Είναι απολύτως δυνατό το δέρμα να αποβάλλει φυσικά έως και 1.000.000.000 κύτταρα την ημέρα 1 . Ένας μηχανισμός εναλλαγής, που πιστεύεται από την εξέλιξη ότι βοηθά στην προστασία ενός ατόμου από εξωτερικές τοξίνες και βακτήρια. Το δέρμα είναι το κύριο εμπόδιο για όλες τις μορφές περιβαλλοντικής επίθεσης. Η υγιής λειτουργία του δερματικού φραγμού προστατεύει το ανθρώπινο σώμα από λοιμώξεις, ασθένειες, φυσικές τοξίνες, ακόμη και από την υπεριώδη ακτινοβολία.
Η λειτουργία του δέρματος και επομένως του δερματικού φραγμού είναι υγιής μόνο όταν τα κύτταρα του δέρματος απορρίπτονται ομοιόμορφα και τακτικά.
Τι είναι η φυσική απολέπιση του δέρματος;
Η φυσική απολέπιση είναι η τεχνική ονομασία που χρησιμοποιείται για να περιγράψει τον φυσικό ρυθμό αποβολής των κυττάρων του δέρματος. Το Squame είναι μια άλλη λέξη για την κλίμακα και χρησιμοποιείται για να περιγράψει μια συλλογή νεκρών κυττάρων του δέρματος – επομένως η απολέπιση περιγράφει την αποβολή νεκρών κυττάρων του δέρματος.
Η φυσική απολέπιση είναι μια ενεργητική και όχι παθητική διαδικασία. Αυτό σημαίνει ότι τα κύτταρα του δέρματος απορρίπτονται ενεργά επειδή οι κυτταρικές αλλαγές τους προκαλούν να το κάνουν. Αυτό είναι σε αντίθεση με έναν ρυθμό παθητικής απολέπισης που θα καθοριζόταν μόνο από το χτύπημα, την τριβή ή την τριβή του δέρματος.
Το δέρμα μπορεί να είναι βέλτιστα υγιές μόνο όταν έχει φυσιολογικό ρυθμό φυσικής απολέπισης. Αυτό συμβαίνει επειδή η απολέπιση επιτρέπει στο δέρμα να δημιουργεί συνεχώς μια ομοιόμορφη δομή από τούβλα και κονίαμα νεκρών κυττάρων του δέρματος συσκευασμένα μεταξύ τους με λιπιδική κόλλα. Ένα φράγμα που επιτρέπει στο δέρμα να διατηρεί την ενυδάτωση και να αντιστέκεται στην επίθεση.
Το ανθρώπινο δέρμα αποβάλλει κατά μέσο όρο από 200.000.000 έως 1.000.000.000 κύτταρα την ημέρα, τα οποία αντιστοιχούν σε έως και 14 γραμμάρια το πολύ την ημέρα. Ενώ η απολέπιση είναι ενεργή, μπορεί επίσης να επιταχυνθεί παθητικά από διάφορους παράγοντες, όπως το πλύσιμο με καθαριστικά 2 , η τριβή των ρούχων και ακόμη και η τεχνητή απολέπιση της επιδερμίδας. Οι λόγοι για τους οποίους και πότε αυτό είναι κατάλληλο θα συζητηθούν λεπτομερώς σύντομα.
Γιατί είναι σημαντική η φυσική απολέπιση;
Αν και έχει προταθεί, η εξελικτική λειτουργία της απολέπισης είναι να προστατεύει το δέρμα από περιβαλλοντικές επιθέσεις, επιτρέποντας επομένως την αποβολή των συρρικνωμένων περιβαλλοντικών τοξινών και ερεθιστικών ουσιών. Δεν αποδεικνύεται. Αυτό που είναι ωστόσο γνωστό είναι ότι όταν τα δέρματα δεν μπορούν να αποκολληθούν με φυσιολογικό τρόπο, το δέρμα γίνεται συχνά.
- Φολιδωτός 3
- Ξεφλουδισμένος
- Αφυδατωμένο
- Ξηρό (ιατρικά ονομάζεται ξερόση)
- Κνησμώδης
- Ιχθυωτική (δερματική νόσος που έχει ως αποτέλεσμα ξηρές, κνησμώδεις φολίδες)
Τα παραπάνω συμπτώματα συνήθως οδηγούν σε οπτικές αλλαγές στο δέρμα που αναγνωρίζονται ως αποσπασματικός και ανομοιόμορφος τόνος δέρματος, γενική πάχυνση του δέρματος, θαμπάδα ή πρόωρη ανάπτυξη λεπτών γραμμών και ρυτίδων. Για το λόγο αυτό, μπορεί να είναι ευεργετικό να επιταχύνετε τον φυσικό ρυθμό αποβολής του δέρματος.
Ενώ η φυσική απολέπιση μπορεί να είναι πιο δύσκολο να επηρεαστεί (λόγω της φύσης της μέσα προς τα έξω), η παθητική απολέπιση και επομένως η επιτάχυνση της κυτταρικής ανανέωσης από έξω προς τα μέσα είναι πολύ πιο εύκολη.
Φυσική Απολέπιση vs Τεχνητή απολέπιση
Η απολέπιση είναι μια φυσική και ενεργητική διαδικασία, που επηρεάζεται από χημικά σήματα ή αλλαγές από μέσα προς τα έξω. Για παράδειγμα, είναι γνωστό ότι μια ανεπάρκεια σε διαιτητικά απαραίτητα λιπαρά οξέα, για παράδειγμα, λινολεϊκό οξύ, προκαλεί στο δέρμα ξηρότητα και φολίδωση 4, δηλαδή επηρεάζει την διαδικασία της φυσικής απολέπισης με αρνητικό τρόπο.
Η τεχνητή απολέπιση, από την άλλη πλευρά, περιγράφει μια «παρεμβατική» διαδικασία κατά την οποία ένα άτομο μπορεί να επιταχύνει την αποβολή των νεκρών κυττάρων του δέρματος χρησιμοποιώντας ένα φυσικό ή χημικό απολεπιστικό υλικό. Η τεχνητή απολέπιση λειτουργεί από έξω προς τα μέσα ενώ η φυσική απολέπιση λειτουργεί από μέσα προς τα έξω. Η χρήση ενός απολεπιστικού υλικού είναι ιδιαίτερα χρήσιμη για τη διόρθωση των οπτικά εμφανών σημαδιών μιας αργής φυσικής απολέπισης, για παράδειγμα, μιας γενικής θαμπάδας του δέρματος ή ενός ανομοιόμορφου δερματικού τόνου.
Πώς λειτουργεί η απολέπιση δέρματος;
Υπάρχουν 2 βασικοί τρόποι με τους οποίους μπορεί να επιταχυνθεί ένας αργός ρυθμός απολέπισης με την τεχνητή απολέπιση. Αυτό γίνεται είτε με χρήση φυσικών απολεπιστικών υλικών, δηλαδή με την τριβή των νεκρών κυττάρων του δέρματος, είτε με χρήση χημικών απολεπιστικών, τα οποία διαλύουν σταδιακά την συνδετική «κόλλα», που συγκρατεί τα νεκρά κύτταρα του δέρματος.
t is entirely possible for skin to naturally shed up to 1, 000, 000, 000 cells per day1. A turnover mechanism which is by evolution thought to help protect a person against external toxins and bacteria. Skin is the major barrier for all forms of environmental assault. Healthy barrier function protects the human body against infection, disease, natural toxins, and even UV radiation.
Skin and therefore barrier function are only healthy when skin cells shed evenly and routinely.
What is desquamation of the skin?
Desquamation is the technical name used to describe the skin’s natural rate of shedding. Squame is another word for scale and is used to describe a collection of dead skin cells – therefore desquamation describes the shedding of dead skin cells.
Desquamation is an active and not passive process. Meaning skin cells shed actively because cellular changes provoke them to do so. This is as opposed to a passive exfoliation rate which would be determined only by the knocking, friction or abrasion of the skin.
Skin can only be optimally healthy when it has a normal rate of natural desquamation. This is because desquamation enables skin to continuously create a uniform brick and mortar structure of dead skin cells packed together by lipid glue. A barrier which enables skin to retain hydration and resist assault.
Human skin sheds an average of between 200,000,000 to 1, 000, 000,000 cells per day which accounts for up to a maximum of around 14 grams per day. While desquamation is active it can also be speeded passively by a variety of factors including – washing with cleansers2, the friction of clothes and even with exfoliating skincare. Reasons for why and when this is appropriate are discussed in detail soon.
Why is desquamation important?
Although it has been proposed the evolutionary function of desquamation is to protect skin against environmental assault, therefore allowing the shedding of contracted environmental toxins and irritants. It is not proven. What is however known is when skins unable to desquamate in a normal manner, the skin will often become;
- Scaly3
- Flaky
- Dehydrated
- Dry (medically called xerosis)
- Itchy
- Ichthyotic (skin disease resulting in dry, itchy scales)
The above symptoms commonly lead to visual changes within skin recognised as a patchy and uneven skin tone, a general thickening of skin, dullness or a premature development of fine lines and wrinkles. For this reason, it can be beneficial to speed the skin’s natural rate of shedding.
While natural desquamation may be harder to influence (due to its inside-out nature), passive exfoliation and therefore an outside to inside speeding of cellular renewal is much easier.
How does skin exfoliation work?
There are 2 primary ways in which a slow desquamation rate may be speeded by exfoliation. This is either by use of physical exfoliants i.e. by a rubbing off of dead skin cells or by use of chemical exfoliants i.e. by a gradual dissolution of the ‘glue’ which holds dead skin cells together.
Below are a few examples of each.
Physical exfoliants include;
- Muslin/cotton cloths such as our griffin+row Exfoliate natural exfoliant cloth
- Konjac sponges
- Facial brushes
- Face scrubs
Chemical exfoliants include;
- Alpha hydroxy acids – e.g. glycolic acid
- Beta hydroxy acids – e.g. salicylic acid
- Retinoic acid (retinol)
- Enzymes – e.g. bromelain and papain (naturally found in papaya)
- Vitamin C as ascorbic acid
- Urea – a component of the skin’s natural moisturising factor
Interestingly a lesser known way to help aid skin exfoliation or natural desquamation is by keeping skin well hydrated. When skin cells mature in the upper layers of skin, they require hydration to swell and therefore induce the weakening of intercellular bindings5. Keeping skin well hydrated with actives such as glycerin (as found in griffin+row Hydrate skin hydration spray) and hyaluronic acid can help naturally re-speed slowing rates of desquamation. It is also noted many of the necessary enzymes required for desquamation are hydrolytic i.e. they require water/hydration for their activity6.
In normal skin, proper hydration and their natural desquamation are greatly impacted by skin’s natural moisturising factor (NMF). A combination of many ingredients including amino acids, sodium PCA and urea, therefore skincare products (i.e. griffin+row Hydrate skin hydration spray) which hydrate or moisturise by using skin-identical components of skin’s NMF are especially helpful.
Symptoms of over-exfoliated skin
It is more than possible to suffer side effects from exfoliation. Such side effects are most common when over-using exfoliating skincare products. As with most natural processes slowing or amplification can often cause unwanted symptoms.
The most common signs of over-exfoliation include;
- Sensitivity and redness
- Spots or an increase in acne
- Dehydration/dry skin
- Tight, squeaky feeling skin
- Itchy skin
- Rash
Exfoliation vs desquamation
Desquamation is a natural and active process influenced by chemical signals or changes from the inside-out. For example, it is known that a deficiency in dietary essential fatty acids, for example, linoleic acid causes the skin to become dry and scaly4 i.e. natural desquamation has been negatively impacted.
Exfoliation, on the other hand, describes an ‘interfering’ process whereby a person may speed up the shedding of dead skin cells by using an exfoliant. Exfoliation works from the outside-in whereas natural desquamation works from the inside-out. Using an exfoliant is particularly helpful for correcting the visually obvious signs of a slow natural desquamation, for example, a general dullness of skin or an uneven skin tone.
Because natural desquamation is an internally driven process it rarely results in side effects. Conversely, manual exfoliation may often result in side effects. Care must be taken with the use of physical exfoliants where the physical pressure used may cause excessive irritation and sensitivity. Exfoliating products which use sharp or grainy exfoliating granules i.e. apricot seeds should be avoided. The best physical exfoliating products use uniform exfoliating beads such as those made from jojoba wax.
A gentle manual exfoliant such as the griffin+row exfoliate natural exfoliant cloth may be used with gentle pressure once a day, however chemical exfoliants, especially those with high strength are best used only a few times per week. Chemical exfoliants pose a heightened risk of over-use as the products continue to work after application/absorption meaning results build days past initial use.
Why exfoliation can cause spots
The most common side effect of incorporating an exfoliating product into a person’s skincare routine is spots or an increase of acne. This is a temporary side effect which should clear after 1 to 3 months.
Spots are the result of an accumulation of dead skin cells inside of pores, therefore both physical and chemical exfoliation can temporarily increase the amount of dead skin cells at risk of becoming trapped. While dead skin cells are trapped inside pores they may breed acne causing strains of bacteria by providing them with a food source. After the introduction of an exfoliant the number of dead skin cells trapped inside of pores may be temporarily increased. This can therefore cause spots or a temporary increase in acne symptoms.
Spots as a side effect of exfoliation are sometimes colloquially referred to as purging. Spots caused by exfoliation induced purging should clear after a few months of regular use – a time period which allows for the temporary speeding of skin’s turnover rate to balance. However if spots and acne continue to worsen, then symptoms are most likely to be a sign of general irritation.
Both spots and acne are inflammatory skin conditions and therefore exfoliating products which cause skin irritation have potential to worsen spots and acne for as long as they’re used. People with sensitive or acne prone skin should be especially careful when introducing exfoliating skincare products.
Why over exfoliation can cause dry skin
When skin has a slow natural desquamation rate skin often becomes dry, scaly and flaky. In theory this is due to a slowed desquamation rate causing an uneven skin barrier. Every individual skin cell behaves like a brick within the barrier of a person’s skin wall. As skin cells mature they replace old skin cells or ‘bricks’. If this process is uneven, a ‘wobbly’ or disrupted skin barrier forms and is unable to perform its job optimally. This results in increased water loss and therefore a continuing dry skin type.
The same side effect may also occur during over exfoliation. Exfoliation removes dead skin cells before they would naturally desquamate. If too many layers of cells are removed prematurely, deeper found layers of skin cells are exposed and if not matured fully, they will be unable to attain a full barrier function. This therefore leads to increased penetration of a person’s skin by environmental irritants and allergens i.e. pollution particles, pollen and bacteria. The result is a dry and sensitive skin type prone to inflammation and therefore redness.
How long is desquamation?
A review article published by the international journal of molecular medicine states the time taken for an individual skin cell to travel from the basal layer of skin to the visible layer is an average of 52-75 days in a normal and healthy individual7. Studies also infer this transit time may be slowed with age, gender, ethnicity and the time of year.
The top layers of skin referred to as the stratum corneum take an average of 2 weeks to turnover/desquamate and therefore reveal new, fresh and healthy skin cells. Therefore exfoliating skincare may have quick and visually recognizable benefits on skin showing signs of dullness and scaling. On the other hand visual irregularities whose cause are found much deeper within skin i.e. hyperpigmentation or post inflammatory hyperpigmentation caused by acne scarring will take much longer to correct. The overall benefits of introducing an exfoliating skincare product into a person’s skincare routine usually begin to show after 2 to 3 months of regular use.
How many skin cells do we shed a day?
A healthy natural desquamation rate and process results in invisible to the naked eye dead skin cell squames which do not clump and are not troublesome. Although these dead skin cells are invisible a considerable number are shed per day. Studies estimate an average of between 2 hundred million and 1 billion are shed each day. In disorders of desquamation such as psoriasis, eczema and dandruff this rate of shedding is visibly increased.
What is the best way to exfoliate your face?
Areas of skin commonly exposed to the environment can often suffer from uneven desquamation or a slowing of desquamation. Skin may look weathered, dull, sallow, uneven and textured. Features which lead to a general perception of skin as older. Therefore it can be beneficial to exfoliate these areas regularly.
Finding the best kind of exfoliate for a person’s face is dependent on their skin type. For example the exfoliate most appropriate for a person with sensitive skin would be different to that for a person with mature skin.
In general a mild physical exfoliant such as the griffin+row exfoliate natural exfoliant cloth is most appropriate for sensitive skin types including sensitive facial areas. During exfoliation it’s important to apply only a delicate pressure with gentle circular motions enabling dead skin cells to ‘buff’ away. Using this process avoids risk of over exfoliation which is most common with chemical exfoliants.
For mature skin types chemical exfoliants may be most appropriate due to a general thickening of skin. Chemical exfoliants are able to exfoliate more deeply than a physical exfoliant and can therefore help increase a mature skin cell turnover to a greater extent.
For dry, oily and normal skin types, choosing an exfoliate is in part down to personal preference and in part down to the sensitivity of skin. Oily skin types may be best exfoliated with salicylic acid as this ingredient dissolves well in oil filled pores – especially helpful for tackling acne. Dry skin types which are prone to redness and therefore sensitivity may be best exfoliated with a mild physical exfoliant and the daily use of hydrating skincare.
- The determination of regional and age variations in the rate of desquamation: a comparison of four techniques. D. Roberts, R. Marks J Invest Dermatol. 1980 Jan; 74(1): 13–16.
- Epidermal desquamation. Leonard M. Milstone, J Dermatol Sci. 2004 Dec; 36(3): 131–140. doi: 10.1016/j.jdermsci.2004.05.004
- Piérard G.E., Hermanns-Lê T., Piérard-Franchimont C. (2017) Stratum Corneum Desquamation. In: Humbert P., Fanian F., Maibach H., Agache P. (eds) Agache’s Measuring the Skin. Springer, Cham
- July 1972 The Journal of Lipid Research, 13, 458-467.
- Corneocyte desquamation. G. E. Pierard, V. Goffin, T. Hermanns-Le, C. Pierard-Franchimont, Int J Mol Med. 2000 Aug; 6(2): 217–221.
- Epidermal desquamation. Leonard M. Milstone, J Dermatol Sci. 2004 Dec; 36(3): 131–140. doi: 10.1016/j.jdermsci.2004.05.004
- Corneocyte desquamation. G. E. Pierard, V. Goffin, T. Hermanns-Le, C. Pierard-Franchimont, Int J Mol Med. 2000 Aug; 6(2): 217–221.
