Unexplained Weight Loss
GeneralIf this is an emergency, call 911 now. This tool is for general information, not emergency guidance. If you're having severe symptoms, don't read this — get help.
What the internet says
Cancer. HIV. Hyperthyroidism. Addison's disease. Endocarditis.
What it probably actually is
Changed eating habits you didn't consciously notice. Stress suppressing appetite. Starting a new medication. Depression reducing appetite. A GI illness that's resolving. More physical activity.
🧠 The full picture
The threshold that matters is losing more than 5% of body weight in 6-12 months without trying. That's genuinely worth investigating. Losing 3-4 lbs over a few months when you've been under stress? Usually nothing. Context matters enormously here.
⚠️ When to actually call your doctor
These are real red flags. If any of these apply, don't wait.
- 5% or more of body weight lost in 6-12 months without trying
- Accompanied by fever, night sweats, or fatigue
- Along with changes in bowel habits
- Loss of appetite that's been building for weeks
- You have a history of smoking or cancer
- Over age 65 — unexplained weight loss in older adults is more significant
📚 Sources
This information is based on guidance from:
NIH MedlinePlusAmerican Cancer SocietyAmerican Geriatrics Society
Always verify important health decisions with your doctor or a qualified healthcare provider.