8 Best Weight Gainers for Dogs 2026

This high-calorie protein powder is a game-changer for aging dogs struggling with muscle loss and low appetite. Specially engineered for senior dogs, it combines egg yolk powder, whole goat milk, and multivitamins into a clean, all-natural formula that supports lean muscle retention and immune resilience. Unlike generic supplements, this one is veterinarian-formulated and free from artificial fillers, making it ideal for older pups whose digestive systems are more sensitive. It directly tackles the core issues of aging: slowing metabolism, reduced energy, and difficulty maintaining weight.

In real-world use, the powder blends seamlessly into meals, and the chicken liver flavor proves irresistible—even for finicky seniors who turn their noses up at most foods. Each 1g scoop delivers targeted nutrition, calibrated at 1g per 4.5 lbs of body weight, making dosing precise and mess-free. While the 4 oz size offers fewer servings than bulk powders, it’s perfect for short-term recovery or trial use. The formula excels on soft foods or wet meals but may clump slightly in very dry kibble if not mixed thoroughly. It’s not the highest calorie option on the market, but its bioavailability and digestibility make up for it in consistent, sustainable gains.

Compared to liquid supplements like PetAg Dyne, this powder is less concentrated in calories but wins in long-term nutritional support thanks to muscle-preserving proteins and immune-boosting zinc. It’s not meant for rapid weight surge but shines as a daily wellness enhancer for senior dogs needing gentle, steady improvement. Ideal for owners focused on quality of life over quick fixes, it pairs well with moderate activity and vet-guided care plans. While Bully Max Liquid offers broader age suitability, this one earns its keep as the top choice for targeted senior support.

When your dog needs a calorie surge fast, PetAg Dyne steps in like a turbocharged energy shot. This high-calorie liquid packs a dense form of energy in a low-volume formula, making it perfect for underweight dogs, lactating mothers, or working breeds burning through fuel. The sweet vanilla flavor is a major win—dogs lap it up whether poured over food or served straight—and its high-fat composition ensures rapid caloric delivery without filling the stomach too quickly. It’s one of the few supplements that truly delivers immediate energy and endurance, especially during recovery or growth phases.

Real-world testing shows Dyne works best when used as a targeted boost, not a long-term staple. It’s incredibly effective at getting picky eaters to consume more calories, thanks to its palatability and liquid convenience. The 16 oz bottle lasts weeks with standard dosing (a few teaspoons daily), and shaking before use ensures even nutrient distribution. However, it lacks the muscle-building proteins found in powders like Bully Max or All American Canine, so it supports weight gain more through fat than lean mass. Some dogs may experience loose stools if the dose isn’t gradually introduced.

Against other liquids, Dyne stands out as the best for picky eaters—its flavor and texture win over even the most reluctant diners. While Under the Weather Ready Cal offers similar gel convenience, Dyne’s higher fat content gives it an edge in calorie density. It’s not ideal for dogs needing immune or joint support, but as a pure energy amplifier, it’s unmatched. Compared to the 11-in-1 chews, it’s less balanced but acts faster. For owners who need a rapid, reliable calorie push, Dyne is the go-to—especially when appetite is the main roadblock.

If you’re after serious bulk, this high-calorie powder from PET CARE Sciences delivers with a punch—each serving packs roughly 600 calories, making it one of the most energy-dense powders in the lineup. Designed for dogs recovering from illness or working breeds needing extra mass, it’s a muscle builder first, fortified with amino acids and natural supplements to support joint health during rapid gain. The sweet bacon flavor is a hit, and the 90-serving size offers great value for sustained use. It’s clearly built for owners who want to see visible size increases without switching their dog’s entire diet.

In practice, the powder mixes well with wet food, though it can settle at the bottom if not stirred thoroughly. Dogs respond quickly, especially when combined with moderate exercise, showing noticeable weight gain within weeks. The formula includes skin and coat-supporting nutrients, which helps offset common side effects of fast weight gain like dryness or inflammation. However, it lacks the immune-boosting or digestive aids found in more holistic formulas, and the ingredient list, while effective, isn’t as transparent as competitors like All American Canine. It’s best suited for short-to-mid-term bulking, not lifelong maintenance.

Next to Bully Max Liquid, this powder offers higher caloric volume per serving but misses the omega-3 and multivitamin depth. Compared to the budget-friendly chews, it’s far more potent but less convenient for on-the-go use. It’s the best high-calorie powder for owners focused on muscle and mass, especially for show dogs or those recovering from injury. While not the most balanced option, its raw caloric power and USA-made quality make it a top contender when size is the priority.

Bully Max Liquid isn’t just a weight gainer—it’s a 2-in-1 multivitamin powerhouse that redefines what a liquid supplement can do. Fueled by whey protein and omega-3-rich fish oil, it supports lean muscle development, skin hydration, and coat shine, all while delivering concentrated calories for healthy weight gain. Its gel-like consistency makes it easy to mix into food or feed directly, and it’s safe for dogs as young as 4 weeks old, making it one of the most versatile options available. It’s especially effective for underweight puppies or adults needing both nutrition and recovery support.

Field testing reveals strong results in coat improvement and energy levels, not just weight. Dogs gain mass without excessive fat, thanks to the high-quality protein base. The 16 oz pouch is convenient and resealable, though some users report leakage if not stored upright. It’s highly digestible with no common fillers, and the absence of artificial ingredients builds trust. However, it’s thicker than Dyne, so it doesn’t pour as easily, and picky dogs may need time to adjust to the taste. It’s not the highest calorie option, but its nutritional breadth makes every calorie count.

Against PetAg Dyne, Bully Max wins in overall health impact—it’s not just about calories but long-term vitality. Compared to the senior-focused powder, it’s more inclusive across life stages. It’s the best liquid supplement for owners who want more than just weight gain—think immune support, joint health, and coat quality in one bottle. While pricier than Dyne, it offers superior ingredient quality and broader benefits, making it a smarter long-term investment for dogs needing comprehensive nutritional support.

All American Canine sets the gold standard for overall performance, blending high-calorie fuel, muscle support, and appetite stimulation into one all-natural powder. With ingredients like beef broth protein, whey, flaxseed, and blueberry powder, it’s formulated for rapid weight gain and recovery, making it ideal for dogs bouncing back from illness or surgery. The 60-serving size is practical, and the beefy taste ensures high palatability—even for dogs with zero interest in food. It’s not just about calories; it’s about whole-body restoration, with joint, immune, and digestive support built in.

In real use, dogs show increased energy and appetite within days, and the powder dissolves well in both wet and moistened dry food. The probiotics and kelp aid digestion, reducing the bloating or discomfort that can come with fast weight gain. Unlike simpler calorie boosters, this formula prevents gains from being “empty” by including essential vitamins and antioxidants. However, it’s not as calorie-dense as PET CARE Sciences’ 600-calorie powder, so it may take longer to see dramatic size changes in very underweight dogs. It’s also more expensive than most, but the ingredient quality justifies the cost.

Stacked against others, it beats Dyne in nutritional completeness and outperforms the senior-specific powder in speed of results. While Bully Max Liquid offers similar benefits, this powder is easier to dose and store. It’s the best overall because it balances speed, safety, and sustainability—perfect for dogs needing fast, healthy recovery without cutting corners. For owners who want maximum impact with minimal hassle, this is the ultimate all-in-one solution.

When your dog is sick, post-surgery, or refusing food, Ready Cal becomes a lifeline. This high-calorie gel is veterinary formulated to jumpstart recovery, delivering 10 vitamins, 7 minerals, and omega fatty acids in a nutrient-dense package that’s easy to administer. The dial-a-dose tube is a standout—no guesswork, no mess—and it allows for precise, controlled feeding even when your dog is weak or uncooperative. It’s designed for short-term crisis use, making it the best for recovery when every calorie counts.

In practice, the gel’s soft texture and tasty flavor make it easy to syringe or dab on the gums, ensuring intake even when appetite is zero. Dogs respond well, showing improved energy and appetite within 24–48 hours. It’s not meant for long-term weight management, but as a rescue supplement, it’s unmatched. The formula supports immune function and skin health, which is crucial during healing. However, it’s low in protein, so it won’t build muscle—just sustain energy. It’s also smaller in volume (100cc), so multiple tubes may be needed for extended recovery.

Compared to Bovine Colostrum gel, Ready Cal has more vitamins and a more precise delivery system, though colostrum offers better immune priming. Against Dyne, it’s less calorie-dense but more medically targeted. It’s not a daily supplement, but as a recovery specialist, it outperforms all others. While the chews are cheaper, they can’t match this level of emergency nutritional support. For owners facing a sick or recovering dog, this is the essential first-aid nutrition tool.

This 2-in-1 nutritional gel stands out by harnessing the natural power of bovine colostrum, a rich source of immunoglobulins and growth factors that support immune resilience and recovery. It’s not just a weight gainer—it’s a whole-body reboot, especially for senior pets or those recovering from stress or illness. The high-calorie gel delivers dense energy while gently encouraging appetite, making it a top pick for older dogs who’ve lost interest in food. Its dual-species design is a bonus, allowing cat owners to use it too—rare in this category.

In real-world use, it’s easy to administer and well-tolerated, though the brand wisely recommends starting with a reduced dose to monitor tolerance. Dogs show improved vitality and eating behavior within days, and the natural flavor helps even skeptical pets accept it. It’s not the most calorie-packed option, but its immune-boosting properties make it ideal for dogs with chronic issues or weakened systems. However, it’s not suitable for diabetic pets, and the 1/3 to full dose ramp-up may slow initial progress. It’s best used as a supportive supplement, not a sole calorie source.

Next to Ready Cal, it’s less precise in dosing but wins in immune fortification. Compared to the muscle-focused powders, it’s weaker in protein but stronger in long-term health resilience. It’s the best immune support option—perfect for dogs with frequent infections, post-antibiotic recovery, or age-related immune decline. While less flashy than high-calorie powders, its natural, holistic approach offers deep, lasting benefits that go beyond the scale.

These muscle gain chews are a budget-friendly powerhouse, packing 11-in-1 support into a tasty, treat-like format. Infused with essential amino acids—L-Arginine, L-Leucine, and L-Glutamine—they’re designed to fuel lean muscle growth and repair, making them ideal for active dogs or breeds like Bulldogs needing extra mass. The chicken flavor is a hit, and the 150-chew count offers exceptional value, especially for owners supplementing long-term. At under $13, it’s the best budget-friendly option that doesn’t sacrifice key ingredients like salmon oil, turmeric, and glucosamine.

In practice, the chews work well as daily supplements or training rewards, providing sustained energy and joint support without digestive upset. Dogs love them, so compliance is never an issue. However, they’re lower in total calories than powders or liquids, so they won’t drive rapid weight gain alone. They’re better suited for gradual muscle building than emergency recovery. The formula lacks the high-calorie density of liquid boosters, and the chews may be too large for small breeds unless broken up.

Compared to All American Canine or Bully Max, it’s less intense but far more affordable. Against Dyne, it’s not a calorie match but offers better long-term joint and inflammation support. It’s perfect for owners who want consistent, low-cost muscle support without daily mixing. While not for dogs needing immediate weight restoration, it’s an excellent maintenance or starter supplement. For the price, it delivers remarkable value and palatability, making gains enjoyable instead of medicinal.