Sun protection habits

Clear guide to photoprotection habits: explains what UVA and UVB rays are, how they cause photodamage, aging and skin cancer, and what measures really work (clothing, shade, sunscreen and oral options as a complement).

Summary in 60 seconds

• Ultraviolet (UV) radiation is a key factor in photodamage and skin cancer ; prevention is based on reducing cumulative dose and intensity. WHO 2022
• UVA and UVB rays contribute to damage: UVB is more associated with sunburn; UVA penetrates deeper and is involved in photoaging and carcinogenesis. D’Orazio 2013
• The most effective strategy is a combination of measures : shade + clothing/hat/sunglasses + sunscreen applied and reapplied. WHO 2024
• Sunscreen capsules can be helpful in specific situations, but they do not replace topical sun protection or healthy habits. Chen 2015

What is photoprotection and why does it matter?

Photoprotection is the set of measures that reduces the skin’s effective exposure to UV radiation. This is important because UV radiation is the main preventable environmental factor associated with skin cancer and also accelerates visible skin aging (spots, wrinkles, loss of firmness, rough texture). WHO 2022

The practical key: it’s not about «avoiding the sun at all costs», but about avoiding excess , especially intense and repeated exposures, and maintaining habits that fit into your daily life.

How does UV radiation cause harm? (simple explanation, no complicated physics)

UV radiation can damage the skin in two main ways:

1. Direct damage to DNA
   UV radiation can cause DNA damage. Although the body repairs some of the damage, repeated exposure increases the likelihood of mutations that, over time, can lead to precancerous lesions and skin cancer. D’Orazio 2013
2. Indirect damage from oxidative stress and inflammation
   UV radiation also increases reactive molecules (oxidative stress), altering proteins, lipids, and inflammatory signals. This contributes to uneven pigmentation and the progressive deterioration of skin structure. D’Orazio 2013

Types of UV radiation: what to remember

• UVB : related to sunburn .

• UVA: penetrates more deeply; is linked to photoaging and also contributes to the risk of cancer.
  In real life, both are active, which is why broad-spectrum protection is recommended. WHO 2022

How do they cause aging?

Photoaging is accelerated aging caused by sun exposure. Over time, collagen degradation increases and elastin is altered; the skin loses firmness, and wrinkles and changes in texture appear. (Fisher 1997)

This doesn’t happen overnight; it’s a cumulative process. That’s why daily sun protection (even basic sun protection) is usually more effective than intensive measures only during vacations.

Why are they precursors to skin cancer?

Skin carcinogenesis is linked to mutations and changes in the skin microenvironment (inflammation, local immunosuppression) induced by UV radiation. Epidemiological and biological evidence supports the idea that reducing UV exposure reduces the risk. WHO 2022

An important point: tanning beds emit UV radiation and have been classified as carcinogenic. IARC 2009

How to choose and how to use it? (concrete steps)

1) Habits (the foundation)

• Plan your schedule : when the sun is strongest, prioritize shade and physical barriers.
• Shade with judgment : reduces dose, but does not eliminate it (there is scattered radiation and reflections).
• Avoid intentional tanning (including tanning beds). IARC 2009

2) Clothing, hat and glasses (constant protection)

• Clothing : tightly woven fabric, long sleeves when exposure will be prolonged; garments with UPF can be useful in sustained outdoor activities.
• Hat : wide brim to protect face, ears and neck.
• Glasses : UV filter (for example “UV400” or “100% UV”).

3) Sunscreen (topical filters): how to choose

• Broad spectrum (UVA/UVB).
• SPF 30 or higher on exposed areas.
• A texture you can tolerate so you can use it daily (this matters more than «the perfect brand»).
  Practical recommendations for use and reapplication are widely supported by dermatological societies. AAD 2025

4) How to apply it (what really changes the outcome)

• Apply a generous, even layer to all exposed areas.
• Reapply if you’re outdoors, and especially if you swim, sweat, or towel dry. AAD 2025
• Areas typically forgotten when applying sunscreen: ears, nape of the neck, back of hands, insteps and hairline.

Different types of photoprotection (including “capsules”)

A) Topical photoprotection: “organic” and “mineral” filters

• Organics : absorb UV radiation and transform it.
• Minerals : based on zinc oxide and/or titanium dioxide; they act by scattering and also absorbing part of the UV.
  In practice, the choice usually depends on tolerance, cosmetics, adherence and context (sports, beach, sensitive skin).

B) Oral photoprotection (“in capsule form”): what it can offer and its limitations

Oral photoprotection is studied as a complement , not as a substitute for clothing/shade/sunscreen.

• Nicotinamide (vitamin B3) : In people at high risk (history of non-melanoma skin cancer), a clinical trial showed a reduction in new non-melanoma skin cancers and actinic keratoses during the period of use. This does not equate to “permission to increase sun exposure.” Chen 2015
• Polypodium leucotomos : There is evidence of a modest systemic photoprotective effect in some studies (e.g., increasing the reddening threshold or modulating markers related to photodamage), with use as an adjuvant. Nestor 2015

Prudent guidelines if anyone wishes to consider them:

• Use them only as reinforcement , not to «withstand more sun».
• If you are pregnant, breastfeeding, have chronic illnesses, take medication, or have a history of skin cancer, discuss this with your healthcare professional before starting them.

Common mistakes

• Apply a small amount so that it «can’t be felt»: in real life, this reduces protection.
• Relying solely on sunscreen and forgetting clothing/shade (the most consistent protection usually comes from barriers). WHO 2024
• Do not reapply when applicable. AAD 2025
• Believing that “if I don’t get burned, I’m not harmed”: UV can cause cumulative damage even if there is no obvious burn.

Frequently Asked Questions

What is the difference between UVA and UVB?

• UVB is more associated with sunburn; UVA penetrates deeper and is associated with photoaging, as well as contributing to cancer risk. WHO 2022

How much sunscreen should I use?

• The key is to apply a generous, even layer to all exposed areas. If you use too little, the actual protection is reduced.

How often should I reapply?

• As a general rule: if you’re outdoors, reapply regularly and always after swimming, sweating, or toweling off. AAD 2025

Does clothing offer more protection than a protector?

• For prolonged sun exposure, heavy-duty/UPF clothing and shade are usually more consistent (they don’t depend on «reapplying»). Sunscreen complements what you can’t cover.

Do I need sun protection on cloudy days?

• UV radiation can reach even with clouds; the need depends on the time spent outdoors and its intensity.

Do «sun capsules» allow me to tan safely?

• No. If used, they are modest adjuvants and do not replace barriers or sunscreen. Chen 2015

Bibliography and sources

• World Health Organization. Ultraviolet radiation . Geneva: World Health Organization; 2022 Jun 21 [cited 2026 May 30] .
• World Health Organization. Radiation: Protecting against skin cancer . Geneva: World Health Organization; 2024 Jul 16 [cited 2026 May 30] .
• American Academy of Dermatology Association. How to apply sunscreen . Rosemont (IL): American Academy of Dermatology Association; 2025 Aug 15 [cited 2026 May 30] .
• US Food and Drug Administration. Sunscreen: How to Help Protect Your Skin from the Sun. Silver Spring (MD): US Food and Drug Administration; 2026 May 11 [cited 2026 May 30] .
• US Preventive Services Task Force. Skin Cancer Prevention: Behavioral Counseling . Rockville (MD): US Preventive Services Task Force; 2018 Mar 20 [cited 2026 May 30] .
• International Agency for Research on Cancer. Sunbeds and UV Radiation . Lyon: International Agency for Research on Cancer; 2009 Jul 29 [cited 2026 May 30] .
• D’Orazio J, Jarrett S, Amaro-Ortiz A, Scott T. UV Radiation and the Skin . Int J Mol Sci. 2013 Jun 7;14(6):12222-12248. doi:10.3390/ijms140612222.
• Fisher GJ, Wang ZQ, Datta SC, Varani J, Kang S, Voorhees JJ. Pathophysiology of premature skin aging induced by ultraviolet light . N Engl J Med. 1997 Nov 13;337(20):1419-1428. doi:10.1056/NEJM199711133372003.
• Chen AC, Martin AJ, Choy B, Fernández-Peñas P, Dalziell RA, McKenzie CA, et al. A phase 3 randomized trial of nicotinamide for skin-cancer chemoprevention . N Engl J Med. 2015 Oct 22;373(17):1618-1626. doi:10.1056/NEJMoa1506197.
• Nestor MS, Berman B, Swenson N. Safety and efficacy of oral Polypodium leucotomos extract in healthy adult subjects . J Clin Aesthet Dermatol. 2015 Feb;8(2):19-23. PMID:25741399.