When it comes to UV protection, we think of protecting our skin using SPF creams. But what about our hair? An article by Klaudija Sebetic et al highlighted that sun exposure, especially excessive sun exposure damages our hair in two ways.
We can protect our hair using substances with SPF protection. Natural oils have some SPF protection, like almond oil which has a natural SPF 5 level.
Split ends are frayed strands of hair caused by damage to the cuticle layer. This causes the cortex to be exposed, and ultimately, the connection between the cuticle layer and cortex is lost.
Once you have split ends in your hair, the only resolution is to cut them off or otherwise you risk the split ends increasing in length further up towards your newer areas of hair.
You can mask split ends by using moisturisers and conditioners, but there are only temporary solutions that require continued maintenance. As "protein is attracted to the keratin, a property known as substantivity", "protein holds the cortex fragments together until the next shampooing occurs" says Draelos in his 2010 article. You can find protein-rich conditioners that can keep maintain your hair despite the split ends.
Of course, prevention in this case is better than the cure unless you want to constantly be trimming your locks. So being kind to your hair is important, not treating it roughly. Detangling your hair carefully without breaking it is important in preventing split ends in the first place.