A mass gainer is a convenient way to add calories and protein when you struggle to eat enough for your weight-gain goals. Start with one serve mixed in water or milk, following the label. Most people take it post-workout, between meals, or before bed to top up a calorie surplus. If a full serve feels like too much, split it into a half serve twice a day.
Quick facts
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How much: one serve as per the label, mixed in a shaker or blender
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Mix with: water for lighter, milk for extra calories and a creamier shake
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When people take it: post-workout, between meals, or before bed — whatever helps you hit your daily calories
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Half-serve strategy: split one serve into two smaller shakes if a full serve is too filling
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Food-first option: a homemade blend of oats, milk, peanut butter and banana is a whole-food alternative
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Works alongside: resistance training and a consistent calorie surplus, not instead of them
How much mass gainer should you take per serve?
Start with the serving size on your product label and adjust from there. A mass gainer is a high-calorie powder, so one full serve delivers a large chunk of calories, carbohydrate and protein in a single shake. That is the point: it gives you a convenient way to add calories and protein when whole food alone is not getting you to your target.
How much you actually need depends on the gap between what you already eat and your daily calorie goal. Most people do not need a full serve every day. If you are only a few hundred calories short, a half serve may be plenty. If you are a hardgainer with a small appetite, a full serve (or a serve split across the day) helps close a bigger gap.
Always read the label for the serving size and macros of your specific product, because they vary a lot between brands. For example, Emrald Post Mass, sits toward the higher-calorie end, while a lean gainer like Emrald Lean Gainer uses a leaner carb-to-protein ratio
When should you take a mass gainer?
There is no magic window. A mass gainer supports weight-gain goals because it adds to your total daily calories, so the best time is simply whenever it helps you hit that total consistently. That said, three timings suit most people.
Post-workout. A shake after training is an easy, practical way to get calories and protein in when you may not feel like a full meal. It is convenient rather than magic, and it works because it tops up your daily total.
Between meals. If you find it hard to eat enough at meals, a shake mid-morning or mid-afternoon adds calories without filling you up the way a big plate of food does. This is often the most useful slot for people with a small appetite.
Before bed. Some people have a shake in the evening to add calories they could not fit in during the day. If a full serve feels heavy at night, a half serve or a milk-based blend is easier to get down.
The honest summary: consistency across the week matters far more than the exact time of day. Pick the slot that fits your routine and stick to it.
How to make a mass gainer shake
A basic shake takes about a minute.
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Add your liquid first. Pour 300 to 400 ml of water or milk into a shaker or blender. Liquid first helps the powder mix cleanly instead of clumping at the bottom.
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Add one serve of powder. Use the scoop provided and level it off. Check your label for the exact serving size.
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Shake or blend for 20 to 30 seconds. A blender gives the smoothest result, especially for higher-calorie powders that are thicker.
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Drink it fairly soon. Gainer shakes thicken as they sit, so they are best fresh.
Want to make it a bigger meal-style shake? Blend in extras like a banana, a tablespoon of peanut butter, or a handful of oats for more whole-food calories and fibre. Milk instead of water adds more calories and protein again.
A homemade mass gainer (food-first alternative)
You do not strictly need a powder to build a high-calorie shake. A homemade blend is a food-first way to add calories, and it is handy if you have run out of gainer or prefer whole ingredients. A simple, well-known combination:
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1 cup milk (dairy or a higher-calorie plant milk) — the calorie base
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1 banana — carbohydrate, plus it makes the shake smoother and sweeter
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1 to 2 tablespoons peanut butter — calorie-dense healthy fats and some protein
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1/2 cup rolled oats — slow-digesting carbohydrate and fibre
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Optional: a scoop of whey or your usual protein to lift the protein content
Blend until smooth. This gives you a genuinely calorie-dense shake from whole food. The trade-off versus a commercial gainer is convenience and consistency: a powder is faster, portable, and gives you a known calorie and protein figure every time, which makes hitting a daily target simpler. Many people use both, whole-food shakes on some days and a gainer when they are busy or travelling.
Mixing tips
A few small things make gainer shakes far more pleasant.
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Liquid before powder. This is the single biggest fix for clumping.
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Use a blender for thick, high-calorie powders. Shakers are fine for lighter serves; blenders win for large, carb-heavy ones.
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More liquid = thinner and easier to drink. If a shake feels like a meal you cannot finish, add more water or milk and it goes down easier.
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Cold liquid and a little ice improve the taste and texture, especially post-workout.
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Do not over-fill your gut before training. If a big shake sits heavily, have it after your session instead.
The half-serve strategy
A full serve of a high-calorie gainer can feel like a lot, especially if you have a small appetite or you are new to it. Splitting one serve into two half serves across the day is a practical fix.
Two smaller shakes are gentler on your stomach, easier to finish, and spread the calories out so you are not forcing down a huge drink in one go. This is often the difference between someone sticking with a gainer and quietly giving up on it. It can also help settle any bloating or fullness some people notice when they start (described neutrally: this is general product-use guidance, not medical advice).
If you are still full at meals after using a gainer, that is a sign to pull the serving back, not push through. The goal is a manageable calorie surplus you can hold for weeks, not a single heroic shake. A leaner, lower-volume option like Emrald Lean Gainer can also suit people who find full gainers too filling.
Stack it (optional)
Many people who are bulking pair a mass gainer with creatine monohydrate, one of the most researched training supplements. Creatine supports strength and training performance when combined with resistance training, and it is easy to add a daily dose to your gainer shake. Browse the creatine range, or grab the convenience of the Post Mass and Creatine bundle. As always, a supplement supports a solid diet and training plan rather than replacing it.
This article is general information, not medical advice. If you are underweight for medical reasons, have a health condition, or take medication, talk to your GP or an accredited practising dietitian before changing your diet.
Frequently asked questions
How much mass gainer should I take a day?
Start with one serve as per your product label and adjust to the gap between what you already eat and your daily calorie goal. If you are only slightly short, a half serve may be enough; a bigger appetite gap may suit a full serve or a serve split across the day. Read your specific label, because serving sizes and calories vary a lot between products.
When is the best time to take a mass gainer?
There is no magic window. A mass gainer supports weight-gain goals by adding to your total daily calories, so the best time is whenever helps you hit that total consistently. Common slots are post-workout, between meals, or before bed. Consistency across the week matters far more than the exact time of day you drink it.
How do you make a mass gainer shake?
Add 300 to 400 ml of water or milk to a shaker or blender first, then one level serve of powder, then shake or blend for 20 to 30 seconds. Milk adds more calories and a creamier texture than water. Blend in a banana, oats or peanut butter for a bigger meal-style shake, and drink it fresh before it thickens.
Can I make a homemade mass gainer?
Yes. Blend 1 cup of milk, 1 banana, 1 to 2 tablespoons of peanut butter and half a cup of rolled oats for a calorie-dense whole-food shake, adding a scoop of protein if you like. It is a good food-first option. A commercial gainer is faster, portable and gives a known calorie and protein figure each time, which makes hitting a daily target simpler.
Can I take a mass gainer without working out?
A mass gainer just adds calories and protein, so it will add to your total whether you train or not. For weight gain that favours muscle rather than mostly fat, a gainer supports muscle gain when combined with resistance training and a calorie surplus. Without training, extra calories are more likely to be stored as body fat.
Should I take a full serve or a half serve?
Take whatever helps you hit a manageable calorie surplus you can sustain. A full serve of a high-calorie gainer can feel very filling, so splitting it into two half serves across the day is often easier on your stomach and easier to finish. If you are still full at meals, reduce the serving rather than forcing it down.
