Osseus

Active · Data research lab for aligned health and biological AI

YC S26

Website YC profile

Why it ranks

How the rank works

7signal of 100 · rising 7

went through YCProgram · this site+4
team of 2Team size · YC's directory+2.5

A sum of public facts, not a judgement and not investment advice.

Competitors

IsidorShared: frontier data, starting, researchSeedcamp 2025Startup →AI

CartpoleShared: learning environment, reinforcement learning, frontierYC X25San FranciscoStartup →AI

Sherpa LabsShared: frontier dataYC W25San FranciscoStartup →AI

idlerShared: frontier data, research lab, trainYC S25San FranciscoStartup →AIAcquiredSymplexShared: reinforcement learning, data engineering, researchYC S19New York CityStartup →Other

Prime IntellectShared: reinforcement learning, evaluationStartup →

Companies closest to Osseus
Company	Category	Status	Program
IsidorShared: frontier data, starting, researchSeedcamp 2025Not statedAI	AI	Not stated	Seedcamp2025
CartpoleShared: learning environment, reinforcement learning, frontierYC X25ActiveAI, Data	AI, Data	Active	YCX25
Sherpa LabsShared: frontier dataYC W25ActiveAI, Data	AI, Data	Active	YCW25
idlerShared: frontier data, research lab, trainYC S25ActiveAI, Devtools	AI, Devtools	Active	YCS25
SymplexShared: reinforcement learning, data engineering, researchYC S19AcquiredAI, Data	AI, Data	Acquired	YCS19
Prime Intellectnot in a program hereShared: reinforcement learning, evaluationElsewhereOther	Other	Elsewhere

Adjacent

Developer tools

Preference ModelShared: learning environment, reinforcement learningSPC 2025San FranciscoStartup →AI

AviroShared: learning environment, reinforcement learning, frontierYC X25San FranciscoStartup →AI

Delightful AIShared: learning environment, reinforcement learning, healthcarespeedrun SR007San FranciscoStartup →Developer tools

VmaxShared: reinforcement learningSPC 2025San FranciscoStartup →AI

ZavoShared: learning environment, reinforcement learning, frontierYC F25LondonStartup →

Companies next to Osseus
Company	Category	Status	Program
Preference ModelShared: learning environment, reinforcement learningSPC 2025Not statedDevtools	Devtools	Not stated	SPC2025
AviroShared: learning environment, reinforcement learning, frontierYC X25ActiveAI	AI	Active	YCX25
Delightful AIShared: learning environment, reinforcement learning, healthcarespeedrun SR007Not statedAI, Data	AI, Data	Not stated	speedrunSR007
VmaxShared: reinforcement learningSPC 2025Not statedDevtools	Devtools	Not stated	SPC2025
ZavoShared: learning environment, reinforcement learning, frontierYC F25ActiveAI, Data	AI, Data	Active	YCF25

Also from S26 in AI

All of S26

Allia HealthAI-Native Medical Group for Mental HealthYC S26San FranciscoStartup →AI

Avoca SystemsThe AI operating system for radiology networksYC S26San FranciscoStartup →AI

Care GPAI agents to run primary healthcare operationsYC S26SydneyStartup →AI

CovaFinancial infrastructure for family caregivingYC S26San FranciscoStartup →AI

CueBenchRL post-training for science reasoning and performance engineeringYC S26San FranciscoStartup →AI

DentaFortune 500 Dental BenefitsYC S26San FranciscoStartup →

Company	Category	Status
Allia HealthAI-Native Medical Group for Mental Healthteam of 3hiringActiveAI	AI	Active
Avoca SystemsThe AI operating system for radiology networksteam of 6ActiveAI	AI	Active
Care GPAI agents to run primary healthcare operationsteam of 10ActiveAI	AI	Active
CovaFinancial infrastructure for family caregivingteam of 2ActiveAI	AI	Active
CueBenchRL post-training for science reasoning and performance engineeringteam of 3ActiveAI, Data	AI, Data	Active
DentaFortune 500 Dental BenefitshiringActiveAI	AI	Active

Founders

Anish MariathasanFounder/CEO
Ayush PatelFounder/CTO

About Osseus

Osseus is building the frontier biomedical AI research lab, starting with the evaluations, reinforcement learning environments, and datasets that help AI labs train more capable, aligned, and safe models. We post-train models for medical and biological tasks, and deploy these in biotech, pharma and healthcare systems to ultimately improve patient outcomes.

YC batch: S26 · Summer 2026
Status, per YC: Active
Category: AI, Data
Team size: 2
Location: London, England, United Kingdom
Founded: 2026
Checked: 6h ago

YC tags: B2B, Biotech, Healthcare, Data Engineering, AI