Decoding UVA/UVB, Visible Light, Infrared-A, Blue Light/HEV and where it comes from.
UVA Radiation
UVA penetrates deeply into the dermis and generates free radicals that damage collagen and elastin fibres. This results in photoaging, including wrinkles, sagging, and loss of skin elasticity. UVA also harms DNA in skin cells and contributes to melanoma and other skin cancers. Additionally, it can provoke inflammatory responses that exacerbate conditions such as melasma.
Where UVA Radiation Comes From
Sun (primary source) - present year-round, even on cloudy days
Tanning beds - emit concentrated UVA, sometimes 10-15 times stronger than the sun
Some fluorescent lights emit small amounts
UV nail lamps used in salons
UVB Radiation
UVB directly damages DNA in skin cells by causing abnormal bonds between DNA building blocks. This triggers the inflammatory response that we observe as sunburn, resulting in redness, swelling, and pain. Repeated UVB damage can lead to mutations that may cause basal cell carcinoma, squamous cell carcinoma, and melanoma.
UVB also stimulates melanin production, contributing to skin tanning, but can trigger pigmentation, hyperpigmentation, and sunspots.
Where UVB Radiation Comes From
Sun (primary source) - strongest between 10 AM and 4 PM, varies by season and latitude.
Tanning beds - though most modern ones primarily emit UVA
Germicidal UV lamps - used for sterilisation
Some medical phototherapy devices
Visible Light
Blue and violet light generate reactive oxygen species in skin cells, leading to oxidative stress. This issue is particularly problematic for individuals with darker skin tones, as it can stimulate melanin production and aggravate hyperpigmentation disorders such as melasma. Furthermore, oxidative damage may also contribute to premature ageing by breaking down collagen.
Where Visible Light Comes From
Sun (contains the full visible spectrum)
LED lights - including household and office lighting
Digital screens - phones, computers, tablets, TVs
Fluorescent lights
Incandescent bulbs
Infrared-A Radiation
IR-A penetrates most deeply into the skin and generates heat, which can denature proteins and create free radicals. It activates enzymes known as matrix metalloproteinases (MMPs) that degrade collagen and elastin. This contributes to skin sagging, wrinkles, and a loss of firmness. The heat also enhances blood flow, which may exacerbate rosacea and other inflammatory conditions.
Where Infrared-A Radiation Comes From
Sun (primary source of IR-A)
Heat lamps and infrared heaters
Fireplaces and wood stoves (think sitting close to a fire in the winter months)
Hot surfaces - ovens, grills, heated car dashboards (particularly important for those who work in kitchens)
Saunas and steam rooms
Some industrial heating equipment
Blue Light/HEV
Similar to other visible light, blue light generates oxidative stress through the formation of free radicals. It can disturb the skin's circadian rhythm and natural repair processes. The high energy of these short wavelengths renders them particularly effective at triggering inflammatory cascades and melanin production.
The cumulative effect of all these exposures over time leads to photoaging and increased cancer risk, which is why broad-spectrum protection is becoming more critical in skincare.
Where Blue Light/HEV Comes From
Sun (strongest natural source)
Digital screens - smartphones, computers, tablets
LED lights - especially "cool white" LEDs
Fluorescent lights
Energy-efficient light bulbs
TV screens and gaming devices
Indoor vs. Outdoor Exposure
While the sun is the strongest source of UV and infrared light, we are increasingly exposed to visible light and blue light indoors through artificial lighting and screens. This is why dermatologists and skincare specialists now recommend broad-spectrum protection, even for indoor workers, particularly those who are near windows or use screens extensively.
