Bloodwork

72 markers built for peptide and hormone therapy.

Most generalist panels (including Function Health's 160-marker panel) test for wellness — not for the things that matter when you're running peptides or hormones. KAYU's panels include IGFBP-3, sensitive estradiol by LC/MS, free testosterone by equilibrium dialysis, calcitonin, cystatin C, CTX, P1NP, and other markers that catch what generalist panels miss.

Quest direct-pay retail for the peptide panel: ~$550/draw. Combined peptide + hormone: ~$800/draw. KAYU covers the bill on Root, Branch, and Canopy memberships.

Peptide Panel

~42 markers

GH/IGF axis, glucose-insulin axis, inflammation, lipids + cardiovascular, thyroid, kidney + liver, CBC, micronutrients. Designed to safely monitor BPC-157, GHK-Cu, GLP-1s, GH secretagogues, TB-500, and metabolic peptides.

Quest direct-pay retail
~$550/draw · ~$2,200/yr
Covered on Root membership →

Peptide + Hormone Panel

~72 markers

Everything in the peptide panel PLUS LC/MS-grade sex steroids, full pituitary/gonadal axis, adrenal, prostate/breast safety, bone turnover, iron/coagulation. Built around Endocrine Society and AUA monitoring guidelines.

Quest direct-pay retail
~$800/draw · ~$3,200/yr
Covered on Branch + Canopy →
Every marker explained

What we test and why.

Every marker tied to a specific clinical question. Hover or tap a marker to see why it's in the panel.

Peptide Panel

Root + Branch + Canopy

GH / IGF axis

  • IGF-1 (LC/MS)
    Titration target for sermorelin, CJC/Ipamorelin, tesamorelin. FDA tesamorelin label requires monitoring.
  • IGFBP-3
    Stabilizes IGF-1 half-life signal. Function Health does NOT run this.
  • GH (random)
    Directional signal during secretagogue protocols.
  • Prolactin
    Rises on ipamorelin/CJC at supraphysiologic doses.
  • IGF-1 z-score by age
    Calculated — keeps you in age-adjusted optimal range, not just 'normal'.

Glucose / insulin axis

  • Fasting glucose
    Baseline metabolic.
  • Fasting insulin
    True early signal of insulin resistance — runs years ahead of HbA1c.
  • HOMA-IR (calculated)
    Quantifies insulin resistance.
  • HbA1c
    90-day glycemic average.
  • C-peptide
    Distinguishes endogenous vs. exogenous insulin — useful on GLP-1s.
  • Fructosamine
    3-week glycemic window for fast titration.

Inflammation + healing

  • hs-CRP
    Systemic inflammation. BPC-157, TB-500, GHK-Cu rationale anchor.
  • ESR
    Inflammatory burden.
  • Ferritin
    Iron + inflammation marker. TRT raises it.
  • Fibrinogen
    Cardiovascular inflammation.
  • Homocysteine
    Methylation + cardiovascular risk.
  • IL-6
    Acute inflammatory cytokine.
  • TNF-α
    Inflammatory cascade marker.

Lipids + cardiovascular

  • Total cholesterol, LDL-C, HDL-C, triglycerides
    Standard lipid panel.
  • ApoB
    Better than LDL — Peter Attia gold standard.
  • Lp(a)
    Once-in-life genetic risk marker.
  • ApoA1
    Reverse cholesterol transport.
  • LDL-P, sdLDL, oxLDL
    Particle-level cardiovascular risk.
  • NT-proBNP
    GH peptides cause fluid retention — early heart failure signal.
  • Troponin-I (high-sensitivity)
    Baseline for any cardiotoxic-risk protocol.
  • Lp-PLA2
    Vascular inflammation.

Thyroid

  • TSH, free T3, free T4
    Standard thyroid axis.
  • Reverse T3
    Detects sick-thyroid pattern. Most generalist panels skip this.
  • TPO antibodies, Thyroglobulin antibodies
    Hashimoto's screen.
  • Calcitonin
    GLP-1 black-box monitor (medullary thyroid cancer). Function Health does NOT run this.

Kidney + liver

  • BUN, creatinine, eGFR
    Standard kidney.
  • Cystatin C
    More sensitive than creatinine on GLP-1 weight loss. Function Health does NOT run this.
  • ALT, AST, ALP, GGT, total + direct bilirubin
    Full liver panel.
  • Lipase, amylase
    GLP-1 pancreatitis safety signal.
  • Uric acid
    Metabolic + kidney.

CBC + electrolytes + nutrients

  • Full CBC w/ differential
    WBC, RBC, Hgb, Hct, MCV/MCH/MCHC, RDW, platelets, neutrophils, lymphocytes, monocytes, eosinophils, basophils.
  • Full CMP
    Sodium, potassium, chloride, CO2, calcium, total protein, albumin, globulin.
  • 25-OH vitamin D
    Hormone precursor + immune.
  • B12, folate (RBC)
    Methylation + nerve health.
  • Magnesium RBC
    Intracellular magnesium — serum magnesium is clinically near-useless.
  • Zinc, copper, selenium
    Hormone synthesis cofactors. Copper specifically for GHK-Cu monitoring.
  • Omega-3 index
    Cardiovascular + anti-inflammatory.

Hormone Panel additions (combined)

Branch + Canopy only

Sex steroids (LC/MS gold standard)

  • Total testosterone (LC/MS)
    Mass spec — accurate at male and female ranges. Quest direct-pay $69.
  • Free testosterone (equilibrium dialysis)
    Gold standard per AUA guidelines. Function Health does CALCULATED free T, not measured.
  • Bioavailable testosterone
    Calculated from total + SHBG + albumin.
  • SHBG
    Sex hormone binding globulin — drives free T calculation.
  • Estradiol — sensitive (LC/MS)
    Required when E2 < 100 pg/mL — i.e., almost every man on TRT. Function Health uses standard E2 immunoassay (useless at low ranges).
  • Estrone (E1)
    Postmenopausal estrogen monitoring.
  • DHT (dihydrotestosterone)
    5-alpha reductase product — critical for TRT and hair-loss workups.
  • DHEA-S
    Adrenal androgen reserve.
  • Androstenedione
    Adrenal + ovarian androgen precursor.
  • Progesterone
    Female luteal + male TRT side-effect monitoring.
  • 17-OH progesterone
    Adrenal + CAH screen.
  • Pregnenolone, allopregnanolone
    Steroidogenesis precursor + GABA neurosteroid.

Pituitary / gonadal axis

  • LH, FSH
    Pituitary signal — diagnostic for primary vs. secondary hypogonadism.
  • AMH (women)
    Ovarian reserve.
  • Inhibin B (men)
    Sertoli cell function on TRT.

Adrenal / stress

  • Cortisol AM
    Diurnal peak.
  • Cortisol PM
    Diurnal trough — circadian dysfunction screen.
  • ACTH
    Pituitary-adrenal axis.
  • Aldosterone, renin
    Mineralocorticoid axis.
  • DHEA (free)
    Adrenal precursor.

Prostate / breast safety

  • PSA total
    Endocrine Society monitoring requirement on TRT.
  • PSA free %
    Differentiates BPH from cancer when total elevated.

Bone turnover (HRT + GH peptide rationale)

  • CTX (resorption)
    Bone breakdown rate. Function Health does NOT run this.
  • P1NP (formation)
    Bone formation rate. Function Health does NOT run this.
  • Osteocalcin
    Bone formation + glucose metabolism.
  • Vitamin K2 (MK-7)
    Bone calcium routing.
  • Intact PTH, ionized calcium
    Calcium homeostasis.

Iron + coagulation (TRT safety)

  • Serum iron, TIBC, transferrin saturation
    TRT raises hematocrit — Endocrine Society contraindicates >54%.
  • PT/INR, aPTT, D-dimer
    TRT thrombosis risk + GH water retention coagulation screen.
  • INSL3
    Leydig cell function on TRT.
Vs. Function Health

We test fewer total markers. We test the right ones.

Function Health markets 160+ markers tested 2x/year for $499/yr. The 160 includes mid-year duplicate draws — about 100 distinct markers, all wellness-oriented. KAYU runs ~118 markers selected specifically to monitor peptide and hormone therapy. The moat is specificity, not count.

What Function Health does NOT run (that we do)

  • IGFBP-3 — GH/IGF axis — pairs with IGF-1 to give the real signal. Function only runs IGF-1 alone.
  • Free testosterone by equilibrium dialysis — AUA gold standard. Function calculates free T from total + SHBG, which is less accurate.
  • Sensitive estradiol (LC/MS) — Required to read E2 below 100 pg/mL — i.e., almost every man on TRT. Standard immunoassay E2 is useless at these ranges.
  • Calcitonin — GLP-1 black-box monitor (medullary thyroid cancer). Required if you're on tirzepatide or semaglutide.
  • Cystatin C — More sensitive kidney marker than creatinine on GLP-1 weight loss.
  • DHT (dihydrotestosterone) — 5-alpha reductase product — critical for TRT and hair-loss workups.
  • CTX, P1NP (bone turnover) — Bone resorption + formation rates. Necessary on HRT and GH peptide protocols.
  • Allopregnanolone, INSL3 — Neurosteroid + Leydig cell function on TRT.

Source: functionhealth.com/what-we-test (verified Apr 28 2026), AUA Testosterone Deficiency Guideline, Endocrine Society 2018 Hypogonadism CPG, FDA EGRIFTA SV (tesamorelin) prescribing information.

Bloodwork covered on every membership tier.

Root: peptide panel quarterly · Branch + Canopy: combined panel quarterly · Canopy: ad-hoc draws as clinically indicated.

See membershipsStart with $49 consult
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