on July 20, 2026
Biological mechanisms of skin aging: intrinsic and extrinsic
Skin aging is a physiological and inevitable phenomenon associated with advancing age, defined as chronological or intrinsic aging. Overlaid on this process is extrinsic aging (or photoaging), triggered by continuous interaction with environmental factors.
Among the main causes of premature aging are ultraviolet (UV) radiation and environmental pollutants. In particular, fine particulate matter (PM) from vehicles and industrial emissions, together with heavy metals and volatile organic compounds (VOCs), significantly increase markers of skin damage. The absorption of UV radiation by skin molecules triggers a massive production of reactive oxygen species (ROS), leading to a state of oxidative stress that directly damages cell walls, lipid membranes, mitochondria, the nucleus, and DNA.
Cigarette smoke acts in a comparable manner to chronic UV radiation, inducing structural alterations in both the epidermis and dermis through the activation of matrix metalloproteinases (MMPs), enzymes responsible for the degradation of the extracellular matrix.
Structural alterations of the dermis and microcirculation
Aging leads to a progressive compromise of the dermis's supporting structures, particularly collagen and elastic fibers. This phenomenon leads to loss of tone, laxity, and skin thinning. At the same time, a slowdown of local microcirculation is observed due to damage to the vascular wall of the blood capillaries. The resulting reduction in nutrient supply and the accumulation of catabolites and cellular toxins accelerate morphological changes: increased roughness, dryness, loss of elasticity, and irregular pigmentation.
Advanced dermocosmetic treatments act either directly — by stimulating fibroblast biosynthesis — or indirectly, by inhibiting the enzymatic activity of collagenases and elastase.
The antioxidant defense system: redox balance
To counteract the action of ROS and maintain cellular homeostasis, human skin has a complex antioxidant defense system divided into:
1. Endogenous antioxidants: Enzymes and molecules synthesized by the body (present mainly in the epidermal layer) that nevertheless tend to gradually deplete with age or due to chronic exposure to pollution, UV, and smoke.
2. Exogenous antioxidants: Compounds that cannot be synthesized by humans (such as vitamins, polyphenols, and phytoantioxidants extracted from leaves and seeds) which, when introduced topically or systemically, restore redox balance, limit toxicological stress, and preserve skin volume, softness, and smoothness.
Phytoextracts and plant lipids with regenerative action
The targeted use of lipid fractions and plant extracts makes a decisive contribution to the regeneration and protection of skin structures:
· Sweet Almond Oil (Prunus dulcis): Obtained by cold pressing, it is rich in polyunsaturated fatty acids (oleic acid 62-86%, linoleic 20-30%, palmitic, stearic) and vitamins E and B. Thanks to its high skin affinity, it increases the skin's resistance to stretching and prevents wrinkle formation.
· Rosehip Oil (Rosa affinis): Characterized by a high content of linoleic acid (45%), alpha-linolenic acid (35%), and natural trans-retinoic acid. These active ingredients promote the regeneration of cell membranes, accelerate tissue renewal, improve healing processes, and reduce pigmentary alterations.
· Avocado Unsaponifiable Fraction (Persea americana): Rich in tocopherols, phytosterols, carotenoids, and avocatin. Avocatin directly inhibits collagenases, preventing collagen destruction and promoting epidermal turnover, barrier function, and microvascular trophism.
· Centella asiatica: The extract, particularly the triterpene fraction (asiaticosides and isomers), shows a marked tropism for connective tissue. It stimulates fibroblast activity and the expression of native collagen and mucopolysaccharides (GAGs), optimizing the dermal scaffold and water retention. Furthermore, it reduces endothelial permeability and improves the tone of the venous vascular wall.
Nutrition and systemic supplementation: an In&Out approach
The prevention and maintenance of skin health require a coordinated intervention that combines topical administration with nutritional supplementation:
· Lifestyle and hydration: Reduction of alcohol intake, smoking cessation, control of caloric intake to avoid sudden weight fluctuations, and constant hydration (through water, herbal teas, and smoothies). Deep tissue hydration is strictly dependent on the water and plant intake from the diet.
· Vitamin A and Carotenoids (Daucus carota): Vitamin A and its precursor $\beta$-carotene stimulate collagen synthesis and perform a protective and reparative action on epidermal structures.
· Essential Omega-6 Fatty Acids (Borrago officinalis): Borage oil, extremely rich in gamma-linolenic acid (GLA) and linoleic acid, acts on the regeneration of cell membranes and the maintenance of deep hydration. Oral supplementation (through 45-60 day cycles) and local application significantly improve the elasticity and appearance of skin imperfections and stretch marks.
Particular preventive attention should be paid early to areas with greater susceptibility to chrono/photoaging, such as the eye contour and lip contour, by synergistically combining topical antioxidant treatments and systemic nutraceuticals.
Bibliographic References
1. Timur Tashan S, Kafkasli A. The effect of bitter almond oil and massaging on striae gravidarum in primiparous women. J Clin Nurs. 2012 Jun;21(11-12):1571-6.
2. Ogalla JM, Canellas M, Espada N. Estudio del aceite de rosa mosqueta en cicatrices postquirurgicas. ResearchGate, Sept 2020.
3. Thiers H. L'olio di avocado ed il suo insaponificabile in cosmetologia ed in terapia dermatologica. Fruits n.2, p.133, 1961.
4. Bylka W, Znajdek-Awiżeń P, Studzińska-Sroka E, Brzezińska M. Centella asiatica in dermatology: an overview. Phytother Res. 2014 Aug;28(8):1117-24.
5. Laugel C, Cohen-Letessier A, Clement A, Laverdet C. Evaluation of the clinical and echographic efficacy of a cream with Centella asiatica in the treatment of the stretch marks. ResearchGate, January 1999.
