When it comes to sun protection, one of the most common questions concerns the number on the label: SPF 30, 50 or 50+? Do they really make a difference, or is it just marketing? This guide explains what the Sun Protection Factor actually means, clears up the most common myths and helps you choose the right SPF based on your activity — especially if you exercise outdoors.
What is SPF? The technical explanation
SPF stands for Sun Protection Factor. It indicates how much longer you can theoretically stay exposed to UVB rays before developing sunburn compared to having no protection at all.
For example, if your skin would normally start to redden after 10 minutes of direct sun exposure, an SPF 50 product could theoretically allow up to 500 minutes of protection.
However, this is a laboratory estimate. In real-life conditions, sweat, water, friction from clothing and insufficient application can significantly reduce a product’s effectiveness. This is why the recommendation is always to reapply sunscreen every two hours, regardless of the SPF level chosen.
It is also important to remember that SPF only measures protection against UVB rays, which are responsible for sunburn. Complete protection also requires defence against UVA rays, which penetrate deeper into the skin and accelerate skin ageing. This is where the concept of broad spectrum protection comes in: a sunscreen without this indication only provides partial protection.
SPF 30 vs SPF 50: what’s the difference?
One of the most common misconceptions concerns the difference between SPF 30 and SPF 50. In percentage terms, they may appear very similar: SPF 30 blocks around 97% of UVB rays, while SPF 50 blocks around 98%.
The real difference lies in the amount of radiation that reaches the skin. With SPF 30, around 3.3% of UVB rays can still penetrate the filter. With SPF 50, this decreases to around 2%.
This difference becomes meaningful during prolonged exposure or when exercising outdoors.
For people who practise outdoor sports, work outside or spend many hours exposed to the sun, moving from SPF 30 to SPF 50 or SPF 50+ can make a real difference to long-term skin health, especially for very fair skin types.
SPF 50+: what changes compared to SPF 50?
The 50+ label means that the product has been tested and demonstrated to provide a protection factor higher than SPF 50. In practice, SPF 50+ represents the highest level of sun protection recognised and recommended by European dermatologists.
SUNO formulations are certified SPF 50+ by Helioscience Expertise Solaire laboratory in Marseille and dermatologically tested at the University of Ferrara.
Broad spectrum: why SPF alone is not enough
The SPF number only refers to UVB protection. However, sunlight also contains UVA rays, which penetrate deeper into the dermis, contribute to photo-ageing — including wrinkles, pigmentation and uneven skin tone — and whose unprotected exposure is also a recognised risk factor for melanoma.
A broad spectrum sunscreen provides protection against both UVA and UVB wavelengths. It is essential to check this indication on the label: a product with SPF 50 but without UVA protection only provides part of the protection your skin needs.
SUNO formulations provide broad spectrum UVA+UVB protection, combined with functional active ingredients designed to help counteract oxidative stress.
Which SPF should you choose for sport? A practical guide
For outdoor athletes, sun exposure is often prolonged, sweating is intense and the skin faces additional stress from wind, cold, water and friction from sports equipment.
In these situations, the right choice is always SPF 50+ — but the SPF level alone is not enough. The formulation also matters.
Traditional sunscreens designed for beach use can run when you sweat, leave a greasy feeling on the skin and affect breathability. For athletes, these are real issues that can impact both comfort and performance.
At SUNO, we have developed specific formulations designed for the real conditions of sport:
- SUNO AIR for high-sweat activities such as running, cycling and trail running;
- SUNO ALPINE for mountain sports;
- SUNO FACE for targeted facial protection with anti-ageing benefits.
4 common SPF myths
1. “If I have a tan, I don’t need sunscreen”
False. A tan provides protection equivalent to approximately SPF 2–4 — a level so low that it cannot be considered protective in any real-life sun exposure situation (Harvard Health Publishing).
2. “A high SPF means I can stay in the sun all day without reapplying”
False. Any SPF product loses effectiveness over time. Reapplication every two hours is essential, especially after sweating or swimming.
3. “Cloudy days are safe”
False. Clouds only filter part of UV radiation: between 20% and 50% can still reach the skin on an overcast day. At higher altitudes, this effect becomes even stronger.
4. “With a high SPF, I won’t tan”
False. Tanning simply happens more gradually, giving the skin more time to adapt without damage. It is not a limitation — it is the body’s natural response working correctly.
Discover SUNO’s SPF 50+ broad spectrum formulations developed specifically for sport: SUNO AIR, SUNO ALPINE and SUNO FACE are available at sunosport.com and on Amazon.
