How does the sun damage your skin?

Sun damage is easy to forget about once a sunburn fades, but this form of skin harm isn’t just short-term redness and discomfort: it's a serious threat to skin health.

UV rays penetrate deep into skin layers, causing long-term damage like premature ageing and skin cancer.

Sun damaged skin can be frightening, we know, so we’re here to arm you with knowledge and provide a deeper understanding of how sun damage affects the skin and the steps you can take to reduce its risks.

The more you know, the easier it is to protect yourself! And quick hint: sun protection involves more than just using SPF.

What you can expect:

• Types of UV rays
• What is photoageing?
• Signs of sun damage
• How to protect yourself from sun damage
• Can you reverse sun damage?

Types of UV rays

First, we have to get familiar with the external factors that cause sun damage – UV rays. There are two main types of UV rays that cause sun damage: UVA and UVB.

UVA (longer-wave) rays activate the skin in an unhealthy way until it tans, but they are not the rays responsible for sunburn. UVA rays go far deeper into skin and trigger skin cancer and premature ageing damage. Unlike UVB rays, the threat from UVA rays is fairly constant whenever it’s daylight. “Many of my patients are surprised to learn that UVA rays can penetrate glass, so the skin damage can even happen when you’re inside near a window or driving,” says dermatologist Dr. McLellan.

UVB (shorter-wave) rays are responsible for causing sunburn and trigger premature ageing damage. It’s mostly absorbed by the top layers of the skin and is considered the common cause of most skin cancers. Although shorter in length than UVA rays, UVB rays are more intense, especially during peak hours, which will typically be between 10 AM - 4 PM, which are the times of day we’re most likely to be outside! “The SPF on your sunscreen indicates how well it protects you from these UVB rays,” points out Dr. McLellan.

What is photoageing?

If you’ve investigated sun damage before, you've probably encountered the word “photoageing” which sounds a lot more complicated than it really is.

Photoageing is a term that’s used to describe all the pro-ageing skin damage (wrinkles, fine lines, uneven tone, dark spots) that the sun and light can cause. Photoageing is accrued throughout your life, every time you step into or are exposed to light. “It is always interesting to compare the sun-protected skin to sun-exposed skin in older people – you can really see the damage that happens over a lifetime of sun exposure,” says Dr. McLellan.

Although UV rays are major contributors, they’re not the only forms of light that can cause photoageing. High-energy visible light, otherwise known as HEV light, and infrared light (which we feel as heat) also add to the skin damage pot that is photoageing.

Signs of sun damage

Beyond the obvious short-term consequences like sunburn, sun damage has far more serious long-term repercussions for our skin.

Essentially, sun damage destroys the skin’s ability to maintain vital components such as antioxidants, essential fatty acids, ceramides, hyaluronic acid and vitamins. Our skin needs these components to look young and healthy. It creates the perfect storm that allows for barrier impairment that can, of course, lead to many other undesirable skin concerns. Unprotected exposure to UV light can even cause immune system damage which impacts our health in numerous ways.

In addition to potentially life-threatening skin cancer and immune impairment, the long-term signs of sun damage and consequences of unprotected sun exposure from UVA and UVB rays include:

• Increased fine lines and wrinkles
• Skin discolourations and uneven tone
• Dry, thin & crepey-looking skin
• Compromised skin architecture, resulting in a less firm appearance
• Build-up of dead cells on and within the surface layers, resulting in dull & congested skin

UVA damage is more insidious because you don’t feel any pain or discomfort from it while it’s harming your skin. Over time, this causes skin abnormalities, resulting in the worst forms of skin ageing and a heightened risk of skin cancer. “We need to end the perception that a tan looks healthy. Even without a sunburn, UVA exposure is leading to skin damage,” says Dr. McLellan.

How does vitamin C work?

It is a natural component of skin, supporting important functions. For example, it firms the architecture of the skin by stimulating beneficial substances like collagen, which defends against oxidative damage (caused by sun exposure) and regulates melanin production to disrupt factors triggering the development of dark spots and uneven tone. In fact, it’s the most abundant antioxidant found in skin!

The research shows that as we age and as we’re exposed to environmental stressors (such as UV rays and pollution), these high vitamin C levels get depleted. Applying a vitamin C product topically – when formulated and packaged correctly – can help counter some of the visible effects (think dark spots, wrinkles and loss of firmness) that occur from this depletion.

How to protect yourself from sun damage

Honestly, prevention is the only way to truly save your skin from sun damage. Once your skin is damaged, some visible repair is possible but there is only so much you can do.

This truth means it’s integral to wear an eye cream or sun cream rated SPF 30+ or PA++++ every day, rain or shine. Ramp up to SPF 50 when you know you’ll be outside for long periods of time or if the sun’s intensity measures an 8 or higher on the UV index. Those with increased risk factors should always follow the SPF recommendation from their doctor.

Remember: It’s never too late to start using an SPF, but the sooner the better. You may be amazed by how quickly your skin begins to look and feel healthier once you start protecting it from UV light. “Sunscreen shouldn’t just be for the beach – I encourage everyone to incorporate sunscreen on exposed areas into part of their normal daily routine for the best protection,” says Dr. McLellan.

Keep in mind that if you’re going to be outside for long periods of time or sweating, you will need to reapply your SPF regularly (if not in water, then every two hours; if in water or sweating profusely, more often!) to ensure you are getting full protection. Also, be aware that some medications and skincare products can make your skin more sun sensitive. Consult your pharmacist if you’re unsure about sun exposure risks of any medications you routinely take.

A couple more prevention tips: lips can get sun-damaged too. Protect them with a lip balm that includes SPF and reapply it regularly because eating, drinking and even talking will make it wear off. “Don’t forget your scalp, ears and hands,” reminds Dr. McLellan. “Many people are focused on protecting their face but forget about these other vulnerable areas.

Preventing sun damage doesn’t stop with sun cream. Other protective measures are equally vital and include wearing a broad-brimmed hat, sunglasses (UV light causes many common eye problems we associate with just getting older), and UPF-rated clothing. Of course, avoid the midday sun whenever possible and seek shade when you can.

Can you reverse sun damage?

No, sun damage can’t be 100% undone but there is skincare that can help diminish the appearance of ageing effects in surprising ways, including the following:

• AHA or BHA exfoliation: helps remove the build-up of unhealthy skin caused by sun exposure, restoring smoothness, improving skin tone and leading to an overall more radiant complexion. Also plays a role in restoring a firmer, plumper look and feel.
• Retinol: visibly prevents and diminishes the appearance of wrinkles and other signs of ageing caused by the sun’s harmful effects.
• Vitamin C: dramatically brightens uneven skin tone brought on by sun exposure.
• Antioxidant serum: helps shield skin against environmental damage (including air pollutants) and boosts the efficacy of your SPF.
• Barrier-fortifying moisturiser: nourishes the skin barrier and hydrates, helping to strengthen defences and prevent future damage.

Sun damage can seem frightening, we get it. But remember, the sooner you act, the better you’ll be able to protect your skin in the long run! Years later you won’t be seeing as many signs of ageing as other older people. Instead, your skin will be noticeably younger and more even.

References for this information:

1. Cleveland Clinic, Accessed July 2023, Webpage
2. International Journal of Molecular Sciences, February 2021, ePublication
3. Photodermatology, Photoimmunology and Photomedicine, January 2018, pages 50-59
4. Journal of Cosmetic Dermatology, February 2020, pages 407-415
5. Biomed Research International, December 2016, pages 1-10