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Nutrition6 min read

The supplements worth buying, and the ones that are not

The supplement aisle is built to make you feel like you are missing something. This is written for healthy adults aged 18 and over without a medical condition, and the list of products with solid evidence behind them is short enough to remember, none of them urgent.

By Chris Mann Dip.IOPNUpdated 2026-08-15

The short answer

Only a handful of supplements have solid evidence for building muscle: creatine monohydrate, protein powder as a convenient way to hit your target, and vitamin D through the darker UK months. Caffeine can help training performance. Everything else is weakly supported at best, and none of it matters until training and food are consistent.

  • Creatine monohydrate is the only muscle-building supplement with strong evidence
  • Protein powder is food in a tub, not a special product
  • Vitamin D is a UK winter issue rather than a muscle one
  • Nothing on the shelf replaces training and eating enough

The short list worth considering

These are the products with enough evidence behind them to be worth the money for a beginner, in the order most people would benefit from adding them.

What the evidence supports
SupplementWhat it doesTypical amount
Creatine monohydrateSmall but reliable gains in strength and training volume3-5g a day, any time
Protein powderConvenience: helps hit a protein target you are missing20-25g per scoop, as needed
Vitamin DCovers low UK sunlight from October to March10 micrograms a day
CaffeineBetter focus and effort in a session1-3mg per kg, an hour before

The ones you can skip

Most of the shelf falls into this group. Some of these do something measurable in a laboratory, but not enough to change what happens to a beginner training three times a week.

Popular supplements with little to show for it
SupplementWhy it is usually skippable
BCAAsPointless if you are already eating enough protein
Testosterone boostersNo meaningful effect shown in healthy young men
Mass gainersMostly sugar you could get more cheaply from food
GlutamineWell studied, and it does not build muscle
Fat burnersMostly caffeine, sold with a large markup
Pre-workout blendsCaffeine plus a long ingredient list you are paying extra for

If you are going to buy something, buy it in this order

  1. Step 1

    Nothing, for the first month

    Get to the gym consistently and get your protein up first. That is where the results come from.

  2. Step 2

    Creatine monohydrate

    Cheap, well studied and the only one with a direct effect on muscle and strength. Plain monohydrate is fine; the fancier forms are not better.

  3. Step 3

    Protein powder, only if you are short

    If you are consistently 30 or 40 grams under your target, a tub is easier than forcing another meal in.

  4. Step 4

    Vitamin D in winter

    UK public health advice suggests 10 micrograms a day from October to March for most adults.

Buying safely

Supplements are regulated as food rather than medicine, so what is on the label is not always what is in the tub. Sticking to plain, single-ingredient products from established retailers avoids most of the risk.

  • Prefer single ingredients over proprietary blends
  • Look for batch-tested products if you are drug tested for sport
  • Be wary of anything promising results that sound like medication
  • Check with a pharmacist if you take prescribed medicines

How to judge a supplement claim yourself

You will meet new products faster than anyone can review them, so the useful skill is reading a claim rather than memorising a list. Four questions filter out almost everything on the shelf.

  1. Step 1

    Was it tested in people, doing the thing you want to do?

    Cells in a dish and rats on a treadmill are where research starts, not where it finishes. A finding in trained or untrained adults lifting weights is what matters here.

  2. Step 2

    How large was the effect, in plain terms?

    "Statistically significant" does not mean noticeable. Ask what it produced: an extra kilogram on a lift, or a difference nobody could feel.

  3. Step 3

    Does the tub contain the dose that was studied?

    Proprietary blends often list an impressive ingredient at a fraction of the researched amount, which makes the label true and the product useless.

  4. Step 4

    Who paid for the study?

    Manufacturer funding does not make research wrong, but independent replication is what turns a promising result into a reliable one.

The creatine worries that come up most

Creatine attracts more myths than the rest of the shelf combined, mostly because it has been around long enough to collect them. Here is what the position guidance actually says, and where the honest limits of that evidence sit.

Common concerns and what the evidence supports
ConcernWhat the evidence shows
It causes weight gainSome early weight gain is water held inside muscle, typically around 1kg. It is not fat.
It damages the kidneysLong-term studies in healthy adults have not shown kidney harm at normal doses. If you have kidney disease, ask your doctor before taking it.
It causes hair lossThis rests on one small study that has not been replicated, so it is not something the evidence currently supports.
You need to loadA loading phase only fills muscle stores faster. 3 to 5g a day gets to the same place in three to four weeks.
It only works for menBenefits have been shown in both men and women; the mechanism is not sex-specific.

Common questions

Do I need supplements to build muscle as a beginner?
No. Muscle is built by training that gets progressively harder and by eating enough protein and calories. Supplements can make small differences at the edges, but none of them are required and none of them work without the training.
Which supplement has the strongest evidence for muscle growth?
Creatine monohydrate. It is one of the most studied sports supplements there is, and it produces small but consistent improvements in strength and training volume, which over months adds up to more muscle.
Are BCAAs worth buying?
Not if you eat enough protein. Branched-chain amino acids are already present in the protein you eat, and studies giving them to people on adequate protein intakes find no meaningful extra benefit.
Is a pre-workout better than a coffee?
For most people, no. The active ingredient doing the work is usually caffeine, and a strong coffee delivers it for a fraction of the price. Pre-workouts are convenient rather than superior.
Should I take a mass gainer if I struggle to eat enough?
It is usually cheaper to make your own with oats, milk, peanut butter and a banana. Mass gainers are mostly maltodextrin and cost several times what the equivalent food does, though they can be useful when you genuinely cannot face eating.

References

Every figure in this guide traces to one of these documents. Open them and check.

  1. ISSN position stand: safety and efficacy of creatine supplementation in exercise, sport, and medicineJournal of the International Society of Sports Nutrition (2017)
  2. ProteinBritish Nutrition Foundation
  3. ISSN position stand: protein and exerciseJournal of the International Society of Sports Nutrition

Educational information for adults aged 18 and over. It does not diagnose, treat or manage any medical condition. If you have a health condition, or symptoms that worry you, speak to a qualified clinician.