Testing guide

How to test your cortisol

Four ways to measure cortisol, what each one actually tells you, and how to choose.

Four ways to measure cortisol

1. Salivary cortisol (4-point) — best for pattern

You collect saliva at four points across the day: wake, +30 minutes (CAR), afternoon, and bedtime. Maps your full diurnal curve. This is the gold standard for assessing chronic stress and the Cortisol Awakening Response.

Cost: $90–250 USD at-home (Everlywell, Eli Health, ZRT). Order: not required for at-home consumer kits. Best for: chronic stress, burnout assessment, CAR evaluation.

2. Blood (serum) cortisol — best for clinical diagnosis

A single blood draw, usually morning. Used clinically to diagnose Cushing's syndrome, Addison's disease, and other adrenal pathology. Highly time-dependent — your number is meaningless without knowing what time it was drawn.

Cost: $30–80 USD with order; often insurance-covered. Order: required. Best for: clinical workup, suspected adrenal disease.

3. 24-hour urinary free cortisol — best for total daily output

You collect all urine for 24 hours. The lab measures total cortisol excreted, giving an integrated read of your day's output. Often used to diagnose endogenous Cushing's.

Cost: $50–150 USD. Order: required. Best for: suspected hypercortisolism.

4. Wearable / biometric estimation — best for continuous trend

No wearable measures cortisol directly. They estimate the pattern using HRV, sleep stages, resting heart rate, and recovery balance — all validated correlates. The advantage: continuous data, every day, no needles or vials. The trade-off: estimation, not measurement.

Cost: $0 (with Apple Watch you already own) + free or subscription app. Order: none. Best for: tracking your pattern over weeks and months, surfacing trends, measuring response to interventions.

Which test should you choose?

The honest answer: if you have severe symptoms, see a doctor and get clinical testing. For most people surveilling their stress and cortisol pattern, the right stack is:

  1. Wearable tracking (continuous, free) for the daily pattern
  2. 4-point salivary test once ($150ish) to baseline your actual curve
  3. Blood test annually if your doctor orders it during routine work

How to read your results

See the cortisol levels reference for normal ranges by time of day, age, and gender. A reading is only meaningful in context of when it was taken and what your baseline pattern looks like.

How Cortisol+ fits in

Cortisol+ doesn't replace a lab test — it gives you the daily pattern that a single test can't show. Most users combine: a one-time saliva test to establish their baseline, then continuous Cortisol+ tracking to watch the trend respond to interventions.

Frequently asked questions

How do you test cortisol at home? +
The most accurate at-home cortisol test is a 4-point salivary cortisol kit (Everlywell, Eli Health, ZRT Labs). You spit into vials at wake, +30 min, afternoon, and bedtime, then mail the kit back. Results map your full diurnal curve. A single morning saliva test is cheaper but only captures the peak, not the pattern. Cost: $90–250 USD.
Saliva vs blood vs urine cortisol — which is best? +
Saliva (4-point): best for circadian pattern, the Cortisol Awakening Response, and chronic stress assessment. Blood (serum): single snapshot — used clinically for diagnosing Cushing's, Addison's, and acute issues. 24-hour urinary free cortisol: integrates total daily output, useful for diagnosing endogenous Cushing's. For most consumer health questions, salivary is the right choice.
Does Apple Watch measure cortisol? +
No consumer wearable, including Apple Watch, measures cortisol directly. Cortisol is a hormone that must be measured in blood, saliva, or urine. Wearables can estimate cortisol patterns from validated correlates — primarily HRV, sleep stages, resting heart rate, and recovery balance. Cortisol+ on Apple Watch combines those signals into a continuous cortisol-pattern estimate.
When should I get a cortisol test? +
Consider testing if you have symptoms of chronic cortisol elevation (poor sleep despite exhaustion, 3-5 AM wake-ups, midsection weight gain, sugar cravings, mood disruption) lasting 3+ months. Also if symptoms of Cushing's (rapid weight gain, easy bruising, purple stretch marks, facial rounding) or Addison's (chronic fatigue, low blood pressure, salt cravings, hyperpigmentation) are present — these are clinical and require a doctor.
How much does a cortisol test cost? +
Single blood cortisol: $30–80 USD with a doctor's order. 4-point salivary: $90–250 USD (at-home kits). 24-hour urinary free cortisol: $50–150 USD with order. Insurance often covers testing when ordered by a doctor for symptoms. At-home consumer kits are out-of-pocket but don't require an order.