What Is GLP? Good Laboratory Practice Explained Without the Jargon

Good Laboratory Practice (GLP) is the quality system for nonclinical safety studies — the lab work that proves a drug, chemical, or product is safe enough to move forward. If regulators will rely on your study data, the study probably needs to run under GLP.

What GLP actually covers

• People: trained, qualified personnel with records to prove it; a Study Director with defined authority; an independent QA unit that audits studies without running them.
• Place and equipment: suitable, qualified facilities; calibrated, maintained equipment with records.
• Process: studies run from signed, approved protocols; SOPs for routine operations; documented deviations and amendments.
• Records: complete, attributable raw data with audit trails — the ALCOA+ principles — retained in a secure archive.

The two rulebooks

In the US, GLP is FDA 21 CFR Part 58. Internationally, the OECD Principles of GLP govern mutual acceptance of data across member countries. Well-built programs satisfy both; the differences are in the details, not the philosophy.

What inspectors actually check

Inspectors from national GLP monitoring authorities don't read every page — they sample. They check that the QA unit is genuinely independent, that SOPs match bench practice, that training records exist for the people who did the work, that equipment was qualified when it generated data, and that the archive would survive a fire, a flood, and a personnel change. Data integrity — who did what, when, and whether anyone changed it — is where inspections are won or lost.

The certification myth

Worth repeating: no private firm can certify you GLP-compliant. GLP recognition comes from national monitoring authorities that inspect facilities. Any vendor selling “GLP certification” is selling something that doesn't exist — what they can legitimately sell is audit, gap analysis, and implementation support.

Where to go from here

If you're starting out, take the readiness quiz (two minutes, honest scoring), read what GLP costs with sourced figures, or get matched with GLP consultants who do this for a living.

Related guides

• GLP vs. GMP: What's the Difference, and Which Do You Need?
• The GLP Audit Checklist: What Auditors (and Inspectors) Actually Look For