Mass gainers are designed for people who struggle to eat enough calories to support muscle growth. A single serving can pack 300 to 1,200 calories alongside 20-50g of protein — convenient, but not cheap. Per serving, mass gainers are some of the most expensive supplements you can buy.
The good news is that the price spread between brands is enormous. The cheapest mass gainer per 100g can cost half as much as the most expensive. This guide shows you how to find affordable mass gainer in the UK and whether it is even worth buying one at all.
Why mass gainers are expensive
Mass gainers use large serving sizes — typically 100-300g per shake. That means a 2.5kg bag only lasts 8-25 servings. Compare that to whey protein, where a 2.5kg bag gives you 80+ servings. You are getting through mass gainer much faster, which makes the per-month cost significantly higher.
The main ingredients in most mass gainers are whey protein and maltodextrin (a cheap carbohydrate). Some premium products add oats, MCT oil, creatine, or other extras that push the price up without necessarily improving results.
Cheapest mass gainers in the UK right now
We track mass gainer prices across 85+ UK retailers. The cheapest options tend to come from Myprotein, Applied Nutrition, and Warrior. Bulk's Complete Mass also offers solid value per 100g.
Check the mass gainer price comparison for today's live prices ranked by cost per 100g. The cheapest product rotates depending on sales and stock levels, so it is worth checking before you buy.
DIY mass gainer — is it cheaper?
A popular alternative to buying a mass gainer is making your own from whey protein, oats, and peanut butter. Here is a rough cost comparison:
- Commercial mass gainer — typically £2-4 per serving (300-500 kcal per serving)
- DIY: whey + oats + peanut butter — roughly £1-1.50 per serving for a comparable calorie and protein content
The DIY approach is almost always cheaper because you are buying each ingredient at its lowest cost per gram rather than paying for a pre-mixed product. The trade-off is convenience — a ready-made mass gainer just needs water, while DIY requires a blender and more prep time.
If you go the DIY route, start with cheap whey concentrate. The cheapest whey concentrate in the UK is your base — add 80-100g of instant oats and a tablespoon of peanut butter for a 500+ calorie shake at a fraction of the mass gainer price.
What to look for in a mass gainer
- Protein per serving — Aim for at least 30g per serving. Some cheap mass gainers are mostly maltodextrin with very little protein.
- Calorie source — Oat-based mass gainers tend to be better quality than pure maltodextrin ones. Check the ingredient list.
- Price per 100g — This is the fairest comparison metric because serving sizes vary enormously between brands. Our comparison table normalises everything to per-100g cost.
- Added extras — Creatine, vitamins, and digestive enzymes are nice-to-haves but are usually cheaper bought separately. Do not pay a premium for a mass gainer just because it includes creatine.
When to use a mass gainer vs extra food
Mass gainers make sense in a few specific situations:
- You genuinely cannot eat enough whole food to gain weight (fast metabolism, small appetite)
- You need a portable, quick calorie source between meals
- You are in a dedicated bulking phase and need 3,500+ calories daily
If you can eat enough through regular meals, whole food is almost always cheaper and more nutritious than a mass gainer. The supplement is a convenience tool, not a requirement.
Finding the best deal
Mass gainer prices fluctuate a lot between retailers and across sales events. The mass gainer price comparison shows every product we track ranked by cost per 100g. For active discount codes that might bring the price down further, check the protein powder deals and discount codes.
If budget is your biggest constraint, seriously consider the DIY route. A bag of cheap whey protein plus supermarket oats will give you more servings for less money than any commercial mass gainer on the market.