About SubstanceWiki

SubstanceWiki is a free, open-source encyclopedia of psychoactive substances built on a simple principle: harm reduction through education.

People use psychoactive substances. They always have, and they always will. Rather than ignoring this reality, SubstanceWiki provides comprehensive, evidence-based information so that individuals can make more informed decisions about their health and safety.

We believe that accurate information about dosage, effects, interactions, and risks saves lives. Every piece of content on this site is designed to help people understand substances more completely — not to encourage or discourage use, but to ensure that anyone seeking information can find it presented clearly, accurately, and without judgment.

Our encyclopedia draws from multiple reputable sources to provide well-rounded, cross-referenced information:

SubstanceWiki is structured as an interconnected knowledge graph. Each substance page contains:

• Overview and pharmacology — chemical classification, mechanisms of action, and general information
• Dosage tables — threshold, light, common, strong, and heavy dose ranges by route of administration
• Duration timelines — onset, come-up, peak, offset, and afterglow durations
• Subjective effects — a detailed index of physical and psychological effects, linked to our Subjective Effect Index
• Interaction data — safety ratings for combinations with other substances via the Interaction Checker
• Experience reports — first-hand accounts from community members
• Harm reduction — practical safety information specific to each substance

An AI-powered Research Assistant is also available to help answer questions about substances and effects using the encyclopedia's data.

SubstanceWiki is fully open-source. The entire codebase, database schema, and seed scripts are publicly available. We believe transparency is essential for a resource that people rely on for safety-critical information.

Being open-source means anyone can review the data, verify our sources, report errors, and contribute improvements. It also means the project can continue to exist independently of any single maintainer or organization.

Encyclopedia content is licensed under Creative Commons Attribution-ShareAlike 4.0 International (CC-BY-SA 4.0). You are free to share and adapt the content with proper attribution.

We gratefully acknowledge our data sources and the communities that make this work possible. All substance data is attributed to its original source. If you believe any content has been used improperly or without proper attribution, please contact us so we can address it promptly.

SubstanceWiki thrives on community contributions. If you would like to help, there are several ways to get involved:

• Report data errors or outdated information via email
• Contribute substance data or experience reports
• Help improve the codebase with bug fixes or new features
• Share SubstanceWiki with communities that could benefit from harm reduction information