Does a Higher SPF Mean a Better Sun Shield?
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Significance of Choosing a Sunscreen With a Higher SPF

Published on Dec 29, 2022 and last reviewed on Feb 06, 2023   -  5 min read


Sunscreen's SPF is a measure of how it protects one from getting sunburned. Therefore, choosing a sunscreen based only on a high SPF can give better results.


Sunscreens are essential products that shield the skin from harmful sun rays. Which sunscreen product is most suitable depends on many factors, such as skin type, that is, how dry or oily the skin is, previous sun and skin cancer history, and medical history.

What Does the SPF Number Mean?

SPF (Sun Protection Factor) is a measurement of how much solar energy (UV radiation) is needed to produce sunburn on protected skin (that exists in the presence of sunscreen) related to the amount of solar energy needed to produce sunburn on unprotected skin. Therefore, as the SPF value increases, sunburn protection increases.

Does the Sunscreen With a High SPF Protect the Skin Better?

Dermatologists and photo biologists, due to the damaging effects of the sun's ultraviolet (UV) radiation on the skin ultraviolet light rays, are invisible to humans because they have shorter wavelengths than sunlight. However, within the UV spectrum, two types of rays can damage one's skin cells' DNA and lead to skin cancer. So, it is essential to protect from both types:

  • UVB rays cause sunburns and play a key role in developing skin cancer. Sunscreen's SPF number refers to the amount of UVB protection.

  • UVA rays cause skin damage leading to tanning and aging skin and wrinkles. The shortest wavelengths of UVA rays also contribute to sunburn. It is essential to look for the words "broad spectrum" on a product's label, which means it has ingredients that can protect one from UVA.

What Is the Purpose of Using Sunscreen?

Sunscreen is mainly used to protect the skin against ultraviolet radiation, which damages the skin. Sunlight generates warmth (infrared) that one can feel, visible light (that one's eyes can see in daylight), and ultraviolet light (UVL), which one cannot see or feel but can penetrate the skin.

  • The UV light that reaches the earth is grouped into shorter UVB and longer UVA wavelengths.

  • The skin makes vitamin D from small amounts of UVB, but more significant amounts of UVB may cause sunburn and contribute to skin cancers.

  • UVA penetrates more profoundly and significantly, or prolonged exposure may cause burning, premature skin aging, and skin cancers.

  • Both UVA and UVB suppress skin immune function.

For these reasons, sun protection is strongly recommended throughout our lifetime. Sunscreens do not provide total security and should be used with other sun protective measures, such as wearing sun protection and staying indoors or out of the sun during peak sunshine hours.

How Is Sunscreen Selected for Use?

Sunscreens protect the skin by absorbing and blocking harmful UVL. See topical sunscreen agents for a list of the active ingredients that make up the many sunscreen preparations available. All sunscreen products must be tested, classified, and labeled according to their sun-protective capabilities.

SPF for UVB:

  • SPF stands for sun protection factor. It shows how long one could expect to be exposed to UVB before burning than no sunscreen. For example, it takes ten minutes to burn without sunscreen and 150 minutes to burn with sunscreen. So the SPF of that sunscreen is 15 (150/10).
  • The higher the SPF number, the better the expected protection.

  • A sunscreen with an SPF 15 provides about 94 % protection against UVB.

  • Protection against UVB increases to 97 % with SPF 30 and 98 % with SPF 50+.

As one can see, the difference in protection when going from a sunscreen with SPF 15 to one with SPF 30 or even 50+ differs only by three to four percent. Also, this protection is only provided if sunscreens are applied in quantities similar to the ones used for testing. Six teaspoons of lotion for the body of one average adult person is enough.

  • In reality, most people apply sunscreen at about one-third of the thickness used for testing.

  • They need to apply it to all exposed areas of the skin.

  • They forget to reapply it every couple of hours or after heavy sweating or swimming.

Therefore, the actual protection may be much less than the tests indicate.

Broad Spectrum for UVA Protection:

  • With increasing awareness about UVA-induced skin damage, it is important to choose a sunscreen that also protects against UVA radiation. These products are labeled with the statement “broad spectrum.” Always choose a sunscreen that has at least one of its ingredients that protects across the full UVA range. These include,

  • Metal oxides.

  • Titanium dioxide.

  • Zinc oxide.

  • Chemical absorbers.

  • Avobenzone.

  • Bemotrizinol.

The UVA protection factor (UVA-PF) must be at least one-third of the labeled SPF, so choosing a sunscreen with a higher SPF will also mean higher UVA protection.


  • One should choose a photostable sunscreen to ensure that it will not break down and become ineffective on exposure to sunlight, such as:

  • Octocrylene.

  • Bemotrizinol.

  • Bisoctrizole is a photostable agent, and when combined with other chemical absorbing agents, it will improve the overall photostability of the sunscreen product.

How Is Sunscreen Selected Based on Skin Type?

Sunscreen selection depends on how sensitive one's skin is responding to sunburns and cosmetics, the dryness or oiliness of the skin, and one's previous general medical history and history of sun exposure and skin cancer.

  • For fair skin people that burn easily, one should choose a high-SPF broad-spectrum sunscreen SPF 50+ seen on the label.

  • If one's skin tans readily, one could choose a sunscreen with an intermediate type of SPF of 15+.

  • If one has darkly pigmented skin and they do not suffer from photosensitivity or abnormal pigmentation, they do not need sunscreen.

Sensitive Skin:

  • Sensitive skin has trouble tolerating sunscreens or cosmetics. Instead, look for hypoallergenic or low-irritant sunscreens. Try using various sunscreen samples before deciding what to use regularly. It causes rashes, which might have a sunscreen allergy, and need to undergo allergy patch screening to identify a particular ingredient in sunscreens causing the problem.

Dry or Oily Skin:

  • If one's skin is dry, one will benefit from sunscreen.

  • If one has oily skin or readily develops acne, choose a sunscreen with a thin base, such as an alcohol-based spray, lotion, or gel.

  • Lighter sunscreens are also available for hairy skin areas.

  • Sunscreen sticks are available and suitable for the nose, lips, and around the eyes.

During Activity:

  • If one gets wet or sweaty, choose a sunscreen labeled “water resistant.” These products show the amount of time one expects to get the declared SPF level of protection during swimming or sweating, for example, SPF 15 – water resistant for 40 minutes.

How to Use Sunscreen?

Apply the sunscreen liberally to all the sun-exposed areas that forms a film when initially applied.

  • It will take 20 to 30 minutes for the sunscreen to be absorbed by the skin, so apply it at least 30 minutes before going out in the sun.

  • Reapply sunscreen every two hours if staying in the sun for about more than an hour during the day.

  • Reapply immediately after swimming, excessive sweating, or if rubbed off by clothing or toweling, even if the product claims to be "water-resistant."

  • Insect repellents can reduce the sunscreen's SPF, so when used together, use a sunscreen with a higher SPF and reapply more often.


UVB rays are the main reason people develop sunburn and heat rashes, and if exposed to a more considerable amount, it can also lead to skin cancer. The number after the SPF entails how much protection it offers from UVB rays. The higher the SPF number, the greater the protection from UVB rays.

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Last reviewed at:
06 Feb 2023  -  5 min read




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