The 5 Biomarkers Every Adult Over 30 Should Be Tracking, Per A Longevity Expert
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What if the lab ranges considered "healthy" are actually steering you in the wrong direction?
That's the what Florence Comite, M.D., founder of the Comite Center for Precision Medicine and author of Invincible, told me in our conversation for the latest episode of the mindbodygreen podcast.
She says the the standard reference ranges we rely on for our health markers are based on population averages that include a lot of unhealthy people, which is why she takes a different approach. Instead of comparing you to a sick population, she asks: What would your lab results look like if you were functioning at your peak, say, between ages 25 and 30?
These are the five biomarkers she thinks everyone should be tracking for longevity, and the optimal range for each of them.
Fasting glucose
Fasting glucose is your baseline blood sugar after an overnight fast, and Comite wants to see it land between 70 and 80 mg/dL. Most people do this test once or twice at the doctors office, but a single morning number only tells part of the story.
Comite recommends wearing a continuous glucose monitor if you want to see how your levels fluctuate in real time throughout the day,
“After eating, you don’t want it to go much beyond 120,” she explains. Going as high as 150 or 180 during a workout is normal, but hitting 200 or above is a red flag.
Most people hear about glucose being too high, but it can also drop too low. If you’re fasting for extended periods and your levels drop below 70, that’s a problem, Comite says.
Fasting insulin
Most doctors don’t order fasting insulin, and some lab reports still list “normal” as up to 19 μIU/mL, which Comite thinks is "unbelievable." She wants fasting insulin in her patients to be undetectable, reaching 2–5 μIU/mL at most.
Insulin should be essentially gone from your system three hours after eating. If it’s detectable while you’re fasting, Comite considers that a sign of insulin resistance, a condition she says almost all of us develop with age.
Insulin resistance sits at the root of nearly every disease of aging, from diabetes and stroke to cancer, which is why she considers this one of the most important numbers to know.
Hemoglobin A1C
Hemoglobin A1C reflects your average blood sugar over roughly 100 days, making it a longer-range view than a fasting glucose snapshot. The conventional cutoff for concern is 5.7% (where pre-diabetes begins), and most lab reports will show anything under 5.6% as “normal.” But Comite sets the bar much higher.
She wants to see A1C under 5%. “As you creep up to 5.4, 5.5, 5.6, you’re heading toward pre-diabetes,” she warns.
Even an A1C under 5% isn’t the complete picture, she adds. Averages can be misleading if your levels are swinging widely between highs and lows.
Cholesterol risk ratio
Rather than fixating on total cholesterol alone, Comite looks at the cholesterol risk ratio. This is calculated by dividing total cholesterol by HDL (the “good” cholesterol). The lower the ratio, the better.
This ratio doesn’t require fancy or expensive testing. It can be calculated from a standard lipid panel available through Quest or LabCorp. She views this as a practical, accessible stand-in for cardiovascular risk that most people can track with their regular bloodwork, no specialist required.
Free testosterone
This last one surprises a lot of people, but testosterone isn't just a male hormone. It's a major longevity lever for both sexes. "It affects everything from metabolism to muscle, to insulin sensitivity, to mood, cognition, brain memory, and cardiovascular risk," Comite says. And it starts declining by 1 to 3% per year in your thirties.
The reason she emphasizes free testosterone over total? "The total testosterone is bound up in protein. It's not free to act," she explains. Free testosterone is the hormone available for your body to actually use.
For men, her optimal range is 180–250 pg/mL, which is much higher than the standard lab. For women, she aims for a wide range that reflects individual variation: at least 6 pg/mL, and up to 30.
What to do with this information
If you want to get a clearer picture of how you're aging, Comite has a few suggestions for next steps:
- Ask for these specific tests: Fasting glucose, fasting insulin, hemoglobin A1C, a lipid panel (so you can calculate your cholesterol risk ratio), and free testosterone. Most doctors don't order all of these routinely, so you may need to request them.
- Get tested more than once: Comite likes to see at least two measurements, taken first thing in the morning after an overnight fast, to ensure consistency.
- Look beyond "normal": If your results fall within the standard reference range but don't hit the optimal targets above, that's worth a conversation with your doctor.
- Consider a CGM: A continuous glucose monitor lets you see how your body responds to food, exercise, and stress in real time, not just in a single fasting snapshot.
- Talk to your doctor about hormone optimization: If your free testosterone is low, there are hormone therapy options that stimulate the body's own production.
The takeaway
Tracking the right biomarkers can help you catch metabolic decline early. Comite's five markers offer a clearer picture of how your body is functioning.
Ask your doctor for these specific tests and strive for optimal levels, because "normal" isn't always good enough.