Sources & Citations Policy
Where our facts come from, and how we cite them.
Last updated September 27, 2026
Primary sources first
We base guides on primary and authoritative sources, including:
- US government health agencies, such as the CDC, NIH and its institutes, MedlinePlus (National Library of Medicine), FDA, CMS, AHRQ and USPSTF.
- Major medical and professional societies, such as the American Heart Association, the American College of Obstetricians and Gynecologists, the American Academy of Pediatrics, the American Diabetes Association and the American Dental Association.
- Peer-reviewed research published in established medical journals, found through PubMed.
- Laws and regulations, cited from official government sources.
What we avoid
- Press releases, marketing material and company claims as sole evidence.
- Forums and social media as sources of medical facts. We may note that a question is commonly asked, but not use those posts as evidence.
- Single small studies presented as proof.
How we cite
Every guide lists its sources at the end with links so you can check them yourself. We cite the most specific page that supports a claim and prefer the latest version of guidance.
Using public domain content
Some US government content is in the public domain. When we quote or adapt it, we credit the source. We do not copy copyrighted material.