Appendix F: The Biological Dashboard

Key Metabolic and Hormonal Markers: Optimal-Function Reference Targets

A Note Before You Begin

The targets in this appendix reflect ranges that some clinicians and researchers associate with optimal metabolic function, rather than the standard reference ranges used to diagnose disease. Standard reference ranges are derived from the distribution of the general tested population; because metabolic dysfunction is common in that population, some researchers argue that "normal" ranges may be broader than what is associated with the best long-term health. This is a reasoned position, not a settled clinical consensus, and the targets below should be read in that light: as optimal-function reference points to discuss with a clinician, not as diagnostic cutoffs or treatment goals.

This dashboard is a reference tool, not a diagnostic instrument. Bring these targets to a qualified physician or licensed healthcare provider. Do not use this information to self-diagnose, self-treat, or discontinue medication without medical supervision. If any of your results fall significantly outside these ranges, consult a doctor before modifying your protocol.

Tier 1: The Metabolic Engine Fuel integrity and insulin sensitivity

These markers measure whether your cells are accepting energy efficiently or fighting a state of chronic fuel toxicity (insulin resistance).

Haemoglobin A1c (HbA1c)

Standard reference range: 5.7–6.4% (pre-diabetic)\ Maha optimal-function target: 5.0–5.4%

Three-month average blood glucose. Large population studies show a U-shaped relationship with mortality: the lowest risk sits roughly in the 5.0–5.4% band, with risk rising both above it and, notably, below it. Lower is not automatically better — values under 5.0% have been associated with increased all-cause mortality in non-diabetic adults, so this is a target band, not a "drive it as low as possible" goal.[1](#ch033.xhtml_ref1)

Fasting Insulin

Standard reference range: Below 20 uIU/mL\ Maha optimal-function target: 2.0–5.0 uIU/mL

The truth detector. Glucose can appear normal while insulin is chronically elevated — the body working hard to maintain the appearance of balance. Low fasting insulin indicates genuine metabolic efficiency. This 2–5 range reflects the functional-optimal band used by many metabolic-health clinicians; note that insulin assays are not fully standardised across laboratories, so use your lab's own reference.[2](#ch033.xhtml_ref2)

Triglycerides

Standard reference range: Below 150 mg/dL\ Maha optimal-function target: Below 70 mg/dL

Fat circulating in the blood. Elevated triglycerides typically reflect excess carbohydrate consumption rather than dietary fat. Lower is generally better within a healthy range — large cohort and genetic studies associate lower triglycerides with reduced mortality — but there is a floor: persistently very low values (below roughly 40 mg/dL) can warrant investigation for underlying causes, so this is not a "drive it as low as possible" target.[3](#ch033.xhtml_ref3)

Triglyceride/HDL Ratio

Standard reference range: 3.0 or above is high-risk\ Maha optimal-function target: Below 1.0

A useful and well-validated proxy for insulin sensitivity available from a standard lipid panel; it correlates well with more direct measures of insulin resistance, though related indices such as the triglyceride-glucose (TyG) index perform comparably or better in some studies. Optimal cutoffs vary by sex and population. Note: this ratio is calculated with both values in mg/dL (US units); the equivalent threshold differs where lipids are reported in mmol/L.[4](#ch033.xhtml_ref4)

Tier 2: The Hormonal Foundation Drive, Resilience, and Metabolic Rate

Hormones are the software instructions for the body. A degraded hormonal signal degrades every capacity downstream of it.

Total Testosterone (Men)

Standard reference range: 300–500 ng/dL\ Maha optimal-function target: Avoid deficiency; mid-normal or higher

Associated with motivated effort, muscle protein synthesis, and metabolic health in men. The evidence is asymmetric: genuinely low testosterone is associated with higher mortality (risk rises notably below ~213 ng/dL, and clinically "low" is generally below 300), so avoiding deficiency matters. But "higher is better" is not supported — large studies decline to recommend raising testosterone to influence mortality, and trials of testosterone therapy have shown increased cardiovascular events in some groups. So the goal is to avoid deficiency and support natural levels (sleep, training, body composition), not to chase a high number. Testosterone therapy is a clinical decision with real cardiovascular and fertility risks, not a self-directed target.[6](#ch033.xhtml_ref6)

Free Testosterone (Men)

Standard reference range: Low-normal\ Maha optimal-function target: Top quartile of range

Total testosterone is potential. Free testosterone — the fraction not bound to carrier proteins — is what tissues actually use.

TSH (Thyroid Stimulating Hormone)

Standard reference range: 0.5–4.5 mIU/L\ Maha optimal-function target: 1.0–2.5 mIU/L

A regulator of metabolic rate. A large individual-participant-data meta-analysis found the lowest cardiovascular and mortality risk in roughly the middle of the reference range (about 1.9–2.9 mIU/L), with higher risk in the upper-normal band above ~2.5 and also at low TSH — so both ends carry risk, and lower is not better. Interpret alongside Free T3 and Free T4, and only with a clinician.[5](#ch033.xhtml_ref5)

Free T3

Standard reference range: Low-normal\ Maha optimal-function target: Mid-range; higher if symptomatic, not maximised

The active thyroid hormone. Low Free T3 is associated with fatigue, cold intolerance, and cardiovascular risk, and treated (T4-only) patients with low-half-of-range Free T3 may remain symptomatic — so the bottom of the range is not necessarily fine. But higher is not simply better: elevated Free T3 raises heart rate, and thyroid-hormone excess (even subclinical) is associated with increased cardiovascular mortality and bone loss. Aim for a healthy mid-range, moving higher only if symptomatic and under clinician guidance — do not maximise it.[7](#ch033.xhtml_ref7)

Note: Testosterone and thyroid optimization are complex clinical areas. The targets here emphasise avoiding deficiency and supporting natural function, not maximising any single number, and should be interpreted with a physician familiar with your full health history.

Tier 3: The Inflammation Index Systemic Defense and Oxidative Load

Chronic inflammation is associated with a range of metabolic and cardiovascular conditions. These markers give a sense of whether the body is carrying a sustained inflammatory or oxidative load.

hs-CRP (High-Sensitivity C-Reactive Protein)

Standard reference range: 1.0–3.0 mg/L\ Maha optimal-function target: Below 0.5 mg/L

A marker of systemic inflammation and a well-validated independent predictor of cardiovascular events. Risk rises continuously across the range, and a level below 0.5 mg/L is associated with very low cardiovascular risk (standard categories: below 1.0 low, 1.0–3.0 average, above 3.0 high). Because it spikes with any infection or acute illness, measure it twice at least two weeks apart in a well state before drawing conclusions.[8](#ch033.xhtml_ref8)

Vitamin D (25-OH)

Standard reference range: 20–30 ng/mL\ Maha optimal-function target: 40–60 ng/mL

Functions as a hormone regulating immune response, mood, and bone density. Low levels are associated with increased cardiovascular and all-cause mortality; the lowest-risk range for most outcomes falls roughly between 40 and 60 ng/mL. Higher is not better: levels above ~50–60 ng/mL have not been shown to add benefit and some studies associate them with increased mortality, falls, and fractures. Important: vitamin D is fat-soluble and can accumulate to toxic levels with over-supplementation. Do not supplement to reach a target without testing your level and monitoring it with a clinician.[9](#ch033.xhtml_ref9)

GGT (Gamma-Glutamyl Transferase)

Standard reference range: Below 50 U/L\ Maha optimal-function target: Below 20 U/L

A sensitive marker of liver stress and oxidative burden. Higher GGT — even within the standard reference range — is associated in large cohort studies with increased cardiovascular and all-cause mortality in a dose-dependent way, so a low value is genuinely favourable here. Elevated GGT is commonly associated with alcohol intake, certain medications, fatty liver, and metabolic dysfunction.[10](#ch033.xhtml_ref10)

The Audit Schedule

Baseline: Immediately. Establish your starting point before beginning any protocol.

Six-month checkpoint: Measure the direction of change. Trend matters more than any single reading.

Protocol verification: If you make a significant dietary or supplementation change, retest Tier 1 markers after ninety days to confirm the expected direction of change.

How to Read Your Lab Results

A number outside the target range is a signal to investigate, not a diagnosis. It is data. Elevated fasting insulin points toward the fasting and carbohydrate-reduction approaches of Chapter 1. Elevated hs-CRP points toward the Nutritional Veto. Low testosterone in a man is worth investigating with attention to sleep, training, body composition, and endocrine-disrupting exposures. These markers are gauges, not verdicts — interpret them, and any changes to your health regimen, in consultation with a qualified clinician.

References and Sourcing Notes

The "optimal" targets in this dashboard are drawn from outcome-association research and from the functional ranges used by metabolic-health clinicians. They are not diagnostic thresholds, and for several markers the relationship with health is U-shaped — meaning both high and low values carry risk. Where the evidence is associational rather than proven-causal, or where clinician consensus rather than trial data is the basis, that is noted. This sourcing is being expanded across all markers in ongoing revisions.

1\. On HbA1c and mortality: Aggarwal V, Schneider ALC, Selvin E. "Low Hemoglobin A1c in Nondiabetic Adults: An Elevated Risk State?" Diabetes Care. 2012 Oct;35(10):2055–2060. DOI: 10.2337/dc11-2531. In the Atherosclerosis Risk in Communities cohort (n=13,288), HbA1c below 5.0% was associated with increased all-cause mortality versus a 5.0–5.7% reference, consistent with a J-/U-shaped relationship; lowest-risk bands cluster around 5.0–5.4%.

2\. On fasting insulin: There is no universally standardised "optimal" cutoff, and insulin assays vary between laboratories. A functional-optimal band of roughly 2–6 µIU/mL is widely used in metabolic-health practice, with values above ~10 associated with early insulin resistance even when glucose and HbA1c are normal.

3\. On triglycerides: Population cohorts (e.g., the Copenhagen City Heart Study) and Mendelian-randomisation (genetic) analyses associate lower triglycerides with reduced mortality. Optimal targets commonly cited range from below 100 mg/dL (American Heart Association) to a 50–90 mg/dL band; persistently very low values (below ~40 mg/dL) may warrant clinical investigation.

4\. On the triglyceride/HDL ratio: Validated as a surrogate for insulin resistance and an independent cardiovascular-risk predictor; related indices such as the triglyceride-glucose (TyG) index perform comparably or better in some studies. Optimal cutoffs vary by sex and population.

5\. On TSH: Xu Y, Derakhshan A, Hysaj O, et al. "The optimal healthy ranges of thyroid function defined by the risk of cardiovascular disease and mortality: systematic review and individual participant data meta-analysis." Lancet Diabetes Endocrinol. 2023 Oct;11(10):743–754. DOI: 10.1016/S2213-8587(23)00227-9. PMID: 37696273. This individual-participant-data meta-analysis found lowest CVD/mortality risk near the middle of the TSH reference range (roughly the 60th–80th percentiles) and elevated risk at both high-normal and low TSH.

6\. On testosterone: Yeap BB, Marriott RJ, Dwivedi G, et al. "Associations of Testosterone and Related Hormones With All-Cause and Cardiovascular Mortality and Incident Cardiovascular Disease in Men: Individual Participant Data Meta-analyses." Ann Intern Med. 2024 Jun;177(6):768–781. DOI: 10.7326/M23-2781. Across 255,830 participant-years, all-cause mortality risk increased below ~213 ng/dL and cardiovascular-death risk below ~153 ng/dL; the authors explicitly did not advocate using testosterone to influence mortality risk. Testosterone-therapy trials have shown increased cardiovascular events in some groups, supporting an "avoid deficiency, do not maximise" interpretation.

7\. On Free T3: Evidence is mixed and direction-dependent. Low Free T3 (e.g., in T4-treated patients) is associated with persistent hypothyroid symptoms, but higher Free T3 raises heart rate, and thyroid-hormone excess (including subclinical hyperthyroidism) is associated with increased cardiovascular mortality and bone loss — supporting a mid-range rather than maximised target. (Full citations to be finalised in the sourcing pass.)

8\. On hs-CRP: Ridker PM, Cook N. "Clinical Usefulness of Very High and Very Low Levels of C-Reactive Protein Across the Full Range of Framingham Risk Scores." Circulation. 2004 Apr 27;109(16):1955–1959. DOI: 10.1161/01.CIR.0000125690.80303.A8. PMID: 15051634. Among 27,939 apparently healthy women, cardiovascular risk rose continuously across hsCRP levels, with very low risk below 0.5 mg/L; CDC/AHA define low/average/high risk as \<1, 1–3, and \>3 mg/L. hs-CRP must be measured away from acute illness.

9\. On vitamin D: Dose–response meta-analyses locate the lowest risk for most outcomes (including all-cause and cardiovascular mortality) roughly between 40 and 60 ng/mL, with low levels clearly associated with higher CVD and mortality risk. Multiple analyses (e.g., in Mayo Clinic Proceedings) associate levels above ~50–60 ng/mL with no added benefit and, in some studies, increased mortality, falls, and fractures — supporting a 40–60 target rather than higher. (Full citations to be finalised in the sourcing pass.)

10\. On GGT: Large prospective cohorts, including the Framingham Study and dose–response meta-analyses, associate higher GGT — even within the reference range — with increased risk of metabolic syndrome, cardiovascular disease, and all-cause mortality; risk rises in a graded fashion, making a low value favourable. (Full citations to be finalised in the sourcing pass.)