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Why You Shouldn’t Mix Ingredients in Your Skin Care Routine

woman trying face remedy

Some things are match-made in heaven but mixing these ingredients in your skincare routine would make far from the perfect pair. Taking care of your skin is essential for maintaining a healthy, radiant complexion. While we all want the best for our skin, sometimes being over-enthusiastic about layering as many skincare products can do more harm than good. Mixing incompatible ingredients can lead to adverse reactions, skin irritation, and even worsen existing skin issues. To help you navigate the world of skincare effectively, we’ve compiled a list of ingredients that should never be combined in your skincare routine. Understanding these no-go combinations will empower you to create a safe and effective skincare regimen.

Retinol – Do Not Mix with Alpha or Beta Hydroxy Acids (AHAs/BHAs), Benzoyl Peroxide and Vitamin C

Mixing retinol with certain other skincare ingredients can lead to potential adverse effects due to their individual mechanisms of action and varying pH levels. Let’s take a closer look at why you should avoid combining retinol with specific substances:

1. Retinol and Alpha/Beta Hydroxy Acids (AHAs/BHAs)

Images by The Ordinary and Paula’s Choice

Mixing retinol with AHAs or BHAs is generally not recommended due to their potential to cause skin irritation and sensitivity when used together. All of these ingredients are powerful exfoliants that work to accelerate cell turnover and improve the appearance of the skin. However, they achieve this through different mechanisms, and combining them can be too harsh for the skin, leading to various adverse effects like increased skin sensitivity. All of these ingredients can individually cause increased skin sensitivity, redness, dryness, and peeling, especially when first introducing them into your skincare routine. Combining them can intensify these side effects and lead to excessive irritation, and over-exfoliation making it challenging for your skin to tolerate the treatment. Using them together may also result in the thinning of the skin barrier and thus increased vulnerability to environmental damage.

Retinol also differs in pH levels from AHAs and BHAs. AHAs are typically more acidic, while retinol formulations might have a higher pH. When used together, there’s a risk of altering the pH balance of the skin, potentially reducing the efficacy of both ingredients.

With that said, it is also best to avoid using AHAs and BHAs together at the same time for the reasons listed above. To avoid potential adverse effects, it is best to use all of these ingredients separately. If you wish to incorporate these ingredients into your skincare regimen, consider using them on alternate days or one in the morning and the other in the evening. For instance, you can use retinol one night and BHAs the following night or BHAs at night and AHAs the next morning.

2. Retinol and Benzoyl Peroxide

Images by The Inkey List and PanOxyl

Mixing retinol and benzoyl peroxide together is generally not recommended due to their potential to cause skin irritation and dryness. These ingredients can be drying to the skin individually, and combining them can worsen this effect, leading to redness and peeling. Combining them may also reduce the effectiveness of both ingredients. Both retinol and benzoyl peroxide are potent acne-fighting ingredients, but they have different mechanisms of action. Benzoyl peroxide works best in an acidic environment, while retinol formulations might have a different pH level. When combined, there’s a possibility that they may neutralise each other’s effectiveness or alter the skin’s pH balance, reducing their ability to address acne concerns. 

Instead of using retinol and benzoyl peroxide together, consider using them in separate routines. For example, you can use benzoyl peroxide in the morning and retinol in the evening. Alternatively, you can use them on alternate days to avoid potential interactions and maintain their individual effectiveness.

3. Retinol and Vitamin C

Images by Sephora and La Roche Posay

Mixing retinol with vitamin C is a topic that has sparked some debate in the skincare community. While there is no definitive consensus, there are concerns about potential interactions between these two powerful ingredients. It’s generally recommended to avoid using them together to minimise the risk of adverse effects like skin sensitivity, redness and peeling and maintain the effectiveness of each ingredient. 


Using both retinol and Vitamin C at the same time can increase the risk of skin irritation, as they both have the potential to cause skin sensitivity, especially when first starting a retinol regimen. This could lead to undesirable effects like redness and peeling of the skin as well as increased dryness as both these ingredients work to slough off dead skin and increase skin cell turnover. 

When vitamin C is exposed to certain conditions, such as light and air, it can oxidise and lose its effectiveness. Retinol can be unstable when exposed to light as well. When combined, the risk of oxidation for both ingredients may increase, reducing their individual benefits.

Vitamin C products are also usually formulated at a lower pH (more acidic) to enhance stability and efficacy, while retinol products can have varying pH levels. Therefore when combined, their conflicting pH levels may destabilise each other, reducing the effectiveness altogether.

Instead of using retinol and vitamin C together, consider incorporating them into your skincare routine at different times of the day or on alternate days. For example, use vitamin C in your morning routine and retinol in your evening routine. This way, you can benefit from the advantages of both ingredients without risking potential interactions or decreased efficacy.

Vitamin C and AHA

Images by Kiehl’s and Summer Fridays

Vitamin C is very pH sensitive, working best at a lower pH level while AHAs are also effective at lower pH levels meaning when used together, there is a risk of neutralising the acidic environment, which may decrease the efficacy of both ingredients and reduce their skin benefits.

Since both vitamin C and AHAs promote exfoliation, removing dead skin cells and encouraging skin renewal, using them together may lead to excessive exfoliation and overstimulation of the skin, potentially causing dryness, redness, and a compromised skin barrier. Therefore, using them together may increase skin sensitivity, particularly for those with sensitive or reactive skin.

Benzoyl Peroxide and Hydroquinone

Image by Paula’s Choice

Combining benzoyl peroxide and hydroquinone may seem like a good idea if your main goal is to address skin discolouration or pigmentation. However, using these ingredients together will not expedite results. Although both ingredients can individually aid in fading dark spots left by acne, using them together may hinder the desired effects as the combination has the potential to temporarily stain the skin. Both benzoyl peroxide and hydroquinone can be drying and irritating to the skin on their own, especially for individuals with sensitive or dry skin. Thus when used together, the risk of skin irritation and redness may increase, leading to discomfort and inflammation.

Hydroquinone and Alpha Hydroxy Acids (AHAs)

Image by Nouvo Body
Image by Drunk Elephant

Hydroquinone is a skin-lightening agent commonly used to treat hyperpigmentation while AHAs promote exfoliation by removing dead skin cells and stimulating skin renewal. Both hydroquinone and AHAs are potent ingredients that can individually cause skin sensitivity, redness, and irritation, especially in those with sensitive or reactive skin. Thus when combined, there’s a risk of exacerbating these effects and potentially compromising the skin barrier.

Remember, it’s best to use hydroquinone-based products separately or only as directed by a dermatologist.


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