Medyx
Active lab — research in progress
Technical dossier — 2026-07-13

A medical LLM trained from scratch on specialized clinical vocabulary.

Before investing in training at scale, we tested the simplest possible hypothesis: does a tokenizer trained on specialized medical text actually segment clinical vocabulary better than a generalist one? Measured result: -32% fewer tokens needed than the current Mistral tokenizer, -21% fewer than GPT-5.6. Every step is published with numbers, not just promises.

Phase 1Medical tokenizer — done
Phase 1.5Corpus — 32,534 tiered documents
Phase 2Pretraining — pipeline ready, awaiting GPU
01

Our approach

Publish the numbers before raising the money.
01

From scratch, not a fine-tune

Weights initialized at random, never borrowed from an existing model. A real proprietary model, not a layer bolted onto someone else's weights.

02

Zero contamination

No training data generated by a proprietary LLM. The rule → case → outcome format comes mechanically from real regulatory text, never from synthetic generation.

03

Public sources, zero patient data

BDPM, PubMed FR, NCBI Bookshelf, open research. Methodology and code reproducible end to end, without ever touching real patient data.

04

Verified, not estimated

Every published number comes from a real run on real data — never a projection, never a marketing figure.

02

The proof, quantified

Before investing in training at scale, we validated the core hypothesis: does a tokenizer trained on a specialized medical corpus actually segment medical vocabulary better than a generalist tokenizer?

Fertility — tokens needed per word (real medical corpus)
Lower is more efficient. Verified against the actually current models as of July 12, 2026.
Medyx tokenizer
1.325
GPT-4o / GPT-5.6
1.686
GPT-4
1.858
Mistral current (2026)
1.938
Mistral (2024)
2.221
Metric: fertility = tokens / word, aggregated over 3,254 real medical documents (full RCP drug labels, PubMed FR literature, frontier research). Methodology and source code reproducible end to end — no patient data used.

What this number does not say: fertility measures segmentation efficiency, not clinical quality. It is a feasibility proof — not an evaluation of the model's knowledge, reasoning, or safety.
-32%
vs. current Mistral tokenizer
(Small 4, March 2026)
-21%
vs. GPT-5.6
(released 07/09/2026)
32,534
medical documents
tagged by ontology
03

The method

Three pillars, each documented and reproducible.

A —

Specialized tokenizer, 100% public sources

BDPM, PubMed FR, NCBI Bookshelf, open research — zero patient data. Vocabulary empirically optimized (32k→50k), not guessed.

Phase 1 — done
B —

Curriculum anchored on biomedical ontologies

Cell Ontology, UBERON, MeSH — 21,287 real concepts used to tier the corpus, from foundational to frontier research.

Phase 1.5 — done
C —

Rule → case → outcome format

Every drug label mechanically split along its own regulatory structure. No data generated by a proprietary LLM.

Ready for Phase 2
04

Regulatory context

Beyond the technical performance measured above, timing works in our favor.

Compliance

French HDS regulation requires health data to be hosted by an HDS-certified provider. OpenAI and Anthropic are not certified, which puts their models out of reach for this data — a regulatory block, not a technical one.

Market

EHR, revenue-cycle, and medical-coding software vendors: AI infrastructure to license, not another consumer product.

05

Roadmap

Two tiers. The first validates the approach at low cost; the second is the real deliverable.

01Tier 1 — validation

~200M parameters

  • ~4 billion tokens, Chinchilla ratio
  • Llama/Mistral architecture, random initialization
  • Data and training pipeline already built and tested
  • Goal: go/no-go signal before Tier 2
02Tier 2 — the deliverable

1–3 billion parameters

  • 20–60 billion tokens
  • Funding target: Bpifrance seed then EIC Accelerator
  • Compute: GENCI/Jean Zay, startup credits (NVIDIA, OVHcloud, Scaleway)
  • Weights trained from scratch — not a fine-tune of a borrowed model
06

Research log

Every step, dated. Not announcements — the real record of work in progress.

In progress · 2026-07-13 Compute

GPU quota requested — Tier 1 training at scale imminent

The pipeline is ready to run. As soon as GPU access clears, Tier 1 moves from CPU to a real run.

2026-07-13 Training

CPU validation run — 550 steps, clean monotonic loss

Confirms the end-to-end pipeline (data → tokenization → training → eval) is stable over hundreds of real steps.

2026-07-13 Funding

Compute-credit applications submitted

Applications filed with startup programs (OVHcloud, Scaleway, AWS) to fund training at scale.

July 2026 Data

Rule → case → outcome pipeline built on real drug labels

Mechanical split of regulatory documents — zero data generated by a proprietary LLM.

July 2026 Data

32,534-document corpus tagged by ontology

Cell Ontology, UBERON, MeSH — 21,287 real concepts tiering the corpus from foundational to frontier research.

July 2026 Proof

Medical tokenizer — -32% fertility vs. current Mistral

First falsifiable technical proof: French clinical vocabulary is segmented more efficiently than with a generalist tokenizer.

07

Request a demo

The tokenizer and data pipeline are real and working today — not slides. The trained model (Tier 1) will be available for demo once real training is complete.

What we can show you right now

  • Live tokenizer comparison on your own medical text
  • The ontology curriculum pipeline (Cell Ontology, UBERON, MeSH)
  • The complete code and methodology, reproducible end to end
Request a demo