Understanding UV Light Spectrum & Its Effects

Monderma

Oliver Belcher

21 Apr 2025

UVA reaches deep into skin
UVB burns the surface layer
UVC is filtered yet hazardous
Each light type affects cells
Knowledge supports care with Monderma

Ultraviolet light appears in daily life through sunlight and artificial sources, so understanding its behaviour helps readers protect their skin with confidence. These light types influence ageing, comfort, and long term skin health.

In this article, we explain the key properties of UVA, UVB, and UVC. You will see how each wavelength affects the skin, how to approach protection, and why informed choices improve resilience over time.

Understanding UV Light

UV light sits beyond the visible spectrum and includes UVA, UVB, and UVC. Each type interacts with skin differently. UVA reaches deeper layers, while UVB affects the surface. UVC rarely reaches the ground due to ozone filtering.

These wavelengths influence collagen, comfort, and cell stability. They also appear in medical and industrial settings, which highlights their wide impact on health and daily routines [1].

UVA Light & Skin Ageing

UVA accounts for most UV radiation reaching the ground and can pass through glass and clouds. This means daily exposure occurs even indoors or in cooler weather [1,4].

UVA moves into the dermis where collagen and elastin sit. Over time this contributes to visible signs of ageing. UVA also links with DNA damage and skin cancers when exposure accumulates [1].

UVA Features

Aspect	Summary
Penetration	Reaches the dermis and passes through glass and clouds [1,4]
Health impact	Contributes to ageing and plays a role in skin cancer [1]

Table 1: UVA characteristics

UVA Uses

Aspect	Summary
Medical use	Appears in PUVA therapy for psoriasis and vitiligo under guidance [3]

Table 2: UVA uses

UVB Light & Surface Damage

UVB focuses on the outer skin layers and increases during midday sun. This wavelength is responsible for sunburn and plays a central role in DNA mutation leading to skin cancer [1,4].

UVB also supports vitamin D synthesis with brief, safe exposure. Medical teams use narrow band UVB therapy to treat psoriasis and eczema, improving symptoms in controlled settings [5].

UVB Features

Aspect	Summary
Penetration	Affects the epidermis and varies with time and season
Health impact	Causes burns and contributes to skin cancer risk [3]

Table 3: UVB characteristics

UVB Uses

Aspect	Summary
Medical use	NB UVB therapy treats psoriasis and eczema with monitored care [5]

Table 4: UVB uses

UVC Light & Hazard Risk

UVC does not naturally reach the skin because the ozone layer absorbs it. Artificial UVC appears in specialised lamps used for disinfection due to its strong ability to disrupt cellular DNA [1,7].

Although useful in enclosed systems, UVC exposure remains unsafe for the skin and eyes. Even short contact may cause burns or photokeratitis, so strict handling measures are essential [3,7].

UVC Features

Aspect	Summary
Penetration	Blocked by the atmosphere and seen only in artificial devices
Health impact	Causes burns and eye injury with no safe direct exposure [7]

Table 5: UVC characteristics

UVC Uses

Aspect	Summary
Industrial use	Disinfects air, water, and surfaces in controlled systems

Table 6: UVC uses

Comparing UVA, UVB & UVC

UVA moves deepest and contributes strongly to ageing. UVB affects the surface and causes burns. UVC is blocked naturally yet highly harmful when used in artificial devices.

Understanding these differences helps readers tailor protection to daily needs and recognise when specialist care or precautions are required.

UV Comparison Table

Type	Summary
UVA	Reaches dermis and contributes to ageing [1]
UVB	Causes burns and supports vitamin D formation [4]

Table 7: UVA and UVB comparison

Type	Summary
UVC	Hazardous artificial light used for disinfection [7]
Protection	Sunscreen, clothing, shade, and avoidance for UVC

Table 8: UVC comparison

Protection & Skin Health

Consistent sun protection helps reduce the impact of UVA and UVB on collagen, pigmentation, and long term skin stability. Sunscreen, clothing, and shade improve comfort and resilience through daily habits [8].

Moisturising and gentle routines help maintain the skin barrier after exposure. These steps support calm, stable skin and reduce irritation linked with environmental stress.

Conclusion

UV light influences skin health in different ways. UVA contributes to deeper ageing, UVB supports vitamin D formation at the surface, and UVC is used for disinfection but should never contact skin or eyes. Understanding these differences helps maintain safe, balanced exposure.

If you would like personalised skincare that reflects your own needs, you can explore a custom formula through Monderma.

Content is for informational purposes only. Monderma treatments are prescribed following consultation. Results and timeframes can vary. Use as directed by your prescriber.