A friend of mine wears a continuous glucose monitor despite having no metabolic disease. He tracks his heart rate variability during sleep. He takes cold showers because a podcast told him it would optimise his cortisol. He spends about $300 a month on supplements. He's 31.
He asked me recently: "What blood tests should I be getting for longevity?"
It's a good question. And it made me think about the gap between biohacking culture, which fetishises data and the pursuit of peak performance, and the clinical reality of what blood tests can actually tell you about how long you'll live and how well you'll age.
The honest answer: quite a lot. Blood markers are genuinely among the best tools we have for predicting metabolic and cardiovascular health trajectories. The markers associated with longevity and healthspan are well-studied, reproducible, and actionable. This isn't wellness theatre. It's evidence-based medicine applied proactively.
But there's also a lot of noise. The biohacking space sells panels of 200+ markers, bespoke protocols, and "biological age" scores that promise to quantify your ageing with precision. Some of this is useful. Some of it is marketing dressed as science. The line between the two isn't always clear.
This article is my attempt to separate signal from noise. The evidence-based markers that genuinely predict long-term health outcomes, the emerging markers worth considering, the things blood tests can't tell you about ageing, and how to build an annual testing protocol that's rigorous without being excessive.
A note before we get into it
General information only. I'm not a longevity physician. The concept of "optimal ranges" for longevity is based on epidemiological data and expert opinion. It's more nuanced and less certain than standard clinical reference ranges.
No blood test can tell you how long you'll live. What blood tests can do is identify modifiable risk factors that, when addressed, are associated with better long-term health outcomes.
What biohacking actually means, and where blood testing fits
Biohacking is a broad term that covers everything from evidence-based health optimisation to fringe experimentation. At its best, it's the application of data-driven thinking to personal health: measuring, tracking, and iterating. At its worst, it's expensive supplements and unvalidated tests sold under the banner of science.
Blood testing sits at the evidence-based end. The markers that predict cardiovascular events, metabolic disease, cancer risk, and overall mortality are well-established. They're not exotic. They're not expensive. Most of them are the same tests your GP would order. They're just being interpreted through a different lens.
The biohacking contribution isn't new tests. It's a new attitude: test proactively, aim for optimal rather than "not yet sick," and track over time rather than testing once and forgetting.
That attitude is genuinely useful. The tests themselves? They're mostly the same ones I've been writing about for 25 articles.
The evidence-based longevity markers
These are the blood markers with the strongest evidence linking them to long-term health outcomes. They're not exotic or expensive, but they're powerful when tracked consistently.
Fasting Insulin and HOMA-IR
The longevity connection
Insulin resistance is arguably the single most important modifiable metabolic risk factor for chronic disease. It underpins type 2 diabetes, cardiovascular disease, NAFLD, certain cancers, and possibly neurodegenerative disease. Fasting insulin can detect insulin resistance years before glucose or HbA1c shift.
Where to aim
Fasting insulin below 8-10 µIU/mL. HOMA-IR below 1.5. Standard lab ranges often extend to 25+, which is the clinical upper limit, not the optimal target.
Test it with Bloody Good:
Product: Fasting Insulin Blood Test
Related reading: Weight gain and blood tests
HbA1c
What it tells you
Your three-month blood sugar average. HbA1c predicts cardiovascular events, microvascular complications, and all-cause mortality across the entire spectrum, not just in diabetics. The relationship is continuous: lower HbA1c within the healthy range is associated with better outcomes.
Where to aim
Below 33 mmol/mol (5.2%). The "normal" range extends to 41 (5.9%), and pre-diabetes starts at 42 (6.0%). Optimisation-minded clinicians target the lower end.
Test it with Bloody Good:
Related reading: HbA1c explained
Lipid Panel (With Context)
The longevity connection
LDL cholesterol drives atherosclerosis. The relationship between cumulative LDL exposure and cardiovascular events is one of the most robust in medicine. But the lipid panel is most informative as a pattern. LDL, HDL, triglycerides, and their ratios tell a more complete story than any single number.
Where to aim
LDL below 2.6 mmol/L for standard risk (below 1.8 for high risk). Triglycerides below 1.0 mmol/L. HDL above 1.0 for men, 1.3 for women. Triglyceride/HDL ratio below 1.5 (a surrogate marker for insulin resistance and small dense LDL).
Test it with Bloody Good:
Related reading: Cholesterol explained, Heart health blood tests
Lipoprotein(a)
Why it's worth knowing
A genetically determined independent cardiovascular risk factor. Elevated Lp(a) affects roughly 20% of the population and amplifies the risk associated with other lipid markers. It's one of the few tests you truly only need once. It doesn't change over your lifetime.
Why biohackers care
It's a risk factor you can't modify through lifestyle. No diet or exercise changes Lp(a). But knowing your level changes how aggressively you manage everything else.
Test it with Bloody Good:
Product: Lipoprotein(a) Blood Test
Related reading: Heart health blood tests
hs-CRP
The inflammation angle
Chronic low-grade inflammation is associated with accelerated ageing, cardiovascular disease, cancer, and neurodegenerative disease. hs-CRP is the most accessible marker of systemic inflammation and adds an inflammatory dimension to the metabolic and lipid picture.
Where to aim
Below 1.0 mg/L. Between 1.0 and 3.0 is moderate risk. Above 3.0 (if not acutely ill) warrants investigation for the inflammatory source.
Homocysteine
What it reveals
Elevated homocysteine is associated with cardiovascular risk, cognitive decline, and bone health. It also functions as a marker of B12 and folate status, making it both a cardiovascular and a nutritional indicator.
Where to aim
Below 10 µmol/L. Above 12 warrants investigation (typically B12, folate, kidney function).
Test it with Bloody Good:
Product: Homocysteine Blood Test
eGFR
The ageing kidney
Kidney function declines with age. The rate of decline is modifiable. Blood pressure control, blood sugar management, and avoiding nephrotoxic medications can all slow progression. eGFR is a fundamental marker of how well one of your most important organs is ageing.
Test it with Bloody Good:
Related reading: Kidney function blood tests
Markers with emerging evidence
These are markers that the optimisation community discusses frequently. The evidence is promising but less definitive than the core panel.
DHEAS. An adrenal androgen that declines steadily with age. Some researchers consider it a marker of biological ageing. Lower DHEAS has been associated with poorer health outcomes in older adults. The clinical utility of supplementing DHEAS is unproven, but tracking it over time provides a data point on adrenal ageing.
Testosterone trajectory (men). Not a single reading, but the rate of decline over years. Faster-than-expected decline may signal metabolic, sleep, or lifestyle issues that accelerate ageing.
Vitamin D (optimised). The standard reference range starts at 50 nmol/L. Optimisation-focused clinicians often target 75-125 nmol/L based on observational data linking higher levels with better immune function, bone health, and cardiovascular outcomes.
Thyroid function. TSH at the upper end of "normal" may represent a suboptimal metabolic rate in some individuals. Tracking TSH over time detects drift before clinical hypothyroidism develops.
ApoB. A marker that some cardiologists consider superior to LDL for assessing atherogenic particle number. Not widely available through standard Australian panels but increasingly discussed in the longevity space.
What "optimal" means, and how it differs from "normal"
Standard reference ranges are based on population distributions. They tell you where 95% of the population falls. They don't tell you what's ideal for long-term health.
"Normal" HbA1c includes 41 mmol/mol. That's the doorstep of pre-diabetes. "Normal" fasting insulin can extend to 25 µIU/mL. That's insulin resistance territory. "Normal" triglycerides can reach 2.0 mmol/L. That's metabolically suboptimal.
The longevity perspective is: don't aim for "not yet sick." Aim for the range associated with the lowest risk.
The caveat: "optimal" ranges are derived from observational epidemiology, not randomised trials. They're the best targets we have, but they're not precise prescriptions. Two people with the same fasting insulin may have very different health trajectories based on genetics, lifestyle, sleep, stress, and a hundred other variables.
Pursue optimal, but hold it loosely. The trajectory matters more than any single number.
The N=1 principle: why tracking matters more than single readings
This is the most important concept in health optimisation blood testing.
A single blood test tells you where you are today. A series of tests over years tells you where you're heading. And the direction matters more than the position.
Fasting insulin of 8 that was 5 two years ago is more concerning than fasting insulin of 12 that's been stable for five years. HbA1c of 34 that was 30 two years ago tells a different story than HbA1c of 36 that's been flat for a decade.
This is the N=1 approach: you are your own control. Your baseline is your reference range. Your trajectory is your signal.
Test the same markers, at the same time of year, under similar conditions (fasting, morning, rested), annually. Build a spreadsheet. Track the trends. The pattern that emerges over three to five years is worth more than any single "advanced panel."
What blood tests can't measure for longevity
Blood work is powerful, but it's not the whole picture. Several factors that strongly influence longevity and healthspan aren't captured in a blood draw.
VO2max and cardiorespiratory fitness. One of the strongest predictors of all-cause mortality. Low fitness carries more risk than smoking, diabetes, or hypertension. A blood test can't measure this, but a structured exercise test can.
Muscle mass and strength. Sarcopenia (age-related muscle loss) is a major predictor of frailty, falls, and mortality in older adults. Blood tests don't assess this. DEXA scans and functional testing do.
Sleep quality. Sleep disruption accelerates biological ageing through multiple mechanisms. Blood tests can reveal some consequences (cortisol, inflammation, glucose dysregulation) but don't directly measure sleep.
Social connection. Loneliness and social isolation are associated with mortality risk comparable to smoking. No blood test for this one.
Psychological wellbeing. Purpose, resilience, and mental health influence longevity through mechanisms that blood markers capture only partially.
Epigenetic age. Emerging tests claim to estimate your "biological age" through DNA methylation patterns. The science is real but the commercial products are variable in quality and clinical actionability. Worth watching, but not yet ready for standard use.
The blood markers are one layer. Fitness, strength, sleep, connection, and purpose are others. Optimise all of them, not just the ones you can quantify in a lab.
Building an annual optimisation protocol
The annual panel (evidence-based core)
Every year, same time:
Fasting insulin + fasting glucose (HOMA-IR)
HbA1c
Full lipid panel (total cholesterol, LDL, HDL, triglycerides)
hs-CRP
eGFR / creatinine
Full blood count
Liver function (ALT, GGT)
Thyroid (TSH, Free T4)
Iron studies (ferritin)
Vitamin D
Vitamin B12
Once in your lifetime
Lipoprotein(a). It's genetically fixed, so one test is enough.
Add based on your profile
Testosterone + SHBG (men, from 30+, annually or biannually). Homocysteine (if B12 is borderline or cardiovascular risk factors are present). DHEAS (if tracking adrenal ageing, every 2-3 years). Cortisol (if stress, sleep, or recovery is a specific concern).
Track in a spreadsheet. Date, values, conditions (fasted, rested, time of day). Compare annually. Look for trends, not single numbers.
Tests to consider through Bloody Good
The most efficient option
The Bloody Good Test covers 100 biomarkers including every marker in the annual protocol above in a single draw. Annual repetition builds the longitudinal data that makes tracking meaningful.
Supplementary tests (not included in the standard panel)
Lipoprotein(a) — once in your lifetime
Homocysteine — cardiovascular + B12/folate functional marker
DHEAS — adrenal ageing marker
Fasting Insulin — insulin resistance (if not included in your chosen panel)
For performance-focused individuals
The Performance Check covers 50+ biomarkers geared toward energy, hormones, and metabolic health. It complements the broader panel if you're also tracking athletic performance.
For age-specific guidance: Blood tests by age
Explore more biomarkers
Browse the Bloody Good Biomarker Directory
General information only. This article is not medical advice and is not a substitute for care from a qualified health professional. If you have concerning symptoms or urgent health issues, seek medical attention promptly.