Bloodwork is not optional for serious peptide research — it is the foundation that makes research interpretable. Without a pre-protocol baseline, you cannot attribute changes in how you feel, perform, or appear to any specific compound or protocol change. With a comprehensive baseline, every data point has context. The 74-biomarker longevity panel at Bioactive Compounds is designed around a simple principle: measure what matters for peptide research, not just what the NHS deems necessary for the absence of disease. The critical distinction — one that runs through every section of this guide — is the difference between not sick (within NHS reference ranges) and optimised (within the ranges associated with the best long-term health outcomes in the research literature). These are not the same, and understanding that distinction is the starting point for serious research.
The NHS reference range gap: NHS normal ranges are derived from the middle 95% of the test population — a population that is largely unoptimised. Being "in range" confirms you are not an outlier in a largely unhealthy reference group. It does not confirm you are optimised. Research shows that Vitamin D at 50 nmol/L (NHS threshold) is associated with significantly worse outcomes than levels of 100–150 nmol/L.
The Essential Pre-Protocol Panel
The minimum viable panel before starting any peptide research protocol comprises four categories: Hormones (Total & Free Testosterone, SHBG, LH, FSH, DHEA-S, Cortisol) — establishing the hormonal baseline that all peptide protocols operate against. Metabolic (HbA1c, Fasting Glucose, Fasting Insulin) — essential safety markers, particularly critical for GH-axis protocols. Inflammation (hs-CRP, Creatine Kinase) — the primary repair and anti-inflammatory research markers. Organ function (ALT, AST, GGT, Albumin, Creatinine) — confirming the metabolic processing organs are functioning properly before introducing any research compound. This minimum panel takes a single fasted morning blood draw and provides the foundation for any serious research cycle regardless of which compound is being studied.
Hormone Panel Deep Dive
The hormone panel is the single most important category for peptide research context. Total Testosterone: NHS range 8–30 nmol/L; optimal research range for men 18–25 nmol/L (morning fasted). Free Testosterone: more clinically relevant than total in many cases — reflects the biologically active fraction; optimal 0.40–0.55 nmol/L. SHBG (Sex Hormone Binding Globulin): high SHBG reduces free testosterone availability; optimal 20–40 nmol/L. LH and FSH: pituitary gonadotropins that confirm the hypothalamic-pituitary-gonadal (HPG) axis is functional — critical baseline before any compound that might interact with GH or gonadotropin signalling. DHEA-S: adrenal hormone that declines with age; the single best endocrine proxy for biological aging. Cortisol (AM): stress axis marker; chronically elevated cortisol suppresses testosterone, immune function, and repair mechanisms.
| Marker | NHS Reference | Optimal Research Range | Protocol Relevance |
|---|---|---|---|
| Total Testosterone (M) | 8–30 nmol/L | 18–25 nmol/L | All protocols — baseline context |
| Free Testosterone (M) | 0.17–0.64 nmol/L | 0.40–0.55 nmol/L | GH-axis, hormone optimisation |
| SHBG | 10–70 nmol/L | 20–40 nmol/L | Testosterone bioavailability |
| LH | 1.7–8.6 IU/L | 3–8 IU/L | HPG axis integrity |
| FSH | 1.5–12.4 IU/L | 2–8 IU/L | HPG axis integrity |
| DHEA-S | Age-dependent | Age-adjusted optimal | Longevity, adrenal reserve |
| Cortisol (AM) | 166–507 nmol/L | 350–550 nmol/L | Stress axis, immune function |
The Metabolic Panel
The metabolic panel is the most critical safety requirement for GH-axis peptide research, and important as baseline context for all protocols. HbA1c (glycated haemoglobin) reflects average blood glucose over the preceding 90 days — the gold standard longitudinal glycaemic marker. NHS diabetic threshold: 48 mmol/mol; optimal non-diabetic range: below 36 mmol/mol. Fasting Glucose: direct same-day measurement of blood sugar in the fasted state; optimal below 5.0 mmol/L. Fasting Insulin: direct measurement of insulin secretion; elevated fasting insulin indicates insulin resistance developing before glucose is visibly abnormal — an earlier, more sensitive marker. HOMA-IR (calculated from Fasting Glucose × Fasting Insulin ÷ 22.5): a standardised insulin resistance index; optimal below 1.5; above 2.5 indicates significant insulin resistance. GH peptides can transiently elevate fasting glucose by inducing mild insulin resistance — these markers must be established before any GH-axis protocol.
Inflammation Markers
hs-CRP (high-sensitivity C-reactive protein) is the most clinically sensitive blood marker of systemic inflammation. Produced by the liver in response to inflammatory cytokines (primarily IL-6), it rises within 6–12 hours of an inflammatory trigger and has a half-life of approximately 19 hours — making it highly responsive to acute changes. Optimal range: below 0.5 mg/L. NHS upper normal: 5 mg/L. Chronic values of 1–3 mg/L indicate elevated cardiovascular and metabolic risk even within NHS normal limits. For BPC-157 and anti-inflammatory protocol research, hs-CRP is the primary response biomarker. Creatine Kinase (CK): enzyme released from damaged muscle and tendon cells. Elevated at baseline indicates active tissue injury — providing critical context for repair-focused protocols. ALT (Alanine Aminotransferase): liver enzyme; optimal below 25 IU/L in men, below 20 IU/L in women. Albumin: serum protein reflecting liver synthesis capacity and nutritional status; optimal 42–47 g/L.
The Advanced Lipid Panel
Standard NHS cholesterol panels (Total Cholesterol, HDL, LDL, Triglycerides) significantly undercharacterise cardiovascular risk. The advanced lipid panel adds three critical markers: ApoB (Apolipoprotein B) — one structural protein per atherogenic lipoprotein particle, making it a direct count of cardiovascular risk particles. Studies consistently show ApoB outperforms LDL-C as a predictor of cardiovascular events, particularly in individuals with metabolic abnormalities. Optimal: below 0.65 g/L. Lipoprotein(a) [Lp(a)]: a genetically determined cardiovascular risk factor that does not respond meaningfully to diet or most lifestyle interventions. Optimal: below 70 nmol/L (30 mg/dL). Up to 20% of the population have elevated Lp(a) — establishing this baseline is essential. Apo A1: the structural protein of HDL particles — a better measure of protective lipoprotein function than HDL-C alone.
Micronutrients That Matter
Micronutrient deficiencies blunt the response to any biological intervention, including peptide protocols. Vitamin D (25-OH): foundational for immune function, testosterone production, muscle repair, and hormonal signalling. NHS sufficiency: 50 nmol/L. Optimal: 100–150 nmol/L. Deficiency is near-universal in the UK population during winter months. Vitamin B12: essential for neurological function, methylation, and red blood cell synthesis. Optimal: above 400 pmol/L (NHS lower limit 200 pmol/L is frequently insufficient for optimal neurological function). Magnesium (RBC): involved in over 300 enzymatic reactions including testosterone synthesis and insulin signalling; serum magnesium is a poor proxy — red blood cell magnesium is more accurate. Zinc: critical for testosterone synthesis, immune function, and wound healing; optimal 12–20 µmol/L.
Thyroid — The Foundation
Thyroid function is often the most underassessed category in baseline bloodwork — and suboptimal thyroid function can significantly blunt the response to virtually every other biological intervention. TSH alone is insufficient — TSH in the NHS normal range (0.35–4.5 mIU/L) does not confirm adequate thyroid hormone production; it only confirms the pituitary is responding. For full thyroid picture: Free T3 (the active thyroid hormone; optimal 5.0–7.0 pmol/L), Free T4 (precursor; optimal 16–22 pmol/L), and Anti-TPO antibodies (ruling out Hashimoto's thyroiditis, the most common cause of hypothyroidism in the UK). A TSH in the upper half of the NHS range (2.5–4.5 mIU/L) often correlates with suboptimal Free T3 and is associated with worse metabolic outcomes.
NHS vs Optimal Ranges — Understanding the Gap
The NHS reference range defines the statistical boundary of "normal" in the tested population — the middle 95% of values in whoever presented for testing. This population is predominantly unoptimised from a longevity perspective. Being "in range" means you are not a significant outlier in an unhealthy distribution — not that you are operating at optimal biological capacity. The optimal range, by contrast, is derived from longevity, performance, and functional medicine research — it represents the values associated with the best long-term outcomes across multiple health dimensions. The healthspan distinction is profound: a Testosterone of 10 nmol/L is within NHS range but associated with significantly worse health outcomes than a Testosterone of 22 nmol/L. An hs-CRP of 2.5 mg/L is within NHS normal but associated with meaningfully elevated cardiovascular risk compared to a value below 0.5 mg/L.
Track All 74 Biomarkers — With Optimal Ranges
The Bioactive Compounds bloodwork tracker includes NHS reference ranges AND optimal longevity ranges for every marker, with peptide-specific interpretation guidance.
Peptide Intelligence — What Your Results Suggest
Specific biomarker patterns point toward specific research pathways. Elevated hs-CRP (above 1 mg/L): systemic inflammation present — BPC-157 (anti-inflammatory mechanisms), GHK-Cu (anti-inflammatory gene expression), and the Wolverine Stack are logical repair/anti-inflammatory research directions. Low Free Testosterone or elevated SHBG: Kisspeptin-10 research may be relevant as an upstream HPG axis modulator. Elevated HbA1c or HOMA-IR: Retatrutide (GLP-1/GIP/Glucagon triple agonist) or MOTS-c (AMPK-mediated insulin sensitivity) are among the relevant research compounds. Low DHEA-S: adrenal reserve is compromised; longevity protocol (Epitalon, Pinealon) and stress axis management are the priority. Elevated hs-CRP + low ALT: gut-origin inflammation may be the driver — BPC-157 oral administration research may be relevant. These are research directionality signals, not prescriptions.
How Often to Retest
The optimal retesting schedule for peptide research: Pre-protocol baseline — full 74-marker panel before commencing any new protocol. This is non-negotiable. 8-week check-in — targeted panel covering the protocol-specific key markers: hs-CRP + CK for repair protocols; Fasting Glucose + HbA1c for GH-axis protocols; hormone panel for any protocol affecting the endocrine axis. 12-week full panel — complete 74-marker panel at end of the standard 12-week cycle. This is the data that makes the cycle interpretable. HbA1c requires 12 weeks for meaningful change (90-day average); IGF-1 changes are best assessed at cycle end. The minimum viable commitment is pre-protocol and end-of-cycle. The 8-week check adds meaningful safety data for GH peptide protocols specifically.
Take Action on Your Bloodwork
Frequently Asked Questions
For BPC-157, the minimum panel includes: hs-CRP (inflammation baseline — the primary response marker given BPC-157's anti-inflammatory mechanism), Creatine Kinase (tissue damage baseline, especially if repair is the research focus), ALT (liver baseline), and Albumin (protein synthesis status). A full hormone panel is also recommended. If gut-targeted research is the focus, adding Calprotectin (faecal inflammation marker) provides additional context. The bloodwork tracker includes the full protocol-specific panel for BPC-157 with optimal range guidance.
NHS reference range for Total Testosterone in adult males: 8–30 nmol/L. The optimal longevity research range for men is typically cited as 18–25 nmol/L (morning fasted sample). Free Testosterone of 0.40–0.55 nmol/L and SHBG of 20–40 nmol/L provide the complete picture — because total testosterone with high SHBG can mean limited bioavailable free testosterone despite a "normal" total. For women, optimal ranges vary significantly by age and menstrual cycle phase; post-menopausal baseline is typically 0.7–2.8 nmol/L Total Testosterone. Always test as a morning fasted sample for reproducibility.
hs-CRP (high-sensitivity C-reactive protein) is the most sensitive blood marker for systemic inflammation. It is produced by the liver in response to inflammatory cytokines, primarily IL-6, and responds within 6–12 hours of an inflammatory trigger. Optimal: below 0.5 mg/L. NHS upper normal: 5 mg/L. Chronic values of 1–3 mg/L — within NHS normal — indicate elevated cardiovascular and metabolic risk. Values above 3 mg/L require investigation of the inflammatory source. For repair peptide research (BPC-157, TB-500, GHK-Cu), hs-CRP is the single most important response biomarker and the primary basis for evaluating protocol effect on inflammation.
Minimum schedule: full baseline panel before any new protocol, targeted key-marker check at 8 weeks (mid-cycle), full panel at cycle end (12 weeks). For GH-axis peptides, Fasting Glucose must be specifically checked at 8 weeks. For longitudinal research, quarterly full panels are ideal. Tracking trends over multiple cycles is more informative than any single data point — the pattern of change across cycles tells a more complete research story than one baseline snapshot.
NHS reference ranges define the statistical middle 95% of results from the test population — a predominantly unoptimised general population. Being "in range" means you are not a statistical outlier, not that you are functioning at optimal biological capacity. Optimal ranges are derived from longevity and functional medicine research and represent values associated with best long-term health outcomes. Example: NHS Vitamin D threshold is 50 nmol/L; the optimal longevity range is 100–150 nmol/L. Being "in range" at 55 nmol/L is very different from being optimised at 125 nmol/L in terms of immune function, hormone production, and repair capacity.
ApoB is one structural protein per atherogenic lipoprotein particle. Since cardiovascular disease is driven by particle penetration of the arterial wall, counting particles (ApoB) is more predictive than measuring cholesterol volume (LDL-C). ApoB is a significantly better predictor of cardiovascular events than LDL-C, particularly in metabolic syndrome and insulin-resistant individuals where LDL particles are small, dense, and more atherogenic per unit of LDL-C than in healthy individuals. Optimal ApoB: below 0.65 g/L. This is not available on standard NHS panels but is accessible via private blood testing.
NHS sufficiency threshold: 50 nmol/L (20 ng/mL). Optimal longevity research range: 100–150 nmol/L (40–60 ng/mL). Severe deficiency below 25 nmol/L is associated with impaired immune function, reduced testosterone production (Vitamin D is a precursor to the vitamin D hormone which supports testosterone synthesis), impaired muscle repair, and blunted response to many biological interventions. The UK population is particularly susceptible to deficiency due to limited sunlight exposure. Vitamin D testing and correction is the highest-value, lowest-cost intervention available to researchers as a foundation before other protocols.
Yes — a full baseline before each new research cycle is best practice. This is essential when starting a new compound for the first time, adding a compound to an existing protocol, resuming after 8+ weeks off-cycle, or after any significant health development. At absolute minimum, the protocol-specific key safety markers must be retested before each cycle regardless of cost constraints — Fasting Glucose for GH-axis peptides; hs-CRP for anti-inflammatory protocols. Skipping baseline bloodwork means any changes observed during the protocol cannot be reliably attributed to the protocol itself.