Meet Our Care Team
Thousands of patients, over a decade of experience.
Consult with the Experts
Our care team has extensive experience in hormone restoration, sexual health treatment, and integrative wellness. They’re passionate about helping patients improve their lives and feel their best.
Defy Medical’s care team is led by Dr. Justin Saya, our medical director and lead practicing physician.
Medical Director and Lead Practicing Physician
Justin Saya, MD
Dr. Justin Saya graduated as class valedictorian from North Carolina State University with a dual bachelor’s degree in Biological Sciences and a bachelor’s degree in Economics. He received his medical degree from the University of North Carolina at Chapel Hill, School of Medicine, and subsequently performed his internship and residency training at the University of South Florida/Morton Plant Mease Family Medicine Residency Program.
In addition to his education and training, Dr. Saya is privileged to hold many certifications, honors, and memberships, including membership to the American Medical Association, the American Association of Family Practitioners, and the World Anti-Aging Academy of Medicine, among many others.
Dr. Saya offers therapy to both men and women who are looking to balance their hormone levels and improve their overall quality of life. His patients have reported benefits such as improved energy levels, restored libido, improved muscle tone and exercise tolerance when combined with an exercise routine, healthy/sustainable weight loss when positive eating and exercise habits are adapted, and much more.
He hears repeatedly from Defy patients that hormone replacement therapy is one of the best decisions they’ve ever made.
Caleb Calkins, MD
Dr. Calkins is focused on optimum health for his patients. He believes in a proactive approach to medicine that emphasizes maintaining an appropriate balance of nutrition, hormones, and fitness. He is dedicated to finding the root causes of his patient’s symptoms and the appropriate treatment regimens for complete wellness.
Dr. Calkins completed his bachelor’s degree in Public Relations with a minor in Nutritional Science at the University of Florida. While there, he was involved with research focused on the benefits of a ketogenic diet in improving epilepsy. He received his medical degree from St. Matthews University, and subsequently performed his internship and residency at Tulane University/East Jefferson General Hospital Family Medicine Residency Program in New Orleans, Louisiana. In addition, he received a master’s degree in Hospital Administration from Davenport University in Grand Rapids, Michigan.
Throughout his education and experience, Dr. Calkins has seen the benefit of using multiple modalities to improve patient outcomes.
Beth Bray, APRN
Beth Bray, APRN, comes to Defy with over two decades of medical experience. She started her career after graduating from Prairie State College and became a Registered Nurse where she worked in hospital settings for orthopedics and oncology.
In 2015, she completed her graduate degree from Northern Illinois University and began working in Primary Care and Integrative Holistic Care.
Beth cites the importance of forming a partnership with her patients to help them work towards optimal health goals and allowing them to live their absolute best lives. Additionally, Beth feels that Defy is on the cutting edge of hormone replacement therapy and integrative wellness.
Beth recently made the trek from icy Illinois to sunny Florida and became a member of the Defy Medical team in February of 2021. Since moving to Florida, she’s developed a passion for gardening and just about anything else the Florida sunshine has to offer. Beth is also an avid reader and is usually zipping through an Octavia Butler Sci-Fi novel in her free time.
Morgan Bulawa, PA-C
Morgan is a Board-Certified Physician Assistant with a strong passion for empowering patients to optimize their health through education and personalized care. A graduate of the University of Houston, she earned her degree Magna Cum Laude while playing collegiate soccer. Morgan then pursued her Master’s degree from the Texas Tech University Health Sciences Center PA program, where she was inducted into the Pi Alpha Honor Society.
Before embarking on her PA career, Morgan was introduced to bioidentical hormone therapy in 2021 through clinical experiences at two different HRT clinics in Texas. Her dedication to hormone optimization grew from these hands-on experiences, and her interest was further shaped by family influence—her uncle and aunt, both pharmacists specializing in HRT, have played a key role in shaping her approach to hormone therapy.
Morgan’s commitment to wellness extends beyond her professional life. With a background in Exercise Science and a passion for staying active, she incorporates her experience with fitness and sports into her treatment plans. Born in Norway but raised in Texas, Morgan enjoys spending her free time at the Florida beaches with her husband.
Corbin Burns, PA-C
Corbin Burns, PA-C, joined Defy Medical with a strong foundation in both emergency medicine and behavioral health. He earned his bachelor’s degree in Biology from Birmingham-Southern College in 2014, followed by a master’s degree in Physician Assistant Studies from the University of Alabama at Birmingham in 2017.
Corbin has long held a professional interest in hormone replacement therapy and testosterone optimization, particularly through a holistic and integrative lens. His approach to patient care is centered on helping individuals achieve long-term wellness by addressing root causes, lifestyle factors, and individualized goals.
Now based in Florida, Corbin spends his free time with his partner and their golden retriever. Outside of the clinic, he enjoys exploring new restaurants, spending time at the beach, and connecting with friends over good food and conversation.
Robin Cozine, APRN, FNP-C
Robin Cozine, APRN, FNP-C, is an experienced Advanced Practice Registered Nurse who brings a wealth of expertise in wellness, medical leadership, and patient-centered care. She holds a Master of Science in Nursing from Austin Peay State University and is board certified as a Family Nurse Practitioner by the American Association of Nurse Practitioners. Licensed in multiple states, Robin has practiced across diverse specialties, including functional wellness, medical aesthetics, weight management, and hormone balancing.
Robin has served in leadership roles throughout her career, from starting up wellness practices to training and mentoring other providers. Her approach combines comprehensive health assessments with personalized lifestyle interventions, focusing on restoring balance and optimizing long-term health for each patient. She has extensive experience in Bioidentical Hormone Replacement Therapy, medical weight loss programs, and intravenous and injectable treatments.
Outside of the clinic, Robin enjoys an active and creative lifestyle. She has performed locally and internationally as a majorette with several adult marching bands — an experience that reflects her passion for teamwork, dedication, and bringing energy to everything she does. Whether in the exam room or on the field, Robin’s goal is to inspire others to live with vitality and confidence.
Jill Dillenburg, RN
Jill Dillenburg, RN, has practiced as a board-certified registered nurse for the past 10 years.
She specialized in the areas of hormone replacement therapy and cardiology and brought her skills and attentive care to Defy Medical in 2014.
Jill graduated from Galen College of Nursing in 2010 with a Registered Nurse degree. She initially practiced in cardiology assisting with clinic patients, nuclear stress testing, and pacemaker implantation before starting with Defy. Jill is enthusiastic about helping individuals rediscover themselves in mind and body for optimal health and happiness.
Her approach to hormone replacement therapy is a holistic one, addressing both hormone levels and lifestyle factors to improve one’s daily quality of life. Due to her many years of practicing as an IV nutritional specialist, she is proficient in evaluating for vitamin and mineral deficiencies that contribute to fatigue, weight issues, and cognitive function. Jill finds patient education via telemedicine both rewarding and gratifying. She empowers individuals to be their own best advocate through a deep understanding and knowledge of their health.
Melissa Faulk, PA-C
Melissa Faulk, PA-C, graduated Summa Cum Laude from South University in 2003 with a Bachelor of Physician Assistant Studies. Melissa is a NCCPA (National Commission on Certification of Physician Assistants) board-certified physician assistant with nearly 20 years of clinical experience in the fields of military medicine, orthopedic trauma, cardiology, and hormone replacement. She has specialized in men’s health for more than 10 years.
Melissa has a passion for U.S. military service members and veterans due to her personal service in the Army. She served as the lead PA for Army’s Center of Aviation SERE-C course, graduated from the Army Flight Surgeon course in 2009, and served several years in Afghanistan caring for U.S. soldiers.
Melissa approaches patient care from a functional perspective, seeking to uncover and address the root cause of imbalance. She also understands that optimized health requires an integration of physical, mental, and psychological well-being.
Melissa is diligent in partnering with patients to formulate individualized plans to meet their health and wellness goals, whether that be increased energy, vitality, or changes in body composition.
Megan Kershner, MSN, APRN, AGNP-C, MSCP
Megan Kershner, MSN, APRN, AGNP-C, MSCP, received her Master of Science in Nursing from the University of South Florida in 2021.
She is a Menopause Society Certified Practitioner by The North American Menopause Society. Megan is also certified by Biote, a leading innovator in precision and preventive health care, to place HRT pellets.
Megan is pursuing continuing education in Hormone Replacement Therapy, diabetes, and functional nutrition, to provide patients with the most up-to-date care and support.
In her free time, Megan loves traveling with her husband, reading, gardening, and making sourdough bread.
Mike Linkous, PA-C
Mike Linkous, PA, completed his bachelor’s degree in Adult Fitness/Exercise Science at Marshall University in West Virginia. He received his Physician Assistant degree from The College of West Virginia in Beckley, West Virginia in 2000. Since then he has worked in Sports Orthopedics, Family Medicine, Integrative Hormone Medicine, and Pain Management.
As a member of the Defy Medical provider team, Mike takes an integrative approach to treating patients. In addition to his extensive medical training and practice, Mike also brings unique personal perspective to his patient consultations as he has been on TRT for more than 15 years.
Marisa Palles, PA-C
Marisa Palles, PA-C completed her Bachelor of Science degree at the University of South Florida in 2018. She then graduated Magna Cum Laude from South University in 2022 with a master’s in Physician Assistant Studies.
Marisa has clinical experience in the urgent care setting and has seen an array of complex medical conditions, but her true passion is in the field of endocrinology. Prior to completing her education as a PA, she assisted Defy Medical patients as a Patient Services Specialist. Now Marisa is thrilled to continue helping Defy Medical patients as a member of the care team.
Marisa’s approach to hormone optimization is centered around patients’ symptoms as well as lab values. She strives to implement her own healthy lifestyle into her practice and takes a holistic approach toward improving patients’ quality of life outside of just hormone imbalance.
Marisa is a member of Florida Academy of PAs (FAPA) and is a National Commission on Certification of Physician Assistants (NCCPA) board-certified PA.
She was born and raised in the Tampa Bay area. Her interests include trying out new exercise routines like resistance and strength training, HIIT, and Pilates.
Mariah Savala, PA-C
Mariah Savala, PA-C, is a dedicated Physician Assistant specializing in the field of men’s health. With a Bachelor’s degree in Science and Arts in Biology from the University of Texas at Austin and a Master’s degree in Physician Assistant studies from South University in Richmond, Virginia, Mariah brings a wealth of knowledge and experience to her role.
Mariah’s professional journey in healthcare began at Baylor College of Medicine, where she gained valuable experience running the laboratory and working as a patient care tech alongside Dr. Larry Lipshultz. Her exposure to Men’s Sexual Health and Hormone Replacement Therapy during this time sparked her passion for Andrology and urogynecology, areas in which she now specializes.
Guided by a holistic approach to patient care, Mariah is a member of prestigious organizations such as the American Urological Association (AUA), Sexual Medicine Society of North America (SMSNA), American Academy of Physician Associates (AAPA), and Virginia Academy of Physician Assistants (VAPA). Her commitment to staying informed through annual conferences ensures she remains at the forefront of advancements in her field.
Beyond her professional pursuits, Mariah enjoys hiking the Appalachian Trail, Latin dancing, exploring diverse cuisines, and outdoor adventures. Mariah Savala, PA-C, is dedicated to enhancing health and wellbeing, offering compassionate care to help patients lead healthier and more fulfilling lives.
Kristian Schoppaul, APRN, FNP-C
Kristian Schoppaul, APRN, FNP-C, is a dedicated Advanced Practice Registered Nurse with a specialization as a Family Nurse Practitioner (FNP-C). She holds a Bachelor of Science in Nursing from the University of South Florida as well as a Master of Science in Nursing from Chamberlain University. Kristian’s nursing experience covers a wide range of specialties, including ER, ICU, COVID ICU, Oncology, Cardiology, PACU, Pediatrics, and Newborn care.
Her interest in Hormone Replacement Therapy (HRT) was ignited during her time in Sports Medicine, where she learned the significance of maintaining hormonal balance for overall wellbeing. Kristian finds fulfillment in helping her patients at Defy Medical feel their best, whether it’s improved mood, energy, libido, joint health, or strength.
Outside of work, Kristian leads an active lifestyle as a bodybuilder and avid hiker. She also enjoys cooking and expressing her creativity through painting and drawing. Her dedication to empowering patients through HRT makes her a valuable asset to Defy Medical, where she positively impacts the lives of those she treats.
Kristian brings a wealth of medical expertise and genuine passion to her role at Defy. With her comprehensive care and focus on HRT, she strives to help patients achieve their optimal health and wellbeing.
Elizabeth “Liz” Thara, APRN, FNP-C
Elizabeth “Liz” Thara, APRN, FNP-C is a committed Advanced Practice Registered Nurse with a rich background in healthcare, having earned her Bachelor’s degrees in Biology (2010) from St. Xavier University Chicago and Nursing (2012) from Loyola University Chicago. She went on to earn her Master of Science in Nursing from Chamberlain University in 2022. With over a decade of experience as a Registered Nurse in labor and delivery, Liz has developed a deep passion for Women’s Health as well as wellness and weight management.
In her current role as a Nurse Practitioner at Defy Medical, she is expanding her expertise into Men’s Health, an innovative area that excites her as she continues to grow in her field. Liz believes in treating each patient as a unique individual, listening carefully to their needs, and working together to create personalized care plans. She is committed to learning from her patients to ensure they feel heard and supported throughout their wellness and hormone therapy journey.
Outside of her professional life, Liz enjoys an active lifestyle in Florida, where she lives with her fiancé, Matt, and their mini-golden doodle, Sunny. For her, a perfect day is one where the sun is shining, the sky is blue, the water is calm, and she can enjoy time outdoors with friends and family.
Ben Walker, APRN, DC
Ben Walker, APRN, DC received his Doctor of Chiropractic degree in 1989 and has been a nurse practitioner since 2014.
His interest in the integrative approach to healthcare inspired him to explore and understand the many facets of optimizing personal health. When working with his patients, Ben applies his years of medical knowledge and practice to understand the physical, nutritional, and emotional aspects of a patient’s lifestyle.
Ben himself has been on bio-identical hormone replacement therapy for the past 4 years and has had the opportunity to get acquainted with the many benefits of a thorough and comprehensive approach to using HRT as a means to restore a patient’s overall well-being. His in-depth and personal experience with integrative healthcare allows him to truly understand the various needs of his patients.
What Patients are Saying
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“Mike is the best!”
Visited on September 12, 2025
Mike is a great provider. He is very knowledgeable, patient, and thorough. He allows me to be involved in my care and treatment plan. I highly recommend Defy and Mike to everyone I know.
–STACEY JACKSON
“Lauren was great!”
Visited on September 19, 2025
Lauren listened to everything. She was very thorough!
–MINDY CARSWELL
“Description”
Visited on September 20, 2025
I learned what I was getting myself into.
–BYRON BULLOUGH
“My struggle is many women’s and I feel better about the future.”
Visited on September 19, 2025
I just feel a little more confident in my outcome and am so hopeful of my bettering soon. Everything was covered well and I suddenly feel hopeful. That’s so important when one is struggling. I feel like she heard me and said let’s go. That’s what those of us deep in meno need. Very appreciative of the knowledge and the plan set forth. Super excellent outcome.
–Bettie B
“Defy Medical provides knowledgeable…”
Visited on September 23, 2025
Defy Medical provides knowledgeable staff and reliable service, making the treatment process straightforward and supportive
–John Carter
“Melissa listened to my all my concerns…”
Visited on September 15, 2025
Melissa listened to my all my concerns and answered all my questions.
–CHRIS OCHOA
“Lauren Page is an exceptional…”
Visited on September 17, 2025
Lauren Page is an exceptional clinician. She gave my appointment plenty of time for discussion and questions and I highly recommend her and will request to see her for my own future appointments.
–ANGELA STOCKMAN
“Marisa is amazing!”
Visited on September 17, 2025
Marisa is amazing! She is intelligent and compassionate. She truly cares about her patients. I am so thankful for her!
–JENNIFER HERLEVI
“Extremely knowledgeable and…”
Visited on October 12, 2025
Extremely knowledgeable and professional. They answered all of my questions thoroughly and made me feel very comfortable—a priority that was deeply appreciated. A highly recommended experience.
–Harriet Avitia
“My experience with Defy Medical was…”
Visited on December 2, 2025
My experience with Defy Medical was very positive and professional. The staff was knowledgeable , took time to answer my questions, and made the whole process feel easy and comfortable. I felt well cared for from start to finish.
–Gabriel Shaw