Watching a hard-keeping horse or a senior citizen of the pasture lose condition despite heaping hay nets and extra grain is a gut-wrenching reality for many owners. The problem isn’t appetite — it’s that standard rations simply lack the concentrated caloric density needed to tip the energy balance toward gain. A targeted equine supplement delivers those extra calories and specific nutrients in a compact, easily digestible form that bypasses the limitations of a hay-and-grain diet.
I’m Mo Mahin — the founder and writer behind Furric. I spend my time comparing feed tags, analyzing guaranteed analysis panels, and cross-referencing owner feedback on digestive tolerance and palatability to identify which formulas actually move the needle on the weigh tape and topline score.
This guide analyzes seven of the most effective options on the market to help you zero in on the right fit for your horse. Whether you are managing an aging Thoroughbred, a rescued mustang, or a performance horse dropping condition during intense training, these reviews break down the caloric sources, fat percentages, and feeding strategies of each supplement to put weight on horses.
How To Choose The Best Supplement To Put Weight On Horses
The shortest path to a weight gain solution lies in matching the supplement’s calorie source and nutrient profile to your horse’s specific challenge. A senior horse with declining digestion needs something very different from a competition horse needing topline muscle.
Fat Content and Calorie Density
Fat provides roughly two and a half times the digestible energy of an equal weight of oats or corn. Look for a crude fat percentage around 20 to 50 percent — this tells you the supplement is designed to deliver concentrated calories without filling the gut with bulky fiber. The higher the fat content, the less volume you need to feed to achieve a meaningful energy surplus.
Protein Quality and Muscle Support
Weight gain is not just about adding fat — rebuilding muscle mass requires quality amino acids. Formulas that list specific protein sources like extruded soy, flaxseed meal, or methionine support top-line development and topline score improvement. A crude protein content between 11 and 18 percent is a solid indicator that the supplement contributes to lean tissue alongside fat deposition.
Palatability and Form Factor
The most perfectly formulated supplement is worthless if your horse refuses to eat it. Powders, crumbles, pellets, and liquid oils all have different palatability profiles. Crumble and powder forms usually mix easily into a grain ration, while liquid oils can be poured over feed. Check owner reviews specifically for picky-eater acceptance — if multiple reviewers mention their horses eat it readily, the palatability is proven in real-world conditions.
Digestive Tolerance and Ingredients
Senior horses, rescued animals, and horses with metabolic issues often have compromised digestive systems. Supplements that include probiotics or prebiotics (like yeast culture or fermentation extracts) support gut health and nutrient absorption. Avoid supplements with high sugar content if insulin resistance is a concern — many fat-based formulas proudly state “no sugar added” for this very reason.
Targeted Use Case
Decide whether your horse needs general weight gain, muscle-specific toplining, or hoof and coat support alongside weight. Some products like Equitop Myoplast are precision muscle builders designed for performance horses needing lean mass. Others, like Formula 707 or Horse Guard Super Weight Gain, are full-calorie builders aimed at any hard keeper. Matching the product to the specific deficiency avoids over-supplementation and wasted money.
Quick Comparison
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| Model | Category | Best For | Key Spec | Amazon |
|---|---|---|---|---|
| Farnam Weight Builder | Powder | General weight & coat health | 50% crude fat, no sugar | Amazon |
| Horse Guard Super Weight Gain | Granule | Senior & hard keepers | 3-in-1: soy, probiotics, vitamins | Amazon |
| Formula 707 Weight Gain Crumble | Crumble | Easy acceptance, simple feeding | Vegetable fat + protein crumbles | Amazon |
| DAC Oil Gallon | Liquid | Coat shine & digestive help | Fish oil + Vitamin E liquid | Amazon |
| PetAg Dyne | Liquid | Intensive high-calorie support | High fat, low volume formula | Amazon |
| LIFE DATA Farrier’s Formula | Pellet | Hoof health + weight aid | Omega fatty acids & amino acids | Amazon |
| Equitop Myoplast | Powder | Specialised lean muscle building | Quality protein for topline | Amazon |
In‑Depth Reviews
1. Farnam Weight Builder Weight Support Supplement for Horses
The Farnam Weight Builder earns its top spot because it addresses the fundamental challenge of weight supplementation — calorie density — with a straightforward 50 percent crude fat formula. At this fat level, a four-ounce serving delivers more digestible energy than a full pound of standard grain, making it highly efficient for hard keepers who need a calorie surplus without a huge volume of feed. The guaranteed analysis includes omega-3 fatty acids from flaxseed meal and heat-stabilized rice bran, contributing to coat gloss and skin health as a secondary benefit.
Palatability feedback is consistently strong across owner reports. Horses that are notoriously picky about “medicine” in their grain gobble the powder without hesitation, which eliminates the biggest compliance barrier. Multiple long-term users on horses aged 22 to 30 years describe it as a “life saving product” that prevents spring weight loss and maintains condition through winter. The formulation contains no added sugar, which makes it a safer choice for horses with insulin resistance or metabolic concerns.
Owners also note an improvement in energy levels and performance output once condition improves. The powder format mixes easily into a standard grain ration without clumping. One minor practical point — the 7.5-pound bag provides a 30-day supply at the full four-ounce serving, so ordering frequency scales predictably. For a balanced, proven, and highly palatable weight-gain solution, this is the standard against which others are measured.
Why we love it
- Very high fat percentage for efficient calorie delivery.
- Proven results with senior and hard keeper horses.
- No added sugar — safer for metabolic concerns.
Good to know
- Requires daily mixing; not a free-choice option.
- Large bag may be bulky for travel or show stalls.
2. Horse Guard Super Weight Gain 10 lb
The Horse Guard Super Weight Gain takes a broader approach than simple fat supplementation by combining full-fat extruded soybeans, a probiotic-prebiotic blend, and a full vitamin-mineral package into a single granule. The extruded soy provides both concentrated calories and high-quality protein, which supports lean tissue accretion alongside fat gain. This makes it particularly well suited for senior horses whose digestive systems have declined — the probiotics support nutrient absorption, and the added yeast culture aids fiber digestion.
Owner reviews frequently cite rapid visible results in horses that had been losing weight despite heavy feeding of grain and hay. The inclusion of 1,500 IU of Vitamin E per serving provides immune support, especially valuable for rescued or stressed horses recovering from neglect or illness.
The granule form is palatable but the feeding volume is higher than some fat-concentrated powders — about 8 ounces per serving for a 1,000-pound horse. Some owners note that the bag can go stale if stored in a warm, sunny spot. A scooper is included, which simplifies dosing. For an owner seeking a comprehensive weight gain supplement that also supports digestion and general health, this is a strong contender.
Why we love it
- Triple-action formula targeting weight, digestion, and immunity.
- Proven results for senior and rescued horses.
- Contains probiotics and prebiotics for gut health.
Good to know
- Higher feeding volume than some concentrated fat supplements.
- Storage can affect freshness over time.
3. PetAg Dyne High Calorie Liquid Nutritional Supplement
PetAg Dyne is not just a horse supplement — it is a high-calorie liquid designed for all classes of livestock, and its concentrated nature makes it a serious tool for rapid weight gain in underweight, stressed, or recovering animals. The formula is dense in fat and includes added vitamins, delivering a high number of calories in a very small volume. This “low volume, high density” approach is particularly valuable when a horse has a poor appetite or is too weak to consume large quantities of food.
Owner feedback spans pigs, goats, dogs, and horses — a testament to its palatability across species. For horses specifically, reviewers report it is effective at stopping weight loss during illness or after surgery. The liquid format makes it easy to dose over grain or even syringe-feed if necessary, though this is less common for horses than for smaller livestock. The product is intended for animals at weaning age and older, which covers the vast majority of equine use cases.
One practical consideration is that the liquid must be shaken well before each use, and the bottle can be messy if not handled carefully. Owners using it for show animals appreciate the coat-health benefits as a secondary effect. For a budget-friendly entry point into high-calorie liquid supplementation, Dyne delivers reliable results. It works best as a temporary boost for animals in a recovery or stress period rather than as a long-term maintenance feed.
Why we love it
- Extremely calorie-dense per ounce — minimal volume needed.
- Versatile across livestock species, well-tested.
- Supports recovery after illness or transport stress.
Good to know
- Needs thorough shaking before each use.
- Can be messy; quality pump helps reduce waste.
4. Formula 707 Weight Gain Crumble Equine Supplement
Formula 707 has been a recognizable name in equine nutrition since 1948, and this Weight Gain Crumble reflects that legacy of straightforward, effective feeding. The crumble format is a distinct advantage for horses that are suspicious of pelleted feeds — the texture and aroma of these crumbles are highly palatable, with owners reporting that even the pickiest eaters treat it like a special reward. The primary calorie source is vegetable fat, which provides easily digestible energy for horses with compromised digestive systems.
The formula is designed to support healthy metabolism alongside weight gain, with high-quality protein included to aid muscle development. It is not a targeted muscle builder but a general weight support supplement. Owners of senior horses and miniatures report rapid improvement in body condition scores, often within the first few weeks. One reviewer described it as “the only answer to weight gain for horses” after trying multiple other options.
The crumble form does mean a higher feeding volume compared to fat-concentrated powders or liquids, but the excellent palatability compensates — horses finish their grain bowls completely. The product is labeled as a support for “hard-to-keep and senior horses,” which matches the most common use cases in owner reviews. For an owner seeking a proven, gentle, and highly palatable crumble supplement, Formula 707 remains a solid choice.
Why we love it
- Extremely palatable crumble — even picky horses love it.
- Long-established brand with proven track record.
- Good for senior and miniature horses.
Good to know
- Higher feeding volume than some concentrated fat sources.
- Not a targeted muscle builder, it’s a general weight gainer.
5. Equitop Myoplast Supplement for Horses
Equitop Myoplast occupies a specialized niche — it is a lean muscle development supplement, not a general weight gain formula. The product is designed to provide a high-quality protein source for horses whose condition deficit is specifically in topline, hind-end, and overall muscling rather than general body fat. It is particularly popular among competition riders, with names like Scott Brash and William Fox-Pitt using it as part of their feeding regime for event and show jumping horses.
Owner reviews confirm that Myoplast delivers noticeable improvements in muscle mass and definition over a period of weeks to months. One dressage horse owner reported a “huge difference in his topline and overall musculature” after putting the horse back on Myoplast after attempting to discontinue it. Racehorse trainers also use it during periods of active training and competition to maintain muscle condition. The product is scientifically formulated and recommended by veterinarians for horses returning to work after box rest or convalescence.
The 1.5-kilogram tub is more compact than many bulk bag supplements, reflecting that the daily serving size is relatively small. The cost per serving is higher than that of general weight gain supplements, but owners targeting lean muscle rather than fat deposition view it as a worthwhile investment. For a performance horse that needs muscle condition without excessive fat, Myoplast is the clear specialist choice. It pairs well with a general weight gain supplement if the horse needs both fat and muscle.
Why we love it
- Specifically formulated for lean muscle development.
- Used by top-level competition riders and trainers.
- Effective for horses returning to work after rest.
Good to know
- Higher cost per serving than general weight gain supplements.
- Not a fat-based weight builder — complementary product.
6. DAC Oil Gallon Jug Horse Weight Gain Supplement
DAC Oil offers a liquid oil supplementation approach with a base of fish oil and added vitamin E. While its primary reputation among owners is as a coat, skin, and joint health product, it does provide a meaningful calorie boost that aids weight gain and weight maintenance. The fish oil base delivers a specific fatty acid profile that differs from vegetable-fat supplements, which can be advantageous for horses needing omega-3 fatty acids for inflammatory support or skin conditions.
Owner reviews consistently highlight the dramatic improvement in coat shine and overall appearance — “my horses just shine” is a recurring theme. Beyond cosmetics, several owners report that DAC Oil helps with constipation and digestive regularity in older horses, a practical benefit not always associated with oil supplements. The palatability is strong, with horses accepting it readily when poured over their grain, though some owners note that careful dosing is needed to avoid overfeeding in horses that are prone to getting too heavy.
The gallon jug format is efficient for multi-horse households but requires a pump for clean, mess-free dispensing — several owners recommend purchasing a quality pump separately to avoid leakage. This is not the strongest single-source weight gain supplement on the list if calorie density is the sole goal, but for owners wanting a multi-benefit oil that supports weight, coat, and joint health simultaneously, DAC Oil is a well-liked option.
Why we love it
- Excellent for coat shine and skin health alongside weight support.
- Helps with digestive regularity in senior horses.
- Palatable and easily accepted by horses.
Good to know
- Gallon jug can be messy without a separate pump.
- Less calorie-dense per dose than fat-concentrated powders.
7. LIFE DATA LABS Farrier S Formula 2X Strength
Farrier’s Formula is a hoof-specific supplement that has earned near-iconic status among farriers and horse owners alike. While it is not a general weight gain supplement, the nutrients it provides — phospholipids, omega fatty acids, vitamins, minerals, and amino acid building blocks — support the overall metabolic health that underlies both weight maintenance and hoof integrity. Horses that are losing weight often present with poor hoof quality as a secondary symptom, and addressing hoof health can be part of a broader weight management program.
Owner reviews are emphatic about hoof improvements: crumbling soles, abscess-prone feet, and brittle walls all respond to consistent use over a period of several weeks to months. One owner described how Farrier’s Formula resolved a severe lameness from a hind hoof abscess and crumbling sole in a 4-year-old mare, restoring soundness within six weeks. The pelleted form is reported to be highly palatable, with even picky horses eating it readily without needing to disguise it in grain.
For a horse that is underweight and also struggling with hoof quality, combining Farrier’s Formula with a weight-specific supplement from this list is a logical approach. This is a specialization tool, not an all-in-one weight gain solution. The 2X Strength formulation means a lower feeding volume than the original formula, which is an advantage for horses on tight grain rations. Recommended strongly by farriers and veterinarians for hoof-specific nutrition.
Why we love it
- Gold standard for hoof health supplementation.
- Double strength reduces feeding volume.
- Very palatable, even for picky eaters.
Good to know
- Primarily a hoof product, not a weight gain supplement.
- Best used in tandem with a targeted weight builder if needed.
FAQ
How quickly will I see results from a weight gain supplement for horses?
Can I use a weight gain supplement for a horse with metabolic issues or laminitis risk?
What is the difference between a general weight gain supplement and a muscle-building supplement like Equitop Myoplast?
How should I introduce a new weight gain supplement to my horse’s diet?
Final Thoughts: The Verdict
For most owners managing a typical hard-keeper or senior horse, the supplement to put weight on horses winner is the Farnam Weight Builder because it delivers the highest fat content with proven palatability and no sugar — a safe, efficient solution for a wide range of equine metabolic needs. If your horse needs comprehensive digestive and immune support alongside weight gain, grab the Horse Guard Super Weight Gain. And for targeted lean muscle building in a performance horse, nothing beats the Equitop Myoplast.