Chain Reaction Fitness & Nutrition

Chain Reaction Fitness & Nutrition Contact information, map and directions, contact form, opening hours, services, ratings, photos, videos and announcements from Chain Reaction Fitness & Nutrition, Gym/Physical Fitness Center, 588 San Mateo Avenue, San Bruno, CA.

We're a personal training studio and gym born from our own experiences and those of the people we love, who faced physical and mental health challenges, injuries, and health scares over the years.

02/04/2026

Pain isn’t a normal part of aging. Run from anyone who tells you otherwise.

Our group classes focus on building strength and on addressing those pain points you’ve always just put up with.

We’ll get you moving like this again. Pain free.

We’ll get you moving like this again. Pain free.

01/30/2026

The gym is calling…

01/26/2026
01/23/2026

True story.

01/20/2026

Been thinking about joining the open gym or one of our group classes? Boy, oh boy, do we have some surprises for you!

While most gyms shut down for the holidays, we stay open for you. Seven days a week, 4am to midnight, every single day o...
11/26/2025

While most gyms shut down for the holidays, we stay open for you. Seven days a week, 4am to midnight, every single day of the year.

Join us Thursday for a free 6am Strength Pilates class. Only six openings, reservation required.

Message us today to claim your class or get your two-day free trial.

11/25/2025

At Chain Reaction, we don’t close. Not for holidays, not for long weekends. Members have access 4am to midnight, every day of the year, without exception. We’ll be open Thanksgiving, and we’re offering a two day free trial this weekend to the first ten people to snag it! DM us or comment here 👇🏼

11/14/2025

BUILD STRENGTH, CONFIDENCE, COMMUNITY AND YOUR B***Y!

B***y Bootcamp is a high-energy program designed to help you strengthen, sculpt, and lift your lower body, all while keeping you accountable and having fun along the way!

Here’s how it works:

Weekly B***y Bootcamp Class:
Meet weekly for a 60-minute circuit-style workout with Coach Jenn through a series of exercises that target those glutes. You’ll learn proper form, muscle building techniques, including progressive overload to help you see and feel those results!

Partner Up for Progress:
You’ll be paired with a workout partner and encouraged to train together 2 additional times per week — performing the same exercises learned in class to reinforce progress and stay motivated.

Accountability & Community:
Your partner workouts will be accessible for online access and tracking, so your coach and community will always be with you! We share wins, stay inspired, and track our consistency, supporting each other, swapping selfies, and celebrating progress together as we go!

FIRST CLASS IS FREE MONDAY, 11/17, SO CLICK THE LINK IN BIO AND GRAB YOUR SPOT!

11/11/2025

Comment or DM us for details!

11/04/2025

FREE Power Hour Strength Training & Pilates class with is tomorrow at 12:30pm!

Use the link in our bio to register while there’s still a spot for you!

Address

588 San Mateo Avenue
San Bruno, CA
94066

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