What Is Good Laboratory Practice (GLP)?

Good Laboratory Practice (GLP) is the set of FDA quality standards, codified at 21 CFR Part 58, that governs how nonclinical (preclinical) safety studies must be planned, conducted, monitored, recorded, and reported. GLP applies specifically to the toxicology and safety studies — often animal studies — that a sponsor runs before a drug, biologic, food additive, or medical device is tested in humans or brought to market, to make sure regulators can trust that the safety data was actually generated the way the study report says it was.

GLP is not a manufacturing standard and not a clinical-trial standard — those are the jobs of GMP and GCP, its two sibling frameworks, covered further down this page. GLP’s job is narrower and specific: data integrity in the safety-study pipeline that feeds an IND, NDA, BLA, or device submission.

Why GLP Exists

Before a new drug or device can be tested in people, regulators need to trust the nonclinical safety data submitted to support that decision — evidence that the product doesn’t cause unacceptable toxicity, organ damage, or other harm in animal or in vitro models. In the 1970s, FDA inspections of contract testing laboratories turned up serious, sometimes widespread problems with how some of that safety-study data was actually being generated and recorded — studies where the paperwork didn’t reliably reflect what had actually happened in the lab. That erosion of trust is the direct reason GLP exists: FDA finalized the Good Laboratory Practice regulations to make the conduct and documentation of nonclinical safety studies auditable, not just their conclusions.

In practical terms, GLP is a data-integrity standard as much as a lab-conduct standard. It doesn’t tell a toxicologist what dose to pick or which species to test — it specifies the organizational controls (a named study director, an independent quality assurance function, written protocols, calibrated equipment, archived raw data) that let an inspector reconstruct, years later, exactly how a given safety study was run and verify the report matches the underlying data.

What GLP Actually Requires

21 CFR Part 58 is organized around a handful of structural requirements that recur across every GLP-compliant testing facility:

• A Study Director — one named individual with overall responsibility for the technical conduct, interpretation, and reporting of a given study; the regulation calls this person “the single point of study control.”
• An independent Quality Assurance Unit (QAU) — a function entirely separate from the staff conducting the study, responsible for auditing protocols, inspecting the study in progress, and reviewing the final report against the raw data before it goes out the door.
• Written protocols and SOPs — a study runs against a pre-approved protocol, with any deviations documented, not conducted ad hoc and written up afterward.
• Equipment and facility controls — instruments used to generate or measure study data (balances, incubators, environmental chambers, and similar equipment) must be adequately tested, calibrated, and maintained, with that maintenance documented.
• Records retention and archiving — raw data, protocols, and specimens are retained and stored in a way that lets FDA reconstruct the study well after it’s finished.

That’s the shape of the requirement at a glance. The mechanics of each piece — Study Director authority, QAU independence, the equipment subpart, exact retention periods, and what a GLP compliance statement actually looks like in an IND filing — are covered in full in CASRAI’s dedicated deep-dive: 21 CFR Part 58: GLP Requirements for Nonclinical Studies. This page is the entry point; that one is the reference.

Who GLP Applies To

GLP applies to nonclinical laboratory studies intended to support an application to FDA — most often the toxicology and safety-pharmacology studies behind an Investigational New Drug (IND) application, a New Drug Application (NDA), a Biologics License Application (BLA), or a device submission. It covers the testing facility running the study (whether that’s the sponsor’s own lab or a contract research organization) and every role inside it: the study director, the QAU, study personnel, and facility management, all of whom carry specific, named responsibilities under Part 58.

It does not apply to routine research, exploratory or discovery-stage lab work, or studies that were never intended to support a regulatory submission — GLP is triggered by regulatory purpose, not by the mere fact that safety data is being generated in a lab. A sponsor’s IND application must state, for each nonclinical study it relies on, whether that study was conducted in compliance with GLP or, if not, why not — so getting this classification right early in a study’s design matters well before the report is ever written.

GLP vs. GMP vs. GCP: The Three “Good Practice” Standards

GLP, GMP, and GCP are commonly confused because they share the “Good ___ Practice” naming pattern and all sit under the broader “GxP” umbrella — but each governs a different stage of getting a regulated product from discovery to a patient:

• GLP (Good Laboratory Practice) — nonclinical safety and toxicology studies, before human testing. FDA: 21 CFR Part 58.
• GMP (Good Manufacturing Practice) — the manufacturing, packaging, and quality control of the finished drug, biologic, or device itself. FDA: 21 CFR Parts 210/211 for drugs.
• GCP (Good Clinical Practice) — the ethical and scientific conduct of clinical trials in human subjects, internationally harmonized through ICH E6.

A single product’s development timeline typically passes through all three in sequence: GLP nonclinical safety studies establish it’s plausibly safe enough to test in people; GCP governs the human trials that follow; GMP governs the manufacturing of every batch, from clinical supply through commercial product. See CASRAI’s dedicated comparisons for a fuller side-by-side: GLP vs. GMP, GCP vs. GLP, and GCP vs. GLP vs. GMP — or the broader family overview at GxP Compliance: What GLP, GCP, GMP, and GDP Actually Require. If you’re specifically trying to understand the other two standards on their own terms, see What Is Good Manufacturing Practice (GMP)? and What Is Good Clinical Practice (GCP)?.

International Recognition: OECD GLP and Mutual Acceptance of Data

GLP isn’t only a US requirement. The Organisation for Economic Co-operation and Development (OECD) maintains its own Principles of GLP, structured similarly to 21 CFR Part 58, which underpin the OECD’s Mutual Acceptance of Data (MAD) system. In practical terms, a nonclinical safety study run under OECD Test Guidelines and OECD GLP Principles in one MAD-adherent country generally has to be accepted for regulatory review in every other adherent country — which is why multinational sponsors typically design pivotal safety studies to satisfy both FDA’s Part 58 and the OECD GLP Principles at once, rather than repeating studies per jurisdiction.

Why This Matters for Research Administration

GLP rarely shows up as an isolated concern — it touches several roles inside a research organization at once:

• Regulatory affairs and compliance staff need to know, early, whether a planned nonclinical study needs to be GLP-compliant to support a future submission — retrofitting compliance onto a study already underway generally isn’t possible.
• Lab managers and study directors carry direct, named responsibility under the regulation for protocol adherence, data accuracy, and reporting.
• Quality assurance staff run the independent audit function Part 58 requires, separate from the study team itself.
• Procurement and equipment managers are responsible for the instrument qualification, calibration, and maintenance records GLP’s equipment requirements depend on — an analytical balance used to weigh dosing formulations in a GLP study, for example, needs its own qualification and calibration record, the same way the study itself needs a protocol. CASRAI’s Balance Qualification guide covers what that looks like for one of the most commonly used instruments in a GLP facility.
• Sponsors coordinating with contract research organizations (CROs) need a way to confirm, going in, that the CRO’s testing facility actually operates a compliant QAU and recordkeeping system — not just that it says it does.

Go Deeper on GLP

This page is meant as the starting point. For the regulatory mechanics — Study Director authority, QAU independence, protocol amendments, equipment records, and exact retention periods under 21 CFR Part 58 — go to 21 CFR Part 58: GLP Requirements for Nonclinical Studies. For a shorter reference definition, see the dictionary entry for Good Laboratory Practice (GLP). GLP sits within CASRAI’s broader Lab Compliance coverage, alongside GxP, ISO 17025 accreditation, biosafety, and device quality content.

Frequently Asked Questions

Is GLP the same as GMP?

No. GLP governs nonclinical safety studies conducted before human testing; GMP governs the manufacturing of the finished product. A drug candidate moves through GLP safety studies first, then GCP clinical trials, with GMP governing manufacturing throughout. See GLP vs. GMP for the full comparison.

Does GLP apply to clinical trials?

No — clinical trials in human subjects are governed by GCP (Good Clinical Practice), not GLP. GLP applies to the nonclinical (preclinical) safety studies that come before a product is ever tested in people.

Who enforces GLP compliance?

In the US, FDA enforces 21 CFR Part 58 through inspections of testing facilities. Internationally, national GLP compliance-monitoring authorities enforce the OECD Principles of GLP under the Mutual Acceptance of Data framework.

What happens if a nonclinical study isn’t GLP-compliant?

A sponsor’s IND application must disclose, for each covered nonclinical study, whether it was conducted under GLP or state why it wasn’t. FDA generally expects pivotal nonclinical safety studies to be GLP-compliant; non-GLP data supporting a pivotal safety conclusion is a recognized basis for a clinical-hold or deficiency finding, though it isn’t an automatic, universal rejection in every case.

Is ISO 17025 the same thing as GLP?

No. ISO/IEC 17025 is a general laboratory-competence accreditation standard for testing and calibration labs, independent of any specific regulatory program. GLP is a specific FDA (and OECD) regulatory framework tied to nonclinical safety studies supporting a product application. A lab can hold ISO 17025 accreditation and separately need to operate under GLP for particular studies.