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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.
Kristian Adair, APRN, FNP-C smiles in her white lab coat at the Defy Medical Tampa clinic.

Kristian Adair, APRN, FNP-C

Kristian Adair, 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 makes a positive impact on 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.

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.

A photo of Defy Medical's Beth Bray, APRN.
A photo of Defy Medical's Jill Dillenburg, RN.

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.

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.

A photo of Defy Medical's Mellisa Faulk, PA-C.
A photo of Defy Medical's Mike Linkous, PA-C.

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.

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.

A photo of Defy Medical's Janel Mayer, MSN, APRN.

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.

Mariah Savala, PA-C, is a dedicated Physician Assistant specializing in the field of men's health.
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 1687 Reviews on Trustpilot

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“Excellent medical staff focused on…”

Visited on December 4, 2023

Excellent medical staff focused on men’s care! I can’t say enough good things about Dr. Justin Saya and team. My overall health, body composition, and appearance have dramatically improved. While there was a full year of hard work coupled with important dietary changes, the results are in–increased lean muscle mass, improved bone density, VO2 max, and significantly reduced bodyfat.

–Win A.

5 out of 5

“Good info and through explanation.”

Visited on December 4, 2023

Good info and through explanation.


4 out of 5


Visited on November 29, 2023

Melissa had my labs in front of her, she reviewed them with me, asked me how I have been feeling, and gave me helpful recommendations based on all of the answers. I am very comfortable talking to her. Thank you


5 out of 5

“So easy to work with and very helpful”

Visited on December 4, 2023

So easy to work with and very helpful. I know that they have my best interest and I appreciate that very much!


5 out of 5

“Very thorough”

Visited on December 4, 2023

Very thorough, listened and cared about my concerns, spent plenty of time giving detailed breakdowns of each step and I absolutely loved that! Amazing!


5 out of 5

“She was very professional like always.”

Visited on November 27, 2023

She was very professional like always.
Met all of my needs.


5 out of 5

“You are in good hands with Dr Saya”

Visited on November 29, 2023

Dr Saya is always thorough, patient, kind and has put my life on a much better path. It takes a while to get dialed in but with patience and consistency I feel great! Dr. Saya knows what to do. Much gratitude!

–John F

5 out of 5

“Mike is always helpful and kind”

Visited on November 27, 2023

Mike is always helpful and kind. He listens and wants to help. Thank you Mike for all you do.


5 out of 5

“My contact at Defy Medical was Ben”

Visited on November 28, 2023

My contact at Defy Medical was Ben. It was my second time talking with him and as always it was very pleasurable, he actually cares how you are doing and feeling, he answered all my question that I had. Ben is also very personable and knowledge, I would highly recommend Defy Medical💪…..ask for Ben!


5 out of 5

“Good experience”

Visited on November 27, 2023

Good experience


5 out of 5