Here is a short list of what I have found to be the most useful resources that I’ve found online about psychedelics. The breadth of information you can find out with these websites is incredibly wide and includes:
  • effects, length of duration, routes of administration
  • info about various interactions between different substances
  • practical, step by step guides, dosages
  • scientific info, such as the structures of compounds and what brain receptors different drugs work on
  • historical and cultural info
  • people’s personal experiences AKA trip reports

Erowid

Erowid is a non-profit educational & harm-reduction resource with 60 thousand pages of online information about psychoactive drugs, plants, chemicals, and more. Erowid documents legal and illegal substances, including their intended and adverse effects.
Information is gathered from diverse sources including published literature, experts in related fields, and the experiences of the general public. Erowid acts as a publisher of new information as well as a library for the collection of documents and images published elsewhere.
Running since 1995 and with their headquarters are based in California, it is the oldest on this list and also the most complete. As a member-supported organization, their mission is to provide access to reliable, non-judgmental information.
Here is their vision:
“We imagine a world where people treat psychoactives with respect and awareness; where people work together to collect and share knowledge in ways that strengthen their understanding of themselves and provide insight into the complex choices faced by individuals and societies alike.
We believe that truth, accuracy, and integrity in publishing information about psychoactives will lead to healthier and more balanced choices, behaviors, and policies around all psychoactive medications, entheogens, herbs, and recreational drugs. Erowid’s vision is to facilitate and create resources that are part of the evolution towards this goal.”

PsychonautWiki

PsychonautWiki is a community-driven online encyclopedia that aims to document the field of psychonautics in a comprehensive, scientifically-grounded manner.

What it sounds like, PsychonautWiki is Wikipedia for Psychonauts. Tonnes of useful info and in the familiar format of Wikipedia.

Their primary motivations include:

  • documenting all aspects of psychonautic theory and practice (including meditation, lucid dreaming, psychoactive substance use, sensory deprivation, ritual, etc.) from an evidence-based, academic perspective
  • providing accessible education, encouraging safe practices, and reforming cultural taboos around the responsible use of psychoactive substances, utilizing both expert and crowd-based sources
  • promoting a culture of free thought and individual responsibility by safeguarding the information needed to make informed decisions over altering one’s consciousness.

The Third Wave

The Third Wave has some very good encyclopaedic style knowledge pages as well as some practical information which can be very helpful, such as their guide to volumetric dosing. They also have a lot of information on microdosing.
Their simple stylish modern design makes them a useful resource to share information about psychedelics with others who might find the topic a bit alien. It can present the information in a familiar and scientific manner which might be more comfortable for friends or family members who you might want to introduce the topic to.
Their mission is:
to share trusted, research-based content that helps you feel safe, supported, and empowered as you follow your path towards personal transformation.

Reddit

And as a bonus one I would like to mention reddit. Though not exclusively about psychedelics it is a great place to be able to ask people and communities questions on specific topics and get answers from a range of people.
Sometimes if I have a question I’d like to put out there and hear others’ thoughts I’ll put it up on reddit.
lsd reddit
The LSD subreddit
Reddit has subreddits on almost everything, which are basically subgroups dedicated to topics e.g. shrooms, LSD, psychonaut, psychedelics and even more niche like Psychedelic studies, psychedelicrock and psilocybin growers.
I have reddit especially useful to read about other peoples experience with combining different types of drugs or drug interactions.
However, don’t always expect the kindest responses and be prepared for some weirdos