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Meet Our Care Team

A male doctor in a lab coat holds a stethoscope and crosses his arms over his chest.

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.

A photo of Defy Medical's medical director and lead practicing physician Dr. Justin Saya.

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.

A photo of Defy Medical's Dr. Calkins.
A photo of Defy Medical's Beth Bray, APRN.

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.

Jill Dillenburg, RN

Jill Dillenburg, RN, has practiced as a board-certified registered nurse for the past 10 years.

She has specialized in the areas of hormone replacement therapy and cardiology. Since 2014, Jill has practiced with Defy as both a provider and the medical manager to Defy’s team of medical assistants.

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.

A photo of Defy Medical's Jill Dillenburg, RN.
A photo of Defy Medical's Mellisa Faulk, PA-C.

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.

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.

A photo of Defy Medical's Mike Linkous, PA-C.
A photo of Defy Medical's Janel Mayer, MSN, APRN.

Janel Mayer, MSN, APRN, FNP-C

Janel Mayer, MSN, APRN, FNP-C obtained her bachelor’s degree in Nursing from Penn College in 2004 and gained valuable experience caring for critically ill patients at some of the finest facilities on the east coast. In 2014, she completed her graduate degree as a family nurse practitioner at Chamberlain College of Nursing. She went on to obtain certifications in the fields of nutrition, weight loss, hormone balancing, and aesthetics through Empire Medical.

As a nurse practitioner with more than 15 years healthcare experience, Janel’s passion for improving overall health and vitality through diet/lifestyle modification and hormone balancing is evident in the meticulous care she provides to her patients. She loves helping patients look and feel their best through comprehensive treatment plans based on their individual needs and desires.

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.

A photo of Defy Medical's Ben Walker, APRN, DC.

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

Showing our most recent 4- & 5-star reviews.

TrustScore 5 out of 5 See All 1204 Reviews on Trustpilot

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“Dr. Saya cool, calm, & competent”

Visited on May 30, 2023

Dr. Saya started off with confirming he read my medical history and then asked about any recent changes and what I already knew. It helped get us focused on treatment versus wasting time. Listened to my concerns. Specifically ended with allowing me to ask questions versus just saying bye. Seemed very knowledgeable and confident in his treatment plans.


5 out of 5


Visited on May 30, 2023

just let me give 5 stars damnit


5 out of 5

“Marissa was so knowledgeable”

Visited on May 31, 2023

Marissa was so knowledgeable, really exceeded my expectations


5 out of 5

“Ben was great!”

Visited on May 31, 2023

Ben was very professional, knowledgeable, and broke the treatment down in easy-to-understand steps.


5 out of 5

“Very informative and helpfull”

Visited on June 1, 2023

Very informative and helpfull. I had a few questions and all were answered thank you


5 out of 5

“Mike is Very Well Informed about Medical Issues”

Visited on May 30, 2023

Mike is nice, thoughtful and great at explaining. He also has a sense of humor which I appreciate. In other words, he laughs at my jokes.
He is very knowledgeable.


5 out of 5

“Very thorough and you could tell he…”

Visited on June 1, 2023

Very thorough and you could tell he cares and is invested in a long term relationship to ensure I get to the level of health I want to be at.

–Todd Waterman

5 out of 5

“Went well, then crickets”

Visited on May 30, 2023

My consultation went well, but since then it’s been impossible to get in touch with anyone. I called their customer line twice. They offer callbacks in order to keep your place in line and not have to sit on hold. I attempted that twice and never received any call back. Frustrating.


4 out of 5

“I enjoyed discussing my issues with a…”

Visited on May 29, 2023

I enjoyed discussing my issues with a female doc. I typically work with girl doctors as they seem more relatable and this was no exception.


5 out of 5

“She listened to my concerns and is…”

Visited on May 28, 2023

She listened to my concerns and is willing to let me try some new options. She went over my labs and pointed out if there were any issues

–Philip Coe

4 out of 5