How to Choose the Right Sunscreen for Your Skin

Introduction

Choosing the right sunscreen has become a tedious task in today’s world, where the multi-billion-dollar beauty industry and pharmaceutical companies constantly compete to convince you that their sunscreen is better than the rest. Social media feeds, OTT platforms, YouTube advertisements, and even influencers bombard us with recommendations every day, making it increasingly difficult to choose the right sunscreen.

Choosing the right sunscreen is not merely a cosmetic decision—it is an important health decision. Think of it like choosing an insurance policy for your skin. Just as an insurance policy quietly protects you against future uncertainties, a sunscreen protects your skin from damage that accumulates silently over years of sun exposure. Its benefits may not be obvious today, but they become invaluable in the long run.

Choosing the right sunscreen is not merely a cosmetic decision—it is an important health decision

To make an informed decision, it is important to understand the science behind sunscreen—why it is needed, what the different terms on the label actually mean, and which features truly matter when choosing one. After all, the primary purpose of any sunscreen is simple: to protect your skin from harmful ultraviolet (UV) radiation.

Let’s begin by understanding the science behind sunlight and sunscreen.

Understanding Sunlight and UV Radiation

It is fascinating how a star located 149.6 million km away from our home is the very reason life exists on Earth as we know it. Sunlight is our only natural source of energy, and throughout history, many civilizations, including our ancestors, revered the Sun as a symbol of life and prosperity. But times have changed. Industrialization, clearing of forest cover, a depleting ozone layer, global warming, and present-day climate change have brought a renewed perspective on the effects of sunlight in our daily lives.

Before understanding how sunscreens work, it is important to understand what sunlight is composed of and, more importantly, the component of sunlight responsible for most of the damage to our skin—ultraviolet (UV) radiation.

Sunlight is composed of ultraviolet (UV) radiation, visible light, and infrared radiation.

Ultraviolet radiation is further divided into UVA, UVB, and UVC. Of these, UVC is completely absorbed, while UVB is attenuated as it passes through the ozone layer before reaching the Earth’s surface.

UVB (290–320 nm) is responsible for most of the damage produced to the skin through its action on DNA. It is the primary cause of acute sunburn and, with prolonged exposure, contributes to the development of skin malignancies.

UVA (320–400 nm) remains minimally filtered by our ozone layer and penetrates into deeper tissues unlike UVB. It produces phototanning, photoageing, and is responsible for many sunlight-induced diseases of the skin.

“UVC is completely absorbed, while UVB is attenuated as it passes through the ozone layer before reaching the Earth’s surface“

Since both UVA and UVB contribute to skin damage in different ways, it is important that our daily sunscreen provides protection against both UVA and UVB radiation.

This naturally brings us to the next question:

Characteristics Of An Ideal Sunscreen

“Better a diamond with a flaw than a pebble without.”

– Confucius

An ideal sunscreen should be:

• A combination of physical and chemical agents
• Broad-spectrum (protection against both UVA and UVB)
• Cosmetically acceptable and pleasant to use
• Water & Sweat Resistance
• Non-irritant and non-acne causing
• Hypoallergenic
• Relatively inexpensive

Unfortunately, there is no sunscreen in the world that meets all these criteria in the truest sense. However, with the wide variety of products available today, it is certainly possible to choose one that best suits your skin and lifestyle.

“With the wide variety of products available today, it is certainly possible to choose one that best suits your skin and lifestyle“

Why Sun Protection Is Important

Sunlight is essential for life and contributes to vitamin D synthesis and psychological well-being. However, excessive exposure to ultraviolet radiation can cause cumulative damage to the skin, leading to a wide spectrum of diseases ranging from mild photodermatoses to skin cancers.

When we talk about sun protection, many people immediately think of applying sunscreen before stepping outdoors. In reality, sun protection is much broader than that. Ideally, the best way to prevent UV damage would be to avoid excessive sun exposure altogether. However, we all know that this is neither practical nor possible in our day-to-day lives.

“When we talk about sun protection, many people immediately think of applying sunscreen before stepping outdoors. In reality, sun protection is much broader than that“

This is where sunscreen becomes an essential part of our daily routine. Used correctly, it acts as a protective shield that reduces the harmful effects of ultraviolet radiation while allowing us to continue our normal outdoor activities.

Why Choosing the Right Sunscreen Matters

Choosing a sunscreen is much like choosing an insurance policy—it emphasizes just how important a decision this is. Like an insurance policy, a sunscreen may not seem particularly beneficial when your skin is healthy and young. However, its true value lies in protecting you from damage that accumulates silently over time. After all, it is always better to have an additional layer of protection, isn’t it?

Interestingly, sunscreens were originally introduced as cosmetic products but were later reclassified by the Food and Drug Administration (FDA) as non-prescription drugs, highlighting their important role in protecting skin health. Apart from reducing tanning and photoageing, sunscreens serve a much greater purpose by helping prevent several sunlight-induced skin diseases, as discussed in the previous sections.

“Like an insurance policy, a sunscreen may not seem particularly beneficial when your skin is healthy and young. However, its true value lies in protecting you from damage that accumulates silently over time“

Unfortunately, choosing the right sunscreen has become increasingly confusing. Marketing claims, attractive packaging, and celebrity endorsements often overshadow the scientific parameters that truly determine how well a sunscreen protects your skin. As consumers, we should understand what these terms actually mean rather than relying solely on advertisements or product popularity.

“Marketing claims, attractive packaging, and celebrity endorsements often overshadow the scientific parameters that truly determine how well a sunscreen protects your skin“

In the following sections, I will simplify the science behind sunscreen using evidence-based dermatology, so that you can confidently choose the sunscreen that is best suited for your skin and lifestyle.

What Does SPF Mean?

“Any fool can know. The point is to understand.”
— Albert Einstein

As a dermatologist, I believe SPF is one of the most misunderstood and misinterpreted terms among consumers today. Many people choose a sunscreen based solely on its SPF value without actually understanding what the number means. Let’s change that.

SPF stands for Sun Protection Factor. At first glance, the term appears self-explanatory, and we naturally assume it tells us how much protection a sunscreen provides against the Sun. Surprisingly, that is not entirely correct.

In simple terms, SPF measures the level of protection a sunscreen provides against UVB radiation, the component of sunlight primarily responsible for sunburn. Scientifically, SPF evaluates the amount of UVB radiation required to produce minimal erythema (redness) on protected skin compared with unprotected skin.

Mathematically:

Now, what does the number next to SPF actually mean?

The most common SPF values you will find are SPF 15, SPF 30, SPF 50, and even SPF 60 or higher. But what do these numbers mean in real life?

Let’s consider a simple example.

Suppose an ‘x’ amount of UVB radiation produces mild redness on your unprotected skin. If you apply an SPF 15 sunscreen correctly, it will require approximately 15 times more UVB energy (15x) to produce the same degree of redness. Similarly, SPF 30 and SPF 50 sunscreens would require approximately 30 times (30x) and 50 times (50x) more UVB energy, respectively, to produce the same effect.

“If you apply an SPF 15 sunscreen correctly, it will require approximately 15 times more UVB energy (15x) to produce the same degree of redness“

At first glance, the difference between SPF 15 and SPF 30 may not seem very large. SPF 15 blocks about 93.3 % of UVB rays, while SPF 30 blocks about 96.7 %.

You might wonder, “That’s only around 4% difference. Does it really matter?”

The answer is yes.

The important point is not how much UVB is blocked, but how much UVB still manages to reach your skin.

With SPF 15, about 6.7 % of UVB radiation reaches your skin. With SPF 30, only about 3.3 % reaches your skin. In other words, SPF 30 allows only about half as much UVB to reach your skin compared with SPF 15.

This difference becomes important because even small amounts of UVB can damage DNA long before you notice redness or sunburn. Therefore, reducing the amount of UVB reaching your skin can provide better long-term protection against photoageing and skin cancer

“With SPF 15, about 6.7 % of UVB radiation reaches your skin. With SPF 30, only about 3.3 % reaches your skin“

The important point to understand is that SPF only increases the threshold of UVB exposure required to produce sunburn—it does not completely prevent ultraviolet radiation from reaching the skin.

Does A Higher SPF Mean Better Protection?

This naturally brings us to another common question:

“I’m using an SPF 30 sunscreen, while my friend uses SPF 50. Is my friend receiving significantly better protection?”

To answer this, we first need to understand how SPF is tested.

During laboratory SPF testing, sunscreen is applied at a standardized thickness of 2 mg/cm². In real life, however, most people apply much less sunscreen—often less than half the amount used during testing. As a result, the actual protection you receive may be significantly lower than the SPF value printed on the label.

💡 Think of it this way

Imagine painting a glass window. If you apply only a thin coat of paint, light can still pass through. As you apply thicker and more uniform coats, progressively less light passes through the glass.

Sunscreen behaves in much the same way.

Although SPF 50 is technically superior to SPF 30, how much sunscreen you apply is often more important than the SPF number itself. A properly applied SPF 30 sunscreen can provide better real-world protection than an inadequately applied SPF 50 sunscreen.

“Imagine painting a glass window. If you apply only a thin coat of paint, light can still pass through. As you apply thicker and more uniform coats, progressively less light passes through the glass“

Understanding PA Ratings

Having understood SPF, let’s now shift our attention to the often-overlooked component of sunlight—the UVA rays.

It is interesting to note that although UVA makes up the majority of ultraviolet radiation reaching our skin, much of the emphasis is usually placed on UVB. This is because, unlike UVB, UVA produces minimal erythema (redness) on the skin, making its harmful effects less obvious. However, due to its deeper penetration into the skin, UVA is closely associated with photoageing, immune suppression, and several sunlight-induced skin disorders.

Protection against UVA is most commonly indicated by the PA (Protection For UVA) rating, which ranges from PA+ to PA++++. In European countries, it is mandatory for the UVA protection of a sunscreen to be at least one-third of its labelled SPF value, ensuring balanced protection against both UVA and UVB radiation.

In my practice, I generally recommend PA+++ or PA++++ sunscreens to my patients. Adequate UVA protection is particularly important for delaying photoageing and preventing the development or worsening of pigmentary disorders such as melasma and post-inflammatory hyperpigmentation.

“In my practice, I generally recommend PA+++ or PA++++ sunscreens to my patients“

Now that we understand how SPF measures UVB protection and PA indicates UVA protection, the next step is to understand the different types of sunscreen filters that provide this protection. 

Chemical vs Mineral Sunscreens

Now that we understand SPF and PA ratings, the next important question is:

What are the ingredients in a sunscreen that actually provide this protection?

The FDA classifies sunscreen filters as organic and inorganic, which are more commonly referred to as chemical and mineral (physical) sunscreens, respectively.

Organic (chemical) sunscreens, as the name suggests, are chemical compounds that primarily absorb ultraviolet (UV) radiation before it can damage the skin.

In contrast, inorganic (mineral or physical) sunscreens, in addition to absorbing UV radiation, also reflect and scatter visible light, thereby forming a physical protective barrier over the skin.

“The FDA classifies sunscreen filters as organic and inorganic, which are more commonly referred to as chemical and mineral (physical) sunscreens, respectively“

You may have noticed this during cricket matches, where players often apply a thick white cream over their face and lips while fielding under the hot sun. Although these formulations provide excellent protection, they are not always cosmetically appealing for everyday use because of the visible white layer they leave behind.

“You may have noticed this during cricket matches, where players often apply a thick white cream over their face and lips while fielding under the hot sun“

This is one of the reasons why most modern sunscreens contain a combination of both chemical and mineral UV filters, allowing them to provide effective protection while remaining cosmetically elegant and comfortable for daily use.

FEATURE	CHEMICAL SUNSCREEN	MINERAL SUNCREEN
Also known as	Organic	Inorganic/Physical
Mechanism	Absorbs UV radiation	In addition to absorption of UVR, it also scatters & reflects visible light
Cosmetic appearance	Usually invisible	May leave a white cast
Best suited for	Everyday use	Sensitive skin, children, pregnancy, post procedure skin

How to Read a Sunscreen Label

Now we have all the info required to make an informed decision on the right sunscreen to choose.

Imagine you are standing in a pharmacy trying to choose between several different sunscreens. Every product claims to be the best, but now you know exactly what to look for.

For our understanding, let’s use the following hypothetical sunscreen label and go through it step by step.

✔ Brand Name

Choosing a reputable brand is always advisable. Many sunscreens available in the market may not consistently deliver the SPF claimed on their labels. As a dermatologist, I personally prefer sunscreens manufactured by well-established pharmaceutical companies, as there is generally greater confidence in their quality control, SPF testing, and product claims. That being said, no product is 100% foolproof.

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✔ Formulation

The formulation of a sunscreen is just as important as its SPF. Choosing the right formulation depends on your skin type and how you intend to use it.

Oily or Acne-Prone Skin

Choose non-comedogenic, oil-free gels, aqueous lotions, or dry-touch silicone-based sunscreens. These formulations are lightweight, reduce greasiness, and are less likely to clog pores.

Dry Skin

Cream-based formulations enriched with moisturizers and humectants such as glycerin provide better hydration and help maintain the skin barrier.

Sensitive Skin

Mineral-based, fragrance-free sunscreens are usually preferred because of their inert nature and lower risk of irritation or allergic reactions.

Combination Skin

Combination skin requires a balance between hydration and oil control. Lightweight gel-creams or oil-free lotions are often ideal, as they moisturize dry areas without making the oily T-zone feel greasy.

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✔ Broad-Spectrum Protection

As discussed earlier, always ensure that your sunscreen is broad-spectrum, meaning it provides protection against both UVA and UVB radiation.

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✔ SPF and PA Rating

For most individuals, I recommend choosing a sunscreen with SPF 30 or higher and a PA rating of +++ or ++++.

Remember, proper application and regular reapplication are far more important than simply choosing the highest SPF available.

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✔ Additional Protection

If mentioned on the label, look for additional protection against visible light and infrared radiation, particularly if you have pigmentary disorders or prolonged outdoor exposure.

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✔ Water and Sweat Resistance

The terms water-resistant and sweat-resistant do not mean that the sunscreen remains effective indefinitely while swimming or sweating.

• Water-Resistant (40 minutes): Maintains its labelled SPF protection for up to 40 minutes during swimming or sweating. Reapplication is required after this period.
• Very Water-Resistant (80 minutes): Maintains its labelled SPF protection for up to 80 minutes during swimming or heavy sweating. Reapplication is required after 80 minutes.

Note: In the United States, sunscreens labelled “water-resistant” or “very water-resistant” may also be labelled “sweat-resistant.”

In simple terms, both water-resistant and sweat-resistant sunscreens still require timely reapplication to maintain their effectiveness.

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✔ Non-Comedogenic

If you have acne-prone skin, look for the term “non-comedogenic.” These formulations are designed to minimize pore blockage and reduce the likelihood of acne breakouts.

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✔ Fragrance-Free

Fragrances are a common cause of irritation in some individuals. If you have sensitive skin or have experienced a reaction to a sunscreen in the past, choosing a fragrance-free formulation is often a safer option.

However, it is important to remember that an allergy can develop to any ingredient in a sunscreen, not just the fragrance. If you experience redness, itching, burning, or persistent irritation after using a sunscreen, consult your dermatologist for further evaluation.

How Much Sunscreen Should You Apply?

SPF testing is performed using a standardized sunscreen application thickness of 2 mg/cm², which corresponds to approximately 30 mL of sunscreen for the entire body surface.

At first glance, this may sound confusing. How do I calculate 2 mg/cm²? How can I measure 30 mL of sunscreen every day, especially when sunscreens are expensive?

These are practical concerns that many people have.

Don’t worry—I have you covered.

Fortunately, researchers have developed simple methods that help us apply approximately the recommended amount without having to measure sunscreen every time.

The Teaspoon Rule

One of the most widely recommended methods is the Teaspoon Rule, which describes how much sunscreen should be applied to different parts of the body.

The infographic below provides a simple visual guide that you can save and refer to whenever needed.

3 mL (slightly more than half a teaspoon)

• for each arm
• for the face and neck

6 mL (slightly more than a teaspoon)

• for each leg
• for the chest
• for the back

The Two-Finger Rule

Another easy method, which you may have heard of before, is the Two-Finger Rule.

In this method, sunscreen is squeezed out in two continuous strips along the index and middle fingers, starting from the first crease at the base of the fingers (palmar crease) and extending all the way to the fingertips.

The entire amount is then applied evenly over the face and neck.

The most important point is not the fingers themselves, but the quantity of sunscreen. The sunscreen should extend from the base crease of the index and middle fingers to their fingertips. This approximates the amount used during laboratory SPF testing for the face and neck.

Is It Practical for Everyone?

I understand that using the recommended quantity of sunscreen every single day may not be affordable for everyone. This is especially true when high-quality sunscreens can be expensive.

Fortunately, sunscreen is only one component of photoprotection.

“I understand that using the recommended quantity of sunscreen every single day may not be affordable for everyone“

Simple lifestyle measures such as avoiding peak sunlight hours (10 AM – 3 PM), walking in the shade whenever possible, wearing protective clothing, hats, and sunglasses can significantly reduce ultraviolet exposure in everyday life.

In addition, Indian skin naturally contains more melanin, which provides some degree of natural protection against ultraviolet radiation. However, this natural protection is not sufficient to replace sunscreen, especially in individuals with prolonged sun exposure or photosensitive skin disorders.

If you have conditions such as melasma, post-inflammatory hyperpigmentation, lupus, polymorphic light eruption, or other photosensitive disorders, regular sunscreen use becomes an essential part of treatment. In these situations, not using sunscreen can ultimately result in a much greater financial and emotional burden due to persistent disease, repeated treatments, and reduced quality of life.

Frequently Asked Questions (FAQ)

Which sunscreen do dermatologists recommend?

There is no single “best” sunscreen for everyone. The ideal sunscreen is one that suits your skin type, provides broad-spectrum protection with SPF 30 or higher and PA+++ or PA++++, is comfortable enough for daily use, and is applied generously and consistently. The best sunscreen is the one you will actually use every day. And remember, sunscreen is just one of the components in sun protection. Maintaining a good sun etiquette is equally important as described in the article.

“Maintaining a good sun etiquette is equally important“

Conclusion

If you have reached this point, congratulations—you now know more about sunscreens than most consumers.

Choosing a sunscreen should never be based solely on advertisements, influencer recommendations, or the highest SPF number on the shelf. Instead, it should be based on an understanding of your skin type, broad-spectrum protection, SPF, PA rating, the right formulation, and, most importantly, using the correct quantity consistently.

References For Further Reading

1. Kaimal S, Abraham A. Sunscreens. Indian J Dermatol Venereol Leprol 2011;77:238-243
2. Kohli M, Srinivas CR, Saraswat A, Ganjoo A, Kathed A, Patel G, Podder I, Krupashankar DS, Sachdev M, Vedamurthy M, Kandhari R, Damisetty R, Rajan R, Aurangabadkar S, Dhoot D, Balasubramanian A, Patil S, Barkate H. Practical Recommendations for Indians on Sunscreen Use-A Modified Delphi Consensus by Indian Sunscreen Forum (PRISM-ISF). J Cosmet Dermatol. 2025 Sep;24(9):e70441. doi: 10.1111/jocd.70441. PMID: 40955142; PMCID: PMC12439021.
3. Taylor S, Diffey B. Simple dosage guide for suncreans will help users. BMJ. 2002 Jun 22;324(7352):1526. doi: 10.1136/bmj.324.7352.1526/a. PMID: 12077052; PMCID: PMC1123459.
4. Isaacs T, Jacobs T, Whitaker D, Visser W, Wiid K, Dlova NC, Wright CY, Tod B. Sun Protection Advice for the South African Population for the Prevention and Management of Skin Diseases. Int J Dermatol. 2026 Jan;65(1):57-68. doi: 10.1111/ijd.17994. Epub 2025 Aug 4. PMID: 40755064; PMCID: PMC12712754.
5. SPF Lies? What Your Sunscreen Isn’t Telling You | Vantage with Palki Sharma | N18G
6. Rook’s Textbook of Dermatology 10e
7. Fitzpatrick’s Dermatology 9e
8. IADVL Textbook of Dermatology 5e