What lab tests should I get before starting peptides?
Baseline panel: CBC, CMP, lipid panel, fasting glucose, HbA1c, IGF-1 if running GH secretagogues, and a thyroid panel if symptomatic. Roughly $100–300.
Updated May 8, 2026 · 5 min read
At minimum: CBC, comprehensive metabolic panel (CMP), lipid panel, fasting glucose, and HbA1c. Add IGF-1 if you're running GH secretagogues or anything that affects the GH-axis. Add a thyroid panel if you have any thyroid symptoms or family history. Total cost from a direct-to-consumer lab is typically $100–300, depending on which markers and which provider. The reason for baseline labs isn't paranoia — it's that without a "before" picture, you can't read drift on the "after" picture, and drift is where most peptide-related health questions actually live.
The minimum baseline panel
| Test | Why |
|---|---|
| CBC | Red and white cell counts — rules out anemia, infection, baseline immunology |
| Comprehensive Metabolic Panel (CMP) | Kidney (BUN, creatinine), liver (ALT, AST), electrolytes, glucose |
| Lipid panel | Total cholesterol, LDL, HDL, triglycerides — GH-axis affects all of these |
| Fasting glucose | Critical baseline if running secretagogues or MK-677 |
| HbA1c | Three-month glucose average — best single insulin-resistance marker |
This panel typically runs $80–150 from Quest, LabCorp, or a DTC marketplace like Marek, Ulta Lab Tests, or Life Extension.
Add-ons depending on your protocol
| If you're running... | Add this | Why |
|---|---|---|
| Sermorelin, Ipamorelin, CJC-1295, MK-677, Tesamorelin | IGF-1 | Confirm baseline GH-axis status; track response |
| MK-677 specifically | Cortisol, prolactin (AM) | MK-677 can affect both |
| IGF-1 LR3 | IGF-1, fasting insulin | Direct relevance to dose response |
| Any with cancer history | PSA (men), CA-125 (women, with clinician), tumor markers per history | Pre-cycle screening |
| Pre-existing hypothyroid risk | TSH, free T4, free T3 | Some peptides affect thyroid axis indirectly |
| Cardiovascular risk profile | Apolipoprotein B, hsCRP | More sensitive cardiovascular drift markers |
For deeper coverage of how peptides affect bloodwork, see peptides and bloodwork.
What "baseline" gives you
The point of baseline labs isn't "passing" — it's that you have a comparison point for the same labs at end-of-cycle:
| Marker | What "drift" means |
|---|---|
| Fasting glucose climbing 5–10 mg/dL | Insulin sensitivity slipping (common on MK-677, secretagogues) |
| HbA1c rising 0.2+ | Confirms a real glucose drift, not a single-day spike |
| LDL rising / HDL falling | Lipid drift on long secretagogue cycles |
| ALT or AST rising | Liver stress — vendor or compound flag |
| IGF-1 above age-adjusted range | Over-shooting on secretagogue dose |
| CBC changes | Inflammatory response, infection, contamination signal |
Without a "before," you can't interpret an "after." Drift is the early-warning signal — see when to stop for the full framework.
Where to get the labs
| Path | Cost | Notes |
|---|---|---|
| PCP with insurance | Copay only | Cheapest if labs are clinically indicated; trickier if you're asking for them as a baseline |
| PCP without insurance | Lab cost only ($100–300) | Usually possible; ask for a self-pay rate |
| DTC marketplace (Marek, Ulta, Life Extension, Quest direct) | $80–250 | No clinician needed; you get the labs back yourself |
| Functional medicine / longevity clinic | $300–1000+ | Most thorough, also most expensive |
| Specialty TRT / men's health clinic | $200–500 | Often packaged into intake |
The cheapest defensible path: a DTC panel for the basics, plus IGF-1 if you're running secretagogues. The most thorough: PCP-ordered through insurance for the standard markers, DTC top-up for IGF-1 and any specialty markers your PCP won't order.
Timing and prep
| Lab | Prep |
|---|---|
| Fasting glucose, HbA1c, lipid panel | 8–12 hour fast (water only) |
| IGF-1 | No fast required, but consistent timing helps |
| Cortisol | AM draw (around 7–9 a.m.) for the standard reference range |
| CBC, CMP | No fast required |
If you're getting everything in one draw, fast for 8–12 hours and go in the morning. That covers the markers that need fasting and doesn't hurt the others.
Repeat schedule
| Stage | Labs |
|---|---|
| Before first cycle | Full baseline panel |
| End of first cycle (4–8 weeks in) | Same panel; compare drift |
| Annual maintenance | Full panel even if not actively cycling |
| Each new compound | At minimum: relevant deltas (IGF-1 for secretagogues, glucose for MK-677, etc.) |
The "annual maintenance" line matters. Drift accumulates over many cycles, not just within one. A reading once a year catches what a single end-of-cycle reading misses.
What labs don't tell you
Baseline labs aren't a green light to use any peptide:
- They don't catch every cancer (hence the family-history conversation)
- They don't predict individual peptide response or side effects
- A "normal" panel doesn't validate the protocol you're considering
- They're a snapshot, not a monitoring system on their own
Pair labs with vendor quality checks, correct dosing math (the calculator), and the basic stop-signal framework in when to stop. Bloodwork is one input, not the whole picture.
A reasonable minimum for someone with no conditions
If you're healthy, in your twenties or thirties, with no family history of cancer, diabetes, or cardiovascular disease, and you're running BPC-157 only:
- CBC, CMP, lipid panel, fasting glucose, HbA1c
- Repeat at 8 weeks
- Repeat annually if cycling continues
That's a $100-ish baseline that catches the most likely problems on the most common starter protocol. It's also the minimum that lets your future self read what changed.