With age, the skin undergoes various biological and physiological changes that can alter its radiance and make it appear more dull. What mechanisms can explain these changes? Let's explore together why the complexion becomes more dull over time.
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Why does the complexion become duller with age?
Summary
- The slowing down of cellular renewal, responsible for the dulling of the complexion
- Dull complexion: Reduced blood circulation as a cause
- Sources
Published January 23, 2025,
updated on January 23, 2025,
by
Pauline, Chemical Engineer
—
6 min read
The slowing down of cellular renewal, responsible for the dulling of the complexion.
Both governed by intrinsic and extrinsic factors, skin aging is a natural process that no one can escape. Skin sagging, loss of flexibility and firmness, decrease in hydration, appearance of wrinkles... It manifests in various ways. The complexion also tends to become more dull with age. This is mainly due to the slowdown of cellular renewal that accompanies skin aging. As a reminder, cellular renewal is a biological process in which the cells of the epidermis constantly renew themselves. Keratinocytes, representing about 80% of the cells of the epidermis, form in the basal layer and gradually migrate to the horny layer, where they die and form a protective barrier. This cycle takes about 28 days in young adults.
Between the ages of 30 and 70, cellular renewal decreases by approximately 50%.
A study has particularly focused on the transit time of cells in the epidermis, that is, the time required for cells to move to an adjacent layer, either from the basal layer to the Malpighian layer, from the Malpighian layer to the granular layer, or from the granular layer to the horny layer. Several volunteers aged 18 to 80 were involved in the study, and the dansyl chloride fluorescence method was used. First described in 1974, this method allows for tracking in vivo skin cell renewal and skin desquamation through fluorescence. The scientists observed an extended epidermal cell transit time of about ten days in older subjects compared to younger volunteers. The results according to age groups are gathered in the table below. The stars next to the numbers indicate that the increase in transit time is significant.
| Age Range | Transit time of cells in the epidermis (days) |
|---|---|
| 18 - 29 years | 19.8 |
| 30 - 39 years old | 20.5 |
| 40 - 49 years old | 20.2 |
| 50 - 59 years old | 24.7 * |
| 60 - 69 years old | 31.0 * |
| 70 - 80 years | 36.8 * |
Cell transit time in the epidermis according to age groups.
This slowdown in cellular renewal leads to a buildup of dead cells on the surface of the epidermis, forming a thick and irregular horny layer. This accumulation prevents light from reflecting properly on the skin, which can make the complexion appear more gray, more tired, and less radiant.
Advice : To mitigate the effects of slowed cellular renewal on skin radiance, it is recommended to exfoliate your skin once or twice a week.
Dull complexion: Reduced blood circulation as a cause.
The efficiency of circular renewal is partly correlated with the proper functioning of microcirculation. Indeed, the latter allows for the supply of skin cells with oxygen and nutrients, an essential element for cellular renewal. In a state of hypoxia, that is, when the body lacks oxygen, the production of keratinocytes decreases, leading to an accumulation of dead cells on the skin's surface and, consequently, to a dull complexion. Moreover, a slowdown in microcirculation is accompanied by difficulties in the removal of waste and pigments by the lymph, which can cause a yellowing of the complexion.
Microcirculation slows down with age, contributing to skin dullness. The deceleration of blood flow is estimated to be 40% between the ages of 20 and 70.
The mechanisms related to the slowing of blood circulation are numerous and complex. For instance, one can mention the reduction in the expression of nitric oxide synthase, an enzyme that enables the production of nitric oxide, one of its primary roles being to relax the arteries. In doing so, this molecule improves microcirculation, and consequently, the oxygenation of skin cells. The decrease in the release of nitric oxide in the body negatively impacts microcirculation and thus indirectly promotes a dull complexion.
Advice : Regular physical activity helps to minimize the slowing of blood flow and its negative effects on the radiance of the skin.
Sources
KLIGMAN A. & al. Age-associated changes in human epidermal cell renewal. Journal of gerontology (1983).
MARSHALL R. & al. A simplified method for measurement of desquamation using dansyl chloride fluorescence. The British journal of dermatology (1984).
SERRI F. & al. Physiological changes in ageing skin. British Journal of Dermatology (1990).
TOBIN D. Introduction to skin aging. Journal of Tissue Viability (2017).
JIN K. A Microcirculatory Theory of Aging. Aging and Disease (2019).
ROBIC G. & al. Yellowness in skin complexion: Analysis of self-perception of women in China evaluated against clinical parameters of yellowness. Skin Research and Technology (2024).
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