When most women hear the word estrogen, they think of one hormone and one number on a blood test.
But estrogen is much more complex than that.
Your body produces different forms of estrogen. Those hormones circulate through the body, interact with tissues, travel through the liver, are transformed into metabolites, and eventually need to be eliminated.
That means there are really several different questions we can ask:
How much hormone is present?
How much is available to tissues?
How is your body metabolizing it?
And where are those metabolites going next?
This is one reason I sometimes use different types of hormone testing in my practice. Blood, saliva, and urine don’t necessarily tell us the same thing—and that is exactly the point.
First: There Is More Than One Estrogen
The three primary naturally occurring estrogens are estradiol (E2), estrone (E1), and estriol (E3).
Estradiol — E2
Estradiol is generally the most biologically potent of the three major estrogens and is the predominant estrogen during the reproductive years.
It plays important roles in the menstrual cycle, bones, brain, cardiovascular system, vaginal and urinary tissues, and many other parts of the body.
During perimenopause, estradiol can fluctuate substantially. After menopause, ovarian estradiol production falls significantly.
Estrone — E1
Estrone becomes relatively more prominent after menopause.
Unlike ovarian estradiol production, estrogen production doesn’t simply disappear after menopause. Estrogens can still be formed through conversion of androgen precursors in peripheral tissues, including adipose tissue.
This is one reason two postmenopausal women can have very different estrogen patterns.
Estriol — E3
Estriol is a weaker estrogen that becomes especially prominent during pregnancy.
Outside of pregnancy, estriol concentrations are much lower. Estriol may also be encountered therapeutically, particularly in some vaginal hormone preparations.
When evaluating hormone testing, it is therefore important to know whether someone is using hormone therapy—and whether that hormone is being taken orally, applied to the skin, or used vaginally.
Measuring Estrogen Is Only Part of the Story
Imagine seeing an estradiol result on a conventional blood test.
That number can be useful.
But it doesn’t necessarily tell you everything about what happens after your body is finished using that estrogen.
That is where metabolite testing becomes interesting.
Estrogens are processed through several metabolic pathways, particularly involving the liver. Estrone and estradiol can be hydroxylated into metabolites commonly described as:
2-hydroxy estrogen (2-OH)
4-hydroxy estrogen (4-OH)
16-alpha-hydroxy estrogen (16α-OH)
These aren’t simply “more estrogen levels.”
They are downstream products that give us information about how estrogen is being metabolized.
The 2-OH Pathway
The 2-hydroxylation pathway is often described as a more favorable pathway because its metabolites generally have less estrogenic activity than some other estrogen metabolites.
This is also the pathway people are often referring to when they talk about supporting estrogen metabolism with cruciferous vegetables.
Broccoli, Brussels sprouts, cabbage, kale and cauliflower contain indole-3-carbinol (I3C), which can form compounds including DIM (diindolylmethane).
DIM can influence enzymes involved in estrogen metabolism, including pathways associated with estrogen hydroxylation.
But here’s an important distinction:
The goal isn’t automatically to “get rid of estrogen.”
Estrogen is not the enemy.
The goal is appropriate estrogen activity, metabolism and elimination for that individual.
The 16-OH Pathway
The 16α-hydroxylation pathway produces metabolites with different biological activity from those produced through the 2-OH pathway.
You may have seen the 2:16 ratio discussed online as a marker of “good estrogen versus bad estrogen.”
I don’t think that’s the best way to explain it.
The ratio can provide information about the distribution of estrogen metabolism, but it should not be interpreted by itself as a test of disease or cancer risk.
Hormone metabolism is more complicated than one ratio.
Why I Pay Attention to 4-OH Estrogen
The 4-hydroxy pathway deserves special attention.
Catechol estrogens such as 4-OH estrogen can undergo further oxidation and form reactive estrogen quinones. Under certain circumstances, these reactive compounds can interact with DNA and contribute to oxidative damage.
Fortunately, the body also has protective mechanisms designed to process these compounds.
One of those mechanisms involves methylation.
Phase II: What Happens Next?
Producing an estrogen metabolite is not the end of the process.
Catechol estrogens such as 2-OH and 4-OH can be methylated by an enzyme called COMT—catechol-O-methyltransferase.
This produces methoxy estrogens.
Think of this as another step in the body’s processing system.
Instead of asking only:
“Which estrogen pathway are you using?”
I also want to know:
“What happens to those metabolites afterward?”
This is one reason urine metabolite testing can provide information that a single estrogen measurement cannot.
So Where Does Saliva Testing Fit In?
Saliva answers a different question.
Salivary hormone testing measures hormones that have entered saliva and can provide information about the unbound fraction of certain steroid hormones.
One of the places saliva testing can be particularly useful is evaluating cortisol across the day.
Cortisol is supposed to follow a circadian rhythm.
Typically, cortisol rises around awakening and then gradually declines throughout the day, reaching relatively low levels at night.
But what if your pattern looks more like this?
You wake up exhausted.
You finally get going later in the morning.
You crash in the afternoon.
Then at 10:00 at night, suddenly your brain decides it is time to reorganize your entire life.
That pattern makes me interested in more than one morning cortisol measurement.
Collecting saliva at multiple points throughout the day can help us see the shape of the cortisol curve.
Is cortisol appropriately high around waking?
Does it decline?
Does it drop too quickly?
Does it rise again at night?
For someone describing herself as “tired but wired,” that daily pattern can sometimes provide useful context.
Saliva vs. Urine: Which Is Better?
Neither test is automatically “better.”
They answer different questions.
Saliva testing can be useful when we’re interested in the bioavailable fraction of certain steroid hormones and especially when we want to evaluate cortisol at multiple points across the day.
Urine hormone testing can provide a different layer of information by showing hormone metabolites and metabolic pathways—including how estrogen is being processed through pathways such as 2-OH, 4-OH and 16-OH and how catechol estrogens are subsequently methylated.
Blood testing provides another important piece of the picture and remains the standard method for measuring many circulating hormones.
Sometimes the best question isn’t:
“Which hormone test should I get?”
It’s:
“What am I actually trying to find out?”
Why Cycle Timing Matters
There is another reason hormone results can be confusing.
Female hormones are supposed to change.
During the follicular phase of the menstrual cycle, estrogen rises.
Estradiol typically peaks around ovulation.
After ovulation, progesterone increases during the luteal phase.
Then both hormones change again as the next menstrual period approaches.
So an estrogen or progesterone result without knowing when in the menstrual cycle it was collected can be difficult to interpret.
The same principle applies during perimenopause, when hormone production can become considerably more variable from cycle to cycle.
Hormone therapy adds another layer. The type of hormone, dose, timing and route of administration can all affect how results should be interpreted.
Don’t Look at Hormones in Isolation
This may be the most important part.
I don’t want to look at an estrogen number and immediately decide that estrogen is “too high.”
I want to know:
What is progesterone doing?
What are testosterone and the other androgens doing?
Where is she in her menstrual cycle?
Is she perimenopausal or postmenopausal?
Is she taking hormone therapy?
How is she sleeping?
What does her cortisol rhythm look like?
What symptoms brought her into the office?
And, when clinically appropriate, what does estrogen metabolism look like?
Because the goal isn’t to chase a laboratory number.
The goal is to understand the pattern.
Stop Guessing About Your Hormones
Hormone symptoms can overlap tremendously.
Fatigue, poor sleep, headaches, brain fog, changes in weight, mood changes, menstrual changes and feeling like you simply “don’t feel like yourself anymore” don’t automatically tell us which hormone is responsible.
And sometimes hormones aren’t the entire explanation.
That is why I believe testing should start with a question—not with ordering every hormone test available.
Your symptoms tell us where to look.
Testing gives us clues.
And then we put those clues together with your history, menstrual status, medications, nutrition, sleep, lifestyle and other laboratory findings.
Your hormones are not just numbers. They’re part of a much bigger story.
At AlphaCare Health, our goal is to help you stop guessing and start understanding what your body may be trying to tell you.
Hormone testing should be selected and interpreted in the context of symptoms, medical history, menstrual status, medications and hormone therapy. Testing does not diagnose a condition by itself.
