Meet the Team

Krystyna Tran, FNP

Clinic Director | Houston Heights

Krystyna holds a national certification with the American Academy of Nurse Practitioners as a Board-Certified Family Nurse Practitioner. She began her career in health care working as a registered nurse in dialysis. Her passion to help others, allowed her to advance in her career and continue her education. Krystyna completed her Bachelor of Science in Nursing with honors at University of Texas and then earned her Master of Science in Nursing as a Family Nurse Practitioner graduated with highest honors at Chamberlain University. She is presently pursing a Doctorate in Nursing Practice at Purdue University. She is dedicated to providing the best patient care possible through listening to her patients and empowering them to take better care of themselves. In her spare time, she loves to travel, craft, and explore great eats.

James Nguyen, APP

Clinic Director | Cypress, TX

James Nguyen is double certified as an Advanced Practice Practitioner, and as a Chiropractic Physician. He has advanced training in Neurosergery, Orthopedics and Interventional Pain Management - from Baylor College of Medicine and Houston Methodist. James also has extensive experience in Men's Health and Wellness, and is is an experienced provider in PRP Injections for Hair Vitality, Sexual Wellness and Joint Pain.

James joined the Men's T Clinic family in 2023 as our Cypress Location Clinic Director, excited to serve the local community by providing the best in Men's Total Wellness Care. James is "driven by the opporunity to enhance his patient's overall quality of life" through his experience, passion and through the comprehensive care and commitment offered to patients at Men's T Clinic.

Nathan Muehlstein, PA-C

Clinic Director | Pearland, TX

Nathan Muehlstein was born and raised in Shiner, Texas. He graduated summa cum laude from Texas State University in San Marcos with a Bachelor of Health and Wellness Promotion degree and obtained his Master of Physician Assistant Studies degree from the UTMB School of Health Professionals. Prior to becoming a Physician Assistant, he was a medic in the US Army Reserves and a paramedic. His previous experience includes primary care/internal medicine for 3 years before starting his focus on hormone replacement for the last 2 years. Nathan prides himself on making his patients feel comfortable by educating them about their conditions as well as providing the highest level of medical care. Nathan is married to his beautiful wife Danica, and they enjoy spending time with their two pugs, Amos and Otis.

Daniel Dao, FNP

Clinic Director | Pasadena, TX

Daniel Dao began his nursing career in 2014 with a Bachelor's of Science degree from Tarleton State University. Throughout his time as a bedside nurse, has accumulated had a wide variety of inpatient experience while working at the metropolitan hospitals in Austin, TX. While working in a fast-paced emergency department, he earned his Master's of Science in Nursing, specializing as a family nurse practitioner. Daniel has diverse background in primary care, as he was groomed by multiple physicians during his clinical training. He is particularly interested in men's health and is dedicated to combining hormone replacement therapy with lifestyle management in order to optimize his patients' quality of life. In his spare time, Daniel participates in powerlifting, works on his motorcycles, and hikes outdoors with his dogs, Winston and Armin.

Shaun Mullen, PA-C

Clinic Director | Spring, TX

Shaun Mullen is a graduate from Stephen F. Austin State University where he earned a Bachelor of Science degree in Biology in 1987. In the same year, he attended the University of Texas Medical Branch at Galveston. He graduated from UTMB with a Bachelor of Science in Physician Assistant studies in 1989. He has been practicing medicine since 1989. Over that time, he spent 17 years in Orthopaedic Surgery. The last 7 years have been dedicated to hormone replacement, predominately in men. He truly believes that hormone replacement and wellness is the key to longevity. He always strives for the best outcomes for his patients and looks for ways to improve future care. When he is not working, he enjoys most outdoor activities and is an avid sports fan. He also enjoys spending time with his wife Jan, sons Ryan and Kyle, and two dogs Clifford and Clementine.