Best Supplements for Weight Gain & Hard Gainers (UK)

If you train hard, eat what feels like plenty and still can't shift the scales, this guide is for you. "Hard gainers" tend to have fast metabolisms, busy schedules and small appetites, which makes hitting a calorie surplus genuinely difficult. The good news: gaining weight is a maths problem before it's a supplement problem. Below we cover the best supplements for weight gain in the UK, and exactly where each one fits.

First, the non-negotiable: a calorie surplus

You cannot build muscle or add body weight without consistently eating more calories than you burn. No powder overrides that. Aim for a modest surplus of roughly 250–500 calories per day above maintenance for steady gains without excessive fat. Track your intake honestly for a week or two, because most people who "can't gain" are simply eating less than they think once busy days and skipped meals are accounted for.

Supplements earn their place because eating big is hard work. When you're full, tired or short on time, a shake delivers hundreds of quality calories in minutes. That's the whole point: they make the surplus easier to hit, not optional. If you want to nail your numbers first, our guide on how to calculate your macros and calories is the right starting place.

Mass gainers: the easiest calories you'll drink

A mass gainer is a blend of protein and carbohydrates (often oats, maltodextrin and sometimes fats) designed to pack a large calorie total into one serving. Where a standard whey shake might give you 120 calories, a gainer can deliver 400–1,300 depending on the scoop size. For a hard gainer with a small appetite, that convenience is the difference between hitting your target and falling short again.

Use them to top up, not replace meals. A common approach is one serving post-training and, if needed, another between meals or before bed. Watch the serving size on the label, as headline calorie figures often assume two or three scoops. Browse the range on our mass gainers collection, and if you want help comparing formulas, read our best mass gainer UK guide. Expect to pay around £25–£45 for a large tub.

Whey protein: your everyday protein source

Protein contributes to a growth in muscle mass and to the maintenance of muscle mass, which is why it sits at the centre of any weight-gain plan. Whey is fast-digesting, convenient and mixes easily, making it a simple way to add 20–25g of protein without much bulk or effort. Most people building size aim for roughly 1.6–2.2g of protein per kilogram of body weight per day.

If your appetite is the bottleneck, whey helps you reach that protein target without feeling stuffed by chicken and rice at every meal. Compare options across our protein powders collection, and if you're new to buying it, how to choose the right protein powder walks through concentrate, isolate and blends. A 1kg tub typically runs £18–£30.

Gainer or whey, which should you buy?

If you struggle mainly to eat enough total calories, a mass gainer does more heavy lifting. If you eat reasonably but fall short on protein specifically, whey plus real-food carbs is more flexible and usually better value per serving. Many hard gainers keep both: whey for everyday protein, a gainer for the days appetite lets them down.

Creatine: a low-cost, well-researched staple

Creatine monohydrate is one of the most researched sports supplements available, and it's inexpensive at around £10–£20 for months of use. Creatine increases physical performance in successive bursts of short-term high-intensity exercise; this benefit is for adults performing high-intensity exercise, at a daily intake of 3g. Many users take between 3g and 5g a day, and it stirs cleanly into any drink.

It's a popular pick with hard gainers and non-gainers alike, and it slots in easily alongside everything else here. See our creatine collection, or start with creatine monohydrate: a beginner's guide if you want the full rundown on dosing and loading.

Calorie-dense extras to close the gap

When even shakes aren't enough, lean on energy-dense add-ons that raise your daily total without filling you up too quickly:

• Carbohydrate powders such as maltodextrin or oat blends stir easily into shakes for an extra 150–200 calories. Explore our carbohydrates collection.
• Nut butters and oats blended into your gainer add calories and unsaturated fats fast.
• Whole milk instead of water in shakes is a classic hard-gainer trick, adding protein and calories with almost no effort.
• Protein snacks like flapjacks and cookies keep intake ticking over on the move.

Small, frequent additions add up. An extra 300 calories a day from milk and a spoon of nut butter is nearly 2,000 calories across a week, entirely without a bigger appetite.

A simple day for hard gainers

Structure beats willpower. Anchor three main meals, then bridge the gaps with liquid calories: whey or a small gainer mid-morning, creatine with any drink, and a larger gainer shake after training or before bed. Prioritise sleep and progressive, consistent training so those extra calories are put to good use. If you're new to lifting, our how to build muscle for beginners guide pairs perfectly with this plan.

A note on results

This article is general information, not medical or nutritional advice. Individual results vary depending on training, diet, genetics and consistency, and no supplement replaces a balanced, varied diet and a healthy lifestyle. Always do your own research and consult a qualified healthcare professional or registered nutritionist before starting any new supplement, particularly if you are pregnant, breastfeeding, taking medication or managing a health condition.

The bottom line

Weight gain comes down to eating in a surplus, training consistently and staying patient. Supplements simply remove the friction: mass gainers and whey make hitting your calories and protein realistic, creatine adds a low-cost, well-researched staple, and calorie-dense extras close any remaining gap. Start with the basics, be consistent for eight to twelve weeks, and let the scales tell the story. Ready to build your stack? Browse our mass gainers and the full supplement range at NE Commerce, with genuine products and fast tracked UK delivery.