Benefits of Hydra-MAX

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✅  8X Active Ingredients vs. other Leading Equine Brands

✅  3.5X Improved Hydration over Water Alone

✅  2X More Water Consumption with Hydra-MAX

✅  26% Greater Plasma Volume Expansion, where Hydration actually counts.

✅  90 Day Money Back Guarantee

✅  *Scientifically Proven Formula

✅  USEF & FEI Compliant & Show Safe

✅  Specifically Formulated for Equine to achieve **True Hydration

*Peterson R, Dietrich J. Post exercise hydration responses to an Electrolyte, Glycerol, and Creatine Supplement in Horses: Peer-reviewed by BMC Veterinary Research. 2026. DOI: 10.1186/s12917-026-05493-w

**This occurs when all three fluid compartments - Intracellular (inside the cells), Extracellular (outside the cells) and Intravascular (bloodstream) - are balanced.  

Disclaimer: The reviews below are for informational purposes and are not intended to substitute veterinary care.

Reviews are written by actual customers and represent their own observations of using 100X Equine products.

What's the science behind the Hydra-MAX ingredients?

Hydra-MAX was formulated to increase intravascular fluid volume by expanding plasma volume within the blood. Fluid for cutaneous evaporative cooling comes from both the intravascular and interstitial compartments (1); therefore, a secondary aim was to increase total body water as a reservoir for increasing thermoregulatory capacity. Maintaining proper plasma volume is a critical step in adequate hydration and increasing plasma volume can directly result in increased exercise performance (2). Additionally, restoring plasma volume and total body water after exercise bouts, especially in a hot environment, is an important factor for recovery. In order to effectively move ingested fluid from the gastrointestinal (GI) tract into the target compartment a gradient must be established. Electrolytes as a hydration aid have been supported by countless articles, textbooks and basic biochemistry. The sensation of thirst is driven by blood osmolality, most notably serum sodium levels rising. The electrolyte selections and doses listed are designed to replace precise amounts lost in sweat in horses during and after exercise (3,4).

Sodium

Sodium is the most abundant electrolyte in human and equine blood (5) and it is the most abundant electrolyte lost during evaporative cooling during exercise or heat stress (6). Elevated sodium concentration in blood serum stimulates thirst. Sodium chloride is the most common electrolyte used in hydration beverages and it is utilized for clinical hydration saline solutions (7). However, if oral sodium chloride doses are too high GI symptoms and palatability can become problematic. Research in equines has supported the GI safety of 30g of sodium delivered in 2 doses top dressed on feed (8). These investigators utilized a blinded, placebo controlled, crossover design with a 2-week washout period. Results suggest that a daily dose of 30g sodium and 39g chloride ingested via pellets did not alter the number or severity of gastric mucosal ulcers

measured via gastroscopy. Alternatively, others have reported that repeated doses of a commercial electrolyte paste totaling ~45g of sodium alone, increased the number and severity of gastric ulcers, measured via gastroscopy (9). Clearly, there is a dose threshold for sodium ingestion and GI symptoms. With regard to palatability, a research study tested palatability for sodium chloride solutions in horses and found a voluntary threshold for sodium chloride ingestion is ~0.6% (10). These studies all utilized sodium chloride; thus, the impact of chloride may have also contributed to these results. Chloride itself is also an important electrolyte for fluid balance (11). However, there have been reports of

GI issues with high chloride due to its involvement in hydrochloric acid in the gut (12). Sodium citrate has a slightly less salty flavor and does not contain chloride making it easier on the GI tract. Sodium citrates is also supported as an ergogenic aid due to its buffering capacity (13).

Potassium

Potassium is another electrolyte involved in fluid balance and is also depleted during heavy cutaneous evaporative cooling, though the losses in potassium are less than that of sodium and chloride (14). Potassium is an important factor for muscle contractility and is intimately involved in blood pressure regulation via fluid retention. In addition to its utility for fluid balance, potassium is important for bone turnover. Potassium bicarbonate will increase the osmolality and help reduce risk of GI distress. Potassium bicarbonate has been safely administered in humans and equine and has additional benefits of lower bone turnover (15).

Magnesium

Magnesium is depleted in sweat in a very small magnitude relative to sodium, potassium, and chloride, but it is still a critical electrolyte for proper physiological functions (3,16). Not only does magnesium increase osmolality as a cation, it is also a cofactor for hundreds of enzymatic reactions (17). Additionally, magnesium has been supported as an important factor in the exercising muscle contraction and relaxation cycle (18). I am recommending magnesium chloride as it has demonstrated high bioavailability and provides the remaining chloride to meet the needs of chloride lost in sweat (19).

Calcium

Similar to magnesium, calcium is lost in sweat in very small amounts relative to sodium, potassium, and chloride, but it is an important electrolyte for proper physiological functions especially during exercise. Calcium is a charged particle which will impact the tonicity and osmolality of Hydra-MAX. Briefly, calcium binds to the troponin-tropomyosin complex to initiate a conformational shift which allows actin and myosin cross bridging. Calcium citrate as it has a high bioavailable and small risk of GI symptoms.

Glucose

Glucose has been utilized in sports beverages for decades, most famously with the creation of Gatorade at the University of Florida in 1965. Interestingly, the addition of carbohydrates to Gatorade was anecdotally reported to serve as replenishment for blood glucose and muscle glycogen. Indeed, this does function as an ergogenic and beneficial step in maintaining physiologic performance. Serendipitously, the ~6% glucose concentration of Gatorade achieves an approximate 320 mOsm/kg H2O, which in combination with the minimal electrolyte content results in a successful rehydrating source. In addition to the hypertonic solution, driven primarily by glucose content, carbohydrate-sodium beverages also take advantage of a co-transport system to improve absorption. Five years prior to creation of Gatorade, Robert Crane presented his theory on a glucose-sodium co-transport, which has been massively impactful in clinical oral rehydration (20) and has since been verified as a critical physiological pathway for fluid transport (21). Additionally, Fructose appears to be a viable option for equine given its easy digestion and conversion to glucose (22).

Glycerol

Glycerol is an osmotically active substance that has been demonstrated to aid in fluid retention. Specifically, glycerol provides benefit by reducing kidney excretion of water and increasing voluntary thirst in equines (23,24). It also appears that the impact of oral glycerol ingestion is potent enough to down regulate hormones required for fluid retention during a rehydration protocol (25). However, there has been some controversy

over if the increases seen with total body water (26) are indicative of increased intravascular fluid, which is commonly the goal for ergogenic effects. This is an unnecessary distinction to make given that fluid for cutaneous evaporative cooling can come from interstitial fluid as well as the intravascular compartment and glycerol is evenly distributed across these physiologic compartments. Additionally, the thermoregulatory benefit of glycerol induced hydration has been documented in humans. When comparing hydration with water alone or water with glycerol, the combined water and glycerol group demonstrated increased sweat rates and reduced heat stress in response to exercise (27).

Creatine

Creatine monohydrate is one of the most popular and researched substances within the last decade. Early skepticism of creatine was based primarily on cellular or mice model data (28), and related to renal impacts. However, these data have been thwarted by a vast amount of data to support, not only the safety of creatine but also an unexpected number of benefits (29). With regard to hydration, creatine is an osmotically active

substance which has resulted in increases in total body water (30). There is controversy on which fluid compartment is primarily impacted by creatine supplementation. The majority of creatine is stored within the muscle cells; therefore, it is likely that the documented increases in total body water are driven primarily by intracellular fluid expansion. While intracellular water is not the principal source of sweat, the human body

is built to maintain a very specific balance between the intra- and extra-cellular fluid states. Therefore, if intracellular changes occur there will be an equal resultant change to interstitial fluid. However, these details have not yet been elucidated despite the relative ease to measure these fluid states in these separate body compartments (31,32).  Additionally, creatine may also protect blood pH during exercise bouts (unpublished

data collected during my research at Cal Poly). This theory is based on the biochemical reaction in which phosphocreatine “lends” a phosphate to adenosine diphosphate (the byproduct of adenosine triphosphate cleaving a phosphate to produce energy, which is primary energy producing reaction). In an unpublished research study conducted at California Polytechnic University, acute low dose creatine supplementation with

carbohydrates increased time to fatigue in endurance trained males and females compared to carbohydrates alone.

References:

1. Brinkman JE, Dorius B, Sharma S. Physiology, Body Fluids. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 [cited 2025 Feb 14]. Available from: http://www.ncbi.nlm.nih.gov/books/NBK482447/

2. Hagberg JM, Goldberg AP, Lakatta L, O’Connor FC, Becker LC, Lakatta EG, et al. Expanded blood volumes contribute to the increased cardiovascular performance of endurance-trained older men. J Appl Physiol (1985). 1998 Aug;85(2):484–9.

3. Lj M, Rj G, Mj H, Gl E, Mi L. Sweating rate and sweat composition during exercise and recovery in ambient heat and humidity. Equine veterinary journal Supplement [Internet]. 1995 Nov [cited 2025 Feb 11];(20). Available from: https://pubmed.ncbi.nlm.nih.gov/8933099/

4. Lindinger MI. Oral Electrolyte and Water Supplementation in Horses. Vet Sci. 2022 Nov 10;9(11):626.

5. Ju JC, Cheng SP, Fan YK, Hsu JC, Chiang SK, Chen EV, et al. Investigation of equine hematological constituents in central Taiwan. I. Distribution of the blood cell parameters and the biochemical compositions of serum. Asian-Australasian Journal of Animal Sciences. 1993 Mar 1;6(1):147–53.

6. McCutcheon LJ, Geor RJ, Ecker GL, Lindinger MI. Equine sweating responses to submaximal exercise during 21 days of heat acclimation. J Appl Physiol (1985). 1999 Nov;87(5):1843–51.

7. Tonog P, Lakhkar AD. Normal Saline. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 [cited 2025 Jan 23]. Available from: http://www.ncbi.nlm.nih.gov/books/NBK545210/

8. Alshut F, Venner M, Martinsson G, Vervuert I. The effects of feeding sodium chloride pellets on the gastric mucosa, acid-base, and mineral status in exercising horses. J Vet Intern Med. 2023;37(6):2552–61.

9. Holbrook TC, Simmons RD, Payton ME, MacAllister CG. Effect of repeated oral administration of hypertonic electrolyte solution on equine gastric mucosa. Equine Vet J. 2005 Nov;37(6):501–4.

10. Randall RP, Schurg WA, Church DC. Response of horses to sweet, salty, sour and bitter solutions. J Anim Sci. 1978 Jul;47(1):51–5.

11. Berend K, van Hulsteijn LH, Gans ROB. Chloride: the queen of electrolytes? Eur J Intern Med. 2012 Apr;23(3):203–11.

12. Tubbs AL, Liu B, Rogers TD, Sartor RB, Miao EA. Dietary Salt Exacerbates Experimental Colitis. J Immunol. 2017 Aug 1;199(3):1051–9.

13. Urwin CS, Snow RJ, Condo D, Snipe R, Wadley GD, Carr AJ. Factors Influencing Blood Alkalosis and Other Physiological Responses, Gastrointestinal Symptoms, and Exercise Performance Following Sodium Citrate Supplementation: A Review. Int J Sport Nutr Exerc

Metab. 2021 Mar 1;31(2):168–86.

14. Terker AS, Zhang C, McCormick JA, Lazelle RA, Zhang C, Meermeier NP, et al. Potassium modulates electrolyte balance and blood pressure through effects on distal cell voltage and chloride. Cell Metab. 2015 Jan 6;21(1):39–50.

15. Allowances NRC (US) S on the TE of the RD. Water and Electrolytes. In: Recommended Dietary Allowances: 10th Edition [Internet]. National Academies Press (US); 1989 [cited 2025 Feb 16]. Available from: https://www.ncbi.nlm.nih.gov/books/NBK234935/

16. Martin KJ, González EA, Slatopolsky E. Clinical consequences and management of hypomagnesemia. J Am Soc Nephrol. 2009 ov;20(11):2291–5.

17. Al Alawi AM, Majoni SW, Falhammar H. Magnesium and Human Health: Perspectives and Research Directions. Int J Endocrinol. 018;2018:9041694.

18. Souza ACR, Vasconcelos AR, Dias DD, Komoni G, Name JJ. The Integral Role of Magnesium in Muscle Integrity and Aging: A Comprehensive Review. Nutrients. 2023 Dec 16;15(24):5127.

19. Schuchardt JP, Hahn A. Intestinal Absorption and Factors Influencing Bioavailability of Magnesium-An Update. Curr Nutr Food Sci. 2017 Nov;13(4):260–78.

20. Hamilton KL. Robert K. Crane-Na(+)-glucose cotransporter to cure? Front Physiol. 2013;4:53.

21. Biology of human sodium glucose transporters - PubMed [Internet]. [cited 2025 Feb 16]. Available from: https://pubmed.ncbi.nlm.nih.gov/21527736/

22. Bullimore SR, Pagan JD, Harris PA, Hoekstra KE, Roose KA, Gardner SC, et al. Carbohydrate supplementation of horses during endurance exercise: comparison of fructose and glucose. J Nutr. 2000 Jul;130(7):1760–5.

23. Schott HC, Patterson KS, Eberhart SW. Glycerol hyperhydration in resting horses. Vet J. 2001 Mar;161(2):194–204.

24. Düsterdieck KF, Schott HC, Eberhart SW, Woody KA, Coenen M. Electrolyte and glycerol supplementation improve water intake by horses performing a simulated 60 km endurance ride. Equine Vet J Suppl. 1999 Jul;(30):418–24.

25. van Rosendal SP, Strobel NA, Osborne MA, Fassett RG, Coombes JS. Hydration and endocrine responses to intravenous fluid and oral glycerol. Scand J Med Sci Sports. 2015 Jun;25 Suppl 1:112–25.

26. van Rosendal SP, Osborne MA, Fassett RG, Coombes JS. Guidelines for glycerol use in hyperhydration and rehydration associated with exercise. Sports Med. 2010 Feb 1;40(2):113–29.

27. Lyons TP, Riedesel ML, Meuli LE, Chick TW. Effects of glycerol-induced hyperhydration prior to exercise in the heat on sweating and core temperature. Med Sci Sports Exerc. 1990 Aug;22(4):477–83.

28. Tarnopolsky MA, Bourgeois JM, Snow R, Keys S, Roy BD, Kwiecien JM, et al. Histological assessment of intermediate- and long-term creatine monohydrate supplementation in mice and rats. Am J Physiol Regul Integr Comp Physiol. 2003 Oct;285(4):R762-769.

29. Hall M, Manetta E, Tupper K. Creatine Supplementation: An Update. Curr Sports Med Rep. 2021 Jul 1;20(7):338–44.

30. Powers ME, Arnold BL, Weltman AL, Perrin DH, Mistry D, Kahler DM, et al. Creatine Supplementation Increases Total Body Water Without Altering Fluid Distribution. J Athl Train. 2003 Mar;38(1):44–50.

31. Zdolsek JH, Lisander B, Hahn RG. Measuring the size of the extracellular fluid space using bromide, iohexol, and sodium dilution. Anesth Analg. 2005 Dec;101(6):1770–7.

32. Cataldi D, Bennett JP, Quon BK, Liu YE, Heymsfield SB, Kelly T, et al. Agreement and Precision of Deuterium Dilution for Total Body Water and Multicompartment Body Composition Assessment in Collegiate Athletes. J Nutr. 2022 Sep 6;152(9):2048–59.

Hydra-MAX: The Secret to a Healthier & Happier Horse