True to its name, an oil cleanser cleanses dirt off your face with the help of oil. It's based on the rule of thumb, “Like dissolves like.” These cleansers dissolve excess sebum and products containing oil, resulting in a balanced, clear complexion.

Sebum is an oily substance produced by the body’s sebaceous glands, through holocrine secretion. Holocrine secretion is a mode of programmed cell death, contributing to the homeostasis of the skin barrier [1]. Human sebum consists of squalene, esters of glycerol, wax and cholesterol, as well as free cholesterol and fatty acids [2] It forms a protective layer on the skin’s surface and prevents pathogens from entering. Sebum production depends upon hormones, medication, and lifestyle. Oil-based makeup can give the skin a gorgeous glow but improper cleansing, like excess sebum, can lead to clogged pores, such as blackheads and pimples. 

Water-based cleansers contain a large concentration of water to cleanse water-soluble impurities like dust and sweat. They’re most commonly found as foam cleansers, which use a surfactant. Surfactants, or surface active agents, lower the surface tension between two fluids. Water-based cleansers, unfortunately, have pros and cons.

Lily Talakoub, M.D., told Sunday Edit “Water-soluble particles, such as dirt and pollution, emulsify in the lather of the surfactant and rinse off the skin,” She further adds, “This, however, also rinses away the natural oils, so water-based cleansers are better for oily or acne-prone skin types.” [3].

Emulsification is defined as a process of dispersing one liquid (in this case, the water-based cleanser) in a second immiscible liquid (impurities in the skin), by applying electrostatic, or hydrophobic, or hydrogen bonding interactions between the bioactive compounds and an encapsulating material [4]. 

Exfoliating is the process of removing dead skin cells from the surface of your skin using a chemical, granular substance, or exfoliation tool [5]. Humans lose 200,000,000 skin cells every hour. During a 24-hour period, a person loses almost five thousand million skin cells [6]. The build-up of dead skin cells that haven't shed completely can lead to dry patches and clogged pores. 

Physical exfoliation can be done with a variety of abrasive products, namely brushes and sponges, and scrubs. Chemical exfoliation involves alpha hydroxy acids and beta hydroxy acids, that break the keratin linking dead skin cells together. 

It’s important to note that exfoliation must not be done daily. The American Academy of Dermatology recommends figuring out a schedule based on your skin type and exfoliation method. Aggressive exfoliation must be repeated less often. Over-exfoliating can cause more harm than good, causing micro-tears in the skin, that leave it red and irritated [7].

Serums are oil or water-based concentrated liquids that are easily absorbed by the skin. While hydrating in nature, serums are designed to target common skin issues, like dark spots, wrinkles, and inflammation. “A skin serum is not a moisturizer, like a lotion or cream,” quotes Dr Abigail Waldman, instructor of dermatology at Harvard Medical School [8]. There are specific compositions of serums for different issues, vitamin C reverses damage from UV rays and stimulates collagen growth. Retinol, a form of vitamin A, and niacinamide, a form of vitamin B3, reduce inflammation by neutralizing free radicals. 

The eyes are the window to the soul, which makes it especially important to take good care of them. The skin around the eye lacks oil glands and collagen compared to the rest of the body which makes it susceptible to fine lines and dehydration [9]. Eye creams are specifically designed with lower concentrations of retinol in an emollient base to suit the delicate eyelid skin [10]. Caffeine, due to its vasoconstrictive properties, and vitamin K, which increases blood coagulation, and reduces the depth of wrinkles and dark circles [9]. 

A good moisturizer is the holy grail of a skincare routine. Moisturizers are proven to increase the water content in the stratum corneum, battling dryness [11]. Hyaluronic acid, vitamin E, and vitamin C are popular ingredients for moisturizers given their lubricant and moisture-retaining properties. 

The Earth’s average distance to the Sun is around 150 million kilometres [12], but that does not mean sun exposure isn’t a cause for concern. Ultraviolet (UV) rays cause damage to the skin, eyes, and immune system by initiating a reaction between two molecules of thymine, a base constituting DNA [13]. Sunscreen must be broad spectrum, that is, protects against UVA and UVB rays, with a minimum sun protection factor (SPF) of 30, and is ideally water resistant. Dr Anna Lien-Lun Chien, M.D. suggests applying sunscreen 15 minutes before going outside and reapplying every two hours [14].