Spectrum of Emerging
Sciences, 2 (1) 2022, 56-65
The Influence of
Soap and Alcohol-based Cleanser on Human Skin
Samrat Paudel1,2, Rekina
Shrestha1,3, Pramod Poudel4, Rameshwar Adhikari1,5*
1 Research Centre for Applied
Science and Technology (RECAST), Tribhuvan University, Kirtipur, Kathmandu,
2 Kathmandu University,
Department of Biotechnology, Dhulikhel, Kavre, Nepal
3 Himalayan White House
International College, Department of Biotechnology, Purbanchal University,
Khumaltar, Lalitpur, Nepal
4 Central Department of
Biotechnology, Tribhuvan University, Kirtipur, Kathmandu, Nepal
Department of Chemistry, Tribhuvan University, Kirtipur, Kathmandu, Nepal
Author: Rameshwar Adhikari
available online at: https://esciencesspectrum.com/AbstractView.aspx?PID=2022-2-1-12
Received: 23 February 2022
Accepted: 23 April 2022
Alcohol based cleanser,
soap and sanitizer,
skin natural flora.
Soap and alcohol or alcohol-based
cleansers have been used as hand disinfectants and routine hand washing
material for a long time. With the COVID-19 being pandemic, there is an
increase in the routine use of soap and sanitizers. No doubt washing hands
for 20 seconds with proper technique and proper soap could kill the Coronavirus
but the effect of regular use of soap on the skin is not addressed by the
general public. It has been shown by the in vitro as well as in vivo studies
that the frequent use of soap and detergents may harm the skin. The harsh
surfactants in cleansers can damage skin proteins and lipids and can cause
dryness, irritation, barrier damage, and itching problems. Furthermore, the
use of soap can change the natural pH and deplete the natural flora of the
skin giving the pathogen an opportunity to transiently colonize the skin
surface. This paper explains the damages that may be caused to skin due to
excessive use of soap and detergents, the ways to mitigate those damages, and
potential alternative to detergent-based soaps.
Hand hygiene which includes
handwashing with soap and water and/or cleaning hands with alcohol-based
sanitizer is one of the simplest yet effective measures to control infections .
Proper and frequent handwashing can prevent gastrointestinal and respiratory
diseases such as cholera, diarrhea, dysentery, typhoid, and soil-transmitted
helminth infections [2–4].
The concept of handwashing to prevent infection has been in existence since
very old age. In 1824 AD, Germain Labarraque, chemist and pharmacist found the
occurrence of puerperal infection, fever, and maternal death rates can be
decreased with handwashing [5,6].
Even though people knew about the importance of hand hygiene, it is still not
taken seriously as it should be. Many people around the world don't have access
to hand washing. Data shows the global population lacking access to hand
washing during 1990 was 33.6%. The percentage of the population lacking access
to handwashing in 2019 is still 26.1%. The comparison between the percentage of
people lacking handwashing facilities in 1990 and 2019 has been presented in Fig. 1 .
Figure 1. Graph showing the estimated percentage of people
lacking access to handwashing in 1990 and 2019 AD . The percentage of
the population lacking access to handwashing facilities in 2019 (shown by
green bars) has decreased as compared to the percentage of people in 1990
(shown by red bars)
the COVID pandemic originated in December of 2019, the perspective of people
towards health and hygiene, specifically hand hygiene has changed. In addition
to the general public, there is increased compliance to hand hygiene practices
during the pandemic among the health workers. This change in perspective has
greatly reduced cases of hospital-associated infections [8–10].
Figure 2. (a) The cleansing action of surfactant
binding the hydrophobic end with oil and hydrophilic end with the water
molecules. (b) Two different ends of a surfactant molecule.
on one hand, more people are washing hands than ever, there are also numerous
cases of skin deterioration due to the frequent use of soap and alcohol-based
sanitizer. Dermatological conditions like eczema are prevalent among many
Research conducted in Thailand among health workers and non-health workers
showed the presence of hand eczema in 20.87% of the study group . Such a
condition is more common in health workers as handwashing is more frequent in
them compared to other people [14–17].
It is necessary to be aware of such
side effects while using soap and alcohol-based cleansers for hand washing and
cleansing. There is an immediate need to use soap and cleanser in a way that
doesn’t hamper the normal physiological condition and surface integrity of the
skin. With this article, we aim to disseminate better ways to use soap and
alcohol-based cleansers so that hand hygiene can be maintained without
compromising skin homeostasis.
Soap and cleanser are substances
designed to remove dirt, sweat, sebum, and oil from the skin. Detergent-based
soaps; synthetic detergent-based soap (Syndets), alcohol and alcohol-based gel
are some of the common cleansers in practice. Soaps are the long-chain fatty
acid alkali soap with a pH between 9
and 10 [18,19]. Most of
the cleansers except alcohol-based disinfectants contain surfactants on them.
The surfactants present in the cleanser not only aids in the upliftment of dirt
and solubilization of oils but also remove the unwanted materials from the skin
surface and promote normal exfoliation thereby rejuvenating the skin. Cleansing
materials are important to maintain proper health hygiene well as they protect
from microbes, mainly bacteria, and viruses [20,21].
However, on the negative side, the
surfactants present in the cleanser can cause damage to the protein and lipids
of the skin surface which leads to dryness, tightness, irritation, itching as
well as barrier damage. For instance, sodium laurate, a twelve-carbon fatty
acid, is a constituent of most soap which is considered to cause more skin
irritation than other constituents [22,23].
The frequent use of soap and detergent-containing cleanser create problems to
the skin like disturbance of natural pH, disturbing the natural microflora of
the skin, and destroying the lipid and protein layer of the skin .
A better and skin friendlier cleanser
should minimize the damages caused to the skin and should be able to deposit
beneficial lipids on the skin. They also should be able to maintain the skin's
hydration and moisture .
A good cleansing agent must combine disinfection and antimicrobial activity
with the maintenance of skin homeostasis. A good cleansing agent must combine
disinfection and antimicrobial activity with the maintenance of skin
homeostasis. But the use of cleansing material comes at the cost of an increase
in skin pH, decrease in moisture of the skin, disturbance of skin microflora,
and lipid integrity.
2. Application of soap and alcohol as
structure of a soap molecule contains both hydrophilic and hydrophobic ends
responsible for the cleansing action of the soap. One end of a soap molecule is
hydrophobic whereas the other is hydrophilic.
cleansing action of a typical surfactant molecule is achieved by binding the
hydrophobic end with oily substances and hydrophilic end with water molecule is
illustrated in Fig. 2. .
Now, the oily particles from the skin surface attached with hydrophobic ends
are suspended in water and eventually washed away .
Figure 3. (a) Illustrative figure showing the
attachment of hydrophobic ends (of surfactant molecules) with the lipid
membrane of Corona Virus and hydrophilic ends with water molecules
(represented by blue-colored circles). (b) The disruption of the viral
membrane during wash when water molecules attract the hydrophilic end. The
disrupted viral fragments are subsequently washed away by water.
In addition to the cleaning action, the presence of
hydrophobic and hydrophilic ends in surfactant molecules makes it possible to
kill the viruses. The surfactant does so by the destruction of the lipid layer
of the enveloped viruses like Coronavirus. The general mechanism of this
process is illustrated in Fig. 3. The hydrophobic end of the soap molecule
binds with the outer lipid membrane of the virus. A 20-second wash will break
the membrane leaving only the RNA of the virus and making it ineffective to
cause disease. The germs are also removed by simple mechanical action during
such as ethyl alcohol, isopropyl alcohol, and propanol are commonly used as
antimicrobial agents although several other alcohols can be effectively used . Alcohols are
widely used for surface disinfection, hard-surface as well as skin. Other
antimicrobial agents such as chlorhexidine can be added in small quantities to
the alcohol to boost its antimicrobial activity. Other excipients are also used
with alcohol to decrease the evaporation time of the alcohol . Even though
there is not much known about the working mechanism of the alcohol, it is
believed that alcohol in the combination of water (generally 70% of ethanol in
water (v/v)) causes damage to the membrane and denature the protein which
ultimately causes interferes with metabolism and cell lysis [28,30].
Risks and hazards of soap and
Disturbance to the natural pH and resident
microflora of the skin
The natural pH of
human skin is acidic and it acts as a barrier for pathogenic bacteria. This
barrier is commonly known as the “acid mantle” . The acidic
pH, as well as concomitant pH over the stratum corneum (SC), are beneficial for
a good skin condition, maintaining natural microflora in the skin as well as
for forming an optimal structure of the lipid barrier and SC homeostasis [32–34]. The
acidic pH on the skin surface helps in the growth of resident microflora, the
microbes commonly found in the skin, and checks the growth of transient
microflora which are opportunistic and potentially pathogenic . The example
of resident microflora includes members of Staphylococci, Micrococci,
Coryneforms, and Cropionibacteria while transient microflora includes
Gram-negative bacteria like Escherichia
and Pseudomonas spp., Gram-positive,
coagulase-positive Staphylococcus aureus,
and Candida albicans . The most
common resident coccus is S. epidermidis
which represents more than 80% of the total microflora of the dry body areas
like arms, legs, and lower torso .
Resident microbes have a mutualistic
symbiotic relationship with the skin. The microbes get the right biotope as
well as lipid (sebum), minerals (sweat), and protein (dead skin cell) from the
Microbes in turn strengthen the first line of defense in the skin. The resident
microflora produces beneficial free fatty acid and prevents the colonization of
the skin by harmful microbes from the surrounding area. The normal acidic pH of
the skin is also maintained by the microbes living on it [36,40]. It is
also seen that the antimicrobial effects of antibacterial protein and lipids of
the skin are boosted at an acidic pH which is explained by the fact that
uncharged lipid and cationic peptides interact better with microbial membranes [38,41,42].
Figure 4. Schematic diagram showing the damages
caused by surfactants to the SC and their retention even after wash. The
enlarged figure on the right shows how surfactant molecules (highlighted
with yellow color) are embedded inside the SC .
The soap and soap-based cleansers are
alkaline and they change the natural acidic pH of the skin to alkaline or
higher pH range .
The study indicates the alteration of skin pH is an important factor that
induces skin irritation. Skin irritation caused in adults needs a long recovery
time and frequent exposure to soap affects the appropriate skin repair . However,
researchers argue that the pH changed by the use of soap is restored to a
normal level after a while [37,44].
The restoration time might differ from 2 hours (after 5 minutes wash)  and some even
took several hours (after 2 minutes wash) .
But there is no argument that the use of soap causes a significant change in
the pH of the skin surface.
Dehydration of skin surface
the proper maturation of SC, skin desquamation, and shedding of the outermost
layer of membrane or layer of tissue, the water content of the SC must be
optimal. The increase in transepidermal water loss hampers the functioning of
enzymes responsible for normal desquamation which results in the visible
appearance of dry and flaky skin .
surfactant present in the soap binds to the SC proteins which cause transient
swelling and hyperhydration during the wash. This is followed by evaporation of
the water due to the de-swelling of the proteins . It has been
also studied that during swelling the surfactants and other cleansing agents
penetrate deeper layers and induce biochemical responses like irritation and
itch. The damage processes in the skin have been illustrated in Fig. 4 . The binding
of surfactants compromises the ability of skin protein to bind with water and
retain it. This in turn causes the lower hydration of skin after washing [48, 50].
reduction in water content of the skin causes a change in the skin’s
viscoelasticity which is seen as after-wash-tightness of the skin within
minutes after wash .
Moisturization of the skin is important to maintain an optimal level of
hydration and plasticization since they retain the normal viscoelasticity of
the skin .
Moisturization processes ensure the proper extensibility and flexibility
required for skin movement. Various problems like lack of flexibility, visible
dryness, skin roughness, scaling, and cracking are observed in the absence of
adequate moisturization. To an extreme degree lack of moisturization can even
lead to irritation in the form of erythema and itching . The nature
of the surfactant as well as the cleansing condition determines the extent of
Damage of lipid and protein present on the
Figure 4. Schematic diagram showing the damages
caused by surfactants to the SC and their retention even after wash. The
enlarged figure on the right shows how surfactant molecules (highlighted
with yellow color) are embedded inside the SC.
There are different lipids and
proteins found on the surface of healthy individuals. Lipids like free
sphingoid bases and fatty acids 
and epidermal proteins like cathelicidins, defensins, and dermcidin in the
sweat play an important role in the cutaneous innate immunity [42, 53]. In
addition, peptides present on the skin surface protect against the invasion
of pathogens. Known as antimicrobial peptides, they form a chemical shield
around the surface of the skin and are believed to trigger and coordinate
various components of innate and adaptive immunity [53, 54].
is scientific evidence of the damages caused by the use of surfactant
compositions on human skin. The detergents and other cleansing agents in the
soap have been found to cause damage to the lipid and protein in the human
skin. It was found by the study using Transmission Electron Microscopy (TEM)
that both lipid and protein regions are significantly damaged after washing
with soap. Fig. 5  is a TEM
image exemplifying the damage caused by the surfactant to the skin [25,55].
above their critical micelle concentration (CMC) are capable of solubilizing
lipids of SC and causing delipidation .
Further, the adsorption and intercalation of surfactants into the SC lipid
bilayer also damage the lipid. It results in increased permeability of the skin
membrane and even lipid bi-layer destabilization [56, 57]. The
level of fatty acid and cholesterol in the skin is significantly reduced even
after a single wash if anionic-amphoteric surfactant is used without any
moisturizing agent. Not only might this but the entire lipid biosynthesis
process be altered due to the use of surfactants which will change the level of
various lipids .
In a study to see the effect on the
confirmation of protein by surfactants, the conformation of Bovine Serum
Albumin (BSA) was changed significantly by surfactant. The same study has
correlated the relationship between skin roughness and change in conformation
of BSA .
The damage of skin proteins occurs by the interaction with keratins and their
denaturation. The swelling of the cell membrane and collagen fibre as well as
cytotoxicity expressed with cellular lysis also causes protein damage . The denaturation
of alpha-helical keratin caused by unfolding the coiled polypeptide chain due
to surfactant – SC interaction was suggested in in-vivo experiments too . This
reversible change in conformation of keratin has been linked with
surfactant-induced swelling of various membranes .
4. Safety and sustainable uses
Approaches to Minimize the Damage
the damage due to soap and detergents is prominent, one cannot deny the role
they play in maintaining hygienic and warding off pathogens. Regular use of soap
containing triclocarban was found to reduce the incidence of impetigo among
children by 47% in a study done in Karachi, Pakistan . Another
case-controlled study suggests the decreased risk of illness from Cholera in
the individual who washed hands with soap before a meal .
mitigate the damage to the skin caused by soap, they have been replaced with
synthetic detergent-based bars or liquids known as syndets which are composed
of non-soap synthetic surfactants like fatty acid isethionates and
sulfosuccinic acid esters .
Syndets are mostly neutral or acidic and don't change the pH of the skin after
The syndets were found to show significantly less irritancy than soap bars in
soap chamber tests .
Another attempt to reduce the side
effects of soap is to incorporate glycerol in the soap. However, glycerol
cannot be delivered effectively during the wash and the benefit of glycerol
cannot be exploited in making soap. Even better than the glycerin-based lotion,
oil-based lotions containing mineral oil, petrolatum or lanolin, are skin
A formulation containing polysaccharides from okra (Abelmoschus esculentus) was able to provide adequate hand hygiene
without causing irritation and significant skin drying. The formulation also
maintained skin hydration for the observation period of 210 minutes . It has been
studied those liquid cleansers can be designed in a way to deposit beneficial
lipids such as cholesterol and fatty acids during the wash . It was shown
with an in vivo study where a moisturizing body wash containing 20%
triglyceride oils and 0.5% sterol was able to deposit about 10 μg/cm2 of
triglycerides and 0.6 μg/cm2 of cholesterol on the skin surface during the wash
While using surfactant-containing products it is wiser to choose one with a
nonionic surfactant as it has a less skin-irritating tendency. Therefore, a
cleanser with nonionic surfactants and silicone surfactants is a better
cleanser. Silicone surfactants like dimethicone can penetrate follicles and
remove debris as well as provide an emollient to soften the skin and check
transepidermal water loss .
Additionally, the use of lukewarm
water instead of cold water and properly drying the hand after washing also
helps to mitigate the undesirable effect of soaps. During long work hours,
gloves can be used which limits the need to wash the hand frequently . All these
techniques can be followed to prevent skin drying and irritation from the
frequent use of soap while preventing the infection from COVID and other
Alcohol-Based Gel: An Alternative to
Detergent Based Cleansers
Figure 5. (a) Gross intracellular damage and loss of intracellular lipids
(represented by the arrow) of human skin due to the treatment with soap
bar containing sodium cocoate, sodium tallowate, water, fragrance, and
Sodium chloride; and (b) loss of most of the cell of SC due to the
treatment of human skin with soap bar containing sodium cocoate, sodium
tallowate, water, fragrance and so on .
The alcohol-based gel has been
commonly used as a cleansing material and also as a hand disinfectant.
Different studies suggest alcohol and alcohol-based gel be superior to
detergent-based soaps. Even when used repeatedly the effect on skin by alcohol
was lesser than the effect on skin by detergents . The
alcohol-based disinfectant was found to be better at reducing the number of
bacteria on hand than washing. Even without standardization, disinfection using
alcohol was robust .
They are also regarded as more skin-friendly than detergent-containing products
The alcohol-based gel was able to decrease the pH of the skin to a value where
the pH could be favorable for the initiation of the epidermal barrier recovery
and normal SC integrity. In a study of skin conditions in association with the
use of alcoholic gel, a gel containing high levels of glycerin and ethanol (70%
v/v) was found to be the most preferred formulation .
advantage of using alcohol and alcohol-based disinfectant is that it is quite
effective to control the Coronavirus. Alcohol can be used in disinfecting lipid
enveloped viruses which include Herpes viruses, paramyxoviruses (measles,
mumps), retroviruses (HIV, AIDS), Hepatitis B virus, and Corona Viruses. But it
should be considered that naked virus families i.e., viruses without envelopes
like adeno, parvo, and picorna are resistant to alcohol and common
alcohol-based gel, however, isn’t without limitation. There are some practical
limitations in the use of alcohol and alcohol-based gel as cleansing material
and hand disinfectants. First of all,
alcohol is used more effectively as a disinfectant rather than a cleansing
agent. The antibacterial activity of alcohol is reduced with the presence of
dirt. Same as that of detergents, alcohol-based gel causes dryness and burning
sensation in the skin to some extent due to the presence of short-chain
But the overall irritation and soreness on the skin was found to be lesser in comparison
with handwashing 
and can be a substitute to the detergent-based soap whenever available.