Skincare Order: Which Product Should Be Applied First and How Is Its Efficacy Tested?

Using skincare is not simply about choosing products with the right active ingredients. The skincare order products are applied also matters because the formulation, vehicle, and preceding products can influence how subsequent products interact with the skin.

However, does applying skincare order in the correct order automatically mean that a product is effective? Not necessarily. For cosmetic manufacturers, claims such as “hydrates the skin,” “strengthens the skin barrier,” “controls excess oil,” “reduces the appearance of wrinkles,” or “protects against UV radiation” should ideally be supported by objective and scientifically appropriate testing.

Table of Content:

• Why Does Skincare Order Matter?
• Common Morning Skincare Order
• What About a Nighttime Skincare Routine?
• Does Correct Skincare Order Guarantee Product Efficacy?
• How Is Skincare Efficacy Tested?
• From Skincare Routine to Scientific Evidence

Why Does Skincare Order Matter?

A typical skincare order may include cleanser, toner or essence, serum, moisturizer, and sunscreen. However, not every step is essential for everyone.

Dermatologists generally recommend following a proper skincare order, starting with cleansing first, followed by treatment products, moisturizer, and/or sunscreen. The principle behind skincare order and skincare layering is not simply cosmetic. Recent scientific literature indicates that sequential topical application can influence cutaneous absorption through changes in skin barrier properties, hydration, occlusion, lipid film formation, and interactions between vehicles.

Therefore, proper product sequencing can help optimize a skincare order, but it does not replace evidence-based efficacy testing.

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Common Morning Skincare Order

1. Cleanser

Cleanser is generally the first step. It helps remove excess oil, dirt, makeup residue, and other substances from the skin surface. A cleanser should be selected according to skin condition because overly aggressive cleansing may compromise the skin barrier.

2. Toner or Essence

Toners and essences are optional steps that may provide additional hydration or other benefits depending on their formulation. A skincare routine does not necessarily become more effective simply because it contains more steps.

3. Serum or Treatment

Serums and treatment products are commonly formulated to address specific skin concerns, such as hydration, pigmentation, signs of aging, or other targeted concerns. The appropriate active ingredient and concentration should be selected according to the intended purpose and skin tolerance.

4. Moisturizer

Moisturizers help maintain skin hydration and support the skin barrier. Humectants can help retain water, while emollients and occlusive ingredients can help reduce water loss.

Skin hydration and transepidermal water loss (TEWL) are among the objective parameters that can be used to evaluate changes in skin condition. Studies commonly use instruments such as the Corneometer and Tewameter for these measurements.

5. Sunscreen

Sunscreen is generally the final skincare step during the daytime. Because sunscreen is intended to protect the skin from ultraviolet radiation, claims such as SPF and UVA protection should be evaluated using appropriate testing methods.

Both in vitro and in vivo approaches can be used to evaluate sunscreen performance, including UVB and UVA protection and water resistance or substantivity.

What About a Nighttime Skincare Routine?

A typical nighttime routine may include:

Cleanser → Toner/Essence → Serum/Treatment → Eye Cream (optional) → Moisturizer

Sunscreen is not required at night. For treatment products that may cause irritation, such as certain active ingredients, application frequency and product combinations should be adapted according to the formulation and skin tolerance.

Using more products does not necessarily produce better results. Excessive layering of active ingredients may increase the risk of irritation.

Does Correct Skincare Order Guarantee Product Efficacy?

Product sequencing is only one part of skincare performance. Efficacy can also be influenced by:

• active ingredient concentration;
• formulation and vehicle characteristics;
• active ingredient stability;
• skin condition;
• frequency of use;
• amount applied;
• duration of use; and
• interactions between products.

The vehicle itself can influence how an active ingredient interacts with the stratum corneum and therefore affect topical delivery and efficacy. This is why cosmetic efficacy testing is important.

How Is Skincare Efficacy Tested?

The appropriate test depends on the specific product claim.

1. Skin Hydration Testing

For products claiming to moisturize or improve skin hydration, skin hydration measurement can be used as an objective endpoint. Corneometry is commonly used to evaluate changes in the hydration of the stratum corneum.

Clinical studies of moisturizers have used Corneometer measurements to assess product performance.

2. Skin Barrier and TEWL Testing

For products claiming to support or improve the skin barrier, TEWL can be an important objective parameter. Changes in TEWL can provide information about skin barrier function.

Research on moisturizers commonly combines TEWL and hydration measurements to evaluate product performance.

3. Sebum Testing

For products designed to control excess oil, sebum measurement can be used as one of the evaluation parameters. Sebum analysis may be combined with hydration and TEWL measurements to provide a broader assessment of skin changes.

4. Anti-Aging Efficacy Testing

Anti-aging products can be evaluated according to their specific claims.

Potential endpoints include:

• wrinkle appearance or depth;
• skin elasticity;
• skin firmness;
• hydration;
• skin texture;
• skin roughness; and
• other instrumental or clinical parameters.

The appropriate endpoints should be selected according to the product formulation and intended claim.

5. Sunscreen Testing

Sunscreen products require testing methods specifically designed to evaluate protection against UV radiation. Testing may include SPF-related UVB protection and UVA protection using appropriate methodologies.

Reliable testing is important because UV protection claims require objective evidence. Scientific literature emphasizes the importance of valid in vitro and in vivo methods for evaluating sunscreen performance.

From Skincare Routine to Scientific Evidence

So, which skincare order product should be applied first? In general, a simple routine can follow:

Cleanser → Toner/Essence → Serum/Treatment → Moisturizer → Sunscreen

However, correct application order is only one component of skincare performance. For cosmetic manufacturers, scientific efficacy testing provides an opportunity to support product claims with measurable data rather than relying solely on consumer perception.

A recent clinical study involving 123 volunteers, for example, evaluated a serum and moisturizer regimen using hydration, TEWL, and sebum measurements at multiple time points. The findings demonstrated the value of objective measurements in assessing skincare order regimen performance.

Turn Skincare Claims into Measurable Evidence

A good formulation is only the beginning. Demonstrating its performance through an appropriate scientific testing strategy can strengthen the credibility of a cosmetic product and its claims.

IML Research can support cosmetic product testing based on the product characteristics and claims being evaluated. Need help determining which efficacy test is suitable for a skincare product? Consult the IML Research team to identify relevant parameters and testing methods.

Author & Editor: Lina

References

Draelos, Z. D. (Ed.). (2010). Cosmetic Dermatology: Products and Procedures. Wiley-Blackwell.

Fluhr, J. W. (Ed.). (2020). Practical Aspects of Cosmetic Testing: How to Set up a Scientific Study in Skin Physiology (2nd ed.). Springer.

Burstein, S. E., & Maibach, H. I. (2026). The Effect of Sequential Topical Application of Dermatologic Medications on Absorption: Clinical Considerations. Dermatology.

Wilson, D., Berardesca, E., & Maibach, H. I. (1988). In vivo transepidermal water loss and skin surface hydration in assessment of moisturization and soap effects. International Journal of Cosmetic Science, 10(5), 201–211.

Heinrich, U., et al. (2008). Multicentre comparison of skin hydration in terms of physical-, physiological- and product-dependent parameters by the capacitive method (Corneometer CM 825). International Journal of Cosmetic Science.

Draelos, Z. D., et al. (2012). Two randomized, controlled, comparative studies of the stratum corneum integrity benefits of two cosmetic niacinamide/glycerin body moisturizers vs. conventional body moisturizers. Journal of Drugs in Dermatology.

Bielfeldt, S. (2021). Performance Metrics of Sunscreen Formulations: In Vitro and In Vivo Techniques. Current Problems in Dermatology, 55, 124–132.

Mayba, J. N., & Gooderham, M. J. (2018). A Guide to Topical Vehicle Formulations. Journal of Cutaneous Medicine and Surgery.

Lodén, M. (1997). Preventive and therapeutic effects of a moisturizer. An experimental study of human skin. Acta Dermato-Venereologica.