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UV Rays and Collagen: Does Sunlight Deplete Collagen?

a woman is getting sunbathe - does the sun depletes collagen

There are some factors proven to deplete the levels of collagen in the skin, thus contributing to the ageing process.

Among these factors, unprotected sun exposure, along with ageing, is the leading factor in collagen decline, according to many studies and research.

This may also explain why sunlight is suggested to be the leading cause of skin ageing (1)


Most of us must have heard many times the name collagen especially in the last five years, through various communication channels, but mainly through advertisements.

What’s been claimed is that collagen has anti-ageing and cell-repair properties and is even called the fountain of youth by many.

That being the case, it shouldn’t be surprising to hear that the sales of collagen-containing beauty products and collagen supplements have risen sharply in recent years (2),(3).

Although there is an ongoing debate on the pros and cons of these products especially collagen supplements, one thing is indeed clear: collagen is an extremely important protein for the human body, particularly for the skin.

Dr Ohara Aivaz, a dermatologist from Cedars-Sinai Hospital, describes the importance of collagen for the skin saying: ” Collagen is what keeps our skin from sagging, giving us that plump, youthful look.” (4).

When collagen levels decrease in the human body for any reason, the skin becomes vulnerable to skin sagging, wrinkles and fine lines, all of which are signs of ageing in modern societies (5),(6),(7).

As mentioned at the beginning of the article; sunlight is one of the major causes of collagen decline. However, it is important to underline that only unprotected years-long sun exposure is considered a threat to your collagen reserves.


Sun Exposure and Collagen Decline

Thus far we have made one thing clear: ” Long-term unprotected exposure to the sun’s ultraviolet (UV) rays can deplete your collagen reserves, thus speed up skin ageing.”. However, we haven’t talked about why sunlight is bad for collagen reserves in your body yet.

In the rest of the article, we will be talking about how sunlight depletes your collagen reserves and also find out how to enjoy sunlight without letting it depleting your collagen fibres.


A-) What is Collagen and Why Is It Important For Your Skin? 

Collagen is the most abundant protein in your body and your body makes it naturally (4),(8),(9),(10). Furthermore, some collagen fibres allegedly can be stronger than steel (8), (11).

There are various roles of collagen in your body, ranging from strengthening your teeth, bones to helping blood clots.

In addition to its many roles throughout your body, collagen is rather important for your skin. In fact, it is safe to say that collagen is one of the most determining factors when it comes to skin quality.

Because, collagen, along with elastin, supports your skin’s structure and provides you with a smooth and youthful appearance (1).

When the collagen level decreases, your skin begins to lose its elasticity. Consequently, your skin becomes susceptible to skin sagging, wrinkles and fine lines.  

According to Robert Rountree, a board-certified family medicine doctor, “The Number one cause of skin ageing is the loss of collagen.” (12),(13).

As we have mentioned above, ageing and unprotected sun exposure are the two major causes of collagen loss.

As you age, not only the production of collagen in your body slows down, but also the quality of collagen becomes lower (14), (15),(16). This must also explain why children have smooth and flawless skin (17).

On the other hand, UV rays that exist in sunlight cause collagen to break down at a faster rate. That is why the sun is heavily associated with premature skin ageing.


B-) How Does Sunlight Deplete Collagen?

We now know that too much unprotected exposure to the sun’s ultraviolet rays is not good for your collagen reserves.

So, how does sunlight deplete collagen in your skin more rapidly and cause you to experience early signs of ageing such as wrinkles and fine lines?

Well, to understand how sunlight or more accurately UV rays deplete your collagen levels, we need to know two things.

  • Location of collagen in your skin
  • Types of UV radiation rays.

Location of Collagen In Your Skin 

Human skin has three layers:

  • Outermost layer: the Epidermis
  • Middle layer: the dermis
  • The bottom layer: the subcutis

Although collagen is found throughout your body, it is found in the dermis in your skin together with elastin, which also provides resilience and elasticity to your skin.

These two proteins, namely elastin and collagen, are vital for your skin structure.



There are two kinds of UV rays that we know can affect the skin. These are UVA and UVB ray and they affect your skin in different ways.

Ultraviolet B (UVB) rays have shorter wavelengths and have slightly more energy than Ultraviolet A (UVA) rays. Note that UVB rays are the main cause of sunburns (18),(19).

On the other hand, the UVA rays have a longer wavelength; therefore, they can penetrate deep into the dermis, where both collagen and elastin fibres are found.

When the UVA rays penetrate the dermis and damage collagen fibres, the body produces an abnormal amount of elastin (20).

When an unusual amount of elastin build-up can, it can lead to a condition in which enzymes mistakenly degrade the collagen and also the skin rebuilds incorrectly, according to the Skin Cancer Foundation (1).

The problem is that if collagen degradation and faulty skin rebuilding due to constant UVA constant exposure happen repeatedly, the skin becomes vulnerable to skin sagging, dryness, wrinkles and fine lines.

Various studies also prove the negative impact of unprotected sun exposure on collagen levels. In one study, researchers demonstrated the significant impact of UV rays on collagen structure (21).


C- How to Protect Your Skin Against The Sun 

One thing is clear now. If you let sunlight contact your bare skin, it can hurt your skin, especially in the long run.

What’s worse is that repeated unprotected sun exposure can significantly increase the risk of skin cancer (22),(23),(24).

So what to do? How to enjoy the sun and get benefits that the sun offers such as happiness and vitamin D.

As you probably guess, sunscreens are the best option. They can not only protect your skin but also help undo previous skin damage (1), (25).

Some of us may not be aware of the fact that sunlight is always with us, even on cloudy days. They can easily penetrate clouds and damage your skin. So, consider wearing sunscreen whenever you go out regardless of the weather.

Other protection options can be wearing a hat and sunglasses, especially on hot days.


D-) Other Factors That Deplete Collagen Levels?

So far, we have dwelled on two factors that deplete collagen levels, ageing and unprotected sun exposure. But there are other factors that can deplete collagen reserves, thus accelerating the ageing process.

Here are some of them:

  • High sugar consumption
  • Smoking
  • Alcohol consumption
  • Genetics



The sun is the main source of life on earth and we all need it. It improves your sleep, alleviates your mood, helps you make vitamin D and more indeed.

That being said, excessive unprotected sun exposure can be quite harmful to your overall health, but mainly to your skin.

In this article, we provided a scientific answer to the question of Does Sunlight Deplete Collagen?. The answer is obvious now, UV rays can destroy your collagen, hence bring about ageing signs such as wrinkles, fine lines and skin sagging.

So, consider showing due diligence when it comes to protecting your skin against the sun UV rays.



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