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A mass gainer does exactly what it says: it adds a lot of calories fast. That is great if you struggle to eat enough. It is less great if you drink a full 1,000-plus calorie shake on top of three big meals and wonder where your abs went. Here is how to use one so the weight you gain is mostly the kind you want.
The short answer
Quick answer
Start with half a serve once a day, between meals or after training, and weigh yourself every week. Half a serve of the mass gainers we stock is 515 to 640 calories with 25 to 26 g of protein. Aim to gain 0.25 to 0.5% of your bodyweight a week: trim the serve if you gain faster, and go up to a full serve only if the scale has not moved after two or three weeks.
- Start with half a serve once a day, not a full one.
- Aim to gain 0.25 to 0.5% of your bodyweight a week. Slower gains mean less fat.
- Drink it between meals or after training, not with a meal.
- Mix with water first, then switch to milk only if you need more calories.
- Weigh yourself weekly and adjust the serve based on the trend.
Start with half a serve
Full gainer serves are big. A loaded serve of Basic Mass Gainer gives you 50g of protein and 190g of carbs for over 1,000 calories. The Dymatize Super Mass Gainer 6lb sits at 1,280 calories and 52g of protein per serve, with a small dose of creatine in each one.
For a lot of people, that is close to a third or even half of their daily calories in one drink. Jumping straight in often ends in bloating, a sluggish gut and faster fat gain than you wanted.
Half a serve is still a meaningful 500 to 650 calories with 25g or more of protein. That is plenty to push most skinny lifters into a surplus. If the scale is not moving after two or three weeks, go up to a full serve.
| Gainer and serve | Powder | Calories | Protein | Carbs |
|---|---|---|---|---|
| Basic Mass Gainer, half serve | 132.5 g | 515 | 25 g | 95 g |
| Basic, full serve | 265 g | 1,030 | 50 g | 190 g |
| Dymatize Super Mass Gainer, half serve | 167.5 g | 640 | 26 g | 122.5 g |
| Dymatize, full serve | 335 g | 1,280 | 52 g | 245 g |
When to move to a full serve
Go up, within the label directions, only when all three are true:
- Your weekly weigh-ins have not moved after two or three weeks on half a serve.
- The half serve sits well and you are still eating your normal meals.
- Your training is progressing and your lifts are going up.
Aim for slow gain
The biggest mistake with gainers is gaining too quickly. Your body can only build muscle so fast, and any extra surplus beyond that mostly ends up as fat.
A good target for most lifters is to gain around 0.25 to 0.5% of bodyweight per week. Research on off-season bodybuilders supports a modest surplus in that range to limit fat gain (Iraki et al., 2019).
For a 70kg lifter, that is roughly 0.2 to 0.35kg a week. It sounds slow, and it is. But over a few months it adds up to real, visible size, and you will not need a brutal cut afterwards. If you are gaining faster than about half a kilo a week, trim the serve.
When to drink it
Timing matters less than total intake, but some slots work far better than others.
Between meals is the best spot. Mid morning or mid afternoon, a gainer adds calories without replacing food. Drink it with lunch and you often eat less lunch, which cancels out the point.
After training is the other good slot. You get protein and carbs in when it is convenient, and a lot of people find a liquid easier to get down than a big meal straight after a hard session.
Before bed can work for some people, but a huge shake late at night keeps others awake. Test it.
Mixing tips
- Water or milk? Start with water. It makes a lighter drink and fewer calories. If you are still struggling to gain, switch to milk for an easy extra boost.
- Use a blender. A full serve of gainer is a lot of powder, and a shaker leaves clumps. A blender makes it smoother and faster to drink.
- Add real food. A banana, a spoon of peanut butter or some oats all blend in well and add calories that do not taste like a supplement.
- Sip, do not chug. Take 10 to 15 minutes to finish it if it sits heavy.
Powder in one serve
Serving weight as listed on each label: the two mass gainers we stock (blue) against four whey powders (black). NZ Supps range, September 2026.
A full gainer serve is roughly 7 to 10 times the powder in one whey scoop, which is why a blender beats a shaker.
Those four whey scoops carry 116 to 140 calories each. If you already eat enough and only fall short on protein, whey protein is the lighter option.
A sample day
Here is how a 70kg lifter aiming to reach 80kg over time might fit a half-serve gainer into a normal day. Adjust portions to your own appetite and weigh-ins.
| Time | What | Notes |
|---|---|---|
| 7am | Breakfast: oats, eggs, fruit | Normal meal |
| 10am | Half serve gainer with water | Between meals |
| 1pm | Lunch: rice, chicken, veg | Normal meal |
| 5pm | Training | Lift 3 to 5 days a week |
| 6pm | Dinner: meat, potatoes, veg | Main post-training meal |
| 9pm | Greek yoghurt or toast | Optional snack |
Going from 70kg to 80kg at the pace above would take somewhere between about seven months and a year. That is the honest timeline for gaining mostly muscle.
Signs you are overdoing it
Warning signs
- You are gaining more than about half a kilo a week, week after week.
- Your waist is growing much faster than your lifts are going up.
- You feel constantly bloated or sluggish after the shake.
- You are skipping meals because the gainer leaves you too full.
If any of these sound familiar, drop back to half a serve or less, and check that your training is progressing.
Where NZ Supps fits
We stock a full range of mass gainers, including the Basic Supplements gainers in several flavours and sizes. If you are still deciding which to buy, our best mass gainers ranked by price guide lines them up.
Not sure whether you need a gainer at all? Read mass gainer vs whey and mass gainer vs weight gainer, or browse our build muscle range for the rest of a bulking stack.
FAQ
How much mass gainer should I take a day? Start with half a serve once a day. A full serve of most gainers is over 1,000 calories, which is a lot on top of normal meals. Move to a full serve only if your weight is not moving after two or three weeks.
When is the best time to drink a mass gainer? Between meals or after training works best. Drinking it with a meal often just replaces food you would have eaten anyway, which defeats the purpose. Mid morning, mid afternoon or post-workout are the easiest slots.
Will a mass gainer make me fat? Only if the surplus is too big. Aim to gain about 0.25 to 0.5% of your bodyweight a week and adjust the serve up or down to stay in that range. Lifting hard while you bulk also helps more of the extra calories go toward muscle.
Should I mix mass gainer with milk or water? Water if you want an easier drink with fewer calories, milk if you need every calorie you can get. A blender makes a big difference with gainers because a full serve is a lot of powder for a shaker.
Is a mass gainer good for beginners? It can be, especially for skinny lifters who struggle to eat enough. Just start at half a serve, keep lifting consistently, and track your weight weekly so you can adjust.
