What’s the Difference Between UVA and UVB Rays?
New Zealand has some of the highest ultraviolet radiation (UV) levels in the world – so we’re warned about the perils of UV damage from a young age.
What we aren’t always told, though, is that there are two main types of solar radiation: UVA and UVB rays. While both are detrimental to the complexion, they have different long-term implications on your skin’s overall health – so it’s important to understand the distinction.
In this guide, we’re helping you do just that. Read on as we explore the differences between UVA and UVB rays, and walk you through a range of supportive skincare and sun-safe habits you can practice to shield your skin from UV damage – all year round.
What is ultraviolet radiation?
Ultraviolet radiation is a type of electromagnetic energy emitted from both natural light sources (sunlight) and artificial sources (lasers, black lights, and tanning beds).
The sun emits two types of UV radiation that reaches our skin: ultraviolet A (UVA) and ultraviolet B (UVB). Ultraviolet C (UVC) is another type of UV radiation, but it can’t pass through the ozone layer1. UV rays account for only 5% of the sun’s rays that reach Earth, but they have a powerful effect on the skin.
1.https://www.hopkinsmedicine.org/health/conditions-and-diseases/ultraviolet-radiation
What is the UV index?
The UV index is used to predict the intensity of UVA and UVB rays throughout the day2 – and the higher the number, the more intense the UV radiation.
If the UV index measures at higher than 10, it is considered “extreme”. In New Zealand, the maximum UV index in summer is typically 12, but in far-northern parts of the country, it can even exceed 132. In winter, the UV index generally measures at one or two2. Sun protection is recommended when the UV index exceeds three3.
2.https://niwa.co.nz/atmosphere/uv-and-ozone/uv-index-information
3.https://www.cancer.org.au/cancer-information/causes-and-prevention/sun-safety/uv-index
What do UVA rays do?
UVA rays have long wavelengths and account for approximately 95% of the UV rays that reach our skin4. UVA rays are present during all daylight hours, all year round – even when it’s cloudy or overcast.
While you don’t necessarily feel the effects of UVA rays on your skin, the consequences accumulate over time, causing cellular damage in the skin. This is known as “photoaging”, and is characterised by increased dark spots, deeper-set fine lines and wrinkles, broken blood capillaries, and changes in skin elasticity.
In addition to visible signs of premature ageing, cumulative UVA exposure can also play a role in skin cancer4.
4.https://www.skincancer.org/risk-factors/uv-radiation
What do UVB rays do?
UVB rays have a shorter wavelength than UVA rays and only make up a small percentage of the solar radiation that reaches the skin – but they’re still dangerous.
The majority of UVB radiation is absorbed by the epidermis, and these rays are responsible for the more obvious, “immediate” effects of UV exposure: suntan and sunburn. As such, they’re typically known as the “burning” UV ray.
Like UVA radiation, long-term exposure to UVB rays is known to cause cell death and skin cancer, especially for those with fairer skin.
UVA and UVB rays: what's the difference?
While both types of UV radiation can have damaging effects on the skin, there are some key differences between UVA and UVB rays
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UVA rays:
- Penetrate deep into the dermis (your skin’s middle layer)
- Always present during the daytime, even when the sun isn’t visible
- Can penetrate clouds and glass
UVB rays:
- Penetrate the epidermis (your skin’s outermost layer)
- Can be more menacing at high altitudes, and their intensity is dictated by seasons and the time of day
- Are blocked by glass, clouds, and protective clothing
So, is UVA and UVB rays? Well, both types of UV rays cause long-term skin cell damage. However, UVA rays are associated with accelerated signs of skin ageing while UVB rays are more often linked to DNA mutations that can cause skin cancer5.
5.https://www.cancer.org/cancer/risk-prevention/sun-and-uv/uv-radiation.html
How can you protect yourself against UV and UVB rays?
Sunscreen is, naturally, the gold standard of care when it comes to sun protection, but you can also support your skin in other ways.
From wearing protective clothing to reinforcing the skin moisture barrier, read on to find out how you can safeguard your skin against UVA and UVB rays damage.
Wear a daily broad-spectrum sunscreen with 50+ SPF
SPF isn’t the only thing that matters where sunscreen is concerned: you also want to make sure that the product you’re buying is labelled “broad-spectrum”.
This means you’re protected against both UVA and UVB rays. But remember, sunscreen should never be reserved for your summer skincare routine alone – it needs to be applied daily to shield your skin from UVA rays.
You can enjoy high UV protection with our Ultra-Light Daily Facial Sunscreen UV Defense SPF 50 PA++++. This non-comedogenic, broad-spectrum sunscreen is also enriched with antioxidants (baicalin and vitamin E) to defend against free radical damage.
For a sunscreen that protects against UV rays and visibly corrects premature signs of ageing, we recommend the Better Screen™ UV Serum SPF 50+ Facial Sunscreen with Collagen Peptide. This advanced lightweight sunscreen serum is formulated with collagen peptide to support smoother, firmer skin.
You should apply sunscreen 20 minutes before going outside to allow time for the product to absorb into the skin before any sun exposure. Sunscreen should be reapplied every two hours or after sweating, swimming, or towel-drying.
Introduce antioxidants into your skincare routine
When you experience UV damage, it triggers a process in the skin called “oxidative stress”: when the number of free radicals in the body exceeds the number of antioxidants. Oxidative stress is a primary driver of photoaging, but you can offset UV-related free radical damage with an antioxidant-rich skincare routine.
Key ingredients to look out for are vitamin C, vitamin E, and niacinamide. As antioxidants, these powerful ingredients help neutralise free radicals in the skin and protect against environmental damage.
For brightening and antioxidant benefits, we recommend the Powerful-Strength Line-Reducing Concentrate, which is formulated with 10.5% pure vitamin C. If your skin is on the oilier side, the Ultra Pure High-Potency 5% Niacinamide Serum can help regulate sebum production while delivering antioxidant protection to the skin.
Support your skin moisture barrier
While not directly related to sun protection, a fortified skin moisture barrier helps keep out harmful stressors – like UVA and UVB rays – acting as the first line of defence for your skin’s deeper, more vulnerable layers7.
You can strengthen your skin moisture barrier with a nourishing face cream like Ultra Facial Meltdown Recovery Cream, which is designed for sensitive, very dry, or compromised skin. Enriched with a blend of colloidal oatmeal, bisabolol, and provitamin B5, this moisturiser helps reinforce a damaged skin moisture barrier, reduce visible signs of redness, and protect against external aggressors.
7.https://pmc.ncbi.nlm.nih.gov/articles/PMC3479513/
Cover up with sun-safe clothing and avoid UV exposure where you can
This might be a no-brainer for us Kiwis, but it’s worth reiterating the importance of following other sun-safety measures whenever possible.
Sunscreen alone isn’t enough: when outside, stay in the shade if you can, avoid direct sunlight when the UV index is high, and try to cover exposed areas (like your scalp) with protective clothing and accessories. Sunglasses, long-sleeve shirts, pants, and broad-brimmed hats can all help shield the skin from UVA and UVB rays rays.
If you’re interested in learning more about one of the major long-term effects of UVA and UVB rays, explore our guide to hyperpigmentation next.
