Sunlight can create harmful molecules in your skin, but your body naturally produces nitric oxide to balance them out—this balance keeps your skin healthy.

When there's less sunlight in winter or far from the equator, your skin makes less nitric oxide from sunlight, which can upset the balance in your skin and make conditions like psoriasis or eczema worse.

When your skin is exposed to sunlight, it releases a natural substance called nitric oxide that helps calm down harmful molecules in your skin and keeps things balanced — but this doesn't work right if you have long-term skin inflammation.

Too much sun exposure can seriously harm your skin by damaging cells, aging it faster, weakening your skin’s defenses, and even leading to skin cancer.

Some light-based treatments might help calm down angry, inflamed skin by copying how sunlight naturally balances certain chemicals in your skin, which could make conditions like eczema or psoriasis feel better.

When mice are exposed to sunlight-like UV rays, adding certain chemicals that neutralize harmful free radicals to sunscreen helps stop skin tumors better—without making the sunscreen block more UV rays. This suggests that these free radicals are a big reason why UV light causes skin cancer.