Got Questions? 
We've Got Answers. 

Zesterra® Frequently Asked Questions

Please take a look at the sections below to find the answers you’re looking for. If you can’t find what you’re looking for or have additional questions, please don’t hesitate to contact us. We’re always here to help!

Last updated: April 2025
Title

What is Zesterra®?

Zesterra® is an all-natural supplement formulated for horses of all types. It’s especially beneficial for performance horses prone to ulcers or digestive issues under stress. Zesterra® helps to:

  • Reduce gastric acid in the stomach
  • Helps heal existing ulcers and stop new ones
  • Support microbial balance in the gut
  • Regulate feed and water intake
  • Enhance nutrient absorption

What are the ingredients used in Zesterra®?

Zesterra® contains a proprietary blend of natural, plant-based ingredients plus colloidal silver.
Ingredients: Colloidal silver, water, corn oil, guar gum, orange extract, onion extract, soybean oil, glycerin, vegetable-based fatty acids, and natural apple flavoring.

How much Zesterra® should I order?

Use our Zesterra® Calculators to determine how much product you’ll need for the 28-day ulcer protocol and beyond. For general support or occasional use, refer to our Dosing Guidelines.

How should I store Zesterra®?

Store in a cool, dry place, away from direct sunlight. No refrigeration is needed.

What is the shelf life of Zesterra®?

Zesterra® has a shelf life of 5 years from the date of manufacture.

My Zesterra® has darkened over time. Is it still good?

Yes! Natural apple flavoring can oxidize and darken, just like a sliced apple—but it doesn't affect the product’s safety or efficacy.

How can I buy Zesterra® liquid and Equine Special 30-Day Supply?

You can order directly from our online store, through authorized dealers, or at select events like the NFR or Equine Affaire.

Where can I buy Zesterra® lick tubs and feed?

Lick tubs and feeds are available through our dealer network across the U.S. Use the Locate a Dealer tool to find one near you.

Is Zesterra® safe for foals, pregnant mares, and senior horses? 

Yes! Zesterra® is 100% natural and safe for horses of all ages and life stages — including foals, senior horses, and pregnant or lactating mares.

 

In fact, we recommend giving foals a dose of Zesterra® within the first 24 hours of life. It helps prime the digestive system to absorb the full benefits of colostrum, supports early nursing success, and encourages the development of a healthy gut microbiome.

 

For seniors and pregnant mares, Zesterra® plays an important role in digestion and nutrient absorption. By neutralizing excess gastric acid and supporting beneficial gut microbes, it helps older horses and broodmares get the most out of every bite — especially important when chewing or intake is limited.

Can I use Zesterra® alongside medications or other supplements?

Yes! Zesterra® is easy to integrate into most feeding and care programs. It’s 100% natural and non-medicated, which means it won’t interfere with medications, dewormers, or other common supplements.

 

In fact, many horse owners use Zesterra® to support appetite, hydration, and digestion during times when medications may be hard on the stomach or stressful for the horse. It can be a valuable part of a well-rounded wellness or treatment plan.

Can I use Zesterra® daily or only during times of stress?

Zesterra® is safe and effective for both daily use and situational support. Many horse owners use it every day to maintain a balanced stomach pH, support digestion, and promote consistent feed and water intake — especially in performance horses, seniors, and hard keepers.

 

It’s also a go-to supplement for stressful events like hauling, changes in routine, weather shifts, or breeding season. Whether used short-term or as part of a daily program, Zesterra® helps keep your horse’s digestive system and stress response in check.

What does Zesterra® taste like? Will my horse eat it?

Most horses love the taste of Zesterra® — in fact, many will lick it straight from the syringe or bucket! It has a naturally sweet apple flavor that makes it highly palatable, even for picky eaters or horses under stress.

 

Zesterra® is also a favorite among horse owners who travel frequently. Adding it to water can help “mask” unfamiliar tastes and encourage horses to drink when they’re away from home — reducing the risk of dehydration during shows, hauling, or clinic stays.

Where is Zesterra® made?

Zesterra® is proudly made in our dedicated manufacturing facility in Coleman, Oklahoma. We use high-quality, naturally derived ingredients and maintain strict production standards to ensure consistency, safety, and effectiveness in every batch.

 

Our products are crafted with care to support horses of all ages and activity levels — from everyday companions to high-performance athletes.

Find Pro Earth Animal Health Dealers Near You in the USA

With more than 1,000 authorized dealers across the United States, Pro Earth Animal Health products are always within reach. Use our dealer locator tool to quickly find a trusted retailer near you and experience the Pro Earth difference firsthand.

Locate a Dealer

We’ve made it easy to find a Pro Earth dealer near you. 

PHONE

1-800-254-0179

ADDRESS

PO Box 336
Aurora, SD 57002

EMAIL

orders@proearthanimalhealth.com

Pro Earth Animal Health

Every member of the Pro Earth team has a vested interest in animal health. As horse and cattle owners, we know first-hand the importance of keeping your animals healthy — whether you’re competing in the arena or counting pounds in the feedlot. This is your primary goal, and it’s ours, too. That is why we are committed to bringing you affordable, effective, all-natural products that deliver reliable, noticeable results.