How much sunscreen do you need to protect your skin?

New Delhi, India Jun 22, 2026 ALN: Sunscreen protects your skin from the damaging effects of UV radiation, and can help prevent skin cancer.

However, despite its importance, experts warn that many individuals do not use enough sunscreen or apply it correctly, which can significantly undermine its effectiveness.

How does the sun damage your skin?

Sunburn is perhaps the most visible sign that your skin has sustained damage from the sun. However, it is crucial to understand that you do not need to experience a sunburn to incur skin damage. The primary culprit behind this damage is UV (ultraviolet) radiation emitted by the Sun.

While some exposure to UV radiation is beneficial, as it enables our skin to produce essential vitamin D, which is vital for the function of bones, blood cells, and our immune system, excessive exposure can lead to detrimental effects. Overexposure to UV radiation can cause premature aging, including wrinkles and sunspots, and significantly increases the risk of developing skin cancer.

The incidence of skin cancer, particularly melanoma, has been on the rise in many countries, including the UK, where the number of new melanoma cases diagnosed has surpassed 20,000 annually for the first time. According to Cancer Research UK, excessive exposure to UV radiation from both natural sunlight and artificial sources like sunbeds is a significant contributor to this alarming trend, with an estimated nine in every ten cases of skin cancer considered avoidable.

Moreover, prolonged sun exposure can also inflict damage on your eyes, leading to conditions such as cataracts and other forms of eye damage.

What is the UV Index and how does it work?

The UV Index is a standardized measure of ultraviolet radiation levels that is used globally to inform the public about the potential for harm from sun exposure. The index ranges from zero, indicating minimal risk, to levels that exceed ten, which signify a very high risk of harm from unprotected sun exposure.

According to Cancer Research UK, when the UV Index reaches three or higher, individuals should consider applying sunscreen and taking additional protective measures, such as covering up with clothing and seeking shade. The UV Index fluctuates throughout the day, typically peaking during a four-hour window when the sun is positioned at its highest in the sky, which is generally from late morning to early afternoon.

Many weather forecasts, including those from reputable organizations like the BBC Weather and the Met Office, include UV Index readings, making it easier for the public to stay informed about UV levels.

How much sunscreen do you need?

The National Health Service (NHS) emphasizes that most individuals do not apply enough sunscreen to ensure adequate protection. It is recommended that adults use approximately six to eight teaspoons of sunscreen to cover their entire body effectively. This amount equates to about 35 milliliters.

For optimal protection, sunscreen should be applied to all exposed skin, including often-overlooked areas such as the face, neck, ears, and scalp (especially if you have thinning hair or are bald). Ideally, sunscreen should be applied about 30 minutes before stepping outside to allow the product to absorb properly into the skin.

Furthermore, it is crucial to reapply sunscreen every two hours, or more frequently if you are sweating heavily, swimming, or towel-drying. This guideline holds true even for sunscreens labeled as water-resistant or long-lasting, as no sunscreen can provide complete protection against UV radiation.

To enhance sun protection, it is advisable to wear clothing that blocks sunlight, such as trousers or skirts made from tightly woven fabric, long-sleeved tops, a wide-brimmed sun hat, and UV-blocking sunglasses. Additionally, seeking shade during the hottest parts of the day can further reduce the risk of sun damage.

How can children be protected from the sun?

Extra precautions should be taken to protect babies and children, as their skin is notably more sensitive to sun damage than that of adults. The NHS advises that children younger than six months should avoid direct sunlight altogether, as sunscreen is not recommended for this age group.

Once children reach six months of age, the NHS recommends using a sunscreen with a minimum SPF of 50, which provides high levels of protection against both UVA and UVB rays. Parents should ensure that sunscreen is applied to all exposed areas of the child's skin and that it is reapplied regularly, especially after swimming or sweating.

Even when wearing sunscreen, children should be encouraged to stay out of direct sunlight during the peak hours of the day, typically between 11 AM and 3 PM. Additionally, wearing protective clothing, such as a wide-brimmed hat and UV-blocking sunglasses, is essential for safeguarding their sensitive skin.

What do the SPF numbers on sunscreen bottles mean?

The sun protection factor, or SPF, is the most prominent number found on sunscreen bottles and indicates the level of protection the product offers against UVB rays, which are primarily responsible for sunburn. The higher the SPF number, the greater the level of protection provided.

According to the British Skin Foundation, correctly applying sunscreen with an SPF of 30 would allow your skin to remain unburned for 30 times longer than it would without any protection. Specifically, an SPF of 30 allows approximately 3% of UVB rays to penetrate the skin, while an SPF of 50 allows about 2% to penetrate.

Both the British Skin Foundation and the NHS recommend using sunscreen with an SPF of at least 30 to ensure adequate protection against sun damage.

What do the star ratings on sunscreen mean?

In addition to SPF ratings, many sunscreen products feature a star rating system ranging from one to five. The NHS explains that this star rating measures the level of UVA protection offered by the sunscreen, with more stars indicating increased protection. Sunscreens with at least four stars are recommended for optimal UVA protection.

If a sunscreen bottle displays the letters "UVA" within a circle, it signifies that the product meets EU safety standards, providing an additional layer of assurance for consumers. Ideally, consumers should choose sunscreens that boast both a high SPF rating and a high star rating to maximize their protection against harmful UV radiation.

Can I use an old bottle of sunscreen?

Proper storage of sunscreen is essential to maintain its effectiveness. The British Association of Dermatologists advises that sunscreen should be stored in a cool, dry place, away from direct sunlight. Unopened sunscreen, when stored correctly, typically has a shelf life of around 30 months.

It is crucial to avoid using sunscreen that has passed its expiration date, as it may lose its effectiveness and fail to provide adequate protection. Some sunscreens do not have a specific expiration date but instead display a "period after opening (PAO)" symbol, which indicates how long the product remains effective once it has been opened. For example, a PAO symbol with "12M" means the sunscreen should be used within 12 months after opening.

What should you do if you get sunburned?

In the unfortunate event of sunburn, it is essential to take immediate steps to cool the skin and keep it hydrated. Drinking plenty of water is crucial to help your body recover, and applying soothing lotions or aloe vera to the affected areas can provide relief from discomfort. It is also important to avoid further sun exposure until the skin has healed to prevent additional damage.

In summary, understanding how to effectively use sunscreen and the importance of sun protection is vital for maintaining skin health and reducing the risk of skin cancer. By following the recommended guidelines for sunscreen application and taking protective measures, individuals can enjoy the sun safely while minimizing the potential harm caused by UV radiation.