Gaining weight: the 3 best-evidenced supplements
Building muscle depends primarily on three things: a slight calorie surplus, sufficient protein, and regular resistance training. No supplement can replace these. However, a few are backed by solid research as being effective at accelerating progress. Here are the three with the strongest evidence — and what you shouldn’t expect from them.
1. Creatine: the most widely studied of all
Creatine monohydrate is the most well-documented bodybuilding supplement. The International Society of Sports Nutrition’s position statement describes it as effective and safe, even in the long term (up to 30 g per day for 5 years in the data reviewed). A meta-analysis of older adults undertaking resistance training found an average gain of 1.37 kg in lean body mass and an increase in strength in both the upper and lower body.
Let’s be honest: creatine does not increase muscle protein synthesis in the short term. Its benefits lie elsewhere — it improves performance during intense exercise and therefore the quality of your sessions, which, session after session, leads to better adaptations. The recommended dose is simple and requires no loading phase: 3 to 5 g a day, whenever suits you.
Key points to remember about creatine
2. Whey: handy, but not a miracle cure
Whey protein is no magic cure: it’s mainly a convenient way to meet your protein requirements. A meta-analysis has confirmed that an adequate intake improves strength and muscle size during training — but it has also shown that beyond around 1.6 g of protein per kg of body weight per day (from all sources), no further gains in lean body mass are achieved. So there’s no point in piling up the shakers.
What sets whey apart is that it is digested quickly and is rich in leucine, the amino acid that triggers muscle growth. For the same intake, it stimulates muscle protein synthesis more effectively than casein or soya after a workout. In practice: aim for a total of 1.6 to 2.2 g/kg/day, and use whey only to make up any shortfall in your diet.
To find out how much protein you’re actually eating, start with a meal plan based on your calorie target — our meal planner adjusts the portion sizes to suit your needs.
Generate a menu3. Beta-alanine: greater volume per session
Beta-alanine does not act directly on the muscle: it increases muscle carnosine, which buffers acidity during exercise. As a result, it delays fatigue during intense exercise by 1 to 4 minutes — the sort of long sets that build muscle. The ISSN’s guidance states that 4 to 6 g per day for 4 weeks is sufficient to increase carnosine levels. When combined with creatine, it has been shown, in a study on resistance training, to have the greatest effect on lean body mass and body composition.
Again, without exaggerating: in some studies, its effect on raw strength or body composition hasn’t been demonstrated — its real benefit is that it allows you to handle a higher training volume. Its only known side effect is a slight tingling sensation (paraesthesia), which can be avoided by spreading the doses throughout the day.
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In summary
| Supplement | What it offers | Effective dose | Evidence |
|---|---|---|---|
| Creatine | Strength and lean body mass | 3–5 g/day | Very sturdy |
| Whey | Complements protein (recovery, muscle) | ~1.6–2.2 g/kg/day in total | Solid |
| Beta-alanine | Endurance over long intervals (1–4 mins) | 4–6 g/day | Solid |
Everything else — progressive training and a balanced diet — is far more important than any supplement. Start by working out your requirements using our calorie calculator, then plan your meals around them.
Every statement in this article is based on the study summaries referenced in our creatine, whey and beta-alanine fact sheets, where you will find the original sources. This is for information purposes only and is not a substitute for medical advice.