The Science of Beauty

What is beauty?

• Beauty is both ingrained in us and subjective. We find features such as symmetry, youth, and happy-looking features as universally attractive. We can also be influenced by cultural norms, media representations, and individual tastes. The "average face" experiment shows that the resulting face is very attractive to individuals, due to their familiarity. This could be explained by koinophilia.
• Fashion can change from year to year and pale skin is prized in one area of the world and tanned skin in another. Effects of globalisation and colonisation has spread European beauty standards around the world, with the perpetuation of harmful standards in many societies.
• The beauty industry plays a large role in our lives, many having health and hygienic purposes and not just an aesthetic role. It allows for self-expression, and boosts confidence and well-being. Financially, studies show attractive people are better off financially than their other counterparts. However, the beauty industry can also have a large role in perpetuating harmful beauty standards, with product marketing amplifying people's insecurities.

Are beauty products harmful?

• These days, in areas with strict regulations like the US and Europe, companies have a legal obligation to demonstrate the safety of their products and it is illegal for them to sell harmful products. Cosmetic products are tested in the same way in terms of toxicology to foods and medications. To work out the risk of a product, scientists have to value the hazard and exposure. The amount of the ingredient is particularly important, for examples there can be traces of heavy metal present that aren't a concern.
• The hazard an ingredient can cause can be from short-term allergic reactions to long-term effects like cancer. A hazard assessment considers:
  • Tests on chemicals, cells, or tissue
  • Tests on animals
  • Computer models
  • Clinical studies from human volunteers
  • Epidemiological studies that look at effects on populations
  • Case reports of people being harmed by the ingredient
  • Data on a similar ingredient that can be extrapolated
• Exposure is how the ingredient can be exposed to the consumer:
  • How much of the product is used
  • The ingredient's properties
  • How it's used in products
  • Total exposure if the ingredient is in multiple products
  • Foreseeable misuse
• Margin of safety of at least a 100 is factored in the testing system, the ratio of a NOAEL (No Observed Adverse Effect Level) and Systemic Exposure Dose.

Are natural beauty products better or safer?

• Technically, everything originated from Earth, so all ingredients are natural. Any substance found in nature can theoretically be synthesised in the lab and the molecule from a natural source is not different from a synthetic source. There are some advantages of synthetic products, for example the reduced cost, environmental depletion, and control of contaminants. Being natural doesn't mean something is safer, for example in the past natural ingredients were present in beauty products such as lead, asbestos, and mould.
• Natural are not more effective - there is no evolutionary pressure for plants to benefit humans. It's largely luck when ingredients are positive in humans. Conversely, synthetic products can be customised to improve their properties, can be produced in a uniform fashion, and far more predictable. An example of this is squalene (natural) and squalane (synthetic).

Are cosmetic ingredients dangerous?

• Many ingredients have been villainised by the media, coming from studies which have weak links or are tested with higher amounts in orders of magnitude. They have been removed from products rather than legitimate safety issue, and have been replaced with an ingredients with less studies and greater health risks. For example, "free from parabens" is a popular claim, evidence being from a weak 2004 study and its estrogenic activity. In 2021, EU safety asessors found that using using 17 products daily with a maximum amount of propylparaben would only expose you 0.008% of the minimum safety limit. Many preservatives that replaced parabens are less effective, with The American Contact Dermatitis Society calling parabens the "non allergen of the year."
• Other demonised ingredients are fragrances and phthalates. Fragrances are secretive but must follow the guidelines set by the International Fragrance Association which regulations are reviewed by independent scientists. Phthalates which are used to make plastics more flexible, where 10 of them are used in consumer products. Diethyl phthalate is the only phthalate widely found in cosmetic products due to a large body of evidence confirming its safety.

Are expensive products better?

• Some factors in production do make products more expensive. These can include more extensive product testing, formula optimisation, higher-quality ingredients, and delivery systems. Many effective ingredients are inexpensive, while expensive and ineffective ingredients such as botanical extracts or diamond can push up the price. Others include marketing costs, especially a celebrity endorsement, operational costs, retail mark-ups, and seller commissions. A retail mark-up price is always above the cost price, however the competition and consumer perception determines the exact mark-up. Typically, 15% of what you pay go into the developing and manufacturing of a product, while the 85% represent profits and operating costs for the companies along the way.

What is an active ingredient?

• An active ingredient is an ingredient that helps a product achieve its main function. In skincare this is something that is intended to produce a longer-lasting effect, but is affected by many environmental factors. The inactive ingredients improve the product's texture, stability, and preservation.

What do marketing buzzwords mean?

• Hypoallergenic - theoretically designed to reduce the chance of allergic reactions and tested on sensitive skin types. But many hypoallergenic products just avoid using common allergens.
• Salon strength - similar to "clinical strength" and "professional strength," is meant to suggest a stronger product than usual but isn't always the case.
• Chemical free - since everything is made from chemicals, this is meaningless.
• Cosmeceutical - products like this claim to have a "pharmaceutical" effect on top of a "cosmetic" one. A marketing term for products that are legally cosmetics.
• Noncomedogenic - these products in theory won't block pores and cause pimples. Most of the time however they avoid ingredients that cause clogged pores.
• Dermatologically tested - this implies that this product was tested on human skin, although not specifically under the supervision of a dermatologist.
• Fragrance free - this product does not have the "fragrance" in its ingredients list, but may still include ingredients with a pleasant scent.
• Unscented - products with no smell, but could include fragrances.

Can I trust the research in beauty marketing?

• Cosmetic products in most regions can only make claims about changing the appearance of the body and not its structure or function. This is why there are qualifiers added to claims in products, such as "reduces the appearance of pigmentation" instead of a therapeutic (drug) claim "fades pigmentation." Some claims are made based on directly testing the product, others just on the ingredients it contains. For many claims, in vivo clinical testing is the most reliable, but it may not reflect actual use. "Clinically proven" is an unregulated term, so there is no guarantee of rigorous testing. Consumer perception tests may be necessary to avoid illegal drug claims, but may also be inaccurate and subjective.

What do beauty product labels tell us?

• Ingredients that are listed in descending order by weight, starting at those with higher concentrations. It does not tell you how they made their product or how well it works.

Can beauty products be sustainable?

• Natural ingredients is often viewed as less harmful than synthetic ones. However, some claims are inaccurate. At the end-of-life cycle for example, zinc oxide is toxic for aquatic wildlife compared to chemical sunscreen. Exploitation of wild ingredients can reduce natural resources, for example sandalwood oil has endangered wild trees and liquorice contributes to desertification.
• Plastic is viewed as more environmentally damaging, but it depends on the context. Newly made plastic is often used from byproducts of fuel production, where paper requires wood, and aluminium and glass requires more heat. While aluminium can be recycled more times and paper is biodegradable, often paper is lined with plastic to make it waterproof that makes it more difficult to recycle than a mono-material plastic. Plastic is more durable and lightweight to transport, while glass can be broken and aluminium can be dented easily.
• Things we can do to be more sustainable is consume less, ask brands for evidence, and recycle thoughtfully.

Are my beauty products cruelty free?

• Cruelty free means usually that the product has not been tested on live animals. The reason why we test on animals is because humans share similar biological processes to other animals. Alternatives to animal testing include inherent properties of chemicals, in-vitro tests, artificial tissues, organ chips, clinical studies, existing data, and computer models. "Cruelty free" has no universally accepted definition, with regulators having the right to test products on animals for market safety. Cruelty free does not automatically mean vegan, as animal derived products can be present in the product.

Pregnancy stuff

What is skin?

• Skin is a barrier between us and the external world. We use it for protection, communication, and response to our environment. It is made up of 3 parts, the epidermis, dermis, and hypodermis. The topmost layer of the epidermis is made up of the stratum corneum, a layer of waterproof dead skin cells surrounded by lipids, and where melanin pigment and vitamin D is produced. It is usually 15 cell layers deep and shed one layer of these cells a day. The bottom of the epidermis contain adult stem cells, which produce keratinocyte cells that push up and form the stratum corneum. Along the way the flatten out, die, lose water, and replace the layers that are shed. The dermis gives skin its elasticity, strength, and flexibility. Blood vessels in the dermis transport nutrients, dilate or contract due to heat, and contribute to skin colour. Nerve endings sense pain, touch, and temperature. Hair follicles originate in the dermis and open the skin to form pores, and sebaceous glands inside hair follicles lubricate the skin. Below the dermis is the hypodermis that contains fat and connective tissue. It absorbs shock, stores energy, and provides thermal insulation.

Why do we even need skincare?

• Skin has evolved to take care of itself, but our environments have changed. Factors such as temperature, hormones, humidity, sun exposure, grooming habits, and skincare have disrupted its function. Experts agree that most people use a cleanser, moisturiser, and sunscreen regardless of their gender or skin type. Skin is translucent, therefore smoothing, hydrating, and compacting the outer layers leads to more reflected light, making skin appear more radiant. Cleansers remove unwanted substances from the skin, including dead cells, sweat, and sebum, which can contribute to clogged pores. Moisturisers make up for the lack of oil or water in the stratum corneum and can help its ability to act as a barrier.

How do I choose a cleanser?

• Many substances that can impair the function of skin are oily, so water alone will not be able to remove them. Cleansers contain surfactants that bind to oil and are able to be washed away. Surfactants are categorised in 3 types, anionic (negatively charged heads), amphoteric (positive and negative charged heads), and nonionic (uncharged heads). Most cleansers contain all 3 types, with a focus on amphoteric and nonionic surfactants to reduce irritation.
• Surfactants are necessary but can also remove the skin's natural proteins and lipids, and also stay attached to the skin after rinsing. This disturbs the barrier, causing dryness and irritation. This is why gentle cleansers are important, ingredients such as multiple surfactants, polymers, moisturising agents, and soothing agents. Cleansers with a slightly acidic pH of 4-6 are helpful for acne-prone and sensitive skin as it helps support a healthy skin biome.

Do i need to moisturise?

• 3 major ingredients are in moisturisers to help moisturise skin. These are occlusives, humectants, and emollients. Occlusives form a water-resistant layer on top of skin to prevent natural evaporation of water from skin, humectants bind to water to slow its evaporation, and emollients are oily ingredients that make the skin look smoother and more lubricated. Dry skin benefits from all 3 moisturiser categories.

What happens to skin as we age?

• Baby skin is thinner, so it is more prone to irritation. Some studies indicate cells are more vulnerable to UV during childhood, so excessive sun exposure can magnify melanoma risk. During puberty, testosterone causes a surge in sebum which causes acne and dandruff, as well as through the menstrual cycle. Internal and external factors affect our skin in adulthood. From age 25, the skin's renewal and maintenance process starts to slow down, exposed areas are more prone to damage through sunlight, smoking, and pollution. All layers of the skin become thin, becoming less elastic and more fragile. Pigment changes are more common in East Asian skin until 40, followed by accelerated wrinkling. In White skin wrinkles tend to occur earlier. Darker skin can become ashy.

Should I change my skincare routine?

• Skin loses water more quickly when it's dry and windy, as well as in artificial heat and long hot showers.

Is face wash better than bar soap?

• Soaps contain surfactants that are made by reacting naturally occurring fats and oils with alkalis like lye or caustic potash. They do not work in hard and acidic water and have narrow structures that can cause irritation. Liquid cleansers have synthetic detergents that work at a lower pH and have bulkier structures that lead to less barrier disturbance.

Do I need to exfoliate?

• Exfoliants should be used gradually, as overuse can thin the stratum corneum. Using 5% alpha hydroxy acid or 2% salicyclic acid twice a week is a good starting point.

What difference does a good night's sleep make?

• Sleep is part of good health, and studies show that you can appear less healthy and energetic with depravation. Skin can functions better with adequate sleep, the skin barrier is more resilient, recovers faster, improves skin hydration, pores look smaller, and there are subtle changes in skin colour. Skin looks plumper and brighter in the morning, as dermal fluid moves towards your face when sleeping horizontally.