Skin Cleansing Methods and History

Skin Cleansing

• October 15 is Global Handwashing Day
• Handwashing with soap and water is recommended
• Skin cleansers are used to remove dirt, makeup, environmental pollution, germs, and other types of soil on the skin.
• Examples of skin cleansers include facial cleansers, bath and shower products, and hand sanitizers.

History of Skin Cleansing

• Salt (Chinese, Egyptians, Greeks) were used for cleansing.
• Soap manufacture began in ancient Babylon (2800 BC) by boiling fats with ashes and water.
• Greeks used strigils to scrape off dirt, oil, and also used clay and sand.
• Romans lived in water-rich areas and developed aqueducts to provide clean water. Bathing became popular.
• Ancient Roman legend claims soap originated from Mount Sapo (Rome) where burnt animals were sacrificed, rainwater washed down a mixture of animal fat and wood ashes into clay soil along the Tiber river. Women discovered that this mixture made cleaning easier.
• After the fall of Rome, bathing declined, sanitary conditions decreased, and hygiene related diseases (including the Black Death of the 14th century and the Plague) resulted in massive deaths (75 to 200 million people in Europe, from 1347 to 1351). Personal cleanliness returned in the 17th century.

Ancient Roman Legend

• Soap's name originated from Mount Sapo (Rome)
• Burnt animal sacrifice took place there.
• Rain washed animal fat and wood ashes into clay along the Tiber River.
• Women found this clay mixture cleaned more efficiently.

After the Fall of Rome

• Bathing declined
• Poor sanitary conditions led to hygiene-related diseases.
• The Black Death (14th century) and the Plague caused millions of deaths (75 to 200 million people in Europe, from 1347 to 1351).
• Personal cleanliness became popular again in the 17th century.

Medieval Times

• Soaps in Northern Europe were made from wood-ash lyes on animal fats and fish-oils.
• They were soft soaps with unpleasant odors.
• Used for cleaning textiles and clothes.
• Hard soap use was not common in Europe before the middle of the eighteenth century and there's no clear description of medieval soap-making techniques.
• Syria was known for its hard soap, pleasant for toilet use
• Soap-making dated back to the 8th century in Syria.
• Geographers in the 10th century reported that Nabulus in Palestine was a prominent exporter of soap.
• Fez, (in 1200 AD) alone had 27 soap manufacturers.
• Hard soap was imported by Europe from the Arab lands of the Mediterranean by way of Italy in the 13th century.
• Earliest surviving European account of soap-making dates to 1547.
• An earlier detailed description of soap making, from the 13th century, was discovered in the work of Al-Antaki.

Hand Sanitizers

• Public belief is that sanitizers replace hand washing, but CDC recommends use only as an adjunct to soap and water.
• Concerns about hand sanitizers as part of infection control arose in the mid-1800s.
• Prof. Ignaz Semmelweis, a Hungarian obstetrician who saved many lives through simple handwashing in a chlorine solution, before examining women.

Skin Cleansers

• Remove dirt, makeup, environmental pollution, and germs.
• Dirt is stuck to skin by sebum.
• Skin scales that are loose also contribute dirt.
• Dust settles on skin.
• Soot comes from smoke.
• Salt and urea are left on skin after sweat evaporates.
• Skin contains bacteria to make it sticky.
• Cosmetics and makeup residues.
• Other substances carried in the air, varying by geographical location and environment.

Removal of Grease From The Skin

• Emulsify grease with soap or surfactant.
• Example products include shower gels, shampoos, and cleansing lotions.
• Dissolve grease with more oil, with a cleansing cream or body oil for example.
• Absorb grease with an absorbent material, like kaolin used in some facial masks.

Soap as a Cleanser

• Soap is made by reacting animal and vegetable fats and oils with alkali.
• Hard soap is comprised of Sodium salt of fatty acids.
• Soft soap (also known as liquid soap) is composed of Potassium salts of fatty acids.
• Sodium stearate is an example of a hard soap.
• Soap's name originated from Roman Legend.

Synthesis of Soap

• Glycerol tristearate (Fat) + Sodium hydroxide (Alkali) → Sodium stearate (soap) + Glycerol

How Does Soap Work?

• Soap particles "coat" fat droplets which are embedded in dirt.
• The dirt is allowed to be washed off.

Disadvantages of Regular Soap

• In hard water (tap water contains calcium and magnesium), soap forms an insoluble scum.
• The scum sticks to the skin, causing irritation.
• The salts of fatty acids formed from soap + hard water are insoluble and cause skin irritation, leading to stickiness.
• Soap as a salt from weak acid and strong alkali has a high pH(9-10) which is higher than skin pH (4-6.5), can cause irritation.

Surfactants as Cleaners

• Water is not effective for cleaning greasy surfaces because water is repelled from them.
• Surfactants are molecules composed of two parts, with part of the molecule soluble in water and the other in grease, to spread over greasy surfaces and wet them.
• Cosmetics and toiletries use surfactants for detergency, foaming, conditioning, solubilization, and emulsification.
• The selection of a surfactant for cosmetics considers intended functions (detergency, emulsification, foam quality, skin gentleness)

Synthetic Soaps (Soapless Soap)

• Composed of surfactants (surface-active agents), in solid or liquid forms.
• Four categories of surfactants: anionic, cationic, nonionic, and amphoteric.
• Sodium salts of fatty acids are anionic surfactants.

Detergents

• Agents to remove dirt.
• Come in various forms (mild, strong, ionic, non-ionic) depending on the type of dirt and surface.
• Essential properties of a detergent include wetting the surface, displacing dirt from a surface, and solubilizing the dirt in solution.
• Detergents are critical for cleaning greasy surfaces when water on its own is ineffective.

Cleansing action of a detergent

• Wetting: Detergent reduces water's surface tension to spread over and wet greasy surfaces.
• Emulsification: Detergents embed their hydrophobic tails in grease, forming droplets. Rinsing removes the emulsified grease and loosened dirt, leaving surfaces clean.
• The emulsification of the grease is helped by warm water to melt the grease and help form droplets and by agitation to move away the droplets.

Surfactant Classes

• Anionic: sulfates, phosphates, carboxylates
• Cationic: quaternary ammonium salts
• Zwitterionic/amphoteric: Amino propionates, glycinates
• Nonionic: ethoxylates

Anionic Surfactants

• Sodium lauryl sulfate (C12)
• Sodium C12-15 Pareth-15-sulfonate

Cationic Surfactants

• Hexadecyl(cetyl) trimethyl ammonium bromide

Amphoteric Surfactants

• Cocoamphoglycinate

Betaines

• Coco-betaine, N-coco-N-dimethyl glycine, used in baby shampoo and to improve lather and viscosity in other shampoos.

Nonionic Surfactants

• Sorbitan esters: Tweens, Spans

Functions of Surfactants in Cosmetics

• Detergency
• Foaming
• Conditioning
• Solubilization
• Emulsification

Functions of Anionic, Amphoteric, Nonionic, and Cationic Surfactants

• Anionic surfactants are commonly chosen for detergency.
• Amphoteric surfactants are milder than anionic surfactants, suitable for mild cleansing.
• Nonionic surfactants have poor foaming abilities but are excellent solubilizers.
• Cationic surfactants tend to be irritating at low levels but are often used as hair and textile conditioners due to their positive charge.

Surfactant Uses

• Kitchen detergents
• Shampoos
• Bath and shower cleansers
• Facial cleansers

Dove Soap

• Dove soap is a synthetic surfactant bar, not an actual soap.

Advantages of Synthetic Soap (Surfactants)

• Usually cause less skin irritation.
• The pH can be adjusted to that of normal skin.

Lather and Foam

• Lather plays little or no part in cleansing.
• High-lather detergents are not ideal for floor washing or automatic washing machines.

Lather and Foam: Useful Purposes

• Indicator of remaining detergent activity.
• Foam holds the cleanser on the face or hair during cleaning.
• Psychological indicator of cleaning power

Other Ingredients in Soaps and Cleansers

• Moisturizers
• Preservatives
• Coloring agents
• Fragrances
• Antibacterial substances
• Substances that alter pH (e.g., citric acid)

Moisturizers

• Soaps and cleansers tend to dry out the skin.
• Therefore, moisturizing agents such as glycerin, lanolin, and vegetable fats are added to counteract this effect.

Hints when using soap

• If you have dry skin, it is best to use soaps with moisturizing agents.
• Use lotions or creams after washing.

Soap for Oily Skin

• Soaps for oily skin have either minimal amounts or no moisturizing agents.
• People with acne should not use moisturizing soaps since it may lead to other skin reactions.

Transparent Soap

• Contains a higher concentration of glycerin.
• The high glycerin content gives the soap its transparency appearance.
• Considered as mild soap.

Antibacterial Substances

• Some antibacterial soaps contain antibacterial substances such as triclosan.
• Some antibacterial substances remain on the skin after washing, helping inhibit the growth of bacteria.
• Prevent body odor and are used in acne-treatment.
• Used for follicle infections and after exposure to dirt/contamination.

Other Ingredients in Soap

• Vitamins and other natural ingredients are added to soaps but typically have no documented medical value, and are quickly washed away.

Mild/Hypoallergenic Soap

• Used for individuals with sensitive skin, especially infants.
• Generally contains no fragrances and coloring agents.
• Contain surfactants from the betaines group (amphoteric) which are relatively mild and do not sting the eyes or skin.

Soaps Versus Soapless Cleansers

• Behavior in hard water: Soap fails to form lather and produces a sticky scum in hard water, whereas soapless detergents form lather and do not produce scum.
• pH: Soapless cleansers have a pH that is adjusted to that of normal skin which causes less irritation compared to regular soaps.

Lotions and Liquid Preparations for Facial Cleansing

• Often oil-in-water emulsions: oils are dispersed in water in the form of droplets
• Effective in removing makeup.
• Suitable for people with dry skin since they contain oils.
• Should be removed quickly to prevent skin irritation.

Abrasive Cleansers (Scrubs)

• Use creams or emulsions containing tiny granules for cleaning.
• Helps remove the outermost skin layer
• Not suitable for healthy skin, as it could cause damage to the skin.
• Not to be used more than once a week.

Solutions of Surfactants in Water

• No oil phase, suitable for oily skin.
• Typical formulation contains 5% surfactants, 93% water, and traces of perfume, color, and preservatives.

Ingredients Causing Safety Concerns: Parabens

• The use of paraben mixtures: lower individual levels and higher preservative efficacy.
• Initial CIR review in 1984 indicated parabens were safe at levels up to 25%. Commonly used in concentrations much lower than 1%.
• Early 21st century re-examination linked parabens to breast cancer based on animal experiments, but this was deemed inconclusive, with limitations by most cancer research organizations.
• Studies showed the potency of butyl paraben, the most potent, is 10,000 to 100,000 times weaker than naturally-produced estrogen.
• In 2006, the CIR concluded that no change was needed to their 1984 conclusion regarding paraben safety.
• The European Commission's Scientific Committee on Consumer Safety (SCCS) in 2011 found methylparaben and ethyl paraben safe at current usage levels, and recommended levels of propylparaben and butylparaben be reduced to less than 0.19%.
• Denmark banned propylparaben and butylparaben in cosmetic products aimed at children under 3 in 2011, and later extended the ban to cover leave-on products for children under 6 in nappies.

Ingredients Causing Safety Concerns: Triclosan

• Antibacterial agent found in cleaning, deodorant, and toothpaste products.
• Clinical benefits not definitively proven for use in patients
• Studies indicate no added benefit of triclosan compared to non-antibacterial hand soaps in reducing bacterial counts.
• Differences (in bacterial reduction) were only seen with longer wash times and higher triclosan concentrations
• Possible harm from contributing to antimicrobial resistance, in addition to high healthcare costs.
• The FDA has reevaluated triclosan's safety and efficacy in antibacterial cleansing products.

Ingredients Causing Safety Concerns: SLS

• Sodium lauryl sulfate (SLS).
• Potential for skin irritation, particularly in leave-on products.
• May cause dermatitis and irritate the mucous membranes.
• Used as a positive control in studies to measure chemical/irritant potential.
• High concentrations, or prolonged exposure on skin, can cause damage and hair loss.
• SLS is relatively safe for short periods and thorough rinsing, but concentrations in leave-on products should be limited to 1%.

Ingredients Causing Concerns: Microbeads

• Tiny particles, either natural or synthetic (plastic).
• Plastic beads pose a threat to the environment.
• Beads can travel through wastewater to end up in oceans.

Other Ingredients in Cosmetics

• Databases for searching cosmetics ingredients include those from the European Commission and in-cosmetics.

Test your knowledge on the methods and history of skin cleansing practices, including the role of soap, surfactants, and the impact of historical events on bathing. Explore the recommendations from health organizations and ancient practices related to hygiene. This quiz covers essential aspects of skin care and cleanliness.