warmth, the mobility of expression.
Concurrently, visible changes in posture, head position, and shoulder alignment frequently accompany these reports. These changes have been recorded as spontaneous reports, preceding the formulation of any hypothesis.
For each individual participant, frontal standing photographs were taken before and after the cleansing-protocol intervention, under the same camera position and lighting. Reference horizontal lines allow the visual confirmation of changes in vertex position, cervical position, shoulder height symmetry, thoracic position, and facial contour.
* To be published upon receipt of written consent.
These observations have not been statistically validated, nor are they the result of a controlled clinical trial. They are, however, phenomena that have appeared repeatedly, in advance of hypothesis — and as such, they stand as observational evidence supporting the biological plausibility of the proposed intervention.
Cleansing is a daily act, universal to humans, that can simultaneously control hydration, temperature, and mechanical stimulation. It is repeated daily, requires no specialized equipment, and can be deployed without the constraints of culture or economy.
By capturing OCT-A images before and after a designed cleansing protocol, the microcirculatory signal that has been treated as “variability” can, for the first time, be evaluated under conditions in which the upstream stratum-corneum variable is controlled.
No new technology, no new pharmaceutical agent is required. It only integrates an existing measurement modality with an existing daily action — through design. The trajectory from laboratory validation to deployment in everyday life can be followed without rupture.
This is a framework that, before the question of "what to intervene upon" in healthspan research, raises the more fundamental question: "what is being measured, and in what state."
This paper takes as its starting point the idea that became the theoretical background for the XPRIZE Healthspan proposal. The proposal actually submitted narrowed the argument to a single line — “stratum corneum accumulation → microcirculation → OCT-A measurement” — but the fuller idea includes further considerations of the proposer’s own, not part of the submitted proposal.
Boundary fatigue as the synergistic action of physical loads (gravity, friction, tension) and chemical loads (surfactants, accumulation of industrial compounds).
The possibility that industrialized daily inputs to the skin — a variable specific to the human — are implicated in the failure of rejuvenation effects observed in animal models to reproduce in humans.
The disproportionately large representation of the face and the hand in the sensorimotor cortex (Penfield’s homunculus) constitutes the theoretical basis for the systemic influence that inputs to these regions can exert.
A structural account of how the neural-crest-derived facial tissues function as a tensional hub for the entire body.
A systematic organization of individual cases.
This paper is at once an invitation to logical scrutiny, and a call to those who would join in opening this unmapped territory. Dialogue is welcomed — with researchers, with clinicians, with specialists in data analysis.
Open the dialogue →