Biohacking · Peptides · Longevity
Česky · English
Longevity Filter
A guide to longevity ranked by the strength of the evidence — not by how well it reads.
Hundreds of books have been written about longevity. Almost all of them share the same flaw: they order their content by how interesting it is. First the newest finding, the most surprising mechanism, the best-told story.
This book does the opposite. Every recommendation carries a grade for how strong the evidence behind it is — and it starts with what is demonstrated, not with what is exciting.
The result is uncomfortable. The things people talk about most usually end up in the last third. The first part is full of boring things that work.
An honest warning, right at the start: the first fifty pages are boring. No new molecule, no discovery from Harvard, nothing you can order online. Just the things that carry the most weight — and come first for that reason.
How it differs
The real value of this book is not the content, it is the grading system. Four evidence levels, a cost, time, and risk for every recommendation — and, above all, one question the other books do not ask: how do you know it is working.
| Level | What stands behind it | What you are buying |
|---|---|---|
| A | Randomized human data on a hard outcome — death, heart attack, fracture | Certainty |
| B | Human data, but only on a surrogate marker | A good estimate |
| C | Weak or conflicting human data | Hope |
| D | Animals, cells, or mechanism only | A seat in the experiment |
Within Level A, the book distinguishes two paths to a strong conclusion: A-RCT, a randomized trial that measured a hard clinical outcome, and A-OBS, where randomization was not realistic but the observational evidence is exceptionally strong, consistent, and biologically plausible. When a recommendation has no honest answer to how do you know it is working, the text says so — it is a warning sign, and the reader is meant to see it.
"Proven to extend lifespan by 30%."
That statement is true. If you are talking about yeast.
Someone who spends five thousand crowns a month on peptides and never checks their blood pressure has not made a bad decision about peptides. They have made a bad decision about order.
A number that changes your priorities
The Cleveland Clinic followed 122,007 people for an average of 8.4 years, measuring cardiorespiratory fitness and tracking mortality.
| Factor | Reported mortality association |
|---|---|
| Coronary artery disease | 1.29 times higher |
| Diabetes | 1.40 times higher |
| Smoking | 1.41 times higher |
| Lowest fitness, compared with elite fitness | About 5 times higher |
The lowest fitness level was associated with substantially higher mortality than smoking in this cohort. That is the scale the rest of the book is measured against.
What is inside
| Length | 152 pages, A5 |
| Structure | 13 parts |
| Sources | 266 reference entries |
| Glossary | 81 terms explained at first use |
| Format | PDF, DRM-free — save it and read it anywhere |
Thirteen parts
The framework for judging evidence · Eight things with the strongest evidence · Level B, worth doing even when less certain · Levels C and D · Hormones · The body that has to carry you — falls, bones, hearing, vision · Recent findings and overlooked questions · Peptides and molecules sold at a high price · What does not work as advertised · What older longevity books miss · What to have measured · The Czech healthcare context · A 30-day and first-year plan.
One part deserves special mention. Part 9 is the chapter about what failed in large randomized trials or never demonstrated clinical benefit — aspirin for primary prevention, routine vitamin D, multivitamins, resveratrol, metformin in healthy people, whole-body MRI, epigenetic clocks. It is the chapter every other longevity book skips, because it does not sell well. Here it carries the same weight as everything else.
About this English edition
Prepared from the corrected Czech edition and the existing English manuscript. Literature cutoff is August 2026. American English is used throughout; Czech healthcare prices remain in Czech crowns (CZK), and Part 12 concerns the Czech healthcare system specifically.
The manuscript includes editorial clarification and, in places, rewriting — particularly where a study association could otherwise be read as a causal effect, or a research finding as an individual treatment instruction. It is not a line-by-line facsimile translation, and it has not undergone a new comprehensive evidence review beyond the corrected Czech edition it is built from.
What this book is not
It is not a digest of other people's books. A handful of well-known titles served as a source of topics and scope, not as a source of text. Sources were not copied from other bibliographies — every study was looked up and verified independently.
It is not medical advice. The content is informational. It does not replace medical care, diagnosis, or an individual doctor's recommendation. Talk to your doctor before changing treatment or a routine while living with an existing condition.
It does not promise a result. It shows what the data says and does not say, and leaves the decision to the reader.
I do not decide for you. I show you what you are paying with.
Who it is for
People who want to know in what order to do things, not just what to do. Anyone who cares about the cost–time–risk ratio of each intervention. And anyone who has already tried supplements and wants to know which of it made sense.
Who it is not for
Anyone looking for a simple recipe on ten pages. Anyone who wants confirmation of what they already do. Anyone expecting a diagnosis or a treatment plan from a book.
Order
11 € · 290 Kč
The complete book as a PDF, DRM-free and without a watermark. The download link is valid for 12 months and can be used repeatedly.
The price is final. Electronic books are exempt from VAT in the Czech Republic under § 71i of the VAT Act.
Questions
Is it a printed book?
No. It is a PDF you download. You are welcome to print it yourself.
Do I need to understand medicine?
No. Technical terms are explained at first use, and the glossary has 81 entries.
Will I learn exactly what to do?
You will learn what is backed by what evidence, how much it costs, how much time it takes, what the risk is, and how to tell whether it is working. The decision stays with you.
Can I lend the book to someone?
The file is DRM-free, so technically yes. The license is personal, though — another reader is expected to get their own copy.
What if the link stops working?
Write to [email protected] and we will send a new one. No questions, no charge.
Second volume — Peptides
This book ends its coverage of peptides with a verdict: what has human data and what does not. It does not say how, because that would need three times the space.
Peptides — what is actually known is that remainder. 443 pages, 13 parts, over 500 sources. Every dose states where it came from — an approved summary of product characteristics, a human trial, an animal model, or a forum thread.
The order applies there too. Peptides are extra money and extra risk, and they only make sense once Level A from this book is in place.
Peptides is written in Czech. An English edition is in preparation — if you would like to be told when it is out, write to [email protected].