Why does sunlight lighten hair while it darkens the skin?

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With the rising temperatures during the summer season, especially in Arab countries that experience scorching heat, it can have an impact on the health and appearance of your hair. This can lead to dryness, split ends, and rough texture. Furthermore, prolonged exposure to the sun can significantly affect the color and luster of your hair. We also understand your desire to enjoy your summer vacation and spend time under the sun or exploring beautiful places, but this can expose your hair to direct sunlight for extended periods. It's essential to understand how sunlight affects your hair, just as you care about its impact on your skin. In this article, we'll explain how sunlight affects hair and why it can lighten hair color while darkening the skin.

Why does the sun lighten hair color?

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In reality, ultraviolet rays from the sun work to break down any tissue exposed to them for extended periods. As we know, hair is made up of a substance called melanin, which is responsible for its natural color. So, sunlight oxidizes the melanin in your hair, turning it into a colorless compound. This is what makes your hair appear lighter and duller compared to its original color. The hair remains light until new hair follicles grow, at which point the hair returns to its natural color.

In other words, sunlight destroys the melanin in the hair, causing it to lose the color it derived from melanin. Strands of hair remain this light color until new hair follicles grow.

Why does the sun darken the skin?

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While the sun's impact on hair color is to lighten it, its effect on the skin is entirely the opposite. Sunlight darkens the skin, and when exposed to significant amounts of sunlight, it can damage skin cells. These damaged cells release chemicals that alert the skin that it's under threat. In response, the skin produces more melanin, which leads to a darker, tanned appearance. This mechanism doesn't apply to hair because the outer part of the hair is considered dead, so there's no defensive response to stimulate increased melanin production. Instead, sunlight destroys melanin without triggering a protective reaction. This is why your hair appears lighter after exposure to sunlight.

In more severe cases, such as prolonged and direct exposure to strong sunlight in high temperatures, it can lead to various degrees of sunburn, causing the skin to become red, irritated, and quite painful.

The Positive Impact of Sunlight on Hair

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In reality, sunlight can have both beneficial and detrimental effects on hair, depending on the amount of exposure it receives each day. Regular and moderate exposure to sunlight over a certain period can bring various benefits to your hair, such as maintaining its strength and natural shine. However, excessive exposure can lead to various hair problems. Here are some of the positive effects of sunlight on hair:

1. Hair Lightening:

The primary effect of sunlight on hair is lightening. Exposing your hair to the sun for a short duration on sunny days with moderate temperatures can help lighten the color of your hair and give it a natural shine. It also contributes to revitalizing your hair, making it look more vibrant and lustrous.

2. Reduced Hair Loss:

Several medical studies have found that regular exposure to sunlight is beneficial for hair health. It increases the production of vitamin D, which is crucial for bone health, and it also helps reduce hair loss by stimulating calcium to bind with the hair, thereby minimizing hair loss. Therefore, regular exposure to sunlight can help you address the issue of hair loss. It's essential to ensure that you follow a diet rich in foods containing vitamin D to maintain hair health.

3. Hair Growth Enhancement: 

During the summer, people are more exposed to sunlight, making it the ideal season for hair growth. Some individuals even shave their heads entirely during this season, as they notice that their hair grows faster compared to other seasons. From a scientific perspective, this is accurate. Regular exposure to sunlight can stimulate blood circulation in the small vessels that nourish the scalp, promoting hair growth. After a few months of sunlight exposure, you may notice your hair has grown a few centimeters longer.

The Negative Impact of Sunlight on Hair

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1. Hair Dryness and Damage:

Even short periods of exposure to sunlight without proper protection in Arab countries with high summer temperatures can lead to hair damage and dryness. It can cause the hair to appear dull and lose its luster.

2. Effect of Seawater or Swimming Pools on Hair:

In this case, the impact of sunlight is indirect. With rising temperatures, many people head to beaches and swimming pools, exposing their hair to saltwater or chlorine commonly found in pools. This can irritate the scalp and accelerate hair damage over time.

How to Protect Your Hair from Sunlight and Its Negative Effects

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1. Avoid Peak Sun Hours: 

During the summer, daylight hours are long, providing ample time to enjoy and benefit from sunlight. However, it's advisable to avoid going out in the afternoon, especially from noon until 4 PM, when the sun is at its highest point. During this time, the sun's ultraviolet rays can cause harm to your skin and hair. Sunburn, especially for children and the elderly, can be severe in some cases.

2. Wear a Hat or Head Covering:

Another effective way to protect your hair from the harmful effects of the sun is to wear a hat, scarf, or head covering. These accessories prevent sunlight from directly reaching your hair. It's also recommended to use a specialized sunshade to protect your skin from the sun. If you're concerned about wearing a head covering due to its potential impact on your scalp, you can read our article on how head coverings affect scalp health to find answers to your questions.

3. Use Sunscreen for Hair:

Many products are available to protect your hair from the sun's rays, as well as from the salt and chlorine found in pools. Hair sunscreen wraps your scalp and hair follicles, helping protect them from various external factors that can damage your hair and make it brittle. Hair sunscreen also moisturizes and nourishes your hair deeply, often in the form of hair conditioner or cream. Additionally, use sunscreen specifically designed to protect your skin from sunlight.

4. Rinse Your Hair with Fresh Water Before and After Swimming: 

The final piece of advice is to rinse your hair with fresh water before and after swimming, whether in the sea or a pool. Prepare your hair before swimming and ensure you have a post-swim hair care routine. These steps will effectively protect your hair color from chlorine or salt-induced changes and help avoid problems like dry and brittle hair caused by swimming. If your hair is long, consider tying it to prevent tangling.

In summary, sunlight offers numerous benefits to hair and skin health in general. However, it also has its drawbacks if you don't understand when and how to expose yourself to it. Regular, indirect exposure without excessive sun exposure is key to reaping its benefits and enjoying the advantages it offers.