The Signal
Notes on hormones, longevity, and what your labs are really saying.
Written and reviewed by Erica Finnan, MSN, APRN-C — hormone, thyroid, and longevity specialist.
Beyond TSH: the thyroid panel most providers don't run
Free T3, Free T4, reverse T3, and antibodies tell a story TSH alone can't. A specialist's guide to a complete thyroid picture.
Optimal thyroid levels vs. normal ranges: what your annual physical isn't telling you
Standard TSH ranges are broad enough to miss early thyroid dysfunction. Here's how a full thyroid panel — and optimal ranges — change the picture.
ApoB vs. LDL: the cardiovascular marker worth asking for
ApoB counts the actual particles that drive plaque. Why longevity specialists prefer it over standard cholesterol panels.
Perimenopause: the hormone shifts that start in your 30s
Estrogen, progesterone, and testosterone don't fall off a cliff at 50 — they fluctuate for years. What to test and when.
Healthspan vs. lifespan: living well, longer
The last 15 years of an American life are often spent in decline. Here's what the science says about compressing that window.
Men, testosterone, and the slow decline no one warns you about
Total T, free T, SHBG, and estradiol — the markers that actually explain energy, mood, and body composition shifts.
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