One of the most common questions I’m asked is how to properly get baseline levels of estrogen, progesterone, and testosterone—and even more importantly, how to monitor those levels once bioidentical hormone replacement therapy (BHRT) has been started.
If you’re confused, you’re not alone. This topic stumps many health care practitioners as well.
Hormones don’t behave in neat little boxes. They fluctuate. They bind. They convert. They exit stage left when you least expect it.
But here’s the truth: BHRT can be both safe and effective when it’s properly dosed and
thoughtfully monitored. The key is using the right test at the right time for the right reason.
Let’s break it down in plain English.
Serum (Blood) Testing
Most conventional practitioners rely on standard bloodwork to check hormone levels. It’s accessible, it’s familiar, and insurance usually covers it.
Here’s the catch: most of your female hormones in the bloodstream are bound to carrier proteins (like SHBG and albumin). Think of them as hormones sitting in the passenger seat with a seatbelt on. They’re along for the ride—but they’re not actively working.
Only the “free” hormones—the small percentage not bound to proteins—can enter your cells and actually do their job.
Standard serum testing primarily measures total hormone levels (bound + free). While labs can calculate or directly measure free testosterone, those levels can be unreliable if you’re using topical testosterone creams.
When to use serum testing:
• As an initial screening tool
• When evaluating ovarian status (FSH, LH)
• When checking SHBG (carrier protein) levels
• When monitoring oral, pellet, and patch hormone therapy
• When insurance coverage is a priority
Serum testing has its place. It’s just not the whole story.
Saliva Testing
Saliva testing measures free, bioavailable hormone levels—the portion that actually enters your cells and gets to work.
That’s why most functional medicine practitioners prefer it, especially for women using topical creams. Topical hormones absorb into tissues first, not directly into the bloodstream. Saliva testing reflects that tissue delivery far better than serum testing does.
Another perk? You can collect it at home. No fasting at sunrise. No fluorescent waiting rooms. No needles.
When to use saliva testing:
• As a baseline test to measure free hormone levels
• To monitor women using topical estrogen, progesterone, or testosterone
• When symptoms don’t match serum results
• When precision dosing is the goal
If you’re using creams and only checking blood levels, you may be adjusting doses based on incomplete information…and this is the most common reason I see patients get overdosed.
Blood Spot Testing
Blood spot testing (also called dried blood spot testing) provides similar information to serum testing—primarily total hormone levels—but with the convenience of home collection.
You prick your finger, place drops on filter paper, and send it off. No lab visit required.
It’s a reasonable middle ground for women who want convenience but still prefer blood-based measurement.
When to use blood spot testing:
• When you prefer blood testing but want at-home convenience
• For baseline screening when topical therapy hasn’t started
• When monitoring non-topical hormone delivery methods
Keep in mind: if you’re using creams, blood spot testing carries the same limitations as serum testing.
Urine Testing
Urine testing is a different animal entirely. Rather than measuring how much hormone is circulating, urine testing evaluates how your body is metabolizing and clearing hormones. In other words, it tells us what happens after your hormones have been used.
• This is especially helpful for understanding:Estrogen metabolism pathways (2-, 4-, and 16-hydroxy metabolites)
• Detoxification patterns
• Hormone breakdown efficiency
What it does not do well is determine your starting hormone dose or fine-tune active BHRT dosing.
When to use urine testing:
• To assess estrogen metabolism patterns
• To evaluate detoxification capacity
• When there is a history of hormone-sensitive conditions
• When symptoms persist despite “normal” circulating levels
Urine testing is about downstream effects—not baseline levels.
So…Which Test Is Best?
It depends. No single test wins the crown in every situation.
Starting therapy and not on hormones yet? Saliva or serum can both be useful, depending on the clinical picture. Using topical creams? Saliva testing usually gives the most accurate reflection of tissue levels. On oral hormones? Serum or blood spot testing are typically appropriate. Want to understand how your body processes estrogen? Urine testing adds valuable insight.
The best testing strategy aligns with your symptoms, your delivery method, your metabolism, and your clinical history. The right test, at the right time, interpreted through the lens of your symptoms—that’s how you get clarity.
If you want an even deeper dive into the proper testing of female hormone levels, stay tuned for my next book: Weight Loss After 40: A Woman’s Guide to Lab Results and Solutions for Hormones, Stress, and Other Metabolic Imbalances…coming soon