About Us

Your Beautiful Skin Begins with our Exceptional Care

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Our Specialists

Our Medical Director

Dr. Leo Shum

Medical Director & Specialist

Dr. Leo Shum, MD, is a dedicated physician in Critical Care Medicine at
Adventist Health Glendale, known for his exceptional skill, compassion,
and genuine care for every patient he treats.

He combines medical expertise with a warm, thoughtful approach, helping people feel supported and confident in their care—whether he’s saving lives in
critical situations or helping patients maintain healthy, glowing skin.

Passionate about the aesthetic industry, Dr. Shum has a keen interest in
enhancing natural beauty and promoting confidence through advanced care.

Outside of his demanding work, he enjoys traveling the world with his
beautiful wife, Tina, and spending peaceful moments fishing whenever he
gets the chance.

With a heart for healing and an eye for beauty, Dr. Shum is committed to
helping every patient look and feel their absolute best.

Meet Our Professionals

Mary Grace Mendoza

Medspa Chief Operations Officer / Nurse

Since becoming a nurse in 2004, caring for people and helping them feel their very best has always been a passion of mine.

I began my career as a Nurse Manager at Southern California Presbyterian Homes, where I built a strong foundation in leadership, clinical excellence, and compassionate patient care.

As my career evolved, I discovered my true passion in dermatology and aesthetics. For the past 21 years, I have had the honor of working alongside Dr. Fortunata Mendoza—first in her original practice and later helping her open and grow Gateway MedSpa in Eastvale. I now continue my journey in aesthetics working along side Dr. Leo Shum, where I am excited to keep growing and serving patients with the highest level of care.

I am truly passionate about all things skin and find great joy in helping clients reach their skincare goals with personalized treatments, honest recommendations, and thoughtful care. My desire is for every client to feel comfortable, cared for, and confident every step of the way.

I am deeply passionate about all things skin and am committed to continuously learning and advancing my skills through ongoing training and education.

Outside of work, I enjoy, dancing, tidying up (yes, I love a good clean at home and the MedSpa,) and discovering new coffee and pastry gems.

Above all, I strive to create a warm, welcoming experience where every client feels seen, valued, loved and empowered. Helping others look and feel their best isn't just my career - it's truly my passion.

Lexee Cain

Esthetician
Skin Transformation Specialist

With over 13 years in the aesthetics industry, I began my career as an esthetician working as an independent contractor before transitioning into aesthetic medicine around 2016.

Throughout my career, I've developed an extensive background in aesthetic sales and advanced skincare treatments. I hold multiple aesthetic certifications, including CoolSculpting, Bioelements, and HydraFacial.

My absolute favorite skincare line is ZO Skin Health by Zein Obagi MD, followed closely by SkinCeuticals.

One of my favorite treatments to perform is a Dermaplane with a customized chemical peel add-on, a combination with an enhanced exfoliation providing a healthy natural glow.

Outside of work, I enjoy going for drives, exploring new places, and trying different foods-always looking for my next favorite spot or hidden gem.

Miranda Eichmann

Aesthetic Operations Manager/
Medical Assistant

I’ve been the Front Desk Coordinator at Gateway MedSpa for nearly four years and truly enjoy being part of each patient’s journey from the moment they walk through our doors.

My passion for skincare is personal—I’ve experienced my own struggles with acne and postpartum melasma, which showed me firsthand that healthy, radiant skin is achievable with the right care and support.

One of the most rewarding parts of my role is watching our patients gain confidence as they progress through their treatments. I recently became a Medical Assistant and look forward to continuing to grow and support our patients alongside the incredible team at Gateway.

When not at the medspa, I enjoy spending time with my husband and daughter, especially visiting Disneyland, going to concerts, and traveling together.

Lidia Hernandez

Aesthetic Registered Nurse

My passion for aesthetics began with a desire to blend beauty and medicine in a way that helps clients feel radiant and confident. I combine medical expertise with elevated beauty treatments to deliver safe, customized, and natural-looking results. My mission is to help you feel empowered in your own skin.

What I love most about this career is watching my patients fall back in love with themselves. There’s nothing more rewarding than helping someone feel beautiful, refreshed, and truly confident.

At Gateway, I’m proud to be part of an aesthetic team that prioritizes safety, education, and personalized treatments while helping clients achieve their aesthetic goals.

Outside of work, I am a busy student pursuing my Master's in Family Nurse Practitioner degree while sharing a beautiful life with my husband and children.

Brianna Ponce

Aesthetic Registered Nurse

My passion for aesthetics began long before I ever picked up a syringe — it started with a deep love for science, beauty, and the way the right treatment can completely transform how someone feels about themselves.

As a Registered Nurse with a focus in aesthetic medicine, I specialize in neurotoxin and dermal filler injections, laser treatments, and peptide wellness therapies. I believe that great results come from understanding both the art and the anatomy behind every treatment — and I take pride in creating natural, balanced outcomes that enhance your unique features rather than change them.

What I love most about this career is the relationship built with every client. From your first consultation to your follow-up, my goal is to make sure you feel heard, educated, and genuinely cared for. I want every person who sits in my chair to leave not only looking refreshed, but feeling completely confident in the process.

At Gateway MedSpa, I'm proud to be part of a team that shares my commitment to excellence, safety, and genuinely exceptional care.

Outside of work, I feed my curiosity by traveling as often as I can — there's nothing like seeing a new corner of the world to remind you how much there still is to learn.

Our Trusted Partners

Our partner companies share our commitment to innovation, excellence, and patient well-being, allowing us to offer an even broader range of services and resources. Together, we help you achieve lasting beauty.

Empowering Wellness, Enhancing Beauty, Transforming Lives Every Day

Our Mission

At Gateway MedSpa, our mission is to help every patient look and feel their very best through innovation, excellence, and a deep commitment to patient well-being.

We believe aesthetic care should be both results-driven and deeply personal. That’s why we combine advanced technology with personalized treatment plans designed specifically for each patient’s goals, lifestyle, and skin needs.

Through innovation, we bring the latest proven treatments and technologies to our patients so they can experience safe, effective, and modern solutions for skin rejuvenation, body contouring, and overall wellness.

Our commitment to excellence means delivering the highest standard of care in everything we do—from consultation to treatment to follow-up. Every patient deserves exceptional service, expert guidance, and results they can feel confident about.

Most importantly, we prioritize patient well-being. We take time to listen, educate, and create a comfortable environment where patients feel supported, respected, and cared for throughout their entire journey.

Our goal is simple: to help you relax, rejuvenate, and radiate confidence.

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Our Vision

Our vision at Gateway MedSpa is to be a trusted destination where patients experience the perfect blend of advanced aesthetics, personalized care, and genuine compassion.

Guided by innovation, we continually invest in leading technologies and treatment methods that deliver natural-looking, beautiful results.

Driven by excellence, we strive to create an exceptional experience for every patient—one where professionalism, skill, and attention to detail are felt in every interaction.

Rooted in patient well-being, we aim to build lasting relationships with our patients by helping them feel confident, empowered, and cared for at every stage of their beauty and wellness journey.

At Gateway MedSpa, we envision a place where patients don’t just come for treatments—they come to feel refreshed, renewed, and truly valued.