What Our Skin Absorbs: Pros and Cons of Penetration Enhancers

As we all know, ingredients in our skincare products are of utmost importance. They directly affect our skin condition – and in general, our health. Most of us pay close attention to the different types of ingredients we apply on our skin. However, here is the big question as we apply layer after layer of product…

What actually gets absorbed among all those products?

Not all of the substances found in skincare products are absorbed by the skin. The skin has three main layers – the outer layer (epidermis) and lower layers (dermis and the hypodermis). The epidermis acts as a protective barrier against foreign substances, preventing dirt from entering the skin.

Due to the complex skin structure, your skin does not absorb everything you apply to it. This is where what we call “penetration enhancers” come into play.

But what exactly are they?

Penetration enhancers are chemicals that help the skin absorb substances. This can happen in two different ways. One, these agents bring the substances directly through the skin cells. Or two, they transport the substances between the cells.

Other drug delivery routes through the skin are through hair follicles, sebaceous glands and sweat glands. These can be advantageous, especially when they are non-toxic, non-irritating and non-allergic. Such methods often work quickly and have a predictable duration of action. Additionally, after the agents are removed from the skin, its protective properties return.

How do they work?

A penetration enhancer interrupts the structure of various skin layers. This occurs when they interact with proteins dilating the space between cells. The uppermost skin layer (the horny layer) makes up the first barrier. It protects the skin, blood vessels and organs.

Many popular salon treatments strip the first layer. Skincare scientists, dermatologists and aestheticians use a variety of methods. The horny level is removed by using methods such as chemical peels, microdermabrasion,, and adhesive tapes. This would then enhance the absorption rate of the skin.

There are also chemicals that have similar properties to an absorption enhancer. Some of these are added to skincare products, and can disrupt your skin. What seems harmless is often drying for the skin and worst, carcinogenic.


Why use penetration enhancers in skincare?

These skin layers prevent many substances from penetrating deeper into the skin. Penetration enhancers help a product or ingredient do more than rest on the skin surface.

Often, certain ingredients have to penetrate the lower skin layers. This is so that the skin can benefit from the skincare product.

Humectants, for example, are substances that reduce the loss of moisture, as in lotions. Those that penetrate the skin deeper moisturizes the skin better and keep it hydrated longer.

Are penetration enhancers present in my skincare products?

Chances are, yes. The effectiveness of topical skincare relies on several things. These include how much of the ingredient the skin maintains, and how much the specific target tissues absorb the beauty-enhancing qualities. The problem lies in the kinds of chemicals (synthetic or organic) used to quicken it.

Today, nearly all skincare products contain a formulation that includes these enhancers. Companies want their skincare product to perform faster. But, they also want to give a financial advantage to the manufacturer and reduce their manufacturing expenses. To meet these requirements, some companies have taken some chemical shortcuts to solve their problems.

What are the side effects of penetration enhancers?

Penetration enhancers make it easier for substances to pass through the skin by using chemicals. These chemicals are expected to be inactive and safe, and are common in topical preparations. In spite of this, penetration enhancers are linked to a high rate of dose-dependent side effects. These range from local irritation to systemic reactions upon acute or chronic use. The toxicological aspects can take many forms, such as skin irritation.

The toxicological aspects of penetration enhancers can take many forms, such as skin irritation.

Common harmful skincare ingredients

Daily exposure to harmful skincare ingredients is well-hidden under different, seemingly harmless names. The most basic of our skincare products may contain harmful chemicals. Therefore, in skincare products, one of the most crucial things to consider is the ingredient list.

Scroll down to find some of the most common harmful skincare ingredients found in our daily skincare products:


Parabens are common chemical preservatives in the beauty industry as they are cheap but effective. However, parabens can be a possible carcinogen. Research shows that parabens mimic a hormone called estrogen, which is thought to cause breast cancer. When absorbed moderately, it is possible that parabens could also cause breast cancer.

Furthermore, parabens remain in the blood when absorbed. It is present in many commercial skincare products. But the cumulative effect could be toxic in the long run.

The chemical has indeed been associated with negative effects. But, parabens have been declared safe for human use. They are also still widely used in the skincare market.

Look out for ingredient names that end with “-paraben”, “methyl-“, “ethyl-“.


Formaldehyde is a known carcinogen. However, it is found in cosmetics and skincare products as a preservative. Although used at very low levels, this ingredient can lead to harmful effects. It has been linked to skin and pancreatic cancer, as well as a possible cause of leukaemia.

The harmful ingredient is also a common skin irritant. It can cause eye irritation in children and scalp burns. Other discomforts include aggravating the skin and irritating the eyes and nose.

However, formaldehyde is generally believed to be harmless when used in minimal amounts. Hence, it remains as a cheaper choice for manufacturers looking for effective preservatives.

Look out for: Formaldehyde, formalin, bromopol, or glyoxal.

Sodium dodecyl sulfate

This ingredient is mostly used in soaps and shampoos. It is the agent that creates the luxurious fluff we love. Sodium Dodecyl Sulfate, also known as Sodium Laureth Sulfate (SLS), acts as a surfactant. This means that it traps dirt and makes it easy to rinse off. This produces a rich lather while giving off a fresh and clean feeling when used.

Ironically, this cosmetic ingredient is a known skin and eye irritant. SLS can cause dry and flaking skin, allergies and redness. It is a harsh detergent that removes the natural oils from your skin when used. Some of the consequences are dermatitis, dandruff and other skin issues. Especially for people with sensitive skin, the effects of SLS can be detrimental.

Although there is little evidence, SLS may have possible links to cancer. This is due to its potential to create a carcinogen called nitrosamines. When mixed with another chemical called triethanolamine, it forms the toxic substance as it metabolizes.

Look out for: SLS, Sodium Laureth Sulfate, Sodium lauryl sulfate, Sodium dodecyl sulfate


Manufacturers often use alcohol as a solvent to mix different ingredients together. It ensures a smooth finish to the product. It’s low evaporation point also makes it useful in certain cosmetics that require drying fast. Alcohol can also act as a penetration enhancer as it helps to increase the skin’s absorption rate.

Fret not, not all alcohols are harmful. The ones in question are what we call “drying” alcohols. Prolonged usage of such alcohols leaves the skin dry and flaky as it eats away at the skin surface. This causes unnecessary stress on the skin surface, eventually interrupting the skin’s renewal cycle. It may also result in an extremely unhealthy skin condition.

People with an oily skin condition, however, might be tempted to use alcohol-based products. Many feel that alcohol help control oil levels of the skin and prevent pimples from forming. Alcohol-based products also tend to have a clean and cooling feeling when used. This gives the impression of de-greasing. Unfortunately, alcohol actually makes the oil production of the skin increase. Expect oilier, shiny skin that is prone to breakouts to eventually become dull and marked with blemishes. Blemishes would also increase due to the damage incurred by the effects alcohol on a cellular level.

Look out for: Ethanol, SD alcohol, Methanol, Denatured alcohol, Ethyl Alcohol


The scent makes for an attractive product, especially for skincare since they are applied to the face. Often, manufacturers add artificial fragrances to mask unpleasant smells due to the mixture of different ingredients. While this sounds harmless, most fragrances are chemicals and may have toxic effects on the body.

The ingredients of most scents include petroleum- or coal-derived chemicals. These are known skin and nose irritants. Fragrances can also be dangerous for people with respiratory issues. It might cause an allergic reaction when used.

Natural scents can be used to replace artificial fragrances as a healthier choice. But many manufacturers go back to artificial fragrances because it is a lot cheaper than extracting natural scents. In fact, many fragrances labelled as “natural” might not actually be natural.

Look out for: Fragrance, perfume, parfum, aroma.


While refined petrolatum is approved for human usage, petrolatum is actually a potentially harmful skincare product. There are risks of contamination when using this ingredient. This is due to the large number of cheap imitations and mass productions, leading to adverse results.

Moisturizing products such as lip balms and moisturizers contain petrolatum. , However, they do not have moisturizing properties. Instead, it creates a barrier that retains moisture. At the same time, it also prevents absorption of external moisture. This causes the skin to suffocate and eventually dry out.

Petrolatum-based products are fast-acting, giving quick but temporary results. This ingredient gives the temporary illusion that the skin is soft and hydrated.

Look out for: Mineral oil, Paraffin wax, Benzene, names that end with ‘-eth’.

Coal tar

The chances are, the more vibrant your lipstick colour is, the more chemicals are present in it. Coal tar can make artificial colours. They make up the many shades of lipsticks and eyeshadows available in the market.

Studies have shown that coal tar is a carcinogen. Manufacturers use minimal amounts in cosmetics so it is “safe” for human usage. However, there has never been a study done on the long-term external use of the harmful skincare ingredient.

Coal tar is also an extremely heavy substance and weighs down the skin. This causes skin irritation, resulting in acne and allergic breakouts.

The constant demand for a newer range of colours compels manufacturers to use this ingredient. Coal tar provides the base for vibrant and brighter colours to meet this demand.

Look out for: FD&C or D&C, chemical colours ( BLUE 1, GREEN 3, etc.).


This is a sneaky harmful ingredient because it hides behind its benefits. Hydroquinone, found commonly in lightening products, promises to lighten dark and stubborn blemishes on the skin. Hydroquinone uses a harmful manner to achieve the desired results by reducing the skin pigment, melanin, in the skin. By reducing melanin, it can cause a temporary whitening of the skin because of the lack of pigment cells. Over time, however, the chemical destroys the skin through its forced and harsh alteration. This leads to skin problems, more blemishes, and even pre-aging.

It is a possible cause of a skin disease called “ochronosis”, where permanent patches of black or blue remain on the skin. Hydroquinone is also a possible carcinogen and may contain other toxic substances.

Look out for: Hydroquinone or tocopheryl acetate


Found in soaps, detergents or skincare products, triclosan may still be doubted for its use and effects that are toxic to the body.

According to research, triclosan is linked to several allergies such as skin and eye irritation. To make things worse, it may also be related to hormone disruption in the human body. These side effects can have adverse impacts on the body, especially in the long run. Triclosan also runs the risk of contamination with other toxic substances such as chloroform. This would definitely be harmful to the body.

For some, triclosan may be an environmental hazard. It accumulates in the environment due to its slow breakdown rate. It is also a potentially toxic substance to marine life and would most likely adversely affect the ecosystem.

Despite the negative associations with the ingredient, many manufacturers still utilize triclosan. This is because of its strong anti-bacterial properties. Aside from that, it is used as a strong preservative in cosmetics to prolong shelf life. It also prevents the growth of mould or bacteria.

Look out for: Triclosan (TSC), triclocarban (TCC).



In a tropical country like Singapore where it is sunny all year round, sunscreen is something we cannot live without. Oxybenzone, a common chemical found in sunscreens, may also create skin allergies.

Sunscreen is something that has to be applied frequently and hence would have to be gentle on the skin. However, oxybenzone is found to cause severe skin allergies, redness and irritation. Oxybenzone is also a hormone disruptor. Studies have shown that oxybenzone mimic the hormone estrogen, possibly leading to conditions such as skin and breast cancer.

Manufacturers still use it because it provides coverage and protection from UV rays. The skin also easily absorbs the substance, without leaving any residue behind. This makes it high in demand among consumers.



In order to meet consumers’ demands for unbreakable cosmetics, many manufacturers turn to phthalates. This ingredient makes cosmetics flexible and less prone to breaking. Also called a plasticiser, many skincare products and cosmetics contain phthalates to keep them soft and pliable.

Phthalates may disrupt hormones, especially in men and children. It could also possibly cause adverse effects on the reproductive system. It has an association with many health issues, such as diabetes, ADHD and even cancer.

Look out for: Phthalate, DEP, DBP, DEHP, fragrance.

Would it really be a wise choice to add penetration enhancers to skincare products?

Penetration enhancers may help increase skin absorption. But many of these enhancers are also chemicals that may cause harm in the long run. Furthermore, penetration enhancers might also increase absorption for even more harmful ingredients like those mentioned above. Instead of helping your skin to better absorb the benefits of skincare, you might be exposing it to more harmful chemicals.

A safer option would be to avoid penetration enhancers altogether. Without running the risk of more chemicals entering your body, using natural and organic products is a better option. If you still feel the need for penetration enhancers, there are natural options. One such option is aloe vera gel. Its benefits include moisturizing, healing and increasing the absorption rate of the skin.

Before buying a skincare product, it always pays to have a look at the ingredient list first. We never know what we purchase under the guise of carefully-designed labels – we might end up harming our skin instead.