What saliva hormone testing is — and why it's so useful
Saliva testing measures the hormone that's free — the small, unbound fraction that actually reaches your cells. It's collected at home, at the exact cycle day that matters, and it gives you progesterone and estradiol from the same sample so your Pg/E2 ratio is a true apples-to-apples comparison.
Measures free (bioavailable) hormone — the fraction your tissues actually use
Collect at home, at the right cycle day, no needles or lab visit
Progesterone and estradiol in the same sample, so your Pg/E2 ratio is apples-to-apples
Ideal for tracking topical/cream hormone therapy, which serum often misses
How collection works
- Kit arrives at your door with tubes, instructions, and a prepaid return mailer.
- Collect first thing in the morning — no food, drink, gum, lipstick, or brushing your teeth for 30 minutes beforehand, and no flossing the night before (blood in the sample invalidates it).
- Cycling? Collect on day 19–22. Not cycling? Any day works.
- Freeze the sample, drop it in the mail, and results come back to you by email.
- Bring your progesterone and estradiol numbers back here and run your ratio.
Common questions
How accurate is saliva hormone testing?
For steroid hormones like progesterone, estradiol, testosterone, DHEA-S and cortisol, validated saliva assays correlate well with the free (unbound) fraction in blood. Reference labs such as ZRT run saliva by LC-MS/MS or validated immunoassay with published precision and reference ranges. Accuracy depends heavily on correct collection: right cycle day, no food, drink, gum, or brushing for 30 minutes beforehand, and no blood contamination in the sample.
Why free hormone matters
Most estradiol and progesterone in blood is bound to SHBG and albumin and is not biologically active. Serum total levels can look 'normal' while the free fraction your tissues actually respond to is low — or vice versa. Saliva reflects that free fraction, which is often why saliva results line up better with how a woman actually feels.
Is saliva better than blood?
Neither is universally better — they answer different questions. Serum is the standard for confirming ovulation, pregnancy, thyroid, and most medication monitoring. Saliva shines for free-hormone status, at-home timed collection, multi-point cortisol curves, and monitoring topical/transdermal hormone therapy, where serum notoriously underestimates delivered dose.
When should I collect?
If you're still cycling, collect in the mid-luteal phase — roughly days 19–22 of a 28-day cycle, or about 5–7 days after ovulation. That's when progesterone should peak and the Pg/E2 ratio is most interpretable. If you're postmenopausal, have no cycle, or have had a hysterectomy, you can collect any day.
What ranges are used?
For saliva, a luteal estradiol of roughly 1.3–3.3 pg/mL with progesterone in the hundreds of pg/mL is typical, and a Pg/E2 ratio of about 100–500 is considered balanced when estradiol sits in that luteal range. Below ~100 suggests estrogen dominance; well above 500 usually reflects supplementation.
Does saliva work if I'm using hormone cream?
Yes — this is one of saliva's biggest advantages. Topical progesterone and estradiol distribute into tissue and are poorly reflected in serum. Saliva (and to a degree blood spot) tracks topical dosing far better, which makes it useful for dialing in a cream or troche dose.
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Educational information only — not medical advice, diagnosis, or treatment. Saliva testing methodology and reference ranges referenced from reference-lab practice (e.g. ZRT Laboratory). Discuss results with your clinician.