Nashville BiohackingWith Scott Crosbie
Scott Crosbie reviewing biomarker results at Next Health Nashville

The Data

What the numbers actually say.

Discrete, citable facts on aging, recovery, cellular biology, and proactive medicine — drawn from Scott Crosbie's book OPTIMIZED and the clinical evidence behind every therapy at Next Health.

Aging Biology

Adults with grip strength scores above 50 kg show strength profiles comparable to healthy 20-year-olds.

Grip strength has emerged as one of the most reliable proxies for biological age and all-cause mortality. The simplicity of the test (a handheld dynamometer for under 10 seconds) belies how much signal it carries.

Source · OPTIMIZED — Scott Crosbie / Next Health

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Functional biomarker testing can identify systemic dysfunction years before symptoms appear.

Standard physicals catch disease when it crosses a clinical threshold. Functional bloodwork uses optimal ranges that flag developing problems much earlier — when intervention is simpler and the system is more responsive.

Source · OPTIMIZED — Scott Crosbie / Next Health

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Cellular

NAD+ levels decline by approximately 50% between ages 40 and 60.

NAD+ is required for energy production in every cell and for DNA repair. The age-related decline is one of the most consistent findings in longevity science, and is the rationale for both NAD+ replenishment therapy and NAD+ precursor supplementation.

Source · OPTIMIZED — Scott Crosbie / Next Health

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Hyperbaric oxygen therapy can increase blood plasma oxygen saturation 10-15× normal atmospheric levels.

Under 2.0-2.4 ATA with 100% oxygen, oxygen dissolves directly into blood plasma at concentrations unachievable at normal atmospheric pressure. This dramatic excess is the mechanism behind HBOT's tissue-repair, neuroplasticity, and stem-cell-mobilization effects.

Source · OPTIMIZED — Scott Crosbie / Next Health

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FOX04, a senolytic peptide, is typically administered in just 5 injections over 10 days.

Unlike most peptide protocols that run weeks or months, FOX04-DRI targets senescent ('zombie') cells and uses a short, intensive cycle. The goal is selective clearance of dysfunctional cells, allowing healthier cells to thrive.

Source · OPTIMIZED — Scott Crosbie / Next Health

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A single Brazil nut provides the full daily selenium requirement (~70 mcg).

Selenium is essential for thyroid function, glutathione peroxidase activity (antioxidant defense), and immune signaling. Brazil nuts are among the densest natural sources — meaning daily intake at trivial cost and effort.

Source · OPTIMIZED — Scott Crosbie / Next Health

Hyperbaric oxygen therapy has been shown to mobilize endogenous stem cells from bone marrow.

Studies on serial HBOT protocols (typically 20+ daily sessions) show measurable increases in circulating stem cells and progenitor cells — providing one mechanism behind HBOT's documented effects on tissue healing and neurological recovery.

Source · OPTIMIZED — Scott Crosbie / Next Health

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IV nutrient delivery achieves 100% bioavailability, compared to 20-50% for oral vitamin C and lower for fat-soluble vitamins.

The digestive system limits how much of any oral supplement actually reaches circulation. IV delivery bypasses digestion entirely, achieving blood concentrations that aren't physiologically achievable through swallowed pills regardless of dose.

Source · OPTIMIZED — Scott Crosbie / Next Health

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An estimated 50%+ of US adults consume below the recommended daily intake of magnesium.

Magnesium is involved in 300+ enzymatic reactions including ATP synthesis, muscle contraction, and nervous system regulation. Sub-optimal intake is associated with sleep disruption, muscle cramps, and impaired recovery — many of which resolve with consistent supplementation.

Source · OPTIMIZED — Scott Crosbie / Next Health

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Cardiovascular

Regular sauna use (4+ sessions per week) is associated with significant reductions in cardiovascular mortality and all-cause mortality.

Large prospective studies — most notably from Finnish populations — show a dose-response between sauna frequency and longevity outcomes. The mechanism appears to combine cardiovascular conditioning (heart rate rises into aerobic ranges), heat-shock protein expression, and circulatory benefits.

Source · OPTIMIZED — Scott Crosbie / Next Health

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Metabolic

Industry experts project 80-90% of adults may be on some form of GLP-1 medication within the next 5 years.

GLP-1 agonists like semaglutide and tirzepatide have shown profound effects on weight, insulin resistance, and cardiovascular markers. Long-term use as a metabolic tool (rather than short-term weight loss) is becoming the dominant clinical pattern.

Source · OPTIMIZED — Scott Crosbie / Next Health

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Recovery

Whole-body cryotherapy chambers operate at -200°F to -250°F dry air.

Despite the extreme temperature, the dry air conducts heat poorly compared to water. A 50°F cold plunge extracts heat from the body faster than a -250°F cryotherapy chamber for the first few minutes — which is why cryotherapy is tolerable in 2-3 minute sessions.

Source · OPTIMIZED — Scott Crosbie / Next Health

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The vagus nerve is the longest cranial nerve in the body, connecting the brain to most major organs.

Vagal tone controls the parasympathetic 'rest and repair' state. Strong vagal tone is associated with better stress recovery, sleep quality, heart rate variability, and recovery from training. Modalities targeting the vagus nerve (BrainTap, certain breathing protocols, cold exposure) are an increasingly active area of optimization.

Source · OPTIMIZED — Scott Crosbie / Next Health

Cancer Detection

Approximately 70% of cancers come from types that don't have routine population screening tests.

Routine screening exists for breast, cervical, colon, lung (high-risk), and prostate cancers. The other ~70% of cancers — including most pancreatic, esophageal, ovarian, and kidney cancers — are typically detected only after symptoms appear, when treatment options are narrower.

Source · OPTIMIZED — Scott Crosbie / Next Health

When cancer is detected at an early stage, 5-year survival can be up to 4× higher than late-stage detection.

Stage-1 cancers have dramatically better outcomes than stage-3 or stage-4 disease across most cancer types. Multi-cancer early detection blood tests like Galleri are designed to shift more diagnoses earlier — improving the survival math.

Source · OPTIMIZED — Scott Crosbie / Next Health

Every Fact Sourced

Read the full reasoning in OPTIMIZED.

Every fact on this page is drawn from the methodology, research, and clinical practice detailed in Scott’s book.