Great
95 reviews
Z-STACKHonesty, pricing, process and quality scores appear once 5 customers have rated them.
Zelenko Labs, built on the legacy of Dr. Vladimir Zelenko, creates products with purpose, precision, and integrity. Every formulation is made with high-quality ingredients and consistent standards, so you can feel confident in what you’re using. Thoughtful, reliable, and principled — Zelenko Labs products are made for people who care about quality.Our All American customer service team is here to help Monday through Friday, 9 AM to 5 PM EST — just give us a call at 1-800-ZELENKO (1-800-935-3656) or email our team at [email protected]
Z-STACK (zstacklife.com) has 95 customer reviews on Rated Honest, with an average rating of 4.1 out of 5.
Showing 71 reviews with 5 stars · Clear filters
Rosario
Posted
I have been taking Z-Stack for several years now, and I haven’t been sick since—not even with a cold. My immune system is very well protected. I am writing from Peru, and I hope to be able to purchase this product again soon. Thank you.
Response from Z-STACK· Oct 21, 2026
Thank you Rosario!
david
Posted
When I take these supplements I don't get sick especially a cold and of course COVID. Dr Z was recognized for his research in fighting COVID and developed Z Stack that actually ALLOWS the zinc to be absorbed thereby KILLING the cold virus. These are the best you can get when it comes to upping the immune system.
Response from Z-STACK· Oct 20, 2026
Thank you David!
Tammy F. Brooklyn, N.
Posted
Zalanko Labs has excellent products and customer service. I really appreciate the wya they handle orders promptly and efficiently and get back to me immediately.
Response from Z-STACK· Oct 8, 2026
Thank you!
Sandra
Posted
My husband and I have taken Z-Stack since the beginning of covid. Neither of us ever contracted covid nor have either of us have had a cold since beginning Z-Stack.
HAPPY C.
Posted
The support team answered and resolved my query very quickly. They were caring in their words when answering and I felt valued as their customer. Thank you support.
Response from Z-STACK· Sep 28, 2026
Thank you :)
Saundra C.
Posted
I have been using Z Labs products since covid. I'm hardly ever ill. My husband and I started with Z Stack and he takes it every day. I use Z Flu gummies, Z Calm and Z Night. I highly recommend them for good health!
Dawn H.
Posted
Zstack has the best products and customer service! Prompt reply’s, and kind folks behind the messages. I’ve been using Zstack for a handful of years now and I’m so impressed by the innovation of their products and the quality ingredients! Highly recommend!!
Response from Z-STACK· Sep 22, 2026
Thank you Dawn! :)
Karla V.
Posted
I have been a customer for several years. Their customer service is always timely and I'm never disappointed in their effort to accommodate my needs. Great company!!!!
Response from Z-STACK· Sep 22, 2026
Thank you Karla :)
