THE BRAND
BEHIND
At Defyne, every detail tells a story shaped by passion, care, and expertise. Our team is made up of dedicated providers and visionaries who bring creativity, skill, and heart to everything we do. From medical excellence to innovative approaches in beauty and wellness, these are the people who make Defyne what it is today.
MEET YOUR PROVIDERS
Dr. Guillermo Castillo is a board certified Family Medicine physician with nearly two decades of experience across clinical care, aesthetics, and healthcare leadership. He completed his medical degree at the USC Keck School of Medicine, followed by a Family Medicine residency at UC San Diego Medical Center. With a foundation in Nutrition Science from UC Davis, Dr. Castillo brings a holistic, precision based approach to wellness integrating genomics, technology, and evidence based medicine to offer highly personalized treatments.
Since 2006, he has worked at the forefront of aesthetic and regenerative medicine, serving as Medical Director for leading medical spas across California. His expertise spans preventive and integrative medicine, aesthetics, and healthcare innovation. Throughout his career, Dr. Castillo has also held key executive roles including CEO and Chief Medical Informatics Officer, contributing to the evolution of patient centered healthcare delivery.
Known for his compassionate demeanor and detail oriented care, Dr. Castillo is deeply committed to improving quality of life through tailored, science backed treatments. His practice emphasizes the connection between internal health and external beauty, empowering patients through education, transparency, and cutting edge solutions.
TANYA AGUILAR
“Hi, I’m Tanya a Family Nurse Practitioner with a passion for wellness, healing, and whole body care.
From an early age, I knew I was meant to be in the medical field. I’ve always been drawn to the idea of caring for others and making a real difference in their lives. Becoming a nurse practitioner allowed me to bring that vision to life, combining evidence based medicine with genuine human connection.
My approach to care is deeply influenced by my training under both a naturopath and a regenerative medicine physician. That experience opened my eyes to the power of integrative health supporting the body’s ability to heal, restore, and thrive from the inside out. Whether it’s optimizing energy, balancing hormones, supporting longevity, or preventing chronic illness, my focus is always on helping patients feel their absolute best naturally and sustainably.
What I love most about this work is the opportunity to walk alongside people on their wellness journey. I take time to really listen, understand the full picture, and create a plan that aligns with each person’s unique goals and lifestyle. I believe that true wellness isn’t one size fits all it’s personal, empowering, and ongoing.
If you’re looking for a provider who sees you as a whole person and not just a set of symptoms, you’re in the right place. I’m so glad you’re here.”
GRACE LEE
“Hi, I’m Grace a nurse practitioner whose heart and work is deeply rooted in helping others.
With a background in nursing and advanced clinical training, I bring both skill and heart to every patient encounter. I specialize in whole person care, focusing not just on symptoms, but on understanding the unique story behind each person. I take pride in creating a safe, supportive environment where people feel seen, heard, and genuinely cared for.
I thrive when I'm making a difference whether that means helping someone navigate a complex diagnosis, offering education and guidance for healthier living and overall fulfillment. My goal is always to meet people where they are, walk alongside them, and help them reach their fullest potential.
I am committed to providing an unwavering & supportive care.
I would be honored to work with you
With humility, Grace.”
Get in touch
We’re here for your questions, thoughts, and everything in between. Reach out we’d love to hear from you.
