Mobility
Joint Flex Plus
Everyday joint flexibility and comfort for performance and senior horses.
$100.64
Joint Flex Plus · In the barn
Common Questions
One pump is one ounce, top-dressed on feed. Load with 2 pumps a day for the first 30 days, then settle into one pump a day. Two pumps a day is also recommended through heavy work and show season. Keep it at least two hours apart from NSAIDs.
A gallon is 128 pumps: about 4 months at one pump a day, which works out to $0.84 a day on subscription. The 30-day load at 2 pumps a day uses a little more up front.
Joint Flex Plus is a palatable liquid that coats the existing ration, so most horses accept it with no fuss. If yours is especially fussy, our equine nutritionists help you transition, included free with every order.
Yes, and most barns do. Gut X handles absorption and gut health, Joint Flex Plus supports the joints. Feed them together →
Anytime. Manage everything in your account or by SMS: pause, change delivery dates, or cancel with no fees and no phone tree.
Most owners report a change in movement and comfort within the first 30 days, and some sooner. Joint Flex Plus is daily, long-term joint and cartilage support, not a quick fix, so the biggest gains come from staying consistent through the load month and into maintenance.
Joint Flex Plus · Liquid Joint Support
Fluid joints. Free movement.
One pump a day.
Joint ComfortCartilage SupportSynovial Fluid
Joints move on synovial fluid. Joint Flex Plus supports that fluid and the cartilage it cushions in one daily ounce, top-dressed over the feed you already give.
Each ounce carries 442 mg of hyaluronic acid and 250 mg of silicon as orthosilicic acid, delivered in a proprietary liquid form with up to 99% availability1, 2. Powders & pellets must first break apart, hydrate, & disperse inside a moving gut, which leaves availability as low as 2.5%3.
1Goodridge et al. (2011). doi.org/10.1038/nature100712Balogh et al. (2008). doi.org/10.1021/jf80170293Du et al. (2004). doi.org/10.1002/bdd.392
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90-day money-back
Pause or cancel anytime
Your 2 Gallon Subscription includes
- ✓2 Gallons of Joint Flex Plus + 2 pumps
- ✓90-Day Money-Back Guarantee
- ✓Free Equine Nutritionist Consultation
Customer reviews
1,545 verified reviews from working barns.
Every discipline. Every level. Real horses on Dr. Peterson’s Protocol.
4.9
★★★★★
out of 5
Based on 1,545 verified reviews
The absorption gap
What your horse can’t absorb,
your horse can’t use.
Most joint supplements are powders or pellets. They have to dissolve and survive the gut before any of it counts, and most of it never does. Joint Flex Plus is liquid and pre-dispersed, so it’s ready the moment it reaches the gut wall.
Liquid Joint Flex Plus
vs
99%
up to 99% availability
Powders & pellets
2.5%
absorption as low as 2.5%1
Oral bioavailability of administered actives. Powder/pellet figure per Du et al. (2004)1; cited in full in the comparison below.
With most supplements, you pay for a full dose and your horse absorbs a fraction of it. You’re not getting what you think you’re paying for. With Joint Flex Plus, what’s on the label is what reaches your horse.
Orthosilicic acid
Already in solution. The hyaluronan and the silicon arrive in the form the joint can actually use, with no dispersion step in between.
Hyaluronan
High molecular weight, pre-hydrated. No breakdown step to lose it in, which matters for a molecule this large.
The physiology
It’s not marketing. Liquid delivery has been the standard in human medicine for decades. Joint Flex Plus brings it to the barn.
Liquid vs. the rest
Why form is the whole game.
The actives aren’t the differentiator, delivery is. Here’s how liquid stacks up against the pelleted and powdered joint supplements in most feed rooms.
Joint Flex Plus · Liquid
Powders
Pellets
Availability
Up to 99%1,2
3–30%3
3–15%4
Goes to work
On contact
Must dissolve first
Needs to break down first
Dose accuracy
One pump, exact
Scoop & settle
Eats around it
Picky-eater approved
Yes
Hit or miss
Hit or miss
Show safe
USEF / FEI
It depends
It depends
References
1Goodridge et al. (2011). doi.org/10.1038/nature10071
2Balogh et al. (2008). doi.org/10.1021/jf8017029
3Du et al. (2004). doi.org/10.1002/bdd.392
4Raval et al. (2025). doi.org/10.2174/0124681873309964240521074809
Ingredients
What’s in the jug, why it’s there, and what the science says.
One pump is one ounce. Both actives below are listed at their amount in that ounce, straight off the Product Facts panel.
Measured delivery
One pump, one ounceOff the Product Facts panel
One ounce is a measured dose, not a scoop you level by eye. Every pump delivers 442 mg of hyaluronic acid and 250 mg of silicon as orthosilicic acid, already in solution, so what the panel says is what reaches your horse.
1 oz
per pump
Hyaluronic AcidHyaluronan
Hyaluronan is a normal component of synovial fluid and extracellular matrix, supplied already in solution.
442
mg / oz
SiliconAs orthosilicic acid
Orthosilicic acid is the bioavailable form of silicon, supplied already in solution. Silicon is used in the collagen that cartilage and connective tissue are built from.
250
mg / oz
References
- 1Goodridge, H. S., Reyes, C. N., Becker, C. A., et al. (2011). Activation of the innate immune receptor Dectin-1 upon formation of a phagocytic synapse. Nature, 472, 471–475. doi.org/10.1038/nature10071
- 2Balogh, L., Polyak, A., Mathe, D., et al. (2008). Absorption, uptake and tissue affinity of high-molecular-weight hyaluronan after oral administration in rats and dogs. Journal of Agricultural and Food Chemistry, 56(22), 10582–10593. doi.org/10.1021/jf8017029
The Protocol
Dr. Peterson’s two-phase protocol
Load with 2 pumps a day for the first 30 days, then settle into a once-daily maintenance pump. Two pumps a day is also recommended through heavy work and show season. Keep it at least two hours apart from NSAIDs.
Day 0Day 30Ongoing
≈ 2-month supply per gallon
≈ 4-month supply per gallon
From the barn
Real horses. Here are a few of them.
Real members, real horses, real results. Tag #100XEquine to be featured.
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Chief Veterinary Officer
47 years of Equine Medicine, in one jug.
The Veterinary Standard Behind 100X Equine
Dr. Russ Peterson, DVM, MS, DACVSMR, Cert. ISELP brings nearly five decades of equine medicine, sport horse performance, rehabilitation, nutrition, and clinical decision-making to 100X Equine.
As Chief Veterinary Officer, Dr. Peterson helps guide the clinical thinking behind every 100X Equine formula, from ingredient selection to dosing strategy to how those actives are delivered inside the horse.
Joint Flex Plus reflects that standard: hyaluronic acid and silicon as orthosilicic acid, both named on the panel and delivered in a proprietary liquid carrier built to keep them stable and ready for biological contact.
Board-certifiedSports Medicine & RehabilitationEquine NutritionFormulation Science
The 2-part joint system
Fluid and cartilage. One joint.
A joint stays comfortable because fluid cushions it and cartilage holds its shape. Joint Flex Plus supplies building blocks for both in one daily ounce.
01
Synovial fluid
Hyaluronan is the molecule synovial fluid is built on. Joint Flex Plus supplies 442 mg already in solution to support normal joint lubrication and flexibility.
02
Cartilage & connective tissue
Orthosilicic acid supplies silicon, which is used in the collagen that cartilage and connective tissue are built from, the cushion a joint depends on under load.
442 mgHyaluronic acid
250 mgSilicon as orthosilicic acid
Amounts are per one-ounce pump, as listed on the current Product Facts panel. Give at least two hours apart from NSAIDs. See the full panel.
Show-Safe Formula
No prohibited substances. Joint Flex Plus is USEF and FEI compliant, so it stays legal for horses competing under both rule sets.
90-Day Money-Back Guarantee
Feed it daily for 90 days. If you don’t see the difference, we refund you, with free shipping on every order.
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Still deciding
Questions, answered.
Most owners report a change in movement and comfort within the first 30 days, and some sooner. Joint Flex Plus is daily, long-term joint and cartilage support, not a quick fix. If you don’t see the difference, you’re backed by our 90-day money-back guarantee.
Joint Flex Plus is a palatable liquid that coats the existing ration, so most horses accept it with no fuss. If yours is especially fussy, our equine nutritionists help you transition, included free with every order.
Your Joint Flex Plus subscription is fully flexible. Manage it anytime in your account or by SMS: pause, change delivery dates, or cancel with no fees and no phone tree.
Yes. USEF and FEI compliant. No prohibited substances, so it’s cleared for horses showing under both rule sets.
The full system
Pair Joint Flex Plus with another protocol.
Stack more and save up to 40% off. Adjust anytime.
Joint, Soft Tissue & Bone
Osteo-MAX
Bone density, joint integrity, and recovery for hard-working and aging horses.
$175.16
Gut & Immune
Gut X
Liquid gut health and immune support, the foundation every other protocol builds on.
$100.64
Topline & Muscle
Amino-MAX
Amino acids for topline, muscle, and a stronger frame under saddle.
$118.45
Electrolytes + Creatine
Hydra-MAX
Electrolyte and hydration support for sweat, travel, and hot, hard days.
$112.22
Calm & Focus
Max Calm
Liquid calming support for focus and rideability, without the dullness.
$100.64
Put your horse on the protocol.
Start with Joint Flex Plus. Synovial fluid and cartilage support in one pump a day, built on Dr. Peterson’s 47+ years of equine medicine.
Start with Joint Flex PlusFeed it daily for 90 days. If you don’t see the difference,
we refund you.
Joint Flex Plus
★★★★★4.91,545 reviews9,000+ horses
Everyday joint flexibility and comfort for all horses.
Subscriptions from
$0.84/day
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- Daily joint flexibilityKeeps everyday movement smooth and easy.
- Comfort in workSupports horses in training and competition.
- Senior supportExtra cushioning for aging joints.
HyaluronanOrthosilicic acidLiquid Delivery
Free shipping
90-day money-back
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Product details
Two actives, both fully disclosed by amount per 1-ounce pump: hyaluronic acid, a component of synovial fluid and cartilage, and silica, a source of silicon.1–12
See the full labelThe systemLiquid Joint Support SystemMeasured liquid delivery1 ozper pump
The liquid format delivers both active ingredients in a consistent, measured 1-ounce pump. One pump supplies 250 mg of hyaluronic acid and 442 mg of silica. The label-directed two-pump loading or performance amount supplies 500 mg of hyaluronic acid and 884 mg of silica daily.
Hyaluronic AcidHyaluronan250mg / oz
Hyaluronic acid is a naturally occurring component of synovial fluid and articular cartilage that contributes to joint-fluid viscosity, lubrication, hydration, and organization of the cartilage extracellular matrix.1–5,11 Equine studies show that inflammation and osteoarthritis can alter synovial HA concentration, molecular weight, and distribution, while experimentally administered HA can help limit the breakdown of synovial HA and cartilage proteoglycans.1–5 Oral absorption and connective-tissue distribution have also been demonstrated in animal studies, although direct oral clinical research in horses remains limited.6,7
SilicaSource of silicon442mg / oz
Silicon is associated with collagen-rich connective tissues, extracellular-matrix development, and skeletal mineral metabolism.8,11,12 Equine studies show that certain supplemental silicon sources can increase circulating silicon and influence silicon retention and mineral balance.8–10 Research in young racing Quarter Horses also reported greater training distance before injury in groups receiving a specific silicon-containing sodium zeolite, while later work in mature horses found no significant increase in synovial collagen-turnover markers.9,10 These findings indicate that silicon’s effects depend on its chemical form, bioavailability, dose, age of the horse, and exercise conditions.
References
1Neuenschwander et al. (2019). 10.4142/jvs.2019.20.e67
2Niemelä et al. (2018). 10.1186/s12917-018-1512-2
3Watkins et al. (2021). 10.1186/s12917-021-02873-2
4Mustonen et al. (2022). 10.1038/s41598-022-21398-8
5Agreste et al. (2021). 10.1016/j.rvsc.2021.09.003
6Balogh et al. (2008). 10.1021/jf8017029
7Serra-Aguado et al. (2021). 10.3390/ani11051264
8O’Connor et al. (2008). 10.1111/j.1439-0396.2007.00724.x
9Nielsen et al. (1993). sciencedirect.com
10Pritchard (2020). proquest.com
11Gupta et al. (2019). 10.3389/fvets.2019.00192
12Nielsen (2023). 10.3390/ani13050789
Load with 2 pumps a day for the first 30 days, then settle into 1 pump a day.
- Pump it straight over the existing ration. The liquid coats the feed, so picky eaters take it without a fight.
- Give at least two hours apart from NSAIDs.
- One gallon is up to a 4 month supply at the maintenance pump.
Smoother, freer movement typically shows inside two weeks, and keeps improving through 180 days of daily feeding.
- Day 1 to 30, the loading dose is doing the work.
- Day 30 onward, one pump a day holds it.
- This is daily long-term joint and cartilage support, not a quick fix.
The comparison
Why form is the whole game.
The actives are not the differentiator, delivery is. Here is how liquid stacks up against the dry supplements in most feed rooms.
Joint Flex Plus liquidPowder / pellet
Delivery form
Pre-dispersed liquid, suspendedDry particles, must hydrate
Availability
Up to 99%1,2As low as 2.5%3
Dose accuracy
One pump, exactScoop, settles and separates
Goes to work
On contactMust break down first
Dose consistency
250 mg HA + 442 mg silica, every pumpVaries with settling
References1 Goodridge et al. (2011). 10.1038/nature10071
2 Balogh et al. (2008). 10.1021/jf8017029
3 Du et al. (2004). 10.1002/bdd.392
2 Balogh et al. (2008). 10.1021/jf8017029
3 Du et al. (2004). 10.1002/bdd.392
Why liquid
Ready the moment it is fed.
Joint Flex Plus is delivered in a proprietary liquid form with up to 99% availability1,2. Powders and pellets must first break apart, hydrate and disperse into usable surface area inside a moving gut, a slow, variable process that leaves availability as low as 2.5%3.
1Goodridge et al. (2011)2Balogh et al. (2008)3Du et al. (2004)
Who formulates it
Dr. Russ Peterson, DVM
MS · DACVSMR · Cert. ISELP
Chief Veterinary Officer
Chief Veterinary Officer
Nearly five decades of equine medicine, sport horse performance, rehabilitation and nutrition. Joint Flex Plus reflects that standard: hyaluronic acid and silica at disclosed amounts per pump, no proprietary blend hiding a dose, and a liquid carrier built to keep both actives stable and dispersed.
Start the protocol
One pump a day. Feed it for 90 days, and if your horse is not moving better, we refund you.
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