India, Nov. 4 -- A sunscreen only works if you consistently wear it, which is why it should have a light texture, no white cast, and be easy to reapply. But beyond comfort, the real question is: does it truly protect your skin as claimed? Many sunscreens rely on in vitro lab testing, which evaluates a sunscreen's effectiveness in controlled laboratory conditions using artificial surfaces that cannot fully replicate how products behave in real life on warm skin, under sunlight, or when mixed with sweat and sebum. That's where in vivo testing sets a higher standard. Conducted on human skin, it measures real-world SPF and UVA protection to confirm a sunscreen's actual performance. It's the most trusted way to ensure that your sunscreen works...