Estrone Sulfate (E1S) Biomarker Testing
It measures estrone sulfate, a circulating estrogen reserve that can shift with age and therapy, with convenient ordering through Vitals Vault and Quest labs.
With Vitals Vault, you have access to a comprehensive range of biomarker tests.
Estrone sulfate (E1S) is one of the main “storage” forms of estrogen circulating in your blood. It can be converted back into active estrogens when your tissues need it, which is why it sometimes explains symptoms even when a single estradiol number looks “fine.”
This test is most useful when you are trying to make sense of estrogen patterns over time, such as during perimenopause, while tracking cycles, or when you are using hormone therapy and want a steadier view than a one-time estradiol snapshot.
Because estrogen biology is timing-dependent, your result is best interpreted alongside your symptoms, your cycle day (if you cycle), and any medications or hormones you use. Lab testing supports clinician-directed care and is not a standalone diagnosis.
Do I need a Estrone Sulfate test?
You might consider an estrone sulfate test if you are trying to connect estrogen-related symptoms to what is happening in your body over weeks and months, not just in a single moment. People often look at E1S when they have cycle changes, new or worsening PMS-like symptoms, hot flashes or night sweats, sleep disruption, vaginal dryness, breast tenderness, or mood changes that seem hormonally patterned.
This test can also be helpful if you are on hormone therapy (including oral, transdermal, or compounded regimens) and your symptoms do not match your estradiol result. Estrone sulfate can act like a reservoir, so it may stay elevated or suppressed in ways that change how you feel, especially when dosing or route of administration changes.
If you are evaluating fertility or perimenopause, E1S is usually not the only number you need. It becomes more informative when it is interpreted with other estrogens and related hormones so you can see whether the pattern fits ovulation, ovarian aging, or medication effects.
You will get the most value when you can share your result with a clinician who knows your history, your goals (symptom relief, cycle tracking, fertility, or therapy monitoring), and your timing (cycle day or time since last dose).
Estrone sulfate is measured on a CLIA-certified laboratory assay; results should be interpreted in clinical context and are not diagnostic on their own.
Lab testing
Ready to order estrone sulfate testing and track your trend over time?
Schedule online, results typically within about a week
Clear reporting and optional clinician context
HSA/FSA eligible where applicable
Get this test with Vitals Vault
Vitals Vault lets you order estrone sulfate testing without needing a separate lab visit planning process. You choose the test, complete checkout, and then get your blood draw through the Quest lab network.
Once results are ready, you can use PocketMD to walk through what your number may mean for your symptoms, your cycle timing, or your current hormone plan. This is especially useful for estrone sulfate because it often makes more sense when you compare it with estradiol and estrone rather than treating it like a pass/fail result.
If you are monitoring hormone therapy, Vitals Vault makes it straightforward to repeat the same test later so you can track trends after a dose change, a route change (for example, oral to patch), or a shift in cycle regularity.
- Order online and draw at a Quest location
- PocketMD helps you interpret results in plain language
- Easy retesting to compare trends over time
Key benefits of Estrone Sulfate testing
- Shows a longer-lasting “reserve” form of estrogen that can differ from estradiol on the same day.
- Helps explain symptoms that fluctuate even when your estradiol result looks in range.
- Adds context for perimenopause patterns, when estrogen output can swing from high to low across cycles.
- Supports hormone therapy monitoring, especially when changing dose or delivery method.
- Improves interpretation of fractionated estrogen testing by separating estrone, estradiol, and estrone sulfate roles.
- Highlights medication effects, such as oral estrogen increasing certain estrogen forms more than others.
- Gives you a baseline you can trend over time and review in PocketMD alongside symptoms and timing.
What is Estrone Sulfate?
Estrone sulfate (often abbreviated E1S) is an estrogen that has been “sulfated,” which makes it more water-soluble and generally less immediately active at estrogen receptors than estradiol (E2). In your body, E1S functions like a circulating storage pool: tissues can convert it back into estrone (E1) and estradiol when needed.
Because it is a reserve form, estrone sulfate tends to be present in higher concentrations than estradiol and can be more stable across short time windows. That stability can be useful when you are trying to understand your overall estrogen environment rather than a single peak or dip.
Estrone sulfate comes from multiple sources, including ovarian production, adrenal contributions, and conversion in peripheral tissues (such as fat tissue). Levels can change with age, body composition, pregnancy status, and medications, and they can shift substantially with hormone therapy.
A key point is that “estrogen” is not one number. Estradiol is often the headline marker, but estrone and estrone sulfate can better reflect certain routes of therapy and longer-term exposure. That is why clinicians sometimes order fractionated estrogens when symptoms and a single estradiol result do not line up.
How estrone sulfate fits into hormone therapy monitoring
If you use estrogen therapy, your estrone sulfate level may reflect how your body is processing and storing estrogen over time. Oral estrogen, in particular, can shift the balance toward estrone-related forms because of first-pass metabolism in the liver. Your clinician may use E1S alongside estradiol, estrone, and symptom response to decide whether your route or dose is matching your goals.
Why timing matters
If you cycle, estrogen markers vary by cycle phase. A result drawn early follicular phase can look very different from a pre-ovulatory peak, and a random draw can be hard to compare month to month. If you are on hormones, timing relative to your last dose (and the type of product) can also change your result, so documenting timing improves interpretation.
What do my Estrone Sulfate results mean?
Low estrone sulfate levels
A low estrone sulfate result can suggest lower overall estrogen reserve or reduced conversion into the sulfated storage form. This may be seen in menopause, after ovary removal, with certain causes of low ovarian function, or when estrogen therapy is insufficient for your needs. If you have symptoms like hot flashes, sleep disruption, vaginal dryness, or low libido, your clinician will usually compare E1S with estradiol and other hormones rather than relying on E1S alone.
Optimal estrone sulfate levels
An “in-range” estrone sulfate result generally means your circulating estrogen reserve is consistent with the reference population used by the lab for your sex and age category. Even with an in-range value, you can still have symptoms if your estradiol is low, if your levels are fluctuating quickly, or if timing of the draw did not match your usual pattern. The most useful interpretation is whether your result matches your life stage, your cycle timing, and how you feel.
High estrone sulfate levels
A high estrone sulfate result can reflect higher estrogen exposure, increased conversion to estrone-related forms, or medication effects. It is commonly seen with certain hormone therapy regimens, especially oral estrogen, and it can also rise with higher body fat because peripheral tissues can contribute to estrogen production and conversion. High E1S does not automatically mean “too much estrogen,” but it can be a clue to review symptoms such as breast tenderness, bloating, headaches, or mood changes and to reassess dose, route, and timing with your clinician.
Factors that influence estrone sulfate
Your cycle phase, pregnancy status, and age can all shift estrone sulfate substantially, so the same number can mean different things depending on timing. Hormone medications (oral estrogens, certain contraceptives, and some fertility protocols) can raise E1S, while low estrogen states can lower it. Body composition, liver metabolism, and differences between assays and reference ranges can also affect interpretation, which is why comparing trends on the same lab method is often more informative than chasing a single “perfect” value.
What’s included
- Estrone Sulfate
Frequently Asked Questions
What is estrone sulfate used for?
Estrone sulfate is used to assess a longer-lasting circulating reserve of estrogen. It is often ordered to add context to estradiol results, to evaluate hormone patterns in perimenopause or cycle tracking, or to monitor how hormone therapy is being metabolized over time.
Is estrone sulfate the same as estradiol?
No. Estradiol (E2) is the most biologically active estrogen in many tissues, while estrone sulfate (E1S) is a sulfated storage form that can be converted back into estrone (E1) and estradiol. They can move differently depending on cycle phase and hormone therapy route.
Do I need to fast for an estrone sulfate blood test?
Fasting is not usually required for estrone sulfate. The more important preparation is documenting timing: your cycle day (if you cycle) and the time since your last hormone dose if you use estrogen therapy.
Why is my estrone sulfate high on oral estrogen?
Oral estrogen is processed through the liver first (first-pass metabolism), which can shift estrogen metabolism toward estrone-related forms and increase estrone sulfate. Your clinician may compare E1S with estradiol, estrone, symptoms, and side effects to decide whether the dose or route is a good fit.
Can estrone sulfate help with perimenopause evaluation?
It can help, but it is rarely a standalone answer. Perimenopause often involves wide swings in estrogen, so a single draw can be misleading. Estrone sulfate may add a steadier signal, especially when interpreted with estradiol, FSH/LH, progesterone (if timing is appropriate), and your symptom pattern.
What is a normal estrone sulfate range?
Reference ranges vary by lab method, sex, age, and sometimes menopausal status, so “normal” depends on the range printed on your report. The most useful question is whether your value is appropriate for your life stage and whether it matches your symptoms and other hormone results.
Should I test estrone sulfate alone or with other hormones?
Testing estrone sulfate alone can be useful for a targeted question, but most people get clearer answers when it is paired with estradiol and estrone (fractionated estrogens). If you are evaluating cycles, perimenopause, or therapy response, adding progesterone, SHBG, testosterone, and gonadotropins (FSH/LH) often improves interpretation.