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 Five Star Index, with an average rating of 4.1 out of 5.
Also known as
zstacklife.com
Website
zstacklife.com
Category
Personal Care
Location
Boca Raton
Listed on Five Star Index
2026
About these reviews
Replies
The company replied to 57% of reviews.
Latest
Most recent review: October 2026.
Edits
Reviews are shown as their authors wrote them. The company can reply, but cannot edit them.
Score
This company cannot pay to remove reviews or change its score.
I started taking Z-STACK during Covid and since then I have had a light case of Covid and last year a bout with bacterial pneumonia. But overall I am quite healthy and strong and enjoy every day looking forward to my 79th birthday very soon. I credit my good health to the good genes passed to me by family and my commitment to taking Z-STACK everyday with breakfast.
MM
Mark M.
I had missed the 20% discount time by…
I had missed the 20% discount time by about 1/2 hr. because I'm on Central time and I didn't realize the sale was on Eastern Time. Yes, I had procrastinated. Anyway I had the products at checkout and then left when the discount wouldn't go through. Z-STACK emailed me about it. I emailed them back to tell why I abandoned the purchase. They said tell us the products you want & we will honor the discount. And so I did. Thank you Z-STACK. I've been taking their products for a few yrs. and have not been sick. Even when I would feel something coming on I would double-up on Z-STACK and it would go away.
SU
Sue
This product is outstanding
This product is outstanding! If you are feeling like your even catching a cold or don't feel well z stack will truly help. A wonderful combination of vitamins. Highly recommend! This was very helpful for covid at that point in time so now I always keep the supplement on hand.
BO
Bo
It's a just a great product
It's a just a great product. I've turned other on to Z-Stack and they love it. But they use Z- Stack differently. They start taking it when they start to feel something coming on. And most tell me whatever they had doesn't last long. I on the other had take 1 capsule every morning. I call it my body preventive maintenance. Like what you do with your car. And I can say, I have never been more healthy.
Response from Z-STACKAug 27, 2026
Thank you Bo!
JA
Janice
I buy this for my son who was getting…
I buy this for my son who was getting sick a lot. Hasn't been sick since he started on these. GREAT PRODUCT and wonderful people to deal with.
Response from Z-STACKAug 27, 2026
Thankyou Janice!
BG
Bill G.
Absolutely Excellent !!
Although the last date of my Uplifting experience with the Z-Stack team, and in this case Shannon, and their products was today, it's simply a repeat of many I've had with their team since Z-Stack's inception during COVID times approximately 6 years ago. Today, I made a personal error in ordering another regular 6 month (6 bottle) supply of Z-Stack after placing the same order yesterday but missing the fact that they'd already promptly notified me confirming the order yesterday. I contacted their support staff and within a few minutes received a response that today's order in question had already just been cancelled and charge card refunded. Over the approx. 6 years I've made about a dozen 6 bottle orders and although ordering is a breeze and shipping is seamless, I've found ways on a few occasions to make a simple technical ordering error but each time they've been met swiftly and with personal care. If everyone strived to serve others as the Z-STACK family does, who proudly carry the Legacy of Dr. "Zev" Zelenko, this world would be a far better place. Dr. Zev proved so much of what he stood for when he initially offered Z-Stack during dangerous times specifically when speaking out for better means of good health & immunity seriously risked losing his reputation and so much more. May he Rest in Peace. On the selfish side of things, I'm now a 69 year old male, average build & weight, moderate to low exercise, random but fair eating habits & non smoker or alcohol drinker. I've continuously been in contact with the public, shaken many hands & hugged or kissed lots of people & grandkids. Having said all of that, I chose not to touch any Pharmaceuticals or mask up over the past 6 years and am a chronic anti-vaxxer. I haven't had as much as a runny nose, cough, sniffle, sore throat, ear ache or anything else you can think of, over the past 6 years with Z-Stack. Seriously. I'll always be an Ambassador for the Z-Stack Family and Products.
Response from Z-STACKAug 10, 2026
Thank you Bill :) That means a lot to me
JK
Joan K.
Since taking Zstack I have stayed very…
Since taking Zstack I have stayed very healthy! Great product. I do add vitamin K3 to it. The response to inquiries is quick and respectful. I recommend.
Response from Z-STACKAug 10, 2026
Thank you Joan!
BH
Brandt H.
your products and your people are great
your products and your people are wonderful. the website however is often hard for me to navigate without accidentally buying something twice or signing up for a subscription. nevertheless it will not stop me from buying your products because they are great and so are your employees thank you bhb