Quick-Acting, Effective & Affordable Pre-Event Joint Support
Innovative, Injection-Free Delivery of Chondroitin,
Glucosamine HCl and Hyaluronic Acid.

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Discover FlexSyn™: Innovative. Fast-Acting. Affordable.
  • No needles! Easy suppository delivery provides a visible pre-event performance boost. 
  • Quick visible results! Effects begin within 12 to 18 hours.
  • Pre-event friendly! Offers discreet administration. Feed-through products simply cannot compare to the rapid, efficient uptake of suppository delivery. Expensive injectables often require several rounds of loading treatments before full effects are realized.
  • Affordable! Maintaining joints on FlexSyn™ costs as little as $90/month, saving hundreds when compared with traditional maintenance. When used regularly, FlexSyn™ may extend the time between joint injections.

FlexSyn™ Delivers All Three: Chondroitin, Glucosamine and Hyaluronic Acid.

FlexSyn™ offers a unique suppository delivery system for its ingredients, providing fast-acting highly effective equine joint support.

Each FlexSyn™ tab delivers a potent and readily bio-available supply of Chondroitin Sulfate, Glucosamine HCl and Hyaluronic Acid making it ideal for both pre-event and maintenance applications.

One tab of FlexSyn™ begins working within 12 hours with full effects evident within 24 hours. Effects are cumulative with repeated administration.

PRE-EVENT DIRECTIONS: Administer 1 tab the day before event. May repeat daily or as needed.

MAINTENANCE DIRECTIONS: Load with 1 tab every 4 days, continuing for 3 doses. Then administer 1 tab once per week or as needed to maintain effect. See insert for additional information.

ATTENTION: Equine management can be dangerous by nature.

Equine Professionals Describe FlexSyn™:

During the development process, FlexSyn™ was field tested and highly recommended by:

Steffen and Shannon Peters

Ian Millar and Millar Brooke Farm

Nick Haness

Jen Bauersachs

Shane Sweetnam

Lainie DeBoer

Shannon Dueck

Randy Wilson

David Belford and Chris Payne

Jim and Ellen Toon

Leah Patipa, DVM

Tim Ober, DVM

Christa Baldwin

Adrienne Lyle

Lauren Sammis

Sam Berry

Kelly and Rick Christy

Quentin Judge

Hunter Holloway

Jen Bliss

Jane Ehrhart

Kenny and Ashley Lakins

Bob & Anita Janssen

Bryan McNabb, DVM

About FlexSyn™

FlexSyn™ offers a simple, all-natural alternative for systemic joint support. The highly potent FlexSyn™ formula utilizes a combination of Chondroitin Sulfate, Glucosamine HCL and Hyaluronic Acid. It is administered in a carrier made of a proprietary blend of plant and fruit butters, cellulose, and combined with ingredients to facilitate rapid absorption through the digestive mucosa. Studies show that this combination of Chondroitin Sulfate, Glucosamine HCL and Hyaluronic Acid is more effective than any one of these three ingredients used separately. (Source.)

FlexSyn™ is easily administered as a suppository, in much the same manner as taking the horse’s temperature. Once inserted it dissolves in 15 to 20 minutes, and the active ingredients are quickly and efficiently distributed.

ATTENTION: Equine management can be dangerous by nature.

FlexSyn™ eliminates the impact of the horse’s highly acidic gastric process on the active ingredients. This allows the Chondroitin Sulfate, Glucosamine HCL and Hyaluronic Acid to be absorbed by the digestive mucosa intact. The return blood supply of the large colon, where absorption of the actives takes place, bypasses the liver, eliminating the normal filtering effect or “first pass” seen in oral application. Studies show that suppository uptake effectiveness is similar to IM or IV injections. (Source.) This allows the actives to be quickly absorbed and distributed unimpeded by the liver to provide maximum joint response within hours.


1. Why a suppository? Risks inherent in IM and IV injections are avoided with no loss of comparable efficacy. Suppositories have been a widely used but little discussed means in human and veterinary medicine for delivering a variety of ingredients efficiently and easily. The elimination of the undesirable destructive effects of the digestive process and the ease of absorption through the large colon have been shown in studies to allow the actives to quickly enter the bloodstream intact. In addition, the effect of the liver which sequesters and eliminates much of the Chondroitin Sulfate, Glucosamine HCL and Hyaluronic Acid when fed to the horse in current products, is bypassed by the colon's return blood supply. Risks inherent in IM and IV injections are avoided with no loss of comparable efficacy. The efficiency of suppository even compared to injection is quite favorable. These features make suppository delivery ideal for these joint supplement ingredients.

2. How quickly does it work? Within 18 to 24 hours. Anecdotal reports indicate that within 18 to 24 hours of first administration users see visible evidence of benefit of supplementation like reduction in joint effusion, improved range of motion and general improved performance. The reported speed of action and improved performance suggests it is a preferred choice for pre-event joint and comfort support.*

3. How long do the effects of FlexSyn™ last? When used pre-event, users report that they see benefits of a single tab persist for 4 to 5 days.* With regular use, the effects are ongoing.

4. Is there a loading period for FlexSyn™? No. While a single pre-event dose seems to provide noticeable benefit for 4 or 5 days, users tell us that administering a single dose 4 days apart for 2 to 3 administrations provides a maintenance baseline. Users then give 1 dose every 7 to 10 days, with added doses used as a pre-performance boost. In high performing situations, a daily dose for 4 consecutive days is also reported to provide outstanding results, with the maintenance follow up of 1 dose per week offering effective maintenance.

5. How do I store FlexSyn™? Avoid storage above 80 degrees. We recommend that FlexSyn™ be stored at room temperature, with care taken to refrigerate if there is a chance of seeing temperatures over 80 degrees.  Because a horse’s body temp is 100 degrees FlexSyn™ is designed to begin softening and dissolving at 90 degrees and become absorbable as it warms in the horse’s digestive tract. If storing in refrigeration, allow 30 minutes to acclimate to room temperature prior to insertion. Softened tabs return to form with refrigeration or sitting at room temperature.

6. My FlexSyn™ was in 90 degree temps and is a little soft to my touch. What do I do? No worries! Simply pop the FlexSyn™ packages into a refrigerator for an hour or two and it will reform. Heat will not damage the actives.

7. What are the ingredients in FlexSyn™ that make it work? Chondroitin, Glucosamine and HA.   FlexSyn™ contains high quality Chondroitin Sulfate, Glucosamine HCL and Hyaluronic Acid, described as proteoglycans and glycosaminoglycans. GAGs are large molecules found in the joint fluid. Administration of these substances is known to be anti inflammatory and benefit the joint metabolism of horses. There are all sorts of Proteoglycan and GAG formulations used orally, IM, IV and IA in joint injections, which are known to aid joint function to various degrees. These ingredients are the gold standard of natural joint health management. What makes FlexSyn™ special is its unique delivery and enhanced absorption technology which allows safe, efficient administration of a large volume of ingredient. (See Question 1. Why a suppository?)

8. Can I give 2 FlexSyn™ tabs at a time for better effect? Yes. Some users have reported increased effect when dosing with two tabs. However, some also mention that the horse may also display more energy because he feels so much better.

9. What will it cost me to maintain my horse on FlexSyn™? Less than $90/month. Most people are buying the multi dose 6 pack or the economical 30 pack. You can supplement your horse to a beneficial level using 1 dose a week for under $100.00, or $3.25 per day. Of course, each horse is unique in his joint issues and performance regimen, and costs can vary as his response stabilizes.

10. Are there studies on FlexSyn™ to prove its effectiveness? FlexSyn™ simply offers a means of supplementing the horse’s natural level of ingredients found naturally within the joint capsule. Custom Veterinary Specialties has done no scientific studies on FlexSyn™ to document its particular efficacy and therefore we make no function claims as to its ability to treat or cure any condition.

*Note: There are no scientific absorption or blood level studies for FlexSyn™.