We often talk about whether your skincare routine is microbiome-friendly (in other words, having either a positive or neutral impact on your microbial communities), but have you ever wondered how your makeup interacts with your skin microbiome?

Skincare ingredients, from peptides to salicylic acid, often attract a lot of buzz; but there tends to be less hype around the ingredients lurking in your foundation or lipstick.

Yet, anything that comes into direct contact with your skin microbiome has the potential to impact it in some way. Even water can alter your microbial communities.

When it comes to choosing make-up products, we often go by what it says on the tin without sparing a thought about what it’s made of.

On average, women use at least 12 products a day, exposing the skin too roughly 168 chemicals. While men typically use six products and around 85 chemicals, according to a study by EWG.

Although many chemicals are ultimately harmless and unavoidable, we’ve listed a few to be warier of.

Propylene glycol can be found in liquid foundation, lipsticks, moisturisers, shampoos, conditioners, and spray deodorants.

It’s otherwise listed in products as: 

• PG
• 1,2-propanediol
• 1,2-diol

The chemical is usually added to skincare products and cosmetics to increase moisture retention. Although most people won’t react to this chemical, propylene glycol can penetrate through the deepest layers of the skin. 

Prolonged exposure to PG has been linked to increased sensitivity, redness of the skin, dermatitis, and allergic reactions.

Parabens are among the most common ingredients in makeup products, body washes, deodorants, moisturisers, and facial cleansers.

Other names include:

• Methylparaben
• Propylparaben
• Butylparaben
• Ethylparaben

Used as preservatives, they are often dubbed ‘oestrogen-mimickers’, as they act similarly to the hormone oestrogen in the body. This can cause disruptions to hormones.

When absorbed by the skin, they can impair the growth of beneficial bacterial colonies and promote the proliferation of harmful microorganisms, thus affecting the skin microbiota’s balance.

Often found in make-up from eyeshadow to lipsticks. Synthetic colours can appear in the ingredient list as FD&C or D&C (Food, Drugs, and Cosmetic-Approved), followed by an identification number.

Although it’s uncommon, they can increase the risk of skin sensitivity and irritation. These chemicals can throw the beneficial bacteria in your skin microbiome off-balance and close your pores, making acne flare-ups more common.

Discovered in 1859, formaldehyde is today used in many cosmetic and skincare products as a preservative. It’s less common in makeup bag residents but can be found in nail polish and nail polish remover, some dental care products, and perfumes that include synthetic fragrances.

It can be listed as: 

• Formalin
• Formic aldehyde
• Methanediol
• Methanal
•  Methyl aldehyde
•  Methylene glycol
• Methylene oxide. 

Formaldehyde can be incredibly irritating for some people and can lead to allergic reactions. Even though levels are relatively low in most cosmetic products, those that are sensitive to the ingredient may experience redness, itching and scaling of the skin.

Although the skincare world is making great strides in putting the skin microbiome first and adapting formulas to boost bacterial growth, there’s still work to be done for make-up products.

That being said, one brand that’s leading the way is Skin Trust Club partner brand Esse Skincare.

Their microbiome-friendly foundation is packed with probiotic lysates and tyndallised Lactobacillus bacteria. These promote the growth of beneficial bacteria and therefore encourage microbial diversity. This strengthens the skin microbiome and barrier.

As soon as you open and begin using your make-up product, it is at risk of contamination.

David Caballero-Lima, Chief Scientist at Skin Trust Club, says: “A make-up brush that has not been washed in three months could contain more bacteria than a toilet”.

A 2019 study that examined lipsticks, eyeliners, mascaras, and makeup sponges, found that between 79% and 90% of the products were contaminated with bacteria including Staphylococcus aureus (the microbe linked to eczema) and E. coli. Makeup sponges were said to be the worst offenders with the highest rate of fungal contamination.

We know the importance of frequently washing our brushes to avoid the risk of clogged pores and instigating acne, but it’s equally as important to regularly cleanse products, too. This will help to prevent microbiome imbalance by accidentally introducing disruptive members like S. aureus.

Confession time: own a product that’s aged a good few years? Fear not. You’re not the only one.

But it’s still worth bearing in mind that the product preservatives, particularly important for liquid products, will become less effective. This allows harmful bacteria to grow.

Naturally, products oxidise over time too. This puts them more at risk of being unstable and therefore cousin skin irritation.

Finally, another healthy habit to adopt is ensuring you thoroughly remove makeup particles from your skin before bed. 

As we naturally sweat while we sleep, leaving make-up on overnight can mingle with excess sebum and consequently block pores. This increases the risk of breakouts.

Learn more about your skin microbiome and meet the bacteria living in yours with our skin test. Order here.