Everyone's injecting peptides. Almost no one is measuring them.
“Bryan Johnson just posted a four-week peptide protocol with a dozen biomarkers behind it. That's the bar. The biohacker wave is running without a feedback loop, and that's the real risk.”
The one-line problem
Bryan Johnson posted a four-week CJC-1295 DAC + tirzepatide protocol on 21 April 2026 and opened with a single sentence: "Everyone's injecting peptides. Almost no one is measuring what they actually do."
That sentence is the state of the peptide market in 2026. Demand is going mainstream — Amazon just entered GLP-1 via One Medical, Patrick O'Shaughnessy is calling it a "once-in-a-lifetime, trillion-dollar public-health revolution" — but almost every self-experimenter is running the intervention without the feedback loop. You take the peptide, you feel different, you decide it worked.
That's not an experiment. That's a story.
Why measurement matters more with peptides than most interventions
Three structural reasons:
- Peptides act through cascading signalling. GHRH analogues raise GH, which raises IGF-1, which shifts glucose handling, which affects insulin sensitivity, which alters sleep and HRV. You cannot tell from "how you feel" which link of the chain is doing the work — or breaking.
- Half-lives vary wildly. A long-acting DAC-bound CJC-1295 sits in your system for a week. An ipamorelin pulse is gone in 30 minutes. The timing of measurement relative to dose matters enormously.
- Side-effect vectors are often opposite to benefit vectors. CJC-1295's GH-driving mechanism can blunt glucose control. Tirzepatide's metabolic win can raise resting HR. Without bloods and HR data, you mistake a side effect for a dose-response.
The Johnson protocol is cited below because he names each of these explicitly and designs around them.
The minimum measurement stack
This is the floor — what any self-experimenter running a peptide protocol should have in place before the first injection. It's a subset of the Johnson template, filtered to what is accessible to a UK or US adult through a private GP and a consumer wearable.
Baseline bloodwork (before dose 1)
A private GP or a direct-to-consumer testing service (Medichecks, Thriva, Randox in the UK; Quest, Labcorp, Marek Health in the US) will run all of these from a single sample.
- IGF-1 — your endogenous growth output. The single most informative marker for GHRH/GH peptides.
- Fasting glucose, insulin, HOMA-IR — insulin sensitivity. Essential before and during any GH-secretagogue protocol.
- ApoB and Lp(a) — cardiovascular risk floor.
- hsCRP — systemic inflammation.
- TSH, free T3, free T4 — thyroid, which shifts with GH work.
- Cortisol (AM) — HPA axis baseline.
- Full lipid panel, full blood count, LFTs, U&Es — standard.
If you are stacking GLP-1s, add HbA1c and fasting C-peptide.
Continuous measurement (during protocol)
- CGM. A two-week Freestyle Libre or Dexcom run during weeks 2–3 will show glucose excursion shifts that fasting-panel bloods cannot. Non-prescription in most EU countries; a private script in the UK.
- HRV and resting HR, 24/7. Any wrist-worn or ring wearable with a validated HRV signal (Oura, Whoop, Apple Watch with the right app). The autonomic signal is the earliest thing to move on a tirzepatide or any GLP-1.
- Sleep architecture. The same wearable gives you deep/REM/latency. GH-driving peptides shift these.
- Daily bodyweight, first thing, same scale, same conditions. On a GLP-1 stack, bodyweight is a dose-response proxy.
Repeat bloods
Weekly at Johnson's dose cadence; every two weeks is a realistic floor for most people. At minimum: IGF-1, fasting glucose, insulin, ApoB, cortisol. On a GLP-1, add HbA1c monthly.
What Pepwizard measures
This site exists because price per milligram is the one measurement peptide buyers almost never see. Vendors price in different vial sizes and different currencies; most buyers end up paying 2–3× what they needed to, not because they chose the wrong peptide but because they compared the wrong units.
Every page here normalises price to £/mg. Every offer is time-stamped. Every vendor is classified by tier (research, telehealth, cosmetic) so you know what regulatory frame you're buying in.
That's one variable, not the whole measurement stack. But it's one fewer thing you have to take on faith.
What you'll see if you actually measure
A short non-exhaustive list of things self-experimenters find when they turn the lights on:
- GH-secretagogue protocols without glucose monitoring often raise HOMA-IR inside 4 weeks. If you weren't looking, you'd call it "bulking fine".
- GLP-1s at starting doses raise resting HR 2–4 bpm in roughly half of users. Most normalise over 6–8 weeks. Some don't. You only know if you measure.
- Ipamorelin daily pre-bed shifts deep sleep up by 10–20 minutes in measured users. You feel it as "slept well"; the wearable shows the actual signal.
- Tirzepatide's appetite suppression plateau hits around week 6 for most people. If you don't weight-track daily, you mistake the plateau for a diet failure.
None of these are inferred. All of them are in the public self-experiment record. They are invisible without measurement.
The one thing worth stealing from Johnson
You do not have to run weekly eCelsius core-temperature capsules to get the benefit of his posture. What you can steal in one minute: before you buy your first peptide, decide what you're going to measure to know whether it worked.
If you can't answer that question, you don't have an experiment. You have a story. Peptides are powerful enough to make the story feel true either way.