Protocols
The 90-Day Biomarker Reset: What We Measure and Why
7 min read
Most health testing is designed to detect disease. Reference ranges are set at the population level, calibrated to identify pathology — the point at which something has gone sufficiently wrong to require clinical intervention. For high performers who want to understand and optimise their biological function, this is the wrong frame entirely.
We do not measure to find out what is wrong. We measure to understand what is actually possible — and to build a baseline precise enough to track meaningful change over time.
The 90-day interval is not arbitrary. It reflects the biological timescales of the systems we are most interested in. Red blood cell lifespan is approximately 90 days, which governs the utility of HbA1c as a glycaemic measure. Hormone levels, inflammatory markers, and lipid profiles can shift significantly in 90 days with targeted behavioural and nutritional changes. It is long enough to see real signal, and short enough to course-correct before trends become entrenched.
What we measure, and why
Metabolic function — Fasting glucose, fasting insulin, and HbA1c together paint a picture of glucose regulation that neither alone can provide. Fasting glucose can be normal while fasting insulin is elevated — indicating early insulin resistance that standard testing misses entirely. HbA1c reflects the 90-day average, smoothing out the day-to-day variability that makes fasting glucose alone unreliable.
HOMA-IR — calculated from fasting glucose and fasting insulin — is the most sensitive standard marker for insulin resistance and is almost never included in routine health panels. It is one of the first things we measure.
Cardiovascular risk beyond cholesterol — Standard lipid panels measure total cholesterol, LDL, HDL, and triglycerides. This is insufficient. LDL particle number and size, Lp(a), ApoB, and ApoA1 provide a substantially more accurate picture of cardiovascular risk — particularly for the high-performing population, where conventional LDL levels are often normal while ApoB is elevated and Lp(a) — a largely genetic, underdiagnosed risk factor — is unknown.
Hormonal status — For men: total testosterone, free testosterone, SHBG, LH, FSH, DHEA-S, and oestradiol. Total testosterone is the figure most commonly cited; free testosterone — the biologically active fraction — is frequently more relevant and can be significantly lower than total testosterone suggests, particularly in the presence of elevated SHBG.
For women: oestradiol, progesterone, testosterone, DHEA-S, FSH, and LH — assessed with reference to cycle phase where applicable, or to the postmenopausal range. The hormonal complexity of the perimenopausal transition is almost universally underassessed in standard GP care.
For all: thyroid panel including TSH, free T3, free T4, and thyroid peroxidase antibodies. TSH alone is insufficient.
Inflammatory status — High-sensitivity CRP (hsCRP) is the standard inflammatory marker — a systemic indicator of low-grade inflammatory activity that correlates with cognitive performance, recovery quality, and long-term disease risk. We also assess homocysteine, which is both an inflammatory marker and an independent cardiovascular risk factor, and is modifiable through targeted nutritional intervention.
Nutritional status — Vitamin D, magnesium (RBC magnesium, not serum), ferritin, B12, omega-3 index. Deficiencies in any of these are common in the high-performing executive population — often produced by chronically high stress, inadequate dietary variety under time pressure, and insufficient sunlight exposure — and all produce measurable effects on energy, cognitive performance, and recovery.
Biological age markers — Where relevant, we include markers associated with biological aging: telomere length, epigenetic age testing, and DHEA-S as a proxy for adrenal reserve. These are longer-interval markers — they change over years, not months — but they provide the deepest picture of whether the system is aging at the rate it should be.
The baseline as infrastructure
The value of an initial comprehensive panel is not primarily the findings themselves. It is the baseline. Without a known starting point, every subsequent measurement is a number without context. With a baseline, the 90-day panel becomes a feedback mechanism — showing precisely which interventions have moved which markers, and by how much.
This is how the Eirloom system works. Not as a one-time diagnostic, but as a continuous measurement loop. Biology is not static. The markers that matter most are the ones that are moving — in the right direction, at the right rate, over the right timeframe.
Measurement without interpretation is noise. Interpretation without a system to act on it is information without value. The 90-day biomarker protocol is the foundation of a system designed to make your biology measurably better with time.