While it can be exciting to experiment with different skincare products, there is such a thing as too many products—especially if the ones you’re using aren’t compatible. That’s right: Some skincare products shouldn’t be used with one another because of their risk of adverse side effects or decreased efficacy.

Some potential interactions can do you more harm than good—which is one of many reasons it’s important to understand what you’re putting on your skin! Here, we’ll break down some common skincare product combinations you might want to avoid so you can make informed decisions on your quest to get a healthier, more radiant complexion. 

Avoid mixing these skincare products 

Mixing certain skincare products can have unintended consequences, and may even cause adverse reactions. Here are some key products that you might want to avoid mixing in your skincare routine. 

Products with strong ingredients

First, stronger ingredients and some chemicals should not be mixed together without professional guidance. For example, combining alpha hydroxy acids (AHAs) with salicylic acid (a beta hydroxy acid) may lead to irritation for some. 

In some cases, strong ingredients can be mixed together, but with caution! For instance, research has shown that topical tretinoin or retinol can be used in conjunction with salicylic acid peeling for photoaging improvement. However, this should only be done under medical supervision and not attempted at home.¹

Always remember to patch-test new products before using them and refrain from experimenting with product combinations on your own. Instead, seek the advice of a dermatology provider who can provide personalized recommendations based on your skin's needs. 

Different products with the same active ingredient 

Avoid using two different products with the same active ingredient together; this will help you avoid applying ingredients beyond their usual recommendations and help you avoid redundancy in your routine. 

Vitamin C and benzoyl peroxide

When it comes to combining vitamin C and benzoyl peroxide in your skincare routine, there are a few considerations to keep in mind. Benzoyl peroxide may potentially oxidize antioxidants like vitamin C when the ingredients are used together. This oxidation process may render vitamin C ineffective. Research has shown that benzoyl peroxide can deplete cellular levels of vitamin E by up to 95% and vitamin C by up to 70%.² This suggests that using both ingredients simultaneously may compromise the effectiveness of these vitamins in your skincare routine.

While there’s no evidence to suggest that vitamin C and benzoyl peroxide should not be used on the same day, we recommend using them at different times (such as applying one in the morning and the other in the evening) to ensure optimal effectiveness. Separating their application can help minimize any potential interactions and allow each ingredient to work as intended.

Retinol and AHAs

Research shows that AHAs can cause skin irritation,³ while retinol can also be a source of skin irritation.⁴

Given the potential for increased irritation when using these two powerful ingredients together, it’s generally not recommended for those who have sensitive skin to combine them in the same skincare routine. Instead, opt for more gentle combinations to avoid overloading your skin. If you wish to incorporate both retinol and AHAs into your skincare routine, consider using them on separate days or during different parts of your skincare routine. This will allow your skin to adjust and minimize the risk of irritation.

Remember, always prioritize the health and well-being of your skin, and if you have any concerns or uncertainties, consult a dermatology provider first. 

Can you mix vitamin C and retinol? 

Recent research has shown that it can be effective to mix vitamin C and retinol in your skincare routine.⁵

That being said, both vitamin C and retinol are powerful ingredients that can potentially irritate your skin if not used properly. It’s important to use them in appropriate concentrations and follow the recommended usage guidelines. 

Can you mix vitamin C and niacinamide?

Yes! Recent research has shown that it’s generally safe to mix vitamin C and niacinamide in a skincare routine. A study demonstrated that combining these two ingredients, along with another substance called PDRN, was effective in reducing skin pigmentation by decreasing melanin production.⁶

As always, follow recommended usage guidelines and consider consulting with a dermatology provider before incorporating both ingredients into your skincare routine.

Can you mix benzoyl peroxide and tretinoin? 

Benzoyl peroxide may potentially inactivate tretinoin if mixed in the same bottle. However, recent research has shown that this is not always the case, and the combination of benzoyl peroxide and tretinoin in optimized formulations can still be effective for treating acne.⁷

They can also be used separately in a routine, with application separated by at least a few minutes. You can also consider using benzoyl peroxide in the morning and tretinoin in the evening. While the combination of benzoyl peroxide and tretinoin is generally safe and effective, individual reactions may vary. 

Why you should speak with a dermatology provider 

When it comes to your skin health, there are so many reasons to consult with the pros! Dermatology providers have extensive training and experience in diagnosing and treating various skin issues. They possess specialized knowledge in dermatology and can develop a personalized treatment plan based on your unique skin type, concerns, and medical history. This tailored approach takes into account factors such as your skin’s sensitivity, allergies, and underlying health conditions.

Dermatologists and other healthcare providers also have the authority to prescribe medications that are not available over the counter. These medications may be necessary for treating certain skin conditions and require professional evaluation and supervision. Dermatology providers can also track your treatment progress and make necessary adjustments to optimize results. 

Get professional skincare advice with Curology 

Experience the benefits of professional skincare advice with Curology. Our team of dermatology professionals is here to provide personalized guidance for your unique skin concerns. Sign up for a 30-day trial* and try our routine essentials to discover the power of personalized skincare. 

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P.S. We did the homework so you don’t have to:

1. Kligman, D.E. and Draelos, Z.D. Combination Superficial Peels With Salicylic Acid and Post-Peel Retinoids. J Drugs Dermatol. (April 2016).

2. Bowe, W.P. and Logan, A.C. Clinical implications of lipid peroxidation in acne vulgaris: old wine in new bottles. Lipids Health Dis. (2010, December 9).

3. Tang, S.C. and Yang, J.H. Dual Effects of Alpha-Hydroxy Acids on the Skin. Molecules. (2018, April 10).

4. Kim, B.H., et al. The mechanism of retinol-induced irritation and its application to anti-irritant development. Toxicol Lett. (2003, December 15).

5. Seité, S., et al. Histological evaluation of a topically applied retinol-vitamin C combination. Skin Pharmacol Physiol. (March-April 2005).

6. Park, H.J., et al. The Combination of Niacinamide, Vitamin C, and PDRN Mitigates Melanogenesis by Modulating Nicotinamide Nucleotide Transhydrogenase. Molecules. (2022, August 2).

7. Del Rosso, J.Q., et al. Absence of Degradation of Tretinoin When Benzoyl Peroxide is Combined with an Optimized Formulation of Tretinoin Gel (0.05%). J Clin Aesthet Dermatol. (October 2010).

8. Al-Niaimi, F. and Chiang, N.Y.Z. Topical Vitamin C and the Skin: Mechanisms of Action and Clinical Applications. J Clin Aesthet Dermatol. (July 2017).

Meredith Hartle is a board-certified Family Medicine physician at Curology. She earned her medical degree at Kirksville College of Osteopathic Medicine in Kirksville, MO.

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Written by

Curology Team

Medically reviewed by

Meredith Hartle, DO