ScienceInsights

Learn safe doses for taking Advil and Tylenol together, how to alternate them, and when the combination may not be right for you.

Most UTIs clear up in a few days with antibiotics, but untreated infections can linger or worsen. Here's what to expect at each stage.

Canker sores usually clear up in 1–2 weeks, but the right treatments can ease pain and speed healing. Here's what actually works.

Viagra typically clears your system in 24 hours, but certain factors slow that down. Here's what actually affects how long it stays in your body.

Teen hair loss is often treatable once you know the cause. Learn what's behind it and when to see a doctor.

There's no single best ADHD medication for adults—the right choice depends on your health history, lifestyle, and how your body responds.

Weight norms for 14-year-old boys vary widely by height and puberty stage. Here's what doctors actually look at to assess healthy growth.

40 ounces of water may not be enough for everyone. Learn how to estimate your personal hydration needs and spot the signs of mild dehydration.

White or pale stool usually signals a problem with bile production or flow. Learn what causes it, when it's serious, and when to see a doctor.