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PepStack

Evidence-based & free

For biohackers who mean business.

Peptide wiki, price comparison from 130+ shops, hormone & biomarker database — all evidence-based, free.

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Compare peptide prices from 130+ shops.

Automatically updated. EU + USA. Independently reviewed.

Updated weeklyEU + USAVendor-verified pricing

Free Tools

Try Our Free Peptide Tools

Calculate reconstitution volumes and visualize serum levels — right in your browser, no sign-up required.

Reconstitution Calculator

Enter your vial content, BAC water volume, and target dose to get the exact draw-up volume.

mg
1.00.80.60.40.20.01ml syringe

Volume to Draw

0.100 ml

Concentration

2.50 mg/ml

Your Dose

0.25 mg

Open Full Calculator

Serum Level Visualizer

See how your serum levels build up over time based on dose, injection interval, and half-life.

Open Full Visualizer

iOS & Android

Track your cycles. Never miss a dose.

The most comprehensive biohacking tracker for peptides, supplements, and TRT.

  • Cycle Tracker — Peptides, Supplements, TRT
  • Smart Reminders — Morning, Noon, Evening
  • Serum Level Curves — Live pharmacokinetics
  • Peptide Wiki — 67 peptides, available offline
  • Share & Import — Share stacks via QR code
  • Cloud Backup — Encrypted, cross-device

Coming soon: Bloodwork Tracking · Coach Mode · Inventory

PepStack App Screenshot

What's Next

We're just getting started.

Coach Mode

Create cycles for clients. Share via QR code. Manage all clients in one dashboard.

Coming Q3 2026

Research Newsletter

Weekly digest: New studies, new peptides, price changes — straight to your inbox.

Coming Soon

Bloodwork Tracking

Track your blood markers over time. See how your values change during a cycle.

Coming Soon
Maximilian Berktold — Founder of PepStack

Meet the Founder

Built by a Biohacker, for Biohackers.

I'm Max — a serial founder from Bamberg, Germany, and CEO of OpenSphere Software. With my company, I help businesses in the fintech and banking space in Germany build digital products. I've trained 10,000+ developers on Udemy and shipped multiple startups. PepStack is a passion project — as a dedicated competitive athlete and biohacker, I needed a real tool to track peptide cycles, bloodwork, and hormones. Nothing out there was good enough, so I made one.

Serial Founder & CEOCompetitive Athlete & Biohacker10,000+ Students
I don't just build this product — I use it every single day.