Functional Medicine for Whole-Body Wellness
Personalized Functional Medicine Focused on Root-Cause Health and Hormone Balance for Perimenopause and Menopause
Susannah Kerwin
Functional Medicine Clinician
Susannah Kerwin
Functional Medicine Clincian
Susannah created Tendwell with a simple but radical belief: You deserve to be truly heard.
A board-certified Advanced Practice Nurse Practitioner with training from the Institute for Functional Medicine, Susannah has spent over two decades helping patients reconnect with their health—and with themselves. Her path has taken her from San Francisco to New York City to Beijing, where she explored traditional Chinese medicine. Along the way, she saw firsthand how rushed, one-size-fits-all care fails to serve real people with complex stories.
At Tendwell, Susannah takes the time to listen deeply and think differently. She blends advanced testing, root-cause analysis, and nutrition-first therapies to create personalized care plans that honor the whole person—not just a set of symptoms. Her patients are active partners in the process and consistently report feeling healthier, more hopeful, and more connected to their bodies.
When she’s not seeing patients, Susannah can usually be found hanging out with her kids, reading, exploring new places, playing soccer, or moving through a Pilates flow.
Leia Desousa
Nutritional Coaching
Meet Leia – Your Partner in Functional Wellness Coaching
Leia is a New York City-based certified health and nutrition coach and personal trainer with deep expertise in functional medicine support. She partners closely with our Tendwell functional medicine practitioners to guide clients on their journey to sustainable health and wellness. With a compassionate yet empowering approach, Leia helps you overcome obstacles, stay motivated, and implement personalized wellness plans tailored to your life.
Whether you need help restocking your pantry with nourishing options, brainstorming high-potein meals, managing your schedule, or building healthy lifestyle habits, Leia will support you in creating a lasting, positive relationship with food and wellness—one small, meaningful step at a time.
Functional Medicine Health Coaching at Tendwell
Tendwell members receive health coaching visits as part of their membership. If you’d like to schedule additional functional medicine coaching sessions, click the link below to purchase.
What patients are saying
“Susannah is patient, kind, asks good questions, a good listener, and very knowledgeable. She made me feel heard and respected. I would definitely come back to see her again. The best medical visit experience I've had.” — Kristina M.
“After trying unsuccessful conventional approaches for years (literally), Susannah helped me attend to what was going on with my body and my mind together as a system. I feel like she provided the missing piece to the puzzle.” — Charlotte T.
"I came to Leia a few years ago, after wrestling with food issues for a long time. In addition to her incredible skill and vast knowledge, it was her attentiveness and genuine care for my well-being that made a huge difference in my progress." — Jared K.