In short: Synthesis is Frederik Schroyens' edited expansion of Kent's Repertory, published in editions from 9.1 to Adonis and licensed for use inside RadarOpus. It is not available online outside that licence; Kent, its foundation, and the Complete Repertory are the alternatives you can use in a browser.
Ask a roomful of homeopaths which repertory they reach for first and Synthesis will be one of the three or four names you hear. Alongside the Complete Repertory and Murphy's MetaRepertory, it is one of the great modern descendants of Kent — and of the three, it is the one built most explicitly around editorial control. This guide covers what Synthesis is, its editions, how it is organised and — since a large share of the people searching for it are really asking an access question — where you can and cannot use it. (Written for practitioners and students, not as self-treatment advice.)
What Synthesis Is
Synthesis — the full Latin title is Repertorium Homeopathicum Syntheticum — is a modern homeopathic repertory edited by the Belgian homeopath Frederik Schroyens. Its method is in the name: a synthesis of the repertory tradition, taking Kent's Repertory as the skeleton and merging into it additions from the classical literature and from contemporary provings and clinical verification.
Two editorial decisions define the work:
- Source-tagging. Additions carry abbreviations identifying their origin — which author, which proving, which clinical report. When you see a remedy in a rubric, you can ask on whose authority it is there, and Synthesis answers.
- Verification before inclusion. Schroyens built an international editorial team around an explicit policy that material is checked before it enters the text. The Complete Repertory works to a similar rule, requiring every addition to be traceable to a documented source, but takes in new material faster and is the larger of the two.
That editorial posture is why teaching institutions have long favoured it, and why practitioners who distrust "rubric inflation" in modern repertories tend to be Synthesis loyalists.
Editions: from the print era to Adonis
Synthesis grew through numbered editions across the 1990s and 2000s, each expanding the verified additions over the Kentian base. For most of the world, the classic reference is Synthesis 9.1, the edition that circulated widely in print and became a standard exam and clinic companion; a further expanded Treasure Edition followed it. The print volumes are substantial — a single fat tome of fine-print rubrics — and second-hand copies still move briskly, which says something about the work's standing.
The current edition, however, is digital-only: Synthesis Adonis, released by Zeus Soft in 2022 and still presented on its Synthesis page as the latest version. Like the Complete Repertory, Synthesis long ago moved from print to software, so a printed edition you can buy is a snapshot of an earlier text.
How It Is Organised
Structurally, Synthesis is Kentian, and anyone who has learned Kent's chapter logic can navigate it immediately: Mind first, then Vertigo, Head, Eye and onward through the body to Generalities, with rubrics running from the general to the particular and remedies graded by type-face. Onto that skeleton Synthesis adds its own apparatus — the source abbreviations after remedy entries, cross-references between related rubrics, and progressively cleaned-up rubric language as editions advanced. The result reads as "Kent, annotated and audited" rather than as a reorganisation: unlike Murphy, which re-sorted everything into alphabetical clinical chapters, Synthesis kept the traditional architecture and invested in the scholarship inside it.
Synthesis Among the Modern Repertories
Of the three modern descendants of Kent, Synthesis puts curation first: verified, source-tagged additions on the Kentian frame, checked by a central editorial team. The Complete Repertory puts coverage first and is the largest of the three by rubric count, with a new edition nearly every year. Murphy's MetaRepertory puts clinical speed first, with alphabetical, modern-language chapters. Complete Repertory 2026 vs Synthesis Adonis sets Complete and Synthesis side by side, figure by figure, and the three-way comparison does the same for Murphy, Kent and Complete.
None of them replaces the classical texts they grew from; a prescriber who understands Kent, Boenninghausen and Boger can use any of the moderns critically instead of credulously.
Where You Can Use Synthesis — and Where You Can't
Here Synthesis differs from every other repertory discussed on this blog: it is exclusive to its own commercial platform. Synthesis is the in-house repertory of RadarOpus, and it is not licensed to third-party software — not to Similia, not to anyone else. Access today means one of three things: the RadarOpus desktop program (Windows/Mac, licence-based), the Synthesis App subscription from the same ecosystem, or a printed edition.
Two honest consequences follow:
There is no legal free download. Synthesis is copyrighted and actively maintained; the editorial work is the product. Sites offering "synthesis repertory software free download" are distributing pirated copies of outdated editions — the free-download reality check covers what those files actually contain and why a practice machine is the last place to run them.
If your school or method requires Synthesis specifically, RadarOpus is where it lives. No online platform can honestly tell you otherwise, and we won't.
If, on the other hand, what you actually need is a rigorous modern repertory rather than that specific title, the same clinical role is filled — legally and online — by the repertories Similia licenses: the Complete Repertory 2026 and Murphy's MetaRepertory as premium editions, layered on a free tier that includes eight complete classical repertories (Kent among them — the very base text Synthesis grew from), 27 classic materia medica books and AI semantic search. The hands-on 2026 software comparison puts Similia and RadarOpus side by side on features and pricing, and how repertory software works explains what any of these platforms actually does with a repertory once it's digital.
The Bottom Line
Synthesis is the repertory of editorial conscience: Kent's architecture, a generation of verified additions, and a source trail behind every remedy. It earned its place in the modern canon, and it remains a platform exclusive — priced, licensed and inseparable from RadarOpus. Know that going in, decide whether you need that book or that function, and choose your software accordingly: if it's the function, start with the free classical library and add a modern repertory when your practice asks for one.
