Med-LLaMA3.2-3B — Medical QLoRA Adapter (LoRA weights only)
Parameter-efficient medical adaptation of Llama-3.2-3B using QLoRA (4-bit NF4 + LoRA).
This repository contains the LoRA adapter only — it must be applied on top of the base
model at load time. For a ready-to-use, standalone checkpoint, see the merged version
linked below.
This is the 3B (balanced / mid-tier) member of the Med-LLaMA3 family introduced in the paper
“Med-LLaMA3: Advancing Medical Question-Answering Through Parameter-Efficient Fine-Tuning of Large
Language Models” (Applied Sciences, 2026). The family adapts the LLaMA-3 architecture to the medical
domain by training only a small fraction of the base model’s parameters (5.70% for this 3B variant),
achieving strong medical question-answering performance while reducing memory use by roughly 75% via
4-bit quantization — enabling development and inference on low-cost, consumer-grade hardware.
The 3B variant offers a balanced trade-off between computational efficiency and capacity — a
competitive mid-tier option with meaningfully better accuracy than the 1B and lower compute than the 8B.
ℹ️ Base checkpoint. A LoRA adapter only loads correctly onto the exact base model it was trained
on. This adapter targets the instruct checkpoint meta-llama/Llama-3.2-3B-Instruct (consistent
with the released fine-tuned model). Use that same base in the code below.
Intended uses
Primary use cases
Medical question answering (multiple-choice and open-ended).
Clinical knowledge lookup and clinical decision support assistance.
A balanced mid-tier option when the 1B is too small and the 8B is too heavy.
A research baseline for parameter-efficient fine-tuning of small LLaMA models in healthcare.
Out of scope / not intended for
Autonomous clinical decision-making or direct patient care without a qualified clinician in the loop.
Generating definitive diagnoses, prescriptions, or treatment plans.
Use as a substitute for professional medical advice, emergency services, or licensed care.
(A pre-merged checkpoint is also published separately — see the link at the top of this card.)
Training data
The Med-LLaMA3 family was fine-tuned on a curated medical instruction dataset of over 1.5 million
samples, organized along a three-axis taxonomy: source type (examination QA, clinical dialogue,
biomedical literature, encyclopedic reference) × clinical granularity (basic science, clinical
reasoning, patient communication) × task format (multiple-choice, open-ended QA, generative
dialogue). All sources were consolidated into a unified instruction–response schema
(system, context, question, answer, choices).
Sources include:
MedAlpaca / Medical Meadow collection — MEDIQA, Medical Flashcards, WikiDoc, WikiDoc Patient
Information, MedQA, CORD-19, and PubMed Causal subsets
MedMCQA — Indian medical entrance exam (AIIMS & NEET PG) multiple-choice questions
Evaluation integrity: The eight MMLU medical subsets were used only for held-out
evaluation and were excluded from the fine-tuning corpus. For benchmarks with official splits
(MedMCQA, MedQA-USMLE, PubMedQA), only the official training partitions were used for fine-tuning.
Training procedure
LoRA and optimization settings are identical across the 1B, 3B, and 8B variants; sequence length, batch
size, and gradient accumulation are scaled to each model’s memory footprint. The settings below are for
the 3B variant.
Setting
Value (3B)
Method
QLoRA (4-bit NF4 base, LoRA adapters in higher precision)
The QLoRA recipe keeps the base weights frozen and quantized, allocating optimizer state only for the
LoRA parameters — which is what makes fine-tuning feasible on consumer hardware.
Evaluation
Evaluation in the paper uses the EleutherAI LM Evaluation Harness with 5-shot prompting on the
eight MMLU medical subsets (Anatomy, Clinical Knowledge, College Biology, College Medicine, Medical
Genetics, Nutrition, Professional Medicine, Virology). Reported comparisons include McNemar’s test
p-values and 95% bootstrap confidence intervals.
The table below reports the 3B model’s 5-shot accuracy (%) on each MMLU medical subset, with 95%
bootstrap confidence intervals (1000 resamples), as published in Table 7 of the paper. For context, the
family’s mean accuracy scales with model size: 1B = 48.64%, 3B = 64.24%, 8B = 75.71%.
MMLU medical subset (5-shot)
Med-LLaMA3.2-3B (acc. %)
Anatomy
59.52 (±4.26)
Clinical Knowledge
68.17 (±2.89)
College Biology
71.53 (±3.77)
College Medicine
57.65 (±3.78)
Medical Genetics
75.00 (±4.35)
Nutrition
68.32 (±2.69)
Professional Medicine
70.59 (±2.77)
Virology
43.17 (±3.84)
Mean (8 subsets)
64.24
The paper reports an untuned baseline only for the 8B model (vs. Llama-3.1-8B-Instruct); it does
not include an untuned Llama-3.2-3B baseline on these subsets. See Table 7 of the paper for the
full cross-model comparison (1B, 8B, and other ≤8B models) with statistical tests.
See the paper for full tables, statistical tests, and
confidence intervals.
Limitations & responsible use
Not a medical device. This model is a research artifact. It must not be used for autonomous
diagnosis, treatment, prescribing, or any decision affecting patient care without review by a
qualified healthcare professional.
Hallucination risk. Like all LLMs, it can produce fluent but incorrect or fabricated medical
information. Always verify outputs against authoritative sources.
Mid-tier capacity. The 3B is a balanced variant; for the highest accuracy on complex clinical
reasoning, prefer the 8B variant when resources allow. For the smallest footprint, the 1B is available.
Abbreviation ambiguity. Medical abbreviations are a known error source. The paper’s safety pilot
shows that context-disambiguation preprocessing reduces the highest-severity abbreviation
errors (from 30% to 10% on a held-out set); consider applying similar preprocessing.
Data & bias. Training data may under-represent certain populations, conditions, or regional
practices, and may encode biases present in the source corpora.
Privacy & compliance. Do not input protected health information (PHI) unless your deployment is
appropriately secured and compliant with applicable regulations (e.g., HIPAA, GDPR).
English only. Performance outside English is not evaluated.
License
This adapter is released under the Llama 3.2 Community License,
inherited from the base model. By using it you agree to Meta’s Llama 3.2 license terms and
Acceptable Use Policy. Review the licenses of the individual training datasets for any additional
restrictions on derived use.
Citation
If you use this model, please cite the paper:
bibtex
1@article{aboelenen2026medllama3,
2 title = {Med-LLaMA3: Advancing Medical Question-Answering Through Parameter-Efficient Fine-Tuning of Large Language Models},
3 author = {Abo El-Enen, Mohamed Ahmed and Ismail, Sally S. and Nazmy, Taymoor Mohamed},
4 journal = {Applied Sciences},
5 volume = {16},
6 number = {12},
7 pages = {6158},
8 year = {2026},
9 publisher = {MDPI},
10 doi = {10.3390/app16126158},
11 url = {https://www.mdpi.com/2076-3417/16/12/6158}
12}
Authors & contact
Mohamed Ahmed Abo El-Enen, Sally S. Ismail, and Taymoor Mohamed Nazmy
Faculty of Computer and Information Sciences, Ain Shams University, Cairo, Egypt.