Editorial policy
How we write and check our guides
Every guide is written from published research and clinical guidance, and every figure is referenced.
Sources
Guides are written from peer-reviewed research (we prefer systematic reviews, meta-analyses and large studies), clinical guidelines from bodies such as the Endocrine Society and NICE, and patient information from the NHS and other official health services. Every number on the site, whether a percentage, a range, a correlation or a sample size, is followed by a numbered reference that links to its source.
Balance
Where the evidence supports a conclusion we state it: for measuring long-term cortisol, hair is the most accurate sample, and we explain why. We also say plainly what a hair test is not for. Clinical guidelines diagnose Cushing's syndrome and adrenal insufficiency with blood, saliva and urine tests, including dynamic tests, and we never suggest that a hair test can diagnose or rule out a condition. Pages about low cortisol carry advice on when to get urgent help.
What we do not do
- We do not claim that a doctor has reviewed a page unless one has, and we name them when they have.
- We do not describe personal experience or say we have tested products ourselves.
- We do not repeat marketing claims we cannot trace to a published source, including the claims of the companies we link to.
- We do not use stock photographs of people, or anything that could look like an endorsement from a clinic or laboratory.
Prices and providers
Prices are taken from each provider's own website and dated. Other providers are listed only if they are major, established brands selling cortisol tests to the public. Inclusion is not paid for, and those links earn us nothing.
Updates and corrections
Each guide shows the date it was last updated. If you spot a mistake, email hello@haircortisoltest.com and we will check it against the source and correct it.