Jakarta, 04 March 2026 – Indonesia is known as a tropical country, where daily exposure to intense sunlight is a constant part of the Indonesian skin’s daily routine, making UVA and UVB radiation almost unavoidable. However, long-term exposure to UVA and UVB radiation can trigger oxidative stress, inflammation, and even skin cell damage. Therefore, sunscreen use is not merely an option, but a basic necessity for maintaining healthy skin in tropical climates.

Today, there are many types of sunscreen with various supporting ingredients, one of which is a type that provides a soothing effect on the skin. Common soothing agents added to sunscreen formulations include Centella asiatica extract, aloe vera, panthenol (pro-vitamin B5), allantoin, and bisabolol. These ingredients are widely known for their ability to reduce redness, calm irritation, and enhance skin comfort after sun exposure. The soothing effect of these agents is often claimed to help minimize skin cell damage by reducing inflammation and supporting the skin’s recovery process. However, are “soothing agents” truly effective in providing extra protection against sunburn, or do they simply mask the damage that still occurs?

UV Radiation Triggers Cellular Damage Behind Visible Redness 

Exposure to ultraviolet rays from the sun not only affects the skin’s surface but also penetrates down to the cellular level. One of the greatest threats to skin is ultraviolet (UV) radiation from the sun, particularly UVB. The emitted UVB radiation can trigger the formation of reactive oxygen species (ROS), which can damage various vital cellular components. ROS are unstable molecules that contain oxygen and readily react with other molecules within the cell. 

Cells located in the outermost layer of the skin are called keratinocytes. These cells play a role in forming the skin’s protective barrier and require significant energy from the mitochondria, which generate cellular energy. However, when the skin is exposed to UVB, ROS production increases, damaging mitochondria and disrupting energy production.

Disrupted mitochondrial activity can increase ROS production, further increasing oxidative stress. If this condition persists and the body’s natural antioxidant system is unable to balance it, cells can suffer serious damage, triggering apoptosis, or programmed cell death. UV exposure not only causes skin to appear red or burnt but also disrupts the invisible energy production process within skin cells.

Do Soothing Ingredients Truly Protect Skin Cells? 

Today, sunscreen products are not only useful as UV filters, but also offer multiple functions and benefits through various innovations in their formulations. Many sunscreen products are now enriched with various agents, including soothing agents. For example, centella extract is widely used as an additional ingredient in sunscreens because it is known to help reduce redness and provide a calming effect after sun exposure. Centella extract itself is known to enhance wound repair, collagen synthesis, and antioxidant and anti-inflammatory responses. Visually and through the feel of the skin, sunscreens containing soothing agents can reduce the appearance of redness, provide a calming sensation, and prevent stinging. 

At the laboratory level, SPF and PA are evaluated by comparing the amount of ultraviolet (UV) energy required to cause a visible biological reaction on skin with and without sunscreen. For SPF testing, which evaluates UVB protection, the skin is exposed to controlled doses of UVB radiation to determine the Minimal Erythema Dose (MED), defined as the lowest UV dose that produces visible redness. The sunscreen is applied evenly at 2 mg/cm², and the test is repeated on protected skin. Because the sunscreen reduces the amount of UVB reaching the epidermis, a much higher UV dose is required to induce erythema. The SPF value is calculated as the ratio of the MED on protected skin to the MED on unprotected skin, meaning SPF reflects how much longer the skin can tolerate UVB exposure before sunburn occurs. 

PA testing evaluates UVA protection using the Persistent Pigment Darkening (PPD) response. UVA penetrates more deeply into the skin and triggers melanin oxidation and redistribution, leading to visible, lasting pigmentation rather than redness. In this test, increasing doses of UVA are applied to untreated skin to determine the Minimal Pigment Dose (MPD), the lowest dose that causes clear darkening. The same procedure is then performed on skin treated with sunscreen at 2 mg/cm². Since effective UVA filters reduce the amount of UVA reaching melanocytes, a higher UVA dose is required to produce pigmentation. The UVA protection factor is calculated by dividing the MPD on protected skin by that on unprotected skin, and this value is translated into the PA rating system used in many Asian markets.  

This method is considered the gold standard for sunscreen evaluation, especially in Indonesia, where human SPF and PA testing remain the only officially accepted methods by the Indonesian FDA for product claims. However, when a sunscreen contains soothing agents that reduce visible redness, interpretation can become challenging. Since SPF assessment is based on visible redness, a sunscreen containing soothing agents may appear highly protective simply because it reduces erythema. However, reduced redness does not always mean that skin cells are fully protected, as oxidative stress or cellular damage may still occur beneath the surface. 

Why is Molecular Level Testing needed? 

Molecular-level testing is necessary to confirm whether soothing agents can truly provide additional protection to the skin. Invisible redness is not a strong enough indicator that cell damage has not occurred. It is possible that soothing agents only serve to “mask” damage caused by UV rays beneath the skin. UV exposure not only triggers inflammation, but can also increase the formation of reactive oxygen species (ROS), decrease cellular energy (ATP) or cell viability, and weaken the skin’s barrier function. These damage processes occur at the molecular level and are invisible to the eye. 

Scientifically, the difference between the “masking” effect and true protection can be distinguished through in vitro testing. A soothing agent is only considered to have a “masking” effect if the only visible change is a decrease in inflammation markers, such as IL-1α or IL-8. This means that the inflammation signal is suppressed, resulting in reduced redness. However, under these conditions, there is no improvement in cell viability, no increase in ATP as an indicator of cellular energy, no reduction in reactive oxygen species (ROS), and no recovery of barrier markers or extracellular matrix (ECM) components. In other words, the skin may appear to improve, but at the molecular level, the cells are still under stress. 

Conversely, truly effective protection shows a more comprehensive pattern, namely a decrease in inflammatory markers (IL-1α/IL-8), an increase in ATP or cell viability, a decrease in oxidative stress, and normalization of barrier markers or ECM. If these things can be proven, then the cells are truly well protected even when exposed to UV rays. 

Soothing agents tend to be “masking” if there are still underlying sources of stress, such as UV exposure, the use of harsh surfactants, excessive exfoliation, and disrupted lipid barrier conditions. If sunscreen formulations do not provide extra support, such as barrier repair, antioxidants, or DNA/cellular protection, then the only improvement is an improvement in the appearance of redness on the face, which looks better but does not actually protect the cells. However, at the cellular level, ROS remain elevated, MMPs remain active, tight junctions are disrupted, and ATP/cell viability decrease. 

This condition can occur in products that claim to have soothing ingredients but also contain potentially aggressive or stress-inducing ingredients. Therefore, molecular evaluations such as In Vitro testing are crucial to ensure that the soothing agents in sunscreen truly provide real cellular protection, not just a “masking” effect or an effect that is only visible to the eye. Some In-Vitro tests that can be conducted include the Cell Viability Test, ATP Assay, ROS Measurement, Inflammatory Marker Assay, and In Vitro SPF & UV Transmittance Test, all of which can be performed at Skinovation.