Sunscreen packaging can be baffling. Terms like SPF, UVA, UVB and broad spectrum are everywhere, yet many people still struggle to understand what they actually mean — and how that affects their skin health. This confusion matters because sun exposure is a major factor in skin damage, ageing and skin cancers, including melanoma.
In this guide we break down the key sunscreen terms in simple language, explain how they relate to skin cancer risk, and clarify what to look for when choosing sun protection.
What Does SPF Really Mean?
SPF stands for Sun Protection Factor. It’s the number you see on nearly every sunscreen bottle and is meant to indicate protection against UVB rays — the type of ultraviolet light that primarily causes sunburn. (AAD)
- SPF15 blocks about 93% of UVB rays
- SPF30 blocks about 97% of UVB rays
- SPF50 blocks about 98% of UVB rays
These percentages assume the sunscreen is applied correctly and generously — something most of us don’t do in real life. (Sky News)
Important: SPF does not tell you anything about protection against UVA rays — the deeper-penetrating rays that contribute to ageing, DNA damage and long-term skin cancer risk. (AAD)
UVA vs. UVB — How Are They Different?
The sun emits many types of ultraviolet (UV) radiation, but two main types reach your skin: UVA and UVB.
UVB Rays
- Shorter wavelength
- Affect the outer layers of skin (epidermis)
- Cause sunburn
- Are linked to some types of skin cancer(Sky News)
UVA Rays
- Longer wavelength
- Penetrate deeper into the skin (dermis)
- Contribute to premature ageing (wrinkles, lines, pigmentation)
- Also linked to skin cancer risk because they damage DNA over time(britishskinfoundation.org.uk)
A useful memory aid:
“UVA = Ageing; UVB = Burning.” (britishskinfoundation.org.uk)
Unlike UVB, UVA rays are present all year round, even on cloudy days, and they can penetrate glass — meaning you’re still exposed indoors or in a car without proper protection. (britishskinfoundation.org.uk)
So What Does “Broad Spectrum” Mean?
Because SPF only measures UVB protection, it doesn’t guarantee any UVA coverage at all. The key is the label:
✔️ Broad-spectrum sunscreen — protects against both UVA and UVB rays. (AAD)
In the UK and EU, a sunscreen that claims to protect against UVA must carry the “UVA in a circle” logo. That means its UVA protection is at least one-third of its UVB protection — a legal standard required for reputable products. (Green People)
This dual protection is essential because both UVA and UVB contribute to skin cancer risk and cumulative DNA damage. (britishskinfoundation.org.uk)
Why Sunscreen Labels Are Still Confusing
Even when labels say “UVA/UVB protection,” many consumers misunderstand what that actually means:
- SPF numbers only refer to UVB protection.
- Labels may use marketing phrases like “protects against UV rays” without clarifying the depth or extent of protection.
- Some products list star ratings, PA ratings (common in Asia), or USP indications — and these aren’t standard across regions, which adds to the confusion. (Reddit)
The bottom line:
Just because a bottle has a high SPF number doesn’t mean it offers strong UVA protection unless it explicitly states broad-spectrum coverage. (TIME)
Choosing the Right Sunscreen
To protect your skin effectively, especially if you’re concerned about skin cancer, melanomas or sun damage:
✔️ Choose a broad-spectrum sunscreen with SPF 30 or higher.
Experts generally recommend at least SPF30, which blocks the majority of UVB rays and often comes with better UVA coverage. (AAD)
✔️ Apply generously and routinely.
Sunscreen must be applied liberally and reapplied every two hours — more often if you’re swimming or sweating. Even the best SPF will fail if applied too thinly. (AAD)
✔️ Combine sunscreen with other sun-safe behaviours.
Shade, protective clothing (wide-brim hats, UV-rated garments) and avoiding peak sun hours (late morning to mid-afternoon) improve protection.
Sun Safety and Skin Cancer Prevention
A 2015 dermatology survey showed most people misunderstand SPF and sunscreen labels, yet many do recognise that sun avoidance and protection help prevent skin cancer.
Sunburn is a known risk factor for melanoma, but DNA damage can begin long before visible redness. That’s why broad-spectrum sun protection is so important, and why clinicians emphasise regular SPF use even when it feels cloudy or cool outside. (britishskinfoundation.org.uk)
Even with sunscreen, regular mole checks and monitoring changes in your skin — especially if you have many moles or a personal/family history of skin cancer — are essential parts of long-term skin health.
Key Takeaways
- SPF measures protection against UVB rays, which cause sunburn. (AAD)
- UVA rays penetrate deeper, contribute to ageing and also play a role in skin cancer. (britishskinfoundation.org.uk)
- Broad-spectrum sunscreens protect against both UVA and UVB. (AAD)
- No sunscreen gives 100% protection — application, reapplication, shade and clothing all matter. (Sky News)
- Sunscreen is one part of sun safety; regular professional mole checks help catch concerning changes early.
Private Mole Checks & Removal
The London Mole Removal Centre is a private company, offering checks and treatment for unwanted moles and other skin lesions (cysts, skin tags, warts, verruca, lipoma etc) at a selection of mole removal clinics.
All consultations and treatments are carried out in person by doctors who are specially trained in the latest laser and skin surgery techniques and are highly experienced in the field.
Further advantages of private treatment at the London Mole Removal Centre include:
- No waiting lists
- Moles can often be removed in the same appointment as the consultation
- Choice of clinics in London and also Bristol
- Removed moles tested with report provided
For more information or to book a consultation, please complete the form on this web page or call 020 7731 3791.