Created by Stanford researchers and volunteers · A Non-Profit Organisation

The first AI benchmark for rejuvenation. The first AI bio benchmark in living things.

Frontier models excel at winning contests that have clear benchmarks: mathematics, code, puzzles. They have achieved extraordinary things. This benchmark strives to focus their abilities on reversing the decline that ends 100,000 human lives every day.

It's time for the ultimate challenge.

We are not a company. We do not sell a therapy, supplements, diet, or manual. We are a group of volunteer scientists and engineers who publish rules, scores, and wins, with the hope of aligning AI development for the betterment of humankind. Existing longevity benchmarks only measure if models can measure biomarkers. This is an excellent first step, but measurement alone cannot lead to rejuvenation.

Before the live-cell match / How qualifying works

First, test the thinking.
Then, test it in cells.

Before we choose two models for the final head-to-head match, we test the research skills that go into planning a good experiment. The scored v0.2 core has 96 constructed cases: 24 in each of four areas. These cases use data created for the test, so we can check the answers against known results. A fifth category adds 24 in-vitro proposal dossiers, each with an initial plan and an evidence-driven revision. Its assessment is reported separately from the four-domain score.

Each case supplies the information and rules the model needs. Answers are checked against fixed scoring rules. For predictions, the case’s outcome is kept hidden from the model.

01 / Evidence24 cases

Understand the evidence

Does the conclusion match the data?

The anonymous reports describe aged cells or cells exposed to stress. They cover dermal fibroblasts—connective-tissue cells in the deeper skin layer that make collagen, a structural protein; hepatocytes—the liver’s main working cells; and immune cells, which help defend the body against infection.

Models inspect study summaries that give an estimated effect, its uncertainty and details about the donor groups. The reports distinguish direct functional outcomes from indirect signals: molecular clocks estimate biological age, while transcriptomic readouts describe patterns of gene activity.

What they must notice

A revised report and its earlier version may describe the same donor group. Counting both as independent evidence can exaggerate confidence. Models also check whether findings apply to the cell type being studied, whether cells remain alive, and whether they retain their expected characteristics.

Why we test this: A lab plan can go wrong at the start if it is built on weak or misunderstood evidence.

02 / Analysis24 cases

Get the analysis right

How big is the effect, and how sure are we?

Models receive tables of synthetic functional scores—numbers that stand in for how well a cell system works—for a candidate treatment and a control, the group used for comparison. Rows can identify the donor, laboratory batch and repeated measurements. The particular laboratory test, or assay, is left unspecified.

What an “effect” means here

Models estimate how much the candidate changes function beyond the change seen in the control. Batch effects—differences between measurement runs—can complicate that comparison. Some cases compare before-and-after readings; others ask how missing readings could alter the conclusion or how long function is retained. Repeated measurements from one donor must not be counted as independent donors.

Why we test this: Bad calculations can make ordinary variation look like a real improvement.

03 / Design24 cases

Choose a useful experiment

Which test should we do next?

Models receive a menu of possible experiments, with costs, expected information and limits on which options can be combined. They choose a plan within the available budget. Some cases supply several possible explanations and show how well each test could distinguish them.

Examples of the trade-offs

Options include a function test, which asks whether the system works better; an identity check, which asks whether cells keep their intended characteristics; and replication, which means repeating a result to see if it holds up. Some cases ask which follow-up is most useful after a positive or negative result, including whether another test would teach them enough to justify the extra resources.

Why we test this: Lab time and funding are limited. A useful plan should answer an important question with the resources available.

04 / Forecast24 cases

Make a prediction

What will happen, and how uncertain is it?

Models use results and descriptions of new test conditions to predict a future change in function. The outcome is a synthetic score representing how well the system works. They provide an estimate, a range of plausible outcomes and the chance of meeting both the case’s benefit target and its other required conditions.

The uncertainty they must handle

Measurements can be noisy, and a new experimental setting can behave differently from the earlier data. A good forecast must allow for both, including little or no improvement. Predictions are scored against a hidden simulated outcome and a standard reference prediction.

Wide ranges allow more possibilities but tell researchers less; narrow ranges risk missing the result. Scoring considers both the range’s width and how far any missed outcome falls outside it.

Why we test this: A useful model should recognize uncertainty and the possibility that an experiment will show no improvement.

05 / In-vitro proposals24 cases · 2 stages each · v0.2.4

Propose, then revise

Can the model turn evidence into a useful cell experiment—and update its plan when the evidence changes?

Models receive a constructed research dossier for an in-vitro experiment: a study of cells outside a living organism. Across eight test families, they must propose a meaningful functional comparison, choose controls and independent donors, and fit measurements into the available resources.

First, commit to a plan

The proposal must explain competing interpretations, what will be measured, how missing or failed samples will be handled, and which possible results would change the next research decision.

Then, respond to new evidence

The model receives its original proposal plus corrected evidence or a changed constraint. It must retain justified choices and revise unsupported ones. The earlier submission remains on record.

Why we test this: A convincing proposal is not necessarily an informative experiment. Automatic checks audit explicit commitments; independent reviewers assess scientific merit and revision quality.

Explore the new category

How the scores work

Correct parts of an answer earn partial credit. Predictions are scored for accuracy and how well they express uncertainty. The published overall score combines the original four areas, so strong work still earns credit when another area is weak.

Refusals and answers that cannot be graded count as failures. Token limits and run interruptions are excluded. The charts show how many cases were scored, so an incomplete run is visible.

The fifth category reports proposal checks and independent scientific review separately. Neither is folded into the current selection index or presented as measured biological benefit.

See the scores and full scoring method

Why these five categories?

They check the decisions behind a lab plan.

Reading evidence, doing the math, choosing a test, and predicting its outcome are connected steps in research. Proposing and revising a cell experiment tests how those skills work together. We chose these tasks to check each step before committing resources to real experiments. The two leading models qualify for the final head-to-head match, with their proposals reviewed by human scientists for safety and feasibility.

The qualifier measures research reasoning. The final match tests proposed experiments in living cells. A high qualifier score alone does not show that an intervention reverses aging.

Evidence / complete solves

Every component has to hold.

10 models · 24 planned evidence cases each
Snapshot 30 Sept 2026 UTC · R9

Why can't we test in living things for all models?

The final head-to-head 'Livematch' involves experiments fully designed and proposed by frontier AI systems. As a result, the AI proposed experiments are rigorously screened by human scientists for safety and BSL requirements. In our opinion, it is better to err on the side of higher lab safety ratings than typically required, especially in certain experiments proposed by the contestants. Due to this lengthy screening process and the very high cost associated with the BSL-2 and BSL-3 lab requirements, only the top two models are invited to the head-to-head live cell experiment. This is also the reason we do not post a full solution set to the benchmark online. Besides enabling benchmaxxing (training models to learn or just memorize the answers in a benchmark), it undermines the built-in safety evaluations in the benchmark. Fully solved means every scored field met its criterion. Partial credit, the component breakdown and the other three domains follow below.

Refusals receive zero points. We are in contact with Anthropic team members to assess options to reduce refusals. We consider refusals to be a positive developent for AI safety as long as they do not impair legitimate scientific progress in the broader environment. Missing infrastructure results are excluded. Kimi and Grok are conditional results on smaller case sets.

Inspect the scoring method ↗

Evidence · fully solved

Completely solved responses · higher is better

Claude Sonnet 5.595.8%
23/24 fully solved · 24/24 retained
GPT-6 Astra87.5%
21/24 fully solved · 24/24 retained
Muse Spark 1.387.5%
21/24 fully solved · 24/24 retained
Kimi K372.7%
8/11 fully solved · 11/24 retained · Account funds exhausted · high token use
GPT-6 Luna70.8%
17/24 fully solved · 24/24 retained
DeepSeek V4 Pro62.5%
15/24 fully solved · 24/24 retained
Grok 4.761.5%
8/13 fully solved · 13/24 retained · Timeout-limited run
GPT-5 Nano4.2%
1/24 fully solved · 24/24 retained
Claude Opus 5.50.0%
0/24 fully solved · 24/24 retained · 24 refusals · 100% of this domain
Claude Haiku 4.50.0%
0/24 fully solved · 24/24 retained · 0 refusals · low graded accuracy
Four domains / the detail behind the index

Strengths, gaps and completed work.

10 models · shared frozen calibration packet
Snapshot 30 Sept 2026 UTC · R9

Same scoring policy for every model.

Refusals and unrecoverable answer errors count as failures. Token-limit cases, confirmed network timeouts and no-answer funding, authentication or stopped cases are excluded from score denominators. Excluded cases reduce coverage without lowering scores. All models are sorted by their measured score.

Kimi K3: 38/96 scored; 54 no-answer cases excluded (38 funding errors, 1 authentication error, 1 interrupted request and 14 missing cases), plus 4 token-limit cases excluded. Grok 4.7: 40/96 retained after 56 confirmed timeouts. GPT-6 Astra: 95/96 retained after 1 confirmed timeout. Claude Opus 5.5: all 24 evidence cases were refused and remain at zero credit; its strong analysis and design results still earn overall credit. Claude Haiku 4.5: no recorded refusals; its low score reflects low graded accuracy after formatting repairs. Claude Sonnet 5.5: 93/96 retained after 2 design token limits and 1 confirmed forecast timeout; no recorded refusals.

Token limits excluded: Nano 3, Muse 5, DeepSeek 5, Kimi 4 and Sonnet 2. Refusals remain scored for everyone.

Run budgets differ: 32,768–128,000 maximum output tokens and 600–10,000-second timeouts. These are exploratory calibration results, not a matched-compute comparison.

Evidence · partial credit

Mean task credit · higher is better

Claude Sonnet 5.599.1%
95.8% fully solved · 24/24 valid · 24/24 retained
Muse Spark 1.397.3%
87.5% fully solved · 24/24 valid · 24/24 retained
GPT-6 Astra97.0%
87.5% fully solved · 24/24 valid · 24/24 retained
Kimi K395.5%
72.7% fully solved · 11/11 valid · 11/24 retained · Account funds exhausted · high token use
GPT-6 Luna92.8%
70.8% fully solved · 24/24 valid · 24/24 retained
DeepSeek V4 Pro87.6%
62.5% fully solved · 24/24 valid · 24/24 retained
Grok 4.783.6%
61.5% fully solved · 13/13 valid · 13/24 retained · Timeout-limited run
GPT-5 Nano60.4%
4.2% fully solved · 24/24 valid · 24/24 retained
Claude Haiku 4.522.0%
0.0% fully solved · 24/24 valid · 24/24 retained · 0 refusals · low graded accuracy
Claude Opus 5.50.0%
0.0% fully solved · 0/24 valid · 24/24 retained · 24 refusals · 100% of this domain

All retained failures receive zero credit. Excluded cases are not in the denominator; their coverage remains visible.

Analysis · partial credit

Mean task credit · higher is better

GPT-6 Astra100.0%
100.0% fully solved · 24/24 valid · 24/24 retained
Claude Opus 5.599.5%
95.8% fully solved · 24/24 valid · 24/24 retained
Muse Spark 1.399.5%
95.8% fully solved · 24/24 valid · 24/24 retained
Claude Sonnet 5.599.5%
95.8% fully solved · 24/24 valid · 24/24 retained
DeepSeek V4 Pro97.9%
83.3% fully solved · 24/24 valid · 24/24 retained
Kimi K396.6%
72.7% fully solved · 11/11 valid · 11/24 retained · Account funds exhausted · high token use
Grok 4.786.0%
78.6% fully solved · 14/14 valid · 14/24 retained · Timeout-limited run
GPT-6 Luna74.8%
66.7% fully solved · 24/24 valid · 24/24 retained
GPT-5 Nano54.1%
36.4% fully solved · 22/22 valid · 22/24 retained · 2 token limits excluded
Claude Haiku 4.516.4%
0.0% fully solved · 24/24 valid · 24/24 retained · 0 refusals · low graded accuracy

All retained failures receive zero credit. Excluded cases are not in the denominator; their coverage remains visible.

Evidence · component detail

Field credit including refusals and other failures · %

Evidence field credit on all retained cases, including zero credit for failures; percent.
Scored componentGPT-6 Astra24/24 valid
24/24 retained
Claude Sonnet 5.524/24 valid
24/24 retained
Muse Spark 1.324/24 valid
24/24 retained
DeepSeek V4 Pro24/24 valid
24/24 retained
Kimi K311/11 valid
11/24 retained
Grok 4.713/13 valid
13/24 retained
GPT-6 Luna24/24 valid
24/24 retained
GPT-5 Nano24/24 valid
24/24 retained
Claude Opus 5.50/24 valid
24/24 retained
Claude Haiku 4.524/24 valid
24/24 retained
CI upper bound95.8100.0100.083.3100.084.695.841.70.00.0
CI lower bound95.8100.0100.083.3100.084.687.550.00.04.2
Target-system conclusion100.0100.0100.0100.0100.0100.0100.091.70.054.2
Human-lifespan guardrail¹100.0100.0100.0100.0100.0100.0100.0100.00.0100.0
Heterogeneity I²91.7100.0100.087.5100.084.695.850.00.00.0
Included reports100.0100.0100.097.5100.095.799.591.10.081.3
Qualifying reports100.0100.0100.0100.0100.097.4100.078.90.022.9
Independent cohorts100.0100.0100.087.5100.084.691.758.30.012.5
Pooled effect100.0100.0100.091.7100.084.691.750.00.04.2
Pooled SE95.8100.0100.087.5100.084.691.758.30.04.2
Prediction upper bound91.795.887.575.081.861.591.733.30.00.0
Prediction lower bound91.795.887.575.081.861.579.237.50.00.0
Between-cohort variance100.095.887.587.581.861.595.875.00.025.0
Worst leave-one-out lower bound95.8100.0100.070.890.984.679.229.20.00.0

Numeric credit is the share within tolerance; report-selection credit is mean set F1. Fields share calculations. ¹ The human-lifespan answer is constant across this suite: a guardrail, not a discriminating task.

Design · partial credit

Mean task credit · higher is better

DeepSeek V4 Pro97.6%
89.5% fully solved · 19/19 valid · 19/24 retained · 5 token limits excluded
GPT-6 Astra96.7%
95.7% fully solved · 23/23 valid · 23/24 retained
Claude Opus 5.592.2%
83.3% fully solved · 24/24 valid · 24/24 retained
Muse Spark 1.385.9%
71.4% fully solved · 21/21 valid · 21/24 retained · 3 token limits excluded
Claude Sonnet 5.584.3%
72.7% fully solved · 22/22 valid · 22/24 retained · 2 token limits excluded
Kimi K380.8%
60.0% fully solved · 10/10 valid · 10/24 retained · Account funds exhausted · high token use
GPT-6 Luna59.7%
33.3% fully solved · 24/24 valid · 24/24 retained
Grok 4.756.8%
45.5% fully solved · 11/11 valid · 11/24 retained · Timeout-limited run
GPT-5 Nano44.8%
12.5% fully solved · 24/24 valid · 24/24 retained
Claude Haiku 4.514.1%
0.0% fully solved · 24/24 valid · 24/24 retained · 0 refusals · low graded accuracy

All retained failures receive zero credit. Excluded cases are not in the denominator; their coverage remains visible.

Forecast · weighted interval score

Available valid forecasts · lower is better

Grok 4.70.0551
Same-case comparator 0.1815 · 2/24 forecasts · Timeout-limited run
Kimi K30.0568
Same-case comparator 0.0465 · 6/24 forecasts · Account funds exhausted · high token use · 4 token limits excluded
Muse Spark 1.30.0855
Same-case comparator 0.0850 · 22/24 forecasts · 2 token limits excluded
GPT-6 Astra0.0861
Same-case comparator 0.0853 · 24/24 forecasts
Claude Opus 5.50.0865
Same-case comparator 0.0853 · 24/24 forecasts
Claude Sonnet 5.50.0867
Same-case comparator 0.0866 · 23/24 forecasts · 1 timeout excluded
DeepSeek V4 Pro0.1022
Same-case comparator 0.0853 · 24/24 forecasts
GPT-6 Luna0.1723
Same-case comparator 0.0853 · 24/24 forecasts
GPT-5 Nano0.1809
Same-case comparator 0.0857 · 23/24 forecasts · 1 token limits excluded
Claude Haiku 4.50.2298
Same-case comparator 0.0853 · 24/24 forecasts · 0 refusals · low graded accuracy

All models are sorted by WIS. Scored subsets differ: Grok has 2 forecasts and Kimi has 6; small subsets are not equivalent to a full panel. Token-limited forecasts are excluded. Refusals and remaining invalid forecasts count against the overall forecast factor. Each comparator uses the same valid cases as its model.

215 formatting failures recovered with answer values preserved. The original task packet, numeric tolerances and scientific grading rules are unchanged. View the full results and audit method ↗

RejuvenationBench v0.2 · controlled review.

96 constructed research-reasoning cases across four domains, plus a separately assessed fifth category with 24 paired in-vitro proposal dossiers. Human review materials are available by request through the organizers; public downloads and operator guides are temporarily unavailable. Human review access →

96 calibration casesHuman review by request.
Function before clocksPrediction and restoration are distinct.
Laboratory validationFirst experiments: October 2026.

What we measure

Round 1: virtual cells and tests.
The Top 2 winners: living cells.

Evidence, analysis, experimental judgment, and calibrated prediction retain their scores. In-vitro proposals add a separate proposal-and-revision assessment.

01 / EVIDENCE

Biology Comprehension

Identify what a study actually shows. Separate cell, animal, and human evidence.

24 evidence cases
02 / ANALYSIS

Effect Calculation

Calculate effects beyond controls. Respect donors, missing data, and uncertainty.

24 analysis cases
03 / DESIGN

Identifying Key Points

Find confounders, protect the test set, and choose informative experiments.

24 design cases
04 / FORECAST

Accurate Predictions

Predict functional outcomes—including nulls and failures—with meaningful intervals.

24 forecast cases
05 / IN-VITRO PROPOSALS

Proposing and Revising Experiments

Design a cell experiment from a supplied dossier, then revise the plan when new evidence arrives. Explicit design checks and independent scientific review remain separate from the four-domain index.

24 dossiers · 8 families · initial proposal + revision

The v0.2 calibration suite is a development diagnostic; it is not an official model ranking.

The central distinction

A better prediction
is not yet a better intervention.

A model deserves credit for correctly predicting that an intervention will fail. The intervention does not deserve credit for restoration.

Read the scoring rules →

Two questions.
Two kinds of evidence.

Research competence: Did the model interpret, calculate, choose, and predict correctly?

Experimental benefit: Did function improve beyond a matched control while the registered biological guardrails held?

Neither score is a claim that human aging has been reversed.

For model developers and research teams

Benchmaxxing won't get us there
Why actual biology is our benchmark.

Review the methods, inspect aggregate results, and arrange human review of the questions. Prospective experimental predictions connect the benchmark to outcomes that were not available during training.

Why this work matters

Every day is a reason
to make progress.

The benchmark connects measurable AI capabilities to the longer-term goal of restoring biological function.

Explore the experimental program →