Understanding Your Bloodwork
For every lab that matters on peptides: what it actually is, why the normal range is that number, what an out-of-range result means for you, and what to do; in plain English. Ranges are US-adult orientation; always read against your lab’s printed range.
Lab reference ranges
| Marker & normal range | What it is & why the range is that number | If it’s out of range, what it means for you & what to do |
|---|---|---|
| IGF-1, by age (ng/mL): 20s 200–400 · 30s 160–340 · 40s 130–290 · 50s 100–250 · 60s 90–210 · 70s+ 70–180 | The growth factor your liver releases when GH is high, it’s the number that actually tracks your growth signal (GH itself is too spiky to measure). It naturally falls with age, so the range is age-based: “normal” means normal for your age. | Above your age range = too much growth signal, it can feed hidden cancer cells and enlarge organs, hands, jaw, and heart. Do: cut the GH-peptide dose until IGF-1 is back mid-range for age. Below range = you’re under-dosed for any real effect. |
| Fasting glucose: 70–99 mg/dL | Your blood sugar after ~8 hours without food. The range is where a healthy body holds sugar steady without over-working insulin. | High (100–125 pre-diabetes, ≥126 diabetes) = sugar creeping up; GH and glucagon peptides push it up. Do: recheck fasting, cut refined carbs, and lower the dose if it keeps climbing. |
| HbA1c: <5.7% | Your average blood sugar over ~3 months (sugar permanently stuck to red cells). One high day won’t move it; a bad trend will. <5.7% is the non-diabetic average. | High (5.7–6.4 pre-diabetes, ≥6.5 diabetes) = your months-long sugar is too high. GLP-1s lower it; GH raises it. Do: recheck every 3 months on a GLP-1. |
| eGFR: ≥60 mL/min/1.73m² | An estimate of how fast your kidneys filter blood, from creatinine + age/sex. ≥60 = normal filtering capacity. | Low (<60) = reduced kidney function, on GLP-1s it’s almost always dehydration, not the drug. Do: hydrate hard and hold the dose; a drop >20% from your baseline = stop and recheck. |
| Total testosterone (men): 300–1000 ng/dL | The main male hormone. 300–1000 is the healthy adult-male band; below it, symptoms usually appear. | Low (<300) = low-T (fatigue, low libido and mood, poor recovery); the reason to consider HCG/kisspeptin or TRT. High (on TRT) = over-replaced; dial back. |
| Estradiol (men): 10–40 pg/mL | Estrogen, men make a little from testosterone and need it for libido, bone, and mood. 10–40 is the male sweet spot. | High (>40) = too much for a man (puffiness, moodiness, breast-tissue/gyno risk). Do: manage it, but don’t crush it to zero, that wrecks libido and bone. |
| Prolactin: men 4–15 ng/mL · women 4–23 ng/mL | A pituitary hormone. Some GH peptides (GHRP-2/6, Hexarelin) push it up as a side effect. | High = disrupts the cycle/ovulation in women, and lowers libido and testosterone in men. Do: switch to a clean GH peptide (Ipamorelin or a GHRH-type) and recheck. |
| Hematocrit: men 41–53% · women 36–46% | The percentage of your blood made of red cells. Too high makes blood thick and slow. | High (>54%) = blood too thick, a real clot and stroke risk; anything raising testosterone or GH can push it up. Do: donate blood or hold therapy. |
| TSH: 0.4–4.5 mIU/L | The pituitary’s “volume knob” to the thyroid. A normal value means thyroid output is balanced (it’s the signal, not the hormone). | High = underactive thyroid (tired, cold, weight gain, low mood); low = overactive (racing heart, anxious, weight loss). Do: recheck 6–8 weeks after any dose change. |
| LDL cholesterol: <100 mg/dL optimal | The “bad” cholesterol that builds plaque in arteries. <100 is optimal, <70 if you have heart risk. | High = cardiovascular risk building over time. Do: GLP-1 weight loss usually improves it; diet or a statin if it stays high. |
| B12: 200–900 pg/mL (aim 400+) | A vitamin your nerves, brain, and red blood cells depend on; your body can’t make it, so it comes from food, pills, or injections. Common to run low on a GLP-1. | Low = deficiency (fatigue, tingling/numbness, brain fog); GLP-1s can deplete it. Do: supplement until you’re mid-range. |
| Vitamin D (25-OH): 30–100 ng/mL (aim 40–60) | A hormone-vitamin for bone, immune function, and mood. | Low (<30) = insufficient (weaker bones, lower immunity and mood). Do: supplement 2,000–5,000 IU/day and recheck. |
| hsCRP: <3 mg/L | A sensitive marker of background inflammation anywhere in the body. | High = inflammation somewhere (infection, injury, chronic disease); not peptide-specific. Do: investigate the cause if it stays up. |
Women’s reproductive panel & when to draw
When to draw (women), optional: if you track your cycle, the reproductive hormones (estradiol, LH, FSH) read cleanest in the first few days of your period, and progesterone about a week after ovulation. Don’t track it? Just draw early in your period and note the date, a provider can read the numbers in context. Men: draw testosterone in the morning, fasted.
| Marker | Range (women) | What it flags |
|---|---|---|
| Total testosterone | 8–60 ng/dL | High points to PCOS; GLP-1s tend to lower it. |
| Estradiol (E2) | Follicular 20–150 · mid-cycle 150–750 · luteal 30–450 · postmenopause <30 pg/mL | Needed to read IGF-1 (oral estrogen lowers it) and to time reproductive peptides. |
| LH / FSH | LH foll. 2–12, surge 20–100 · FSH foll. 3–10, menopause >25 mIU/mL | Reproductive-peptide response; a high LH:FSH ratio suggests PCOS. |
| Progesterone | Follicular <1 · luteal >3–5 ng/mL | Luteal >3 confirms you ovulated. |
| SHBG | 18–144 nmol/L (men 10–57) | Low in PCOS / insulin resistance; oral estrogen raises it. |
| Pregnancy (β-hCG) | Negative, required | Before GLP-1s and most peptides in women who could conceive. |
Worked example, reading your IGF-1
You’re 45, so your age band is 130–290 ng/mL. 200: mid-range, hold the dose. 310 (just over): slightly high, small dose cut, recheck in 6 weeks. 450 (well over): too much growth signal, cut the dose meaningfully and confirm your cancer screening is current. 120 on estrogen pills: blunted, not truly low; switch to a patch first.