About Synthesis

Synthesis offers an exclusive 3-day psychedelic retreat in Amsterdam to forward-thinking individuals who want to utilize moderate-to-high doses of psilocybin truffles to catalyze creative breakthroughs, deepen self-understanding, and feel ready to make their next big ‘leap’ in life.

When used within a modern, legal, medically supervised and structured framework, it is one of the only modalities that creates dramatic, impactful change within just hours of utilization.

We administer the truffles in a unique way to eliminate physical discomfort and nausea. Then, taking into consideration your intention, sensitivity, and previous experience, we then optimize the best dosage for you. Finally, we integrate the latest findings and best practices from the psychedelic research community to ensure your experience is as profound and effective as possible.



Our vision

Synthesis will pave the way in facilitating research about the efficacy of psychedelic medicine on facilitating optimal body, mind, and spiritual wellness. By combining psilocybin with other modalities (sound meditation, yoga, and breathwork, etc.) and measuring outcomes for well being, we will build a database of optimal mind-body approaches to healing.



The Synthesis Team

Your Facilitators:


Natasja Pelgrom

Lead Facilitator

Natasja is a Holistic Transformational Mentor with significant experience in counseling; life and business coaching with over ten years of practice.

She is a highly intuitive guide and has trained, assisted and facilitated in 500+  psychedelic ceremonies. As a medicine woman operating internationally, she curates medicine retreats and teaches empowerment workshops.

Natasja brings a rich and extensive resource of skills to Synthesis.

Daan Keiman


Daan holds an MA in Spiritual Care and previously worked for the renowned mental health care and addiction research institute, the Trimbos-institute. His experience with guiding and caring for people in altered states of consciousness spans over a decade.

He draws from his personal contemplative practices, psychedelic research and his professional experiences to create compassionate and powerful containers for personal transformation. As an avid explorer of consciousness, he is highly capable of guiding others through the landscapes of the mind.  

Tessa Van de Ven

ASSISTANT Facilitator

In her roles as operations manager and intuitive guide, Tessa’s mission is to design modern retreat programs for the transformational work with plant-origin psychedelics.

Over the past three years she has participated, assisted and facilitated in 50+ ceremonies with psychedelic medicines from European, South American, Middle Eastern and African cultures. Her strong empathy skills and deep connecting with the natural world, makes her an excellent guide on your journey of consciousness exploration.



Paul Austin

Co-Founder & Director of Business Development

Paul is this generation’s leader for utilizing micro and moderate doses of psychedelics for personal and professional development. In developing Synthesis with Martijn, Paul has committed to creating a legal container to initiate lasting change and transformation in your personal and professional life. He is also the Founder of The Third Wave.

Martijn Schirp

Co-Founder & EXECUTIVE Director

Martijn first reached out to psychedelics when he was in search of new perspectives and clarity to reorient his life. With a background in interdisciplinary science and philosophy, he aims to make psychedelic tools accessible in a safe, legal, and modern context. He is a Co-Founder of High Existence.

Myles Katz

Director of Operations & Finance

Myles has spent his career on three different continents launching or leading VC-funded startups with technological, socially responsible, and green initiatives. He believes impact-focused businesses will play a key role in increasing access to safe, legal and professionally-guided psychedelic experiences.

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Kristyn Judkins

General Counsel

Kristyn oversees legal matters for the Synthesis team.

She joins us from a global law firm where she focused her practice on dispute resolution and complex international tax and corporate transactions. A few psychedelic experiences of her own fueled a desire to help our community.