1. Photochemical Damage:

   • UV radiation can initiate photochemical reactions within the hair fiber. Specifically, it can break down disulfide bonds, which are crucial for maintaining the structural integrity of the hair.
   • This bond breakage results in the formation of free radicals and reactive oxygen species (ROS) within the hair shaft, leading to oxidative stress and damage to proteins and lipids.

2. Protein Degradation:

   • UV radiation primarily targets the proteinaceous components of hair, such as keratin. Keratin proteins undergo structural changes, including fragmentation and cross-linking, due to UV-induced photochemical reactions.
   • These alterations in protein structure compromise the mechanical strength and elasticity of the hair, making it more susceptible to breakage and brittleness.

3. Moisture Loss:

   • UV radiation can disrupt the lipid layer on the hair's surface, which serves as a protective barrier against moisture loss.
   • As a result, the hair becomes more porous, allowing water molecules to escape more easily. This leads to dehydration and dryness, exacerbating issues such as frizz and rough texture.

4. Color Fading:

   • UV radiation can cause photodegradation of melanin pigments present in the cortex of the hair shaft. Melanin absorbs UV light to protect the underlying tissues from damage.
   • However, prolonged exposure to UV radiation can lead to the degradation of melanin molecules, resulting in fading of natural hair color or premature fading of artificial dyes.

5. Surface Damage:

   • UV radiation alters the structural arrangement of the hair cuticle, the outermost layer of the hair shaft.
   • The cuticle cells may become lifted, roughened, or even completely stripped away, exposing the underlying cortex to further damage.
   • This disruption of the cuticle's integrity contributes to increased friction between hair fibers, leading to tangling, breakage, and the development of split ends.

6. Scalp Effects:

   • Direct exposure of the scalp to UV radiation can lead to sunburn, characterized by redness, inflammation, and discomfort.
   • Sunburn on the scalp may also disrupt the normal function of hair follicles, potentially leading to temporary hair loss or scalp conditions such as folliculitis.

Overall, the cumulative effects of sun exposure on hair can result in compromised structural integrity, diminished aesthetic quality, and increased susceptibility to damage and environmental stressors. To mitigate these effects, it's essential to use protective measures such as wearing hats or scarves, applying UV-protective hair care products, and limiting sun exposure during peak hours.

1. Dryness and Brittle Hair: Sun exposure can strip the hair of its natural oils, leading to dryness and brittleness. This can make the hair more prone to breakage and split ends.

2. Fading of Color: Prolonged sun exposure can cause the color of dyed or natural hair to fade over time. This is particularly true for those with lighter hair colors, as the sun's UV rays can oxidize the pigments in the hair, causing them to lighten.

3. Weakened Hair Structure: The sun's UV rays can damage the protein structure of the hair, weakening its overall integrity. This can result in hair that feels rough and coarse to the touch.

4. Scalp Damage: Sunburn on the scalp is not uncommon, especially in individuals with thinning hair or those who part their hair in a way that exposes the scalp to direct sunlight. Sunburn on the scalp can cause redness, irritation, and flaking.

5. Frizz and Flyaways: Sun exposure can cause the outer layer of the hair, known as the cuticle, to become rough and raised. This can result in frizz and flyaways, making the hair appear unruly and difficult to manage.

6. Accelerated Aging: Just like the skin, prolonged sun exposure can accelerate the aging process of the hair, leading to premature graying and loss of elasticity.

To protect your hair from the harmful effects of the sun, consider wearing a hat or scarf when spending extended periods outdoors, using hair products containing SPF, and applying a leave-in conditioner or oil to help maintain moisture levels. Additionally, it's essential to stay hydrated and maintain a healthy diet rich in vitamins and nutrients that support hair health.