The Biology of Cleansing: Why Washing Your Face Once a Day Is Enough

By Wendy Ouriel, M.S. Cellular Biology — Founder, OUMERE Laboratories

In 30 seconds:

• Daily cleansing is essential for removing pollutants and preserving barrier function.
• Over-cleansing strips lipids, accelerates aging, and paradoxically causes acne.
• Evening cleansing only — with a pH-balanced, oil-based cleanser — supports healthy sebum regulation.
• Morning cleansing may disrupt the microbiome and barrier recovery cycle.

Why washing matters

Daily cleansing isn't just for those with oily or acne-prone skin. Removing surface pollutants and oxidized oils each night is a biological necessity. Urban air carries polycyclic aromatic hydrocarbons and heavy metals that adhere to the lipid layer of the epidermis. When left overnight, these compounds can generate free radicals and DNA mutations — microscopic aging at the cellular level.

Evening cleansing removes this film of oxidants, preparing the skin for restorative repair. The Oil Dissolution Theory is designed for this very purpose: dissolving pollutants and oxidized sebum without disturbing barrier lipids or the microbial biome.

Why you shouldn’t wash in the morning

If you sleep on a clean pillowcase and in a cool, dry environment, your skin’s barrier remains balanced overnight. Morning cleansing often removes protective lipids and microbiota accumulated during nocturnal repair, leading to two primary biological consequences:

• Dryness and micro-wrinkling: stripping the lipid barrier increases transepidermal water loss (TEWL), accelerating fine line formation.
• Reactive sebum overproduction: over-cleansing stimulates sebaceous glands to compensate, producing oleic-acid–rich sebum that clogs pores and inflames tissue.

This paradox explains why many individuals with oily or acne-prone skin worsen their condition through excess washing.

The myth of “dirty skin acne”

Acne is not caused by uncleanliness. If it were, the acne industry wouldn’t exist. Acne stems from inflammation, keratinocyte dysfunction, and microbial imbalance — not hygiene failure. Over-washing merely amplifies these processes by destabilizing the lipid matrix and microbiome, fueling the very inflammation it aims to cure.

In biology, too much cleansing is as disruptive as none at all. Skin thrives on equilibrium, not eradication.

Best cleansing practices for barrier longevity

• Cleanse only once per day, in the evening.
• Use an oil-based, pH-balanced cleanser that mimics natural sebum composition.
• Avoid foaming, alkaline, or abrasive products — including face brushes or devices.
• Pat dry with a soft towel; avoid rubbing or friction.
• Sleep on clean, natural-fiber pillowcases and maintain a cool sleeping temperature.

Further Reading & Research

References

• Grice, E. A., & Segre, J. A. (2011). The skin microbiome. Nature Reviews Microbiology, 9(4), 244–253.
• Lee, S. H. et al. (2018). Sebum composition and barrier function. Experimental Dermatology, 27(4), 452–459.
• Rogers, J., & Harding, C. (2004). Transepidermal water loss and lipid barrier recovery. International Journal of Cosmetic Science, 26(3), 129–138.

Scientific disclaimer: This content summarizes current dermatologic and biological findings for educational purposes and is not medical advice. Individuals with skin disorders should consult a qualified professional before changing cleansing routines.