The question that arises in everyone’s mind is, “What sunscreen is best?” The answer depends on the sunscreen’s SPF levels. So, understanding what SPF means before you buy sunscreen is crucial.
SPF is the number you see on sunscreen bottles for sun protection. It stands for sun protection factor.
SPF determines the amount of UV radiation it takes to burn sunscreen-protected and unprotected skin. (1) The sunburn protection from UVB radiation measures SPF values. Therefore, SPF numbers show sunscreen’s UVB protection. (2)
Previously, the highest SPF you could get in sunscreen was SPF 30. However, nowadays, higher SPF levels in triple digits are available, promising sun protection.
According to experts, high SPF levels increase sunburn protection. (2) A 2020 (3)(4) and 2018 research reported that SPF 100 protects the skin against UV radiation effectively, (5) more than any other SPF level.
Note: People with sensitive skin may experience some allergic reactions or skin irritation to certain sunscreen ingredients. These allergic reactions could also be through the nanoparticles of these ingredients.
Continue reading to learn more about the different SPF levels of sunscreen.
SPF 30, 50, 70, or 100: What’s Best Based on Scientific Evidence
A 2012 research reported that SPF 70 or above sunscreens have clinical benefits. SPF 70 is the minimum SPF for photodamage and skin cancer prevention. SPF 30 or 50 sunscreens might not protect your skin adequately at basic consumer usage levels. (6)
A 2020 research published in the Journal of the American Academy of Dermatology observed that high-SPF sunscreens with SPF 50 or more protect from sunburn in beach settings.
According to some clinical research, SPF 100+ was more effective for sunburn protection. It reduces the skin’s UV-induced erythema (acute UVB exposure stimulates the skin’s inflammatory response, causing erythema (reddening) and 24-hour increased blood flow). (7)(8)
In a 2018 research published in the Journal of the American Academy of Dermatology, about 199 adult participants were asked to wear different SPF sunscreen on either side of their face, such as SPF 50 on one side and SPF 100 on the other, and then spend the day in natural sunlight.
The researchers then measured the sun damage on either side of the face and reported that SPF 100+ was more effective in sunburn protection than SPF 50+. (9)
Therefore, a higher SPF provides more UVB radiation protection.
SPF 30, 50, 70, and 100: The Differences
SPF is sunscreen’s ability to block UV rays, especially UVB rays (the leading cause of skin cancer and sunburn).
SPF 30, 50, 70, and 100 are different sun protection levels indicating the amount of UVB radiation filtered out. A higher SPF offers higher protection. However, the difference is little.
According to researchers:
- SPF 15 offers 93.3% protection from UVB absorption.
- SPF 30 offers 96.7% protection from UVB absorption.
- SPF 45 offers 97.8% protection from UVB absorption.
- SPF 50 offers 98% protection from UVB absorption. (10)
- SPF 60 filters out almost 98% of all UVB rays.
- SPF 70 offers 99% protection from UVB absorption.
- SPF 100 offers 99.9% protection from UVB reaching the skin but also has some drawbacks.
The difference between SPF 30 and 100 is only 3% points, and the difference between SPF 50 and 70 is even smaller, meaning no sunscreen has the potential to block 100% of the UVB rays.
Other essential factors that must be considered, in addition to SPF number, are broad-spectrum coverage, water resistance, application, and reapplication.
Tips for Sunscreen Application While Sailing
Here are some valuable tips on sunscreen application for you to remember while sailing:
- Apply enough sunscreen, at least 1/4 tsp of sunscreen on your face, 1/4th tsp on your neck, 1/2 tsp on each arm, and 1 tsp on each leg, back, and chest.
- Evenly distribute the sunscreen by dabbing it gently instead of rubbing it, as it creates exposed spots. So, spread it in a thin, consistent layer throughout.
- Reapply sunscreen every 2 hours of sun exposure.
- No matter how diligently you reapply or how high the SPF is, a sunscreen with the wrong formula is useless. Therefore, wear a sweat or water-resistant sunscreen, preferably sebum-resistant (labeled as “sport” sunscreen), for heavy-duty activities. They don’t wear off easily.
Downsides of Using High-SPF Sunscreen
Here are a few potential downsides of high-SPF sunscreen:
- Certain sunscreen ingredients may cause allergic reactions or skin irritation, especially in people with sensitive skin.
- People mistake high SPF for prolonged sun exposure without reapplication. However, you must reapply sunscreen every 2 hours, especially if swimming or sweating.
- Sunscreen with high SPF is costlier than low-SPF ones.
- Sunscreen with high SPF may not protect from certain UV rays, such as UVA, which is responsible for wrinkles and aging.
- Sunscreen with high SPF may not be available in some places.
Sunscreen application is imperative, but be aware of its drawbacks. Go for a sunscreen that suits your skin type and is fit for the outdoor activities you will be doing.
Also, note that using sunscreen with other sun-protection measures, such as wearing protective clothing and staying in the shade, is also important.
The Difference Between UVA and UVB
The following are the differences between UVA and UVB rays.
UVA (320-400 mm)
- Not absorbed by biological targets directly
- Penetrates deeper than UVB
- Produces reactive oxygen and affects connective tissues, also creating profound immunosuppression
- Causes photoaging, tanning, exogenous photosensitization, photocarcinogenesis, and several idiopathic photodermatoses (including polymorphous light eruption)
UVB (290-320 mm)
- Causes the most severe damage
- Impacts cell DNA and proteins directly
- Causes acute damage, such as sunburn
- Causes long-term damage, such as cancer
What Is the Grading System of SPF?
A 2011 research reported the following grading system for SPF:
- SPF 2–15, low
- SPF 15–30, medium
- SPF 30–50, high
- SPF >50, higher (11)
Do the Lips Need Sunscreen?
Lips are a sensitive part of the body and are prone to skin cancer. Therefore, dermatologists suggest using a lip balm or lipstick with SPF 30 or more.
Sunscreen protects the skin from the harmful UV rays and their effects, such as skin cancer, skin damage, and sunburn. Therefore, it is a crucial and foremost part of skin care.
However, not every sunscreen is equal; their SPF levels differ. SPF indicates how much UVB rays a sunscreen can block. A higher SPF offers higher protection from UVB rays. However, it does not measure the protection against UVA rays responsible for aging and skin damage.
Therefore, choose a broad-spectrum sunscreen for both UVA and UVB protection.
- Latha MS, Martis J, Shobha V, et al. Sunscreening Agents: A Review. The Journal of clinical and aesthetic dermatology. January 2013. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3543289/.
- Center for Drug Evaluation and Research. Sunscreen: How to help protect your skin from the sun. U.S. Food and Drug Administration. https://www.fda.gov/drugs/understanding-over-counter-medicines/sunscreen-how-help-protect-your-skin-sun.
- Author links open overlay panelIndermeet Kohli PhD a ∗, a, b, et al. Greater efficacy of SPF 100+ sunscreen compared with SPF 50+ in Sunburn Prevention during 5 consecutive days of sunlight exposure: A randomized, double-blind clinical trial. Journal of the American Academy of Dermatology. September 19, 2019. https://www.sciencedirect.com/science/article/abs/pii/S0190962219327550.
- Sander M, Sander M, Burbidge T, Beecker J. The efficacy and safety of sunscreen use for the prevention of skin cancer. CMAJ : Canadian Medical Association journal = journal de l’Association medicale canadienne. December 14, 2020. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7759112/.
- Williams JD;Maitra P;Atillasoy E;Wu MM;Farberg AS;Rigel DS; SPF 100+ sunscreen is more protective against sunburn than SPF 50+ in actual use: Results of a randomized, double-blind, split-face, natural sunlight exposure clinical trial. Journal of the American Academy of Dermatology. https://pubmed.ncbi.nlm.nih.gov/29291958/.
- Ou-Yang H;Stanfield J;Cole C;Appa Y;Rigel D; High-SPF sunscreens (SPF ≥ 70) may provide ultraviolet protection above minimal recommended levels by adequately compensating for lower sunscreen user application amounts. Journal of the American Academy of Dermatology. https://pubmed.ncbi.nlm.nih.gov/22463921.
- The immune response to influenza is suppressed by the synthetic food … https://faseb.onlinelibrary.wiley.com/doi/abs/10.1096/fasebj.2019.33.1_supplement.505.3.
- Kohli I;Nicholson CL;Williams JD;Lyons AB;Seo I;Maitra P;Tian X;Atillasoy E;Lim HW;Hamzavi IH; Greater efficacy of SPF 100+ sunscreen compared with SPF 50+ in Sunburn Prevention during 5 consecutive days of sunlight exposure: A randomized, double-blind clinical trial. Journal of the American Academy of Dermatology. https://pubmed.ncbi.nlm.nih.gov/31542406/.
- SPF 100+ sunscreen is more protective against sunburn than SPF 50+ in … https://www.jaad.org/article/S0190-9622%2817%2932908-0/fulltext.
- Dale Wilson B, Moon S, Armstrong F. Comprehensive Review of Ultraviolet Radiation and the current status on Sunscreens. The Journal of clinical and aesthetic dermatology. September 2012. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3460660/.
- Seth P. Sunscreens. Indian Journal of Dermatology, Venereology and Leprology. February 28, 2011. https://ijdvl.com/sunscreens/.