Ultraviolet (UV) radiation from the sun can penetrate the skin and cause damage to the DNA within skin cells. This damage can lead to genetic mutations and disruptions in cellular processes, ultimately contributing to aging, and even skin cancer. Studies have shown that UV-induced DNA damage can result in the accumulation of mutations and impair the skin's ability to repair itself effectively.

Collagen is a crucial protein that provides structural support and elasticity to the skin. Prolonged sun exposure can trigger the breakdown of collagen fibers in the skin through a process called collagen degradation. Research has demonstrated that UV radiation activates enzymes known as matrix metalloproteinases (MMPs) that degrade collagen, leading to the loss of skin firmness and the appearance of wrinkles.

Sun exposure promotes the production of reactive oxygen species (ROS) in the skin, leading to a state of oxidative stress. ROS are highly reactive molecules that can damage cellular components, including lipids, proteins, and DNA. Studies have linked oxidative stress caused by sun exposure to skin aging processes such as inflammation, tissue damage, and impaired cellular functions.

UV radiation stimulates the production of melanin, the pigment responsible for skin color. Prolonged sun exposure can lead to the uneven distribution of melanin, resulting in hyperpigmentation, such as age spots or sunspots. Furthermore, it can exacerbate conditions like melasma, causing patches of darker skin.

With a long-lasting sunblock, individuals could enjoy extended protection against harmful UV radiation without the need for frequent reapplication. This would be particularly useful in situations where access to sunblock or reapplication is limited, such as during outdoor activities, swimming, or in remote areas.

Having a sunblock that lasts for two weeks would reduce the need for frequent application, making it more convenient for individuals who may find regular application cumbersome or easy to forget. It could be especially beneficial for those with busy schedules or who spend significant time outdoors.

Some people may be more likely to use sunblock consistently if they don't have to worry about frequent reapplication. A sunblock that lasts for an extended period could encourage better adherence to sun protection practices, which is crucial for preventing skin damage and reducing the risk of skin cancer.

Using a long-lasting sunblock could potentially reduce the frequency of purchasing sunblock products, resulting in cost savings over time. This benefit would be particularly significant for individuals or families who frequently use sunblock or have multiple people to protect.

Many people do not apply enough sunblock or fail to reapply it regularly, which can reduce its effectiveness.

Some sunblocks may not provide broad-spectrum protection, meaning they may not shield against both UVA and UVB rays. It is important to choose a sunblock that offers broad-spectrum coverage.

Some individuals may be sensitive or allergic to certain chemical ingredients commonly found in sunblocks, such as oxybenzone or avobenzone. In such cases, alternative options like physical sunscreens (containing zinc oxide or titanium dioxide) may be recommended.

Wearing sunblock should not be the sole method of sun protection. Relying solely on sunblock may lead to a false sense of security, causing individuals to stay in the sun for longer periods without taking additional protective measures like seeking shade or wearing protective clothing.

Certain chemical sunblock ingredients can have harmful effects on aquatic ecosystems when they wash off during swimming or water activities. Using reef-safe or environmentally friendly sunblocks can help mitigate this issue.