Best Weight Gainer For Teenagers in the UK in 2023

A picture of Best Mass Gainer UK founder, personal trainer Andy Williams
Written By
Andy Williams
Last Updated on
Best Carbs-To-Protein Ratio
Photo of the Transparent Labs Mass Gainer scoop and tub
Transparent Labs Mass Gainer
The #1 Mass Gainer For Teens 
Two bags of Crazy Nutrition Mass Gainer
Crazy Nutrition Mass Gainer
Best Value Mass Gainer For Teens
A bag of Bulk Mass Gainer
Bulk Mass Gainer

A mass gainer is a useful supplement for teenagers who want to gain weight and increase the size of their muscles. The trick is to make sure you buy a good product that has healthy ingredients that actually work.

Having started taking weight gainers as a teen myself—and having tested over 60 of them in recent months—I think I’m in a strong position to recommend the best mass gainer for teenagers who want to gain muscle mass.

In addition to reviewing the best weight gainers for teens, I’ll be explaining why most mass gainers are actually perfectly safe for teenagers to consume—providing that they’re used correctly. More on that later.

Top 7 Best Weight Gainers For Teenagers in the UK 

Here are the 7 best weight gainers for teenagers who want to gain strength and muscle mass. Any of these mass gainers will help you gain muscle size and increase your strength, but I do think that some are better than others, as you’re about to learn.

1. Crazy Nutrition Mass Gainer — #1 Best Mass Gainer For Teenagers

Two bags of Crazy Nutrition Mass Gainer

With Crazy Nutrition Mass Gainer, teenagers don’t need to choose between building muscle and staying healthy. Even though this looks like a very hardcore supplement with its black and yellow packaging, the ingredients are 100% clean and highly nutritious.

For example, the 488 calories—an ideal amount for teens to create a calorie surplus—come from whey protein, milk protein, oats, and MCTs.

The 40-gram combination of whey and milk protein means that your muscles will get stronger quicker because they’re receiving a blend of both fast-acting and slow-digesting amino acids.

Also, unlike other weight gainers, Crazy Nutrition Mass Gainer uses oats for its 55g of carbohydrates rather than cheap, bloat-inducing maltodextrin, making this supplement the best weight gainer for teenagers by far.

The 10.5g of healthy fats come from MCTs, which provide a convenient source of energy that teens can easily burn off during exercise.

Bags of Crazy Nutrition Mass Gainer in chocolate and Vanilla

And with less than 8g of sugar per serving, Crazy Nutrition Mass Gainer doesn’t give you that big energy crash that so many other weight gainers do, making it ideal for teenagers who’re looking to bulk up.

I really like the fact that this supplement is formulated with digestive enzymes so that you can make the absolute best possible use of all the weight-gaining nutrients that you’re consuming—you won’t waste any calories or protein when you get Crazy Nutrition Mass Gainer.

And as any Crazy Nutrition Mass Gainer reviews will tell you, the taste is absolutely delicious. Seriously, other supplement manufacturers should take note, because Crazy Nutrition is way ahead of the game in the flavour department.

  • Rated as the #1 best mass gainer for teenagers in the UK and US
  • Provides 488 clean and effective calories for teens to gain weight
  • Provides a sizeable 39.73g of protein per serving for muscle growth and repair
  • Fuels workouts and weight gain with 55g of carbs from oats
  • Has less than 8g of sugar—get energised without the crash
  • Amazing taste and excellent mixability
  • A bit expensive unless you subscribe and save

2. Transparent Labs Mass Gainer — Best Carbs-To-Protein Ratio

A tub of mass gainer from Transparent Labs along with a shaker cup and scoop

Providing 750 clean calories, 110g of organic carbohydrates, and 53g of grass-fed whey protein, Transparent Labs Mass Gainer is easily one of the best mass gainers for teens that you can buy.

The 2:1 carbs-to-protein ratio is considered ideal by many for bulking up because it gives you the carbohydrates that you need to increase your body weight and the protein that you need to build and repair muscle.

You’ll be pleased to know that Transparent Labs Mass Gainer is also third-party tested for purity, so you can be confident that you’re getting a safe and effective weight gain shake here.

I like that Transparent Labs includes 14g of good fats from coconut milk powder and MCTs because healthy fats like these really are important for growing teenagers.

Photo of the Transparent Labs Mass Gainer scoop and tub

It’s worth noting that each serving of Transparent Labs Mass Gainer contains 3 grams of creatine, which is used by a lot of teenage athletes who want to increase their muscle strength and size.

The only downside (for those of us in the UK) is that Transparent Labs Mass Gainer is a US product, meaning that, for us Brits, shipping can be a bit more expensive than usual. So unless Crazy Nutrition Mass Gainer is out of stock for some reason, you might want to save yourself money by sticking with the #1 choice.

  • Contains 750 calories in each delicious shake
  • Provides 53g of whey protein and 110g of organic maltodextrin for a 2:1 carbs-to-protein ratio
  • Includes 14g of healthy fats (that are easy to burn off) from MCTs and coconut milk powder
  • Mixes really well and doesn’t leave any clumps
  • Has 3g of creatine per serving for muscle strength and size
  • It’s expensive if you live in the UK
  • Not every teen wants creatine in their weight gainer

3. Bulk Mass Gainer — Best Value Mass Gainer For Teens

A bag of Bulk Mass Gainer

Although it might lack the firepower of the top 2 weight gainers for teenagers, Bulk Mass Gainer still packs an incredible amount of muscle-building ingredients into its teen-friendly formula.

What I love most about Bulk Mass Gainer is its simplicity—it’s basically just protein powder and oats, which provides a nutritious and convenient source of liquid calories.

One 538-calorie serving has 40g of protein from whey, milk, and eggs, meaning that you’re getting fast-digesting as well as slow-release protein, which creates the ideal internal environment for muscle growth.

A bag of Bulk Mass Gainer ready to be reviewed

As mentioned in my Bulk Mass Gainer review, the 66g of clean, complex carbs are 100% derived from oats, so you’re getting plenty of natural fibre (8 grams) for healthy digestion, and lots of energy to fuel your workouts and weight-gaining ambitions.

Unlike Transparent Labs Mass Gainer, Bulk Mass Gainer doesn’t have any creatine, meaning that you can take your own creatine separately at a dose of your choice if you so wish.

This mass gainer from Bulk is also a good option for parents because the shakes are smooth and tasty, meaning that you can easily get your teen to drink them regularly and put on some weight.

  • Provides a simple, clean formula with 538 healthy calories for bulking up
  • Contains 66g of complex carbohydrates from oats for long-lasting energy and workout fuel
  • Builds muscle with an optimal 40g of protein from whey, milk, and egg
  • Contains 8g of fibre to promote healthy digestion and better nutrient absorption
  • Tastes great and has a smooth texture (even with the oats!)
  • The oats can be quite filling if you’re not used to mass gainers

4. Warrior Mass Gainer — Highest Calorie Content

Warrior Lean Mass with a scoop and shaker bottle

Out of all the weight gainer supplements for teenagers on this list, Warrior Mass Gainer has the highest calorie content with 1059 calories per serving—plenty for an active teenager to put on weight.

Each serving provides a massive 61g of protein from whey and casein, which means that your muscles can stay in a growing state for longer because they’re getting quick amino acids from the whey and slow-digesting protein from the casein.

Warrior Mass Gainer has 180g of carbs and thus a 3:1 carbs-to-protein ratio, which is useful for getting in those extra calories without overconsuming protein.

A person making a serving of Warrior Mass Gainer in a blender

Even though the formula contains 47.5g of sugar, you’re getting a good blend of carbs from the waxy maize, the maltodextrin, and the Scottish oats, which gives you both fast fuel for training and steady energy throughout the day.

As I mentioned in my Warrior Mass Gainer review, opinions are mixed when it comes to the taste, but I really liked the Vanilla Cheesecake flavour because it was tasty but not overpowering. 

The only thing I found was that I needed to use a bit more liquid than the 300ml they recommended to achieve my desired consistency. But aside from that, I have no real complaints; you’re getting a big 5kg bag of mass gainer for a fair price.

  • Contains 1059 calories for teens to gain weight and muscle mass
  • Has 180g of carbs for mass-building workouts and weight-gain fuel
  • Provides 61g of protein from whey and casein for an optimal supply of amino acids
  • Affordable, GMO-free, and comes in a big 5kg bag
  • The flavours have mixed reviews
  • 1000+ calories might be too much for some teenagers

5. Serious Gainz — Cheapest

A tub of Serious Gainz next to a shaker bottle

If you don’t want to spend a lot of money but still want to make good gains, then Serious Gainz might just be the weight gainer that you’ve been looking for.

Packed with 468 calories, 81g of carbs, 30g of protein, and 3.5g of fat, Serious Gainz is undeniably effective for increasing your body weight.

As I said in my Serious Gainz review, this supplement is very good value for money because one 5kg tub will last you for 40 days if you have one shake per day. Much better value than CNP Mass XL.

The only downside, depending on your point of view, is that Serious Gainz uses soy protein, which isn’t to everyone’s liking. However, the high-calorie formula also has whey concentrate, whey isolate, and casein protein, so you’re getting a good balance of fast-acting and slow-digesting amino acids.

  • Provides an ideal amount of calories (468) for teens to achieve a surplus
  • Contains a sizeable 81g of carbs for oats and ultra-premium maltodextrin
  • Contains 30g of protein from fast-acting and slow-digesting sources for sustained muscle growth
  • Only has 3.5g of fat and 9g of sugar
  • Offers great value for money; a big 5kg tub will last longer than a month
  • Contains some soy protein

6. Nature’s Best Weight Gainer — Best All-In-One Formula

A weight gainer from Nature's Best

If you’re looking for an all-in-one UK-made formula, then Nature’s Best Weight Gainer is the best mass gainer for teens because one shake has an optimal dose of protein and creatine, as well as muscle-building extras like HMB and beta alanine.

What I especially like about this supplement is that the macros are really balanced. In other words, you’re not drinking hundreds of grams of sugar that you don’t need. Instead, you’re getting 34.8g of quality carbs from oats and maltodextrin and just 3.9g of sugar, which shows just how clean this UK-tested gainer really is.

Creatine is well-known for increasing muscle strength. But did you know that creatine can actually make you gain weight as well?

A mass gainer in a shaker bottle

Because creatine draws water into your muscle cells—helping your muscles to look bigger and fuller—this extra water weight actually leads to an increase in body mass, which can be really motivating because you’re getting fast weight gain in the first couple of weeks.

Obviously, if you’re already taking creatine, then the benefits won’t be noticeable.

Considering that this weight gainer has nearly 40g of whey protein per serving, I think you’re getting excellent value for money, especially considering that a medium-sized bag will last you for 20 full days.

To learn more, you can read my full Nature’s Best Weight Gainer review. Or, if you want to get started now, you can click below for the best UK price.

  • A great all-in-one weight gain shake for teenagers that’s made and tested in the UK
  • Contains 5g of creatine (the ideal dose) for muscle strength and extra weight gain
  • Provides 40g of protein and 35g of carbs for muscle mass accumulation
  • Has 1.5g of HMB to keep muscle loss at bay
  • Has less than 4g of sugar per serving
  • Tastes fantastic and mixes without any fuss
  • Some teens might not like the added beta alanine

7. Myprotein Impact Weight Gainer — Decent All-Rounder

A bag of Impact Weight Gainer from Myprotein

With 388 calories, 50g of carbs, and 31g of protein, you can’t go wrong with Myprotein Impact Weight Gainer.

Sure, it doesn’t have the next-level formula of Crazy Nutrition Mass Gainer, but it’s still a good supplement for the price.

People buy Impact Weight Gainer, it seems to me, because of Myprotein’s extreme popularity. And to be fair, the ingredients are really clean and effective because you’re getting whey protein, milk protein, oats, and only a bit of maltodextrin.

I just wish the calorie and protein content was a bit higher because research does show that a 40g protein dose is optimal for building muscle, especially after a weight lifting workout. 

Finally, the taste, although pleasant, was slightly gritting towards the end of the shake. This is an easy fix if you just add some extra water and shake again, and honestly, I was half expecting some grittiness considering the oat-dense formula.

You can check out my Myprotein Impact Weight Gainer review to find out more, or you can scroll down to get the lowest price.

  • Contains 388 quality calories to help teens put on weight and muscle
  • Supports muscle growth with 31g of protein from whey and milk
  • Almost all of the 50g of carbs are from oats
  • Has less than 3g of sugar
  • Ideal for teens who don’t need loads of extra calories
  • The texture can be a bit gritty towards the end of the shake

Can Teenagers Take Mass Gainers?

A man drinking a weight gainer

Many supplement companies don’t recommend their weight gainers for people under 18 (some say under 16). However, this doesn’t stop many parents from buying mass gainers for their teenage children, especially if their teen is athletic or goes to the gym.

We have to understand that a weight gainer is basically just a powder that contains liquid calories, such as whey protein, oats, and sometimes maltodextrin.

Elite athletes use mass gainers to help them meet their calorie requirements, and these people are, for the most part, extremely fit and healthy.

Mass gainers are obviously much healthier than junk food and energy drinks, which many teenagers consume on a daily basis at great detriment to their health.

So, in my opinion, teenagers can take mass gainers under the supervision of an adult if they need to gain weight.

See Also: Ronnie Coleman King Mass Gainer Review

How Should Teens Use Weight Gainers?

Weight gainer scoops with powder inside them

Put simply, teenagers should use weight gainers as a supplement to their diets (and so should adults, for that matter). Mass gainers are not the same as meal replacement shakes, meaning that most don’t contain added vitamins and minerals.

Teens should get most of their calories from whole foods and then take a serving of the best weight gainer for teenagers in order to achieve a calorie surplus, which is required to gain weight.

Don’t try and rush weight gain by drinking loads of mass gainer, as this will just lead to unwanted and unnecessary fat gain. 

Instead, take one serving each day and exercise your patience as well as your body. In a few weeks, your body weight will probably increase, and in a few months, you’ll likely have put on a significant amount of muscle mass.

Conclusion: What is the Best Mass Gainer For Teenagers in the UK?

The best weight gainers for teens in the UK

I’ve used weight gainers for a long time now, and I’ve tested every single one on the UK market. Honestly, most are just a bunch of sugar and amino-spiked protein, but as you’ve seen in this article, there are also some great weight gainers for teens (I wish that was the case when I started working out!).

With that in mind, the best mass gainer for teenagers to gain muscle and increase their body weight is definitely Crazy Nutrition Mass Gainer.

With an optimal 40g protein dose and an ideal 488 calories for creating a surplus, Crazy Nutrition Mass Gainer provides a high-quality weight gain shake that’s guaranteed to get you results if you take it consistently.

With added zinc and magnesium as well as digestive enzymes, this supplement is healthy as well as effective, making it a suitable choice for teens who are looking to bulk up.

Although more expensive than your average mass gainer, you can get some great savings (30%!) when you subscribe to this supplement, which is truly the best weight gainer for teenagers that I’ve come across.

The #1 UK Mass Gainer
Crazy Nutrition Mass Gainer
Two bags of Crazy Nutrition Mass Gainer positioned side by side
  • Contains 488 bulking calories from 100% clean sources
  • Packed with a proven 40g protein blend for quick muscle repair and growth
  • Provokes noticable weight gain with 55g of complex carbs from oats
  • Tastes amazing (to my surprise!) and mixes easily
  • Offered at the absolute lowest UK price during July
A picture of Best Mass Gainer UK founder, personal trainer Andy Williams
Andy Williams
Andy Williams is a UK-based personal trainer and bodybuilder who coaches gym-goers of all levels using proven evidence-based techniques in strength training, nutrition, and supplementation. He’s tested over 70 different mass gainers for their ingredient quality and muscle-building effectiveness and regularly shares his findings in his mass gainer reviews.
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