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Our retreats are centered around the ceremonial use of high-dose, legal truffles containing psilocybin to catalyze this transformation, but the retreat experience goes far beyond that. 
We have curated an expert team of facilitators and meditation and breathwork instructors, and designed an experience that blends the best of ancient wisdom, with cutting edge science. 
You’ll be joining a community of over 500 pioneering professionals, who have trusted us to guide them through their self-exploration and ultimately, growth.
Our passion for stewarding the psychedelic renaissance has led us to create a retreat program that our participants are reporting as one of the most impactful experiences of their lives.
While everyone’s experience is unique, here are some of the incredible results that our study has shown:


The national average of positive mental health is 50.7. Four weeks after a Synthesis retreat, our participants go from 48.6 to 54.5. A tremendous 10% increase.



Synthesis participants report better sleep, decreased rumination on negativity, positive mood, improved concentration, and healthier lifestyle habits including nutrition and exercise.

Greater ConnectedneSs

Greater Connectedness 

The degree of connection that each participant experienced to themselves, others, and nature, more than doubled after Synthesis, an increase of 118%. About half of participants expressed having a full mystical experience.



The degree of fear and stress reported by participants decreased by and remained lowered by 13.8%.

*Data was collected and analysed independently in participation with Imperial College London. Baseline was two weeks before a Synthesis retreat and during. Follow up was two and four weeks after. Data and analysis can be found here.

Ready to start your journey?


The Synthesis Experience

Synthesis is leading a movement to transform the way people approach emotional, cognitive, and spiritual well-being, through safe and legal truffle experiences. Our retreat model represents a fusion of modern science, therapeutic modalities, and wisdom-traditions proven to catalyze deep psychological wellness and, meaningful change.

We have strategically partnered with the Psychedelic Research Group of Imperial College London to contribute to the emergence of psychedelic science and ensure that our programs are as effective and scientifically informed as possible.
Medical Safety


Our team of professionals perform comprehensive health screenings for all applicants in order to identify any personal health risks, ensuring the safety of all of our participants.



The Synthesis Retreat Team consists of experienced professionals; trained in the best practices used in research trials, they have prepared and guided hundreds of participants safely through the full variety of psychedelic experiences.


Scientifically Validated

Through our collaboration with the Psychedelic Research Group at Imperial College London, Synthesis is contributing to pioneering data.


Your Journey


More than just a trip

We will guide you through our carefully designed truffles containing psilocybin journey to experience the full potential of psychedelics. Lying down comfortably with your eyes gently covered, we will provide you with the best way to consume the truffles to minimize nausea, letting yourself be guided through an amazing sound experience, knowing you are safe and supported.


1. Preparation

  • In-depth Exploration Call

  • Individual Health Screening

  • Group Preparation


2. Retreat

  • Private 1:1 Coaching
  • Carefully Designed Set & Setting
  • Meditation & Breathwork
  • Ceremonial Truffles Containing Psilocybin Experiences
  • Educational Workshops

3. Integration

  • Group Integration
  • Access to Additional Programs
  • Private Inner Circle Membership
  • Post-ritual screening

In committing to this experience, you will be a pioneer in your own right, joining a specially curated list of attendees who are contributing to the next conscious evolution of humanity in a significant way.

Your Experience Could Include:

  • Peak experiences

  • Mystical states of consciousness

  • Overcoming destructive attachments

  • Deep and lasting sense of connection

  • Remembering meaningful memories

  • Challenging and confronting visions

  • Processing childhood experiences

  • Synesthesia — see sounds

  • Experiences of intense love and bliss

  • IDENtify and release suppressed feelings

  • Intellectual epiphanies

  • Enhanced self-acceptance and compassion

  • Heightened states of creativity

*While there are no guarantees as to what kind of journey you will have - these are the most-commonly known types of psychedelic experiences.


How To Start Your Journey

Schedule your complimentary Exploration Call where you will speak privately one-to-one with a Synthesis team member. This is your time to dive deeper into your intentions, questions, hopes and potential concerns about the journey ahead.

With your safety as our priority, prior to your call, you complete a health screener form that is reviewed by professionals to ensure your safety before, during and after your journey.

During your Exploration Call, you could be invited to attend a retreat and we will discuss the best options to suit your needs including dates and programs.

Prior to your retreat, you will receive all the practical information you need, as well as an invitation to your first group preparation call, where you will have the opportunity to meet and connect with your facilitators and fellow participants.


Our Venues: Houses Of Well Being


Choose Your Journey

Expansion by Synthesis

Expansion by Synthesis 

Our most comprehensive program, Expansion is a complete 7-week program designed for deep transformations. More than just a truffles containing psilocybin ceremony, you will use this window of plasticity to grow your presence, self-acceptance, focus, and expand your range of states of consciousness in your daily life.

Core by Synthesis

Core by Synthesis

Our standard 3-day retreat near Amsterdam in which you experience one moderate-to-high dose of truffles containing psilocybin to catalyze emotional breakthroughs and deepen self-understanding.

Women’s Leadership Retreat

Women’s Leadership Retreat

Leadership is born from the relationship we have with ourselves; it is not a job title, it is a decision. We believe that true leadership is something that all women can access, with the right tools. During this five-day wellness retreat, made by women for women, you will relax, explore, learn, discover, breathe, heal, recharge and reach a state of alignment with your past, present and future selves, and the world around you.

Men's Retreat Synthesis

Men's Retreat

This unique Synthesis men-only retreat is a rite of passage that will support deep personal exploration of oneself within a strong, safe and mature container. Diving deeply into ‘liminal realms’ and non-ordinary states of consciousness with truffles containing psilocybin, we will explore together what it means fully to be a man who is capable of discernment, protection, heartful relating and embodied leadership. 

Private Retreat

Private Retreat

Synthesis offers private retreats, an opportunity to work with two facilitators privately instead of participating in our larger group retreat model. The private retreat format offers participants the ability to customize their ceremony, tailoring the individual needs to maximize the transformational potential of their experience. Click below to see if this retreat is right for you.


Here's What You Need To Know




Synthesis: Legal Truffles Containing Psilocybin Experiences

Based in the Netherlands, we offer a 100% legal way to explore your mind with truffles. Access to expanded states of consciousness in a modern, comfortable, professionally supervised context.

Contributing to Science

Synthesis is committed to science-based data and contributing to research. To date we’ve collaborated with The Psychedelic Research Group of Imperial College London in a pilot study where we discovered that the biggest factors for a transformational psychedelic journey are: sense of safety, quality of intention, the absence of escapist behaviours and distractions, and the feeling of community - all important aspects that we safeguard. By attending Synthesis you get the opportunity to contribute to pioneering science and furthering the well-being of our planet.

Personalised Care

Your journey begins with an in-depth exploration call to fully understand your background and needs, so we can provide absolute clarity in the journey ahead and how to get the most out of your experience. Throughout the retreat, we cater to your individual needs by offering workshops for all levels and one-on-one consultations with our professionals, in order for you to go in prepared and process your experience to extract valuable life lessons.

Professionally Supervised

The application procedure involves a thorough check by our health team to ensure your safety. Experienced practitioners are present during the retreat.

Preparation & Integration

All our programs include a preparation and integration program. Preparation is key for maximising the potential of a beneficial psychedelic experience and integration is important for prolonging the well-being benefits. We are dedicated to ensuring that our participants understand the unique ways that truffles containing psilocybin can aid in healing and growth, the importance of set, setting, intentions, and personal practices.

Set & Setting

We designed your whole journey in order to reduce any anxiety or nervousness you might feel. From the sound experience to personalized care, every element is planned to ensure your optimal mindset and comfort in the setting, preparing you for your psychedelic experience with as little resistance as possible.

Inner Circle

You will receive lifetime access to our private community as part of your retreat commitment. This ever-evolving community offers access to professional support and networking as you continue the process of your own psychedelic journey and personal development.



Upcoming Retreats




COVID-19 restrictions continue to impact our ability to offer wellness retreats.

Due to the ever-changing COVID-19 global health impacts, travel restrictions and extended lockdown in the Netherlands, we’re still unable to reopen our wellness retreats.

We’re closely monitoring the rules and regulations of the Dutch government and as soon as international travel and group gatherings are authorized we will resume our retreats, with the prospective dates below.

Our team looks forward to guiding you through your next journey of deep self-exploration in the near future.



Featured Stories



750+ people have embarked on a journey through Synthesis They happily share with you how it has impacted their lives

How would you rate your experience
The experience has been nothing short of life changing. From the facilitators, to the people I shared the venue with, everyone was warm, caring, and accepting. The Synthesis team is doing amazing work, long may it continue. I can't wait to attend again!
William, 37, Recruitment, UK

It would be impossible for me to speak too highly of the benefits of undergoing the Synthesis psilocybin retreat. The guidance offered, in the in the weeks leading up to the retreat itself, through the care and commitment of the facilitators before, during and after the ceremony/experience, coupled with the offer of support and assistance, guarantees (to those who ensure they arrive with the right mindset) a successful outcome. I took away from my time in Amsterdam a foundation which I know I can continue to build on in the years to come.

My perception of the benefits I've gained have already been confirmed by those near and dear to me and already the benefits have extended beyond the merely personal into my deepest relationships. This has been one of the most truly transformative experiences I've ever undergone. It is without question unlike any of the other modalities I have undertaken over many years and clearly the one that to date has had the most significant impact in enabling me to understand who I am, why I have lived my life as I have to date and what I will now do with what of it remains.
Stewart, 62, Insurance, Australia

For those of us searching for meaning or redirection, Synthesis and its facilitators can help you self-guide to what is your higher calling or purpose.
Lauren, 34, Accountant, USA

I really appreciated the way the Synthesis team was informative, educational and to the point and at the same time sacred and ceremonial. Last but not least I appreciated how they were kept totally secular, that is important to me. What struck me as surprising was that the actual psychedelic journey was a much lesser piece of the overall experience than I had expected. I did expect the surrounding activities to be nice and interesting, but not that they would be essential to the experience and the possibility to learn from it in the way that they turned out to be.
Jonah, 40, Teacher, Sweden

I couldn't think of a better place for a psilocybin retreat. The Synthesis team is very loving and supportive, the building modern and beautiful, the food lovingly prepared. I am glad that I took part and I will come again.
Marcel, 53, Teacher, Switzerland

The Synthesis team is amazing, from the first email to the emotional goodbye hug they are top class every step of the way. Having been to many spiritual/development focused retreats (meditation, motivational speakers, etc) this was one of the most professionally run and knowledgeable I’ve ever been to. Also, as a complete novice to entheogens/psychedelics it was amazing to see how the retreat catered to those of all levels, helping a rookie like me feel very safe & secure while still keeping those with more experience really engaged! Lastly, they do a great job of curating groups of awesome people, while our group was very diverse there was no drama or issues. Amazing experience, people and team!
Daniel, 27, Market Research & Analytics, Canada

This retreat allowed me to explore areas in my life I had not been able to easily access. Everyone was professional and lovingly compassionate and caring. A beautiful experience.
Marion, 66, Psychotherapist, USA

Find out why our participants rate us 9.7/10


Contact Us


We’re committed to making your transformative journey the most meaningful it can be

Talk to us

Send us a message or schedule an exploration call to find out whether Synthesis is right for you.

Connect with us

Find us and numerous Synthesis Retreat alumni on LinkedIn, Facebook and Instagram


Frequently Asked Questions

About Synthesis

What is Synthesis?

Synthesis is pioneering transformative wellness to help you achieve wisdom-lessing, improved connections, lasting betterment in your mood, outlook on life, relationships, and overall mental wellbeing through medically-overseen, guided psychedelic experiences. We use a combination of truffles containing psilocybin, evidence-based wellness programs, and the support of an interdisciplinary team of experienced guides to optimize your healing journey. Read more about us.

Who is Synthesis for?

Synthesis is for people who are looking for the best in mental health and wellness practices. We work with professionals of all walks of life and ages, from those who are new to expanded states of consciousness, as well as the highly experienced. Read more about who comes to Synthesis.

How does it work?

You begin by scheduling discovery call with your Synthesis guide to see if a truffles retreat is right for you. Before your call, we will ask you some personal and medical data. Then, we’ll book your dates, send you your preparation information, and introduce you to your group and lead facilitator for your retreat. Book your call.

How much do your programs cost?

Our retreat types differ in time and value, and therefore in price.

Core 3-day retreat - $3000
Expansion 5-day retreat - $5000
Women’s leadership 5-day retreat - $5000
Private 3-day retreat - $9000

Please ask about our scholarship program.

Are there scholarships available?

We have scholarships available. Please ask for on your exploration call what is possible for you.

I’m looking for psychedelic therapy. Can you help?

It’s important to know that we do not offer any therapy. While our protocols and trainings are based on the best therapeutic practices currently available in this field, scientific research is still working on what constitutes proper therapy. What we offer is a safe and compassionate space where you can explore your own consciousness with all the beauty and darkness, love and difficulties that reside within it. We adhere to the best professional standards, but do not give treatment nor actively work with depression or traumas at this time.

We're working hard to develop our capacities which will allow us to offer legal therapeutic treatment in the near future. We're happy to keep in touch over email as we fulfill this long-standing ambition.

On Truffles Containing Psilocybin

Are truffles really safe?

According to recent studies, psilocybin mushrooms (which have the same active ingredient as truffles) are the safest drug currently known - safer than tobacco, cannabis, and alcohol. These substances are non-addictive, non-toxic, and, when taken within a structured setting under the guidance of medical professionals, hold little to no risk. Read more about truffles.

What is the active ingredient?

The active ingredient in truffles is psilocybin.

Psilocybin, upon entering the body, is quickly metabolized into psilocin, which is responsible for the well-known psychedelic effects. Psilocin acts on serotonin at the 5-HT2A receptor, increasing the amount of serotonin available in the brain, and producing profound changes in perception, such as visual and auditory hallucinations, tactile perceptions (such as tingling or warmth), and synaesthesia (the merging of senses).

Users of psilocybin report entering a profound state of mind where the usual limits of consciousness are expanded. Realizations about the self and the universe may come to the forefront, and people will often describe feelings of unity, interconnectedness, and unconditional love. Studies have shown that psilocybin can induce a mystical experience and that this positively correlates with the benefits that users report following the trip.

What is the dosage used in the retreat?

We determine our dosage together with you during your 1-1 conversation. What we recommend varies, depending on your intentions, previous experience, your sensitivity to expanded states of consciousness, and your anxiety level on retreat. On average we use the clinical standard of 30mg/70kg of psilocybin and psilocin. When it is your first time, we recommend a slightly lower dose to get more comfortable with these states of consciousness. If you have more experience or a strong contemplative practice, we are open to provide much higher dosages.

I’m on antidepressants. Does this disqualify me for attending a retreat?

The simple answer to this question is that we review applications on a case-by-case basis based on both psychological and medical history, as well as current medications, to look for any contraindications before we can formally accept or not accept an applicant.

Our medical team is sometimes able to tell you under which conditions it’s safe for you to come on retreat, for example if you are able to taper off under correct supervision and receive sufficient aftercare after your retreat.

Everyone who we can’t accept at this time gets put into a contact list where we will monitor and reconnect as we expand our capacity to take on more and more people through building up and improving upon our support capabilities - which include therapeutic support pre-retreat and post-retreat. To learn more, read our article ‘Can you take shrooms on antidepressants?’

In any case, you're invited to book an Exploration Call and go through the Health Check.

The Synthesis Experience

How do I book directly?

We would like to make sure you have all your questions answered and trust a Synthesis retreat is right for you. That is why the first step towards joining a retreat is to book an exploration call with us. During this call, we'll explore your intentions, your questions and any concerns you might have. We'll also share more about our programs and explore if we are a good fit.

However, if there is a reason you do wish to attend the call, or would like to make an urgent booking, here is what to do:

Click, BOOK A CALL and follow the process outlined. While you pick your date and time, complete a few questions to help us personalize your experience.

Next, complete the medical screening process, and if approved, you will receive an email from us confirning your call. To bypass the exploration call stage simply reply to that email (or email us directly at and indicate the reason for not attending the call and the dates and program you would like to attend. We will correspond through email with you.

What if I don't pass your health screener?

In order for us to accurately assess your suitability and safety for a psilocybin journey, as well as to provide you with a personalized experience during your retreat, we would love to get to know you better first and see whether Synthesis is right for you.

If your screener identifies anything that requires a closer look by our medical team, we will wait until we get clearance from them. In the meantime, we will postpone your Exploration Call while we work with you on your case.

There are three possible outcomes of this review:

  1. Your Health Screener is approved and you are invited to reschedule your Exploration Call
  2. To get a better understanding of your condition, we may request some more information from you. This may be over email or in the form of a brief call.
  3. If we don't feel as though we can support you safely through your psilocybin experience, we may decline your application and therefore your Exploration Call (if this happens, we will send you an email with further details) Throughout this entire process, we handle your information with the utmost care and consideration for your confidentiality.

We understand this may feel like a roadblock and we want you to know that our medical team will work with you, with your best interests at heart, to determine the best course of action. Thank you for your patience and understanding. Your safety is our primary concern.

Why the retreat model?

Studies have shown that the context of a group retreat and having experienced guides are essential ingredients to properly optimize for safety and getting the most out of a psychedelic experience. From years of retreat experience we know the value of this experience is rooted in the whole process, from being able to surrender fully because there is medical and professional support, to the meaningful relationships you will build with others.

How will the psychedelic sessions be set up?

We provide a comfortable indoor space with mattresses to lay down on, eye shades, and profound music. There are also creative spaces inside and outside to explore. In creating an optimal environment for your psychedelic experience, we combine ceremonial aspects rooted in age-old tradition with modern approaches that have proven, in scientific research, to be effective at facilitating a deep, meaningful experience.

Is there any preparation and integration work included with the retreats?

Upon arrival, guests participate in both group and individual workshops to help prepare them for the truffles ceremony. On the day of the ceremony, guests participate in a breathwork session and are carefully supported by experienced practitioners, including an on-site medic as they experience truffles in a therapeutic context. After the ceremony, guests participate in group and individual workshops focused on integration before customers return home. Additional preparation and integration support is also offered digitally outside of in-person retreat dates.

What is the typical age of people attending retreats at Synthesis?

Although psychedelic retreats are mostly associated with younger generations, Synthesis participants come from a variety of age groups. Starting at 18 years old, which is the age to be legally eligible for a retreat, we regularly host individuals in the midst of the early, mid, and late stages of life. These distinct stages each come with their own trials and tribulations, something which our retreats and team of experts are equipped to support.

To learn more about the use of psychedelics in mid to late life, read our article Psychedelics and Age.

Will my personal information be confidential?

We keep all personal information confidential, none of it will be shared with third parties.

Do you offer 1-to-1 guided sessions if I prefer to do this in private?

Yes, we do! Please see our private retreat offer for more details. We also offer 1-to-1 preparation and integration coaching as an option during our group retreats, for an additional fee.

Can I do more than one retreat?

Yes, you can. A second retreat can be a quite different experience, certainly not just a repetition. In case it‘s your second overall psychedelic experience, many people tend to be even better prepared and relaxed as there is a familiarity that allows them to let go or direct their experience even more. For experienced psychonauts on the other hand, each experience can have its own focus or topic, exploring different aspects.

Can I stay an extra night at your venue?

You are welcome to stay an extra night at the venue either pre-retreat, post-retreat or both. We charge an additional cost of $200 for each night.

Please note that because your extended stay is beyond our normal retreat schedule, you will be responsible for your own transportation and your own meals during this time. We will be very happy to assist or point you in the right direction for both. Your apartment’s kitchen is well equipped for cooking and there are many restaurants and grocery stores within a short walk of the venue.

Check in time early arrival: between 12pm and 19:00 / 7:00 PM* Check out time late departure: 10:00 AM

  • We kindly ask you to communicate your arrival time to our venue manager, so that she can get everything prepared for your arrival.

You are welcome to use the sauna and the facilities in your apartment, but the access to the rest of the building will be restricted. The retreat team is preparing for your retreat, and so the common areas like the church and ceremony space are off limits. We appreciate your understanding.

What’s the ideal flight schedule for my arrival / departure?

Arrival to Schiphol International Airport: Please keep in mind that you should land by 10.30 AM CEST (local time) at Amsterdam Airport on the first day of your retreat to make it through customs on time. The shuttle service to the venue leaves at 11.30 AM CEST.

We are aware that the time window for arrival might be limited. If you have trouble booking a flight that lands before 11.00AM on the first retreat day, please contact us so we can help you with the travel schedule.

Departure from Schiphol International Airport: We advise to book your returning flight after 19.00pm CEST on the day of departure, as the retreat will wrap up at 16.00pm CEST and drop off will be at Amsterdam Central Station or Schiphol International Airport at 16:30 - 17:00pm. This should give you sufficient time to make it through customs without any unnecessary stress.

What’s your take on couples (or family members, friends) attending together?

Coming together or not is a very personal decision. Many couples join us for a retreat together and have a wonderful time. Coming together can be a very bonding experience for both of you, a transformative experience to share and remember. Our Director of Operations actually came as a participant to one of our first ceremonies with her husband. She often reminisces with a smile that the experience brought them much closer together.

In some cases, it might make sense to come alone. If you have a personal issue you’d like to work on during the retreat, having your significant other around could be a distraction for you. For instance, you might end up worrying about them and be unable to focus on your own process. In this case coming separately might be better.

Have you already decided that you’ll come together? Excellent. This is how it works: Both of you need to sign up for an Exploration Call, which is followed by our Health Check. The Health Check is a mandatory step for each of you. You may schedule your call together or separately, that’s up to you, but please let your exploration guide know in advance if you come together on your call.

Ready To Join One Of Our Retreats?