Zelenko Labs Z-STACK ZINC, QUERCETIN DIHYDRATE, VITAMIN C & D. a Dr. Zelenko Kosher Vitamin
Zelenko Labs Z-STACK ZINC, QUERCETIN DIHYDRATE, VITAMIN C & D. a Dr. Zelenko Kosher Vitamin
Z-stack is an Immune System Formula
Developed by Dr. Vladimir (Zev) Zelenko OBM
to Prevent & Treat Viruses and Maximize Your Immune Function
Contains Zinc sulfate, Quercetin dihydrate, Vitamin C, Vitamin D.
Zinc Immune Support
Zinc is one of the active ingredients in Z-Stack.
It is one of the most well-known immune support ingredients to date.
Quercetin Plant-based Nutrients
Quercetin is a leading active ingredient in Z-Stack.
Being a plant flavonol, quercetin is a natural source of vital nutrients.
Vitamin C
Vitamin C is an essential nutrient involved in the repair of tissue and the enzymatic production of certain neurotransmitters
Vitamin D
Vitamin D is a group of fat-soluble secosteroids responsible for increasing intestinal absorption of calcium, magnesium, and phosphate, and many other biological effects Immune Function
Suggested use
Take 2 Capsules Per Day.
to inhibit the replication of RNA viruses
Other information
- Brand / Zelenko Labs
- Product / Z-Stack
- Formulated By / Dr. Zelenko
- Function / Maximize Immune Function
- Suggested Use / 2 Capsules per Day
- Bottle Size / 60 Capsules
- Ingredients / Zinc, Quercetin, Vitamin C, Vitamin D
- Certifications / Kosher, GMP, FDA
- Manufactured In / United States
Frequently Asked Questions
Who is Dr. Vladimir Zelenko?
Dr. Vladimir Zev Zelenko M.D. is a board-certified family physician. Dr. Zelenko has practiced family medicine in New York’s HudsonValley. He has been described by his patients as a family member to thousands of families and is a medical adviser to the volunteer ambulance corps in Kiryas Joel, New York. Dr. Zelenko is known for developing his now-famous “Zelenko Protocol,” which has saved countless lives worldwide.
What is Quercitin & How Does It Support the Immune System?
Quercetin is known for its antioxidant activity in radical-scavenging and anti-allergic properties characterized by stimulation of the immune system, antiviral activity, and more.
Quercetin has a number of great health-promoting benefits. Some of the top Quercetin benefits include the ability to help your body reduce inflammation and to improve your immune system’s health.
Research has shown that Quercetin has powerful anti-inflammatory and antioxidant effects.
It was recently published in the journal of Nutrients in 2016, that Quercetin is a safe and effective supplement both for reducing inflammation and for improving immune system functions.
What is Zinc & How Does It Support the Immune System?
Zinc is found in cells throughout the body. It helps the immune system fight off invading bacteria and viruses. Zinc is essential for our immune system because it affects how our cells respond to infections. It can also help keep inflammation under control.
Zinc increases the activation of cells in the body that are responsible for fighting infection. It also activates enzymes that break down proteins in viruses and bacteria to reduce the chances of spreading.
Due to its direct antiviral properties, it can be assumed that zinc administration is beneficial for most of the population, especially those with suboptimal zinc status.
What is Vitamin D & How Does It Support the Immune System?
Vitamin D is effective for COVI... Random effects meta-analysis of the 11 treatment studies to date shows an estimated reduction of 75% in the effect measured. Sufficiency studies show a strong association between vitamin D sufficiency and outcomes. Meta-analysis of the 24 sufficiency studies shows an estimated reduction of 58%
What is Vitamin C & How Does It Support the Immune System?
Vitamin C, or ascorbic acid, is a water-soluble vitamin well known for its role in supporting a healthy immune system. Vitamin C contributes to immune defense by supporting various cellular functions of both the innate and adaptive immune systems. Because our bodies cannot make vitamin C, it must come from the foods you eat every day.
Research shows vitamin C is essential for the growth and repair of tissue all over the body. Vitamin C helps heal wounds and repair and maintain healthy bones, teeth, skin and cartilage — a type of firm tissue that covers the bones. Taking vitamin C supplements appears to be able to both prevent and treat respiratory and systemic infections.
Free shipping to the continental USA
| Brand: | Zelenko Labs |
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| Isin: | I1TACSCB9O2Z |
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Z-stack is an Immune System Formula
Developed by Dr. Vladimir (Zev) Zelenko OBM
to Prevent & Treat Viruses and Maximize Your Immune Function

Contains Zinc sulfate, Quercetin dihydrate, Vitamin C, Vitamin D.
Zinc Immune Support
Zinc is one of the active ingredients in Z-Stack.
It is one of the most well-known immune support ingredients to date.
Quercetin Plant-based Nutrients
Quercetin is a leading active ingredient in Z-Stack.
Being a plant flavonol, quercetin is a natural source of vital nutrients.
Vitamin C
Vitamin C is an essential nutrient involved in the repair of tissue and the enzymatic production of certain neurotransmitters
Vitamin D
Vitamin D is a group of fat-soluble secosteroids responsible for increasing intestinal absorption of calcium, magnesium, and phosphate, and many other biological effects Immune Function

Suggested use
Take 2 Capsules Per Day.
to inhibit the replication of RNA viruses
Other information
- Brand / Zelenko Labs
- Product / Z-Stack
- Formulated By / Dr. Zelenko
- Function / Maximize Immune Function
- Suggested Use / 2 Capsules per Day
- Bottle Size / 60 Capsules
- Ingredients / Zinc, Quercetin, Vitamin C, Vitamin D
- Certifications / Kosher, GMP, FDA
- Manufactured In / United States

Frequently Asked Questions
Who is Dr. Vladimir Zelenko?
Dr. Vladimir Zev Zelenko M.D. is a board-certified family physician. Dr. Zelenko has practiced family medicine in New York’s HudsonValley. He has been described by his patients as a family member to thousands of families and is a medical adviser to the volunteer ambulance corps in Kiryas Joel, New York. Dr. Zelenko is known for developing his now-famous “Zelenko Protocol,” which has saved countless lives worldwide.
What is Quercitin & How Does It Support the Immune System?
Quercetin is known for its antioxidant activity in radical-scavenging and anti-allergic properties characterized by stimulation of the immune system, antiviral activity, and more.
Quercetin has a number of great health-promoting benefits. Some of the top Quercetin benefits include the ability to help your body reduce inflammation and to improve your immune system’s health.
Research has shown that Quercetin has powerful anti-inflammatory and antioxidant effects.
It was recently published in the journal of Nutrients in 2016, that Quercetin is a safe and effective supplement both for reducing inflammation and for improving immune system functions.
What is Zinc & How Does It Support the Immune System?
Zinc is found in cells throughout the body. It helps the immune system fight off invading bacteria and viruses. Zinc is essential for our immune system because it affects how our cells respond to infections. It can also help keep inflammation under control.
Zinc increases the activation of cells in the body that are responsible for fighting infection. It also activates enzymes that break down proteins in viruses and bacteria to reduce the chances of spreading.
Due to its direct antiviral properties, it can be assumed that zinc administration is beneficial for most of the population, especially those with suboptimal zinc status.
What is Vitamin D & How Does It Support the Immune System?
Vitamin D is effective for COVI... Random effects meta-analysis of the 11 treatment studies to date shows an estimated reduction of 75% in the effect measured. Sufficiency studies show a strong association between vitamin D sufficiency and outcomes. Meta-analysis of the 24 sufficiency studies shows an estimated reduction of 58%
What is Vitamin C & How Does It Support the Immune System?
Vitamin C, or ascorbic acid, is a water-soluble vitamin well known for its role in supporting a healthy immune system. Vitamin C contributes to immune defense by supporting various cellular functions of both the innate and adaptive immune systems. Because our bodies cannot make vitamin C, it must come from the foods you eat every day.
Research shows vitamin C is essential for the growth and repair of tissue all over the body. Vitamin C helps heal wounds and repair and maintain healthy bones, teeth, skin and cartilage — a type of firm tissue that covers the bones. Taking vitamin C supplements appears to be able to both prevent and treat respiratory and systemic infections.
Free shipping to the continental USA





- Expiration Date: 11/2026
- When to Take: With Food
- Active Ingredients: Quercetin, Vitamin C (Ascorbic Acid), Vitamin D, Vitamin D3 (Cholecalciferol), Zinc Sulfate
- Department: All, Child, Adult
- Features: Kosher, Alcohol Free, Animal Cruelty-Free
- Dosage: 2 capsules
- Country/Region of Manufacture: United States
- UPC: 0684417851457
- Main Purpose: Cold, Flu & Cough Support
- Brand: Zelenko Labs
- Type: Vitamin
- Formulation: Capsule
- Ingredients: Vitamin C (Ascorbic Acid), Vitamin D, Quercetin, Zinc
- Number of Pills: 60
- MPN: NOT SPECIFIED
- Flavor: Neutral
Processing Time
- We process and ship orders Monday through Friday, excluding holidays.
- Most orders are processed within 1–3 business days, depending on product availability.
- Processing time does not include delivery time, which varies based on your location and the product’s shipping origin.
Shipping Coverage
We currently ship to addresses within the United States only.
Products may ship from:
- Our U.S. warehouses, or
- Our international fulfillment centers (including Korea, Japan, China, Australia, Mexico, Canada, the United Kingdom, and the EU).
Each product page clearly displays the “Ships From” location before checkout.
Shipping Methods & Estimated Delivery
| Shipping Method | Estimated Delivery | Cost |
|---|---|---|
| Free Shipping (US) | 5–10 business days | Free, available on eligible items |
| Standard Shipping (US to US by Item) | 5–10 business days | $6.50 for the first item, $2.00 each additional |
| Standard Shipping (From US Warehouse by Weight) | 3–7 business days | Starts at $6.50, increasing by $2 for every additional 4 oz (0.25 lb) up to 1 lb, then by $4 for each additional pound beyond 1 lb. |
| Extended Delivery (Ships from Overseas Warehouse) | 10–15 business days | $14.50 for the first item, $2.00 each additional |
Shipping costs vary by product weight, quantity and origin. Exact rates and delivery estimates are displayed on each product page and confirmed during checkout.
Free Shipping
We offer free standard shipping on select products or during promotional periods. Availability of free shipping will be displayed on the product page and at checkout.
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We primarily use USPS and UPS for U.S. deliveries. Items shipped from international warehouses may be handled by partner carriers depending on the country of origin.
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You can track your shipment anytime using the Track Your Order page on our website.
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If you need to modify or cancel an order, please contact our customer support team as soon as possible. Orders can only be canceled before they ship. Once shipped, cancellations are not possible, but you may request a return after the item is delivered.
Contact: support@ibspot.com
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Order Cancellation Policy
Customers may request to cancel an order before it has been shipped.
Once the package has been shipped, cancellations are no longer possible; however, you may still request a return after receiving your order.
How to Request a Cancellation
You can contact us through:
- Email: support@ibspot.com
- Contact Form: Submit a request through our Contact Us page
Please submit your cancellation request as soon as possible after placing the order to allow us to process it before shipment.
Return Policy
We accept returns for most items within 30 days of delivery for a full refund.
To be eligible for a return:
- The item must be unused, in the same condition as received, and in its original packaging.
- A tracking number must be provided to confirm the return shipment.
Non-Returnable Items
Certain products cannot be returned, including:
- Perishable goods (for example, food, flowers, newspapers, magazines)
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Partial Refunds (If Applicable)
Partial refunds may be granted in specific situations, such as:
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Shipping Cost for Returns
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If a return is sent back without prior contact or without our provided label, we cannot be held responsible for return shipping costs.
For items valued over $75, we recommend using a trackable shipping service or purchasing shipping insurance.
We cannot guarantee that we will receive your returned item if shipped independently.
Refund Processing
Once your return is received and inspected:
- In-store returns are refunded to the original form of payment or issued as a gift card.
- Mail-in returns using our prepaid label are refunded to the original payment method within 3–5 business days after we receive your return.
Please allow:
- 5–7 business days for the return to reach our Returns Center.
- An additional 3–10 business days for your bank to post the refund to your account.
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Exchanges
We do not process direct exchanges.
The fastest way to get what you need is to return the original item and place a new order once your return is accepted.
Return Address
IBSPOT Return Center
15 Sawmill Ln
Dover Plains, NY 12522
United States
Customer Support
Our support team is available 24/7 to assist with cancellations, returns, or general inquiries.
Email: support@ibspot.com
Contact Form: Contact Us page
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