The struggle to gain weight isn’t about eating more—it’s about eating the right calories in a format your body can actually use. Skinny guys, hardgainers, and those recovering from illness often find themselves drinking heavy shakes that leave them feeling bloated without the muscle payoff, or worse, piling on pure fat instead of lean tissue.
I’m Mohammad — the founder and writer behind ProteinJug. My research focuses on dissecting supplement label claims, verifying ingredient quality against third-party lab reports, and comparing macronutrient ratios across hundreds of mass gainers to identify which products actually deliver on their protein-per-scoop promises.
This guide breaks down the seven most effective products I’ve found for packing on size, comparing calorie density, protein sources, and digestive tolerance so you can pick the right tool for your metabolism. These are the top candidates for the title of best thing to gain weight without the unnecessary junk.
How To Choose The Best Thing To Gain Weight
Not all weight gain supplements are created equal. Some are just protein powders with extra carbs, while others are full meal replacements packed with vitamins and minerals. The key is matching the product to your metabolic needs and digestive comfort.
Calorie Density vs. Serving Size
A mass gainer that requires four scoops for 600 calories forces you to drink more volume, which can be hard to stomach. Look for products that deliver high calories in fewer scoops—this makes it easier to hit your surplus without feeling overly full. Products like the MuscleMeds CARNIVOR Mass Gainer pack over 700 calories in a moderate serving, while others require larger volume for the same energy.
Protein Source and Digestive Tolerance
Whey-based gainers are common, but they can cause bloating for lactose-sensitive individuals. Beef protein isolate, egg white, and pea protein offer excellent alternatives with zero lactose. The Animal Meal uses a whole-food blend that’s gentle on digestion, while the Optimum Nutrition Gold Standard Pro Gainer relies on a whey blend that works well for those without dairy sensitivity.
Carb Quality and Sugar Content
Cheap mass gainers use maltodextrin and sugar to spike calories, leading to fat gain and energy crashes. Premium options use oats, sweet potato powder, or tapioca dextrose for slower-digesting carbs that support muscle glycogen without the sugar spike. Check the carb source—whole-food carbohydrates always outperform simple sugars for lean mass accumulation.
Quick Comparison
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| Model | Category | Best For | Key Spec | Amazon |
|---|---|---|---|---|
| Optimum Nutrition Pro Gainer | Premium Mass Gainer | Serious caloric surplus | 650 cal, 60g protein | Amazon |
| MuscleMeds CARNIVOR Mass | Beef Protein Gainer | Lactose-free bulking | 700+ cal, 50g protein | Amazon |
| Animal Meal | Whole Food Replacement | Clean meal replacement | 500 cal, 46g protein | Amazon |
| Animal M-Stak | Supplement Packs | Hardgainers needing a boost | 21 packs, pill form | Amazon |
| Jocko Fuel Whey Protein | Lean Protein | Adding protein without carbs | 22g protein, low sugar | Amazon |
| KATE FARMS Organic Shake | Medical Nutrition | Gentle weight gain | 455 cal, 20g protein | Amazon |
| Optimum Nutrition Creatine | Performance Powder | Muscle fullness & strength | 5g creatine per serving | Amazon |
In‑Depth Reviews
1. Optimum Nutrition Gold Standard Pro Gainer
Optimum Nutrition is a brand you can trust, and this Pro Gainer delivers a massive 650 calories with 60 grams of protein per serving. The Vanilla Custard flavor is rich and creamy, mixing easily in a shaker without clumps. Users report gaining 5 pounds in under a week with just one shake daily, which speaks to the calorie density and absorbability.
With over 80 grams of carbohydrates and less than 8 grams of sugar, the carb source is primarily from a maltodextrin blend that provides quick energy without excessive sugar spikes. This makes it ideal for post-workout recovery or as a calorie-dense meal replacement for those struggling to eat enough food.
The whey protein blend is effective, but those with lactose sensitivity may experience some bloating. The serving size is also quite large, requiring a substantial volume of liquid to mix, which might be difficult for some users to finish in one sitting. Despite this, it remains the most reliable high-calorie option on the market.
Why it’s great
- High protein-to-calorie ratio for lean mass gains
- Taste and mixability are industry-leading
- Rapid results reported by users within 1-2 weeks
Good to know
- Lactose may cause issues for sensitive individuals
- Large serving size requires a big shaker or blender
- Serving count is 14, not 28 as some expect
2. MuscleMeds CARNIVOR Mass Gainer
If dairy wreaks havoc on your digestion, this beef protein isolate mass gainer is a game-changer. At over 700 calories with 50 grams of protein per serving and zero fat or sugar, it delivers a clean caloric surplus without the bloat. The chocolate peanut butter flavor is surprisingly palatable for a beef-based product, tasting more like chocolate milk than you’d expect.
The protein source is 350% more concentrated in amino acids than steak, and the carb load of 125g is designed to spike insulin and glycogen synthesis, which is exactly what hardgainers need. Users with fast metabolisms report this helps them maintain and gain weight after failing with other gainers. It mixes thin enough to drink three scoops in one shaker without turning into pudding.
On the downside, the fine powder can become sticky and clumpy if not mixed properly, and a blender is recommended for best results. The high carb count also means it’s not for those watching their carb intake. Some users note a faint beef aroma, though the flavoring largely masks it.
Why it’s great
- Zero lactose and dairy-free, perfect for sensitive stomachs
- Very high calorie density in a manageable serving
- Fast-absorbing protein and carbs for muscle synthesis
Good to know
- Requires a blender for smooth consistency
- High in carbs, not suitable for low-carb diets
- Slight beef aftertaste in some batches
3. Animal Meal
Animal Meal is not your typical mass gainer—it’s a meal replacement that actually tastes and feels like real food. With 500 calories and 46 grams of protein from egg white, beef protein isolate, and pea protein, it avoids the whey concentrate and maltodextrin found in most gainers. The chocolate flavor is naturally sweetened with stevia and monk fruit, without any artificial aftertaste.
The carb blend comes from sweet potato powder, pea starch, tapioca dextrose, and rolled oats, providing slow-release energy that won’t spike blood sugar. Users report it digests easily and keeps them full for hours, making it a solid choice for replacing a meal or adding a nutritious shake between meals. Improved energy levels are noted within a week of daily use.
It’s not the cheapest option per serving, with about 20 servings per container, so daily use adds up. The texture is slightly gritty due to the real food ingredients, though it mixes well with a shaker. Those expecting a super-sweet candy flavor may be disappointed, but users who prioritize clean ingredients love it.
Why it’s great
- Clean, whole-food ingredients with no artificial fillers
- Lactose-free and gentle on digestion
- Sustained energy from complex carb sources
Good to know
- Premium price per serving compared to standard gainers
- Slightly gritty texture from real food powders
- Only 20 servings per container
4. Animal M-Stak
Animal M-Stak takes a different approach to weight gain—instead of dumping calories, it uses nutrient partitioning to help your body direct the food you eat toward muscle rather than fat. Designed specifically for hardgainers, this 21-day pack contains six different complexes that support nitrogen retention, reduce cortisol, and increase anabolic drive. It’s not a mass gainer powder, but a pill-based supplement that enhances your existing diet.
Users report gaining 10-15 pounds of muscle over a cycle, along with improved energy and recovery. The pre-workout energy boost comes from a caffeine component, which some users skip if they want to avoid stimulants. It’s ideal for those who already eat enough calories but still can’t seem to keep weight on.
The pills are large, which may be a downside for those who struggle with swallowing supplements. Some initial dehydration is reported, so extra water intake is necessary. It also works best when combined with a solid training and nutrition plan, rather than as a standalone solution.
Why it’s great
- Specifically targets hardgainers who struggle to gain weight
- Supports muscle gain without adding body fat
- Convenient pack format for easy daily dosing
Good to know
- Large pills can be difficult to swallow
- Requires a solid diet to see best results
- May cause initial dehydration if water intake is low
5. Jocko Fuel Whey Protein Powder
Jocko Fuel’s MÖLK is a protein blend of whey concentrate, whey isolate, micellar casein, and egg protein, creating a time-release effect that keeps amino acids flowing for hours. The chocolate peanut butter flavor is exceptional, with a clean sweetness from monk fruit and allulose that avoids artificial aftertaste. It mixes thick and creamy, perfect for adding to Greek yogurt or blending into a shake.
With digestive enzymes and probiotics included, it’s formulated to reduce bloating and improve gut health, which is a common problem with other protein powders. At 22g of protein per serving and minimal carbs/sugar, this is more of a lean protein supplement than a mass gainer. It’s best used as an add-on to a calorie-surplus diet rather than a standalone weight gain solution.
The price point is higher than standard whey, and the bag’s Ziploc seal tends to fail after repeated use. Some users find the scoop large for the serving size. It’s an excellent choice for those who want high-quality protein without excess calories or sugar, but it won’t provide the caloric punch of a dedicated mass gainer.
Why it’s great
- Superior taste, especially chocolate peanut butter
- Time-release protein supports sustained growth
- Digestive enzymes and probiotics reduce bloating
Good to know
- Higher cost per serving than basic whey
- Not a mass gainer—low in calories
- Bag Ziploc seal prone to failure
6. KATE FARMS Organic 1.4 High Calorie Shake
KATE FARMS offers a medical-grade nutrition shake that’s USDA Organic, Non-GMO, and free from common allergens. At 455 calories with 20g of protein and 27 vitamins and minerals per bottle, it’s a complete meal replacement in a ready-to-drink format. The vanilla flavor is smooth and neutral, making it easy to blend with fruit or peanut butter for extra calories.
This shake is designed for those with increased calorie and protein needs—whether due to medical recovery, aging, or struggling with appetite. Users report it helps with weight gain and digestive issues, and one reviewer noted it was a lifesaver for their 91-year-old mother. The plant-based phytonutrients from organic fruits and vegetables add an extra nutritional boost.
The biggest drawback is the cost—at roughly per bottle, it’s significantly more expensive than powder alternatives. Some users also receive the wrong variant in shipments, so careful ordering is required. The vanilla flavor, while pleasant, may need additions to taste truly delicious.
Why it’s great
- USDA Organic with clean, verified ingredients
- Ready-to-drink convenience, no mixing required
- Complete nutrition with vitamins and minerals
Good to know
- Very expensive per serving
- Vanilla flavor benefits from added fruit or sweetener
- Package variant errors reported in shipments
7. Optimum Nutrition Micronized Creatine
Creatine monohydrate is the single most researched and effective supplement for increasing muscle mass and strength. This Optimum Nutrition version is micronized, meaning the powder particles are smaller, which allows for better mixing and absorption. It’s unflavored, so it dissolves completely in any beverage without altering taste—no grit, no clumps, just easy daily dosing.
While it doesn’t provide direct calories like a mass gainer, creatine increases water retention in muscle cells, giving you fuller, harder-looking muscles while also improving strength output. Users report noticeable gains in performance and muscle size within weeks. The 600-gram container provides 120 servings at 5 grams each, offering exceptional value.
Some users note that it doesn’t come with a scoop, which can make measuring inconvenient. Also, it’s not a weight gain solution on its own—you still need a calorie surplus to see size increases. It’s best used as a foundational supplement alongside any mass gainer or meal replacement for maximum results.
Why it’s great
- World’s most researched muscle-building compound
- Micronized powder mixes instantly with no grit
- Exceptional value with 120 servings per tub
Good to know
- No scoop included for measuring
- Requires a caloric surplus for visible weight gain
- Unflavored, but mixes easily in anything
FAQ
Can I use creatine monohydrate to gain weight?
How many calories per day should a mass gainer provide?
Why do I feel bloated after using mass gainers?
Final Thoughts: The Verdict
For most users, the best thing to gain weight winner is the Optimum Nutrition Gold Standard Pro Gainer because it delivers the highest protein-to-calorie ratio in a proven, great-tasting formula that works fast. If you want a lactose-free option that still packs a caloric punch, grab the MuscleMeds CARNIVOR Mass Gainer. And for whole-food clean bulking with zero dairy, nothing beats the Animal Meal.