★ 5

Lived, worked, and worked out In San Buno since the 90’s. This is truly the best, gym in San Bruno for people looking for good community that accepts everyone. No I’ve made more progress here in six months then other gyms

Source: Google

★ 5

I love this gym! Everything I need and never super busy.

Source: Google

★ 5

TLDR imagine a gym with none of the negative experiences of the usual commercial gyms.

Best gym in the bay! All the right equipment and attachments, clean, and spacious. Literally no crowds, but the folks that do go are super friendly. Owner is the best and takes great care of the place. She offers everything from general gym memberships to classes, as well as personalized coaching and nutrition plans. Parking lots behind the gym are free before 8am and after 6pm, and plenty of free street parking 1 block away from the main street.

Source: Google

★ 5

Chain Reaction is one of the best gyms I’ve been to in the bay. I’ve never had a bad experience here, it’s never crowded, and the environment is what really makes it. AHH and the amount of machines, attachments, free weights, and all are amazing. You won’t find all these things in your typical gym, especially when it comes to the people!
You can tell the owner is passionate and cares about creating a safe space for you to reach your goals or just have an amazing workout. I love the little community this gym is creating.

Source: Google

★ 5

I'm 13, and I decided I should get into a fitness routine. Since chain reaction was close to where I used to do karate I started looking into training 1 on 1 with a personal trainer. Pam is my personal trainer and it is so fun with her and the general vibe of the gym is awesome. There is also a membership program and seasonal programs that are much cheaper than other places with more included and more fun too! Highly recommend.

Source: Google

★ 5

Love it here! No more having to wait for machines at crowded gyms lol! Clean, spacious, and the owner is a vibeeeee!!!

Source: Google

★ 5

I recently started personal training with Pam at Chain Reaction Fitness and she's amazing! So skilled, friendly, and knowledgable. She really listens to my goals and past injuries, and so skillfully designs personalized sessions for me to meet my goals and remain injury free. I really enjoy my sessions with Pam, and Chain Reaction is filled with all kinds of super cool and fun equipment and she very patiently is teaching me how to do different exercises with the equipment. Very reasonable rates too. I HIGHLY recommend Pam for personal training, or the gym offers group classes too if that's more your thing.

Source: Google

★ 5

This is a fantastic gym! The equipment is top-notch, everything is very well-maintained, and the space is impressively clean. You can tell a lot of care goes into keeping it that way. What really makes the place stand out, though, is Pam — she’s the owner and is incredibly kind, helpful, and welcoming. Whether you’re new to the gym or just looking for a change of pace, this is definitely a spot worth checking out!

Source: Google

★ 5

Pam is amazinggg!. Needed someone to push me and hold me accountable and she was exactly what I was missing. Her location and flexibility with time was the cherry on top! She works with you and your body and listens to any concern you have. 100/10 recommend.

Source: Google

★ 5

I was in the market for a new gym as I felt I outgrew my old place. I had seen Chain Reaction before strolling around downtown SB, but it always seemed closed (jokes on me it’s actually open pretty much 24 hours 🫣).

🌟3 Quick Highlights

✅CLEAN SPACE and well kept/no need to wait in line for equipment!!!
✅ Community-centered atmosphere. Everyone I’ve met while using the space is suuuper nice! Whether you want to be in your own headspace or chat it up, the people are great.
✅Fitness (and nutrition) coaching tailored to your needs/wants at accessible rates!

BONUS: The owner is a total vibe 😎

Source: Google

★ 5

I've been going to Chain Reaction since June, and I genuinely couldn’t be more grateful for the experience. What stands out most to me is the strong sense of community. It’s not just a gym — it’s a supportive environment where everyone is focused on growth, without any of the intimidation you might feel at other places.

The space is always clean and well-maintained, which makes it that much easier to stay consistent and focused. Whether I’m lifting, stretching, or just showing up to move, I leave feeling better every time. Huge thanks to the owner for creating such a thoughtful and respectful atmosphere — it really makes a difference.

Source: Google

★ 5

Chain Reaction Fitness is the newest gem in San Bruno. My husband became a member shortly after this gym opened in November 2024. It quickly became part of his routine and he convinced me to join in January 2025.

This gym has every different machine you could want, it’s clean and you can go workout whenever it fits your schedule. Like literally... it’s open from 4am to midnight and you get a code to the door!

As busy parents of toddlers, we are not in a season where we can commit to signing up for a class ahead of time like some other gyms require because life happens. We have also both done the big name brand gyms that are overcrowded and overstimulating.. where you have 20 different TVs to watch as you wait for a machine to use… this is NOT one of those gyms and that makes Chain Reaction perfect for us. Personal training is available if you want/ need it, but not forced on you which we appreciate!

Pam and Chain Reaction fitness are the perfect addition to San Bruno because she values community! We’ve walked by this place a bunch over the last 5 years that we’ve lived in the neighborhood but within the last few months there is new ownership and energy and it’s definitely worth checking out!

We’re excited to be part of the Chain Reaction community and encourage anyone thinking about joining to set up a time with Pam to chat. She is friendly, kind, knowledgeable and genuinely looking to build a community of people supporting each other from fitness journeys to beyond!

Source: Google