Does birth control increase cortisol? What the pill does to test results

Yes, on a blood test. Birth control pills that contain estrogen raise the protein that carries cortisol in your blood. A blood test measures that protein-bound cortisol, so the result reads higher. The cortisol that is active in your body, the free part, isn’t raised by this. The effect is on the measurement, and it is the reason clinicians ask what hormone medicines you take before they read a cortisol result.

This page is about test results. It isn’t a reason to start, stop or change birth control. That is a decision for you and your prescriber.

What the pill does to a cortisol result

Most cortisol in blood travels attached to a protein made in the liver. A 2024 paper in the Journal of the Endocrine Society explains the link. High estrogen from oral contraceptive pills, and in pregnancy, makes the liver produce more of this protein. Serum total cortisol rises by about 67% in women taking the pill, and pregnancy causes similar rises. The paper says tests that measure free cortisol, urinary free cortisol and salivary free cortisol, aren’t affected by the pill or pregnancy.

MedlinePlus agrees on the practical point. It lists birth control pills with stress, pregnancy, exercise and hot and cold temperatures as things that can affect cortisol levels, and says an abnormal cortisol result does not always mean a condition that needs treatment.

A 2024 study in the Journal of Clinical Endocrinology and Metabolism adds details about combined pills, which contain estrogen and a progestin. The rise in the carrier protein has been reported to depend on the estrogen dose, and not on the progestin part. And because pill formulations differ in estrogen dose, the degree of effect can differ from one pill to another. We found no approved source on pills that contain only a progestin, so this page doesn’t cover them.

Why this matters for testing

It can look like Cushing’s syndrome. The Journal of the Endocrine Society paper says a raised total cortisol from the pill can cause false-positive results on baseline and dexamethasone-suppressed serum cortisol, two tests used when someone might have too much cortisol. A 2023 review lists estrogens among the causes of false-positive results for the same reason, and says a longer, two-day dexamethasone test may be preferable for women on the pill. See prednisone, steroids and cortisol results for how that test works.

It can hide low cortisol. The Journal of Clinical Endocrinology and Metabolism study tested 41 healthy women on combined oral contraceptives and 46 without exogenous estrogens. After a stimulation test, plasma cortisol was higher in the pill group. The authors point out that a woman with adrenal insufficiency who takes the pill is at risk of an apparently normal result. They note that higher morning plasma cortisol cut-offs have been suggested for pill users, but that pill doses differ, so a single cut-off could be unreliable. Saliva cortisol and cortisone were slightly lower in the pill group, not higher, and the authors say they were considerably less affected than plasma cortisol.

In practice, this is why a blood cortisol result in a woman on the pill gets read with care. It is also one reason clinicians sometimes choose a free-cortisol test. See free vs total cortisol and cortisol-binding globulin.

Does the effect fade if you stop the pill?

The change in the carrier protein is not instant in either direction. It builds after a pill is started and wears off over a period of weeks after it ends. Whether anything needs to change before a test is a clinician’s decision, made case by case. Do not stop a pill to prepare for a test on your own.

Skin patches, hormone therapy and other routes

The 2023 review says the carrier protein rises with oral estrogens but not with transcutaneous (through-the-skin) estrogens. So the route matters. A pill taken by mouth and a patch worn on the skin are different in this respect. We found no source on vaginal rings, so this page doesn’t cover them.

The same logic applies to menopausal hormone therapy that contains oral estrogen. The 2024 Endocrine Reviews article says exogenous oral estrogens increase the carrier protein and give a falsely elevated total cortisol. We found no approved source showing that hormone therapy raises, lowers or improves active cortisol, and this page doesn’t suggest it as a way to change cortisol. If you take hormone therapy, tell the clinician how you take it. See cortisol and menopause.

Common questions

Does the pill make my cortisol higher in real life?

The effect we can source is on the measurement. In that study, salivary cortisol and cortisone after stimulation were slightly lower in pill users, not higher. We found no approved source showing that the pill raises the active cortisol your body uses, or that it causes symptoms.

Does cortisol increase estrogen?

We found no approved source that answers this, so this page doesn’t.

Should I stop my pill before a cortisol test?

No, not on your own. Tell the clinician or lab which medicine you take and how, and ask them whether it matters for the test you are having.

What to do

• Tell the clinician and the lab which birth control or hormone medicine you take and whether it is by mouth or on the skin.
• Ask whether a free-cortisol test (saliva or 24-hour urine) is better suited to your question than a blood test.
• Keep taking your medicine as prescribed. Ask the prescriber before any change.
• If you may be pregnant, see cortisol in pregnancy. The same carrier-protein effect applies.

If you are thinking about ordering a test

A single blood cortisol can’t diagnose or rule out Cushing’s syndrome or adrenal insufficiency, and the pill makes it harder to read. Before you order any cortisol test, check whether it reports total or free cortisol, and follow the draw time and fasting instructions on your order. If the result is unusual, take it to a clinician along with the name of your pill.