Which Supplements Actually Work? An Honest Guide for Lifters

Walk into any supplement shop and you would think progress comes in a tub. It does not. Training, food and sleep do almost all of the work. But a small number of supplements do have years of good research behind them, and knowing which ones can save you a lot of money.

This guide sorts the most popular supplements into three groups: the ones with strong evidence, the ones that help in specific situations, and the ones most people can skip. Every verdict is based on expert position stands and reviews, linked at the bottom.

Why most supplement money is wasted

In the UK, food supplements are regulated as food, not as medicines. That means a product does not have to prove it works before it goes on sale. Labels have rules about what they can claim, but the marketing around them often goes much further, with "clinically dosed" badges, influencer codes and before and after photos.

The result is predictable. It is easy to spend a lot every month on fat burners, BCAAs and testosterone boosters while skipping the handful of supplements with real evidence, which are usually the cheapest and most boring products on the shelf.

The proven four

These four have consistent results across many trials and are backed by position stands from the International Society of Sports Nutrition (ISSN), the International Olympic Committee (IOC) or the NHS.

Creatine monohydrate

Creatine is the most researched supplement in sport. It increases the creatine stored in your muscles, which helps you produce more work in short, hard efforts like heavy sets and sprints. Over weeks of training, that translates into more strength and muscle. The ISSN position stand concludes it is both effective and safe for healthy people at the recommended doses.

Take 3-5 g a day, at any time of day. A loading phase is optional: it saturates your muscles faster, but you get to the same place within about a month either way. Plain creatine monohydrate is the form with the evidence, and it is cheap. Our complete creatine guide covers the details.

Caffeine

Caffeine reliably improves performance across endurance, strength and high-intensity exercise. The ISSN position stand puts the effective range at 3-6 mg per kg of body weight, taken about 60 minutes before training. For a 75 kg person that is roughly 225-450 mg, and many people do well at the lower end.

Coffee works as well as a pre-workout. The bigger risk is sleep: caffeine late in the day can cut into your sleep, and poor sleep costs you more than caffeine gives you. If you train in the evening, use a smaller dose or skip it.

Protein powder

Protein powder is not magic. It is food in a convenient form. What matters is your total protein across the day. A large meta-analysis found that extra protein improved gains in muscle and strength from resistance training, with the benefit levelling off at around 1.6 g of protein per kg of body weight per day.

If you hit that from food, you do not need a shake. If you struggle, a scoop of whey or a plant blend is one of the cheapest ways to close the gap. Our guide to the cheapest high-protein foods in UK supermarkets shows how powder compares with real food on cost.

Vitamin D

From October to March, the UK sun is not strong enough for your skin to make enough vitamin D. The NHS advises that everyone should consider a daily supplement of 10 micrograms during autumn and winter, and some people all year round, such as those who rarely get outside or cover most of their skin. It is cheap, and it is the one supplement almost everyone in the UK should think about.

Worth it in specific situations

These have real evidence, but only for certain goals or people. They are worth it if you fit the profile and pointless if you do not.

• Beta-alanine. Raises carnosine levels in muscle and can help with hard efforts lasting roughly one to four minutes, such as high-rep sets, rowing intervals or a 400 m run. It takes weeks of daily use to work, and the harmless tingling it causes is normal.
• Dietary nitrate (beetroot juice). Can improve endurance performance by making exercise slightly less costly in oxygen. Most useful for runners, cyclists and team sports, and less consistent in highly trained athletes.
• Omega-3. Worth considering for general health if you eat little oily fish. The evidence for direct muscle or performance gains is weaker.
• Vitamin B12. If you are vegan, the NHS advises getting B12 from fortified foods or a supplement, because it is found naturally almost only in animal foods.
• Iron. Only if a blood test shows you are low. Taking iron you do not need is not harmless, so get tested first.

What most people can skip

For gym goals, these either have weak evidence or a cheaper, better option already exists.

• BCAAs. Branched-chain amino acids are already in every protein-rich meal. On their own they cannot support muscle building properly, because your body needs all the essential amino acids. If you eat enough protein, BCAAs add nothing.
• Testosterone boosters. A review of 50 popular products found that most claimed to raise testosterone, but published research supported that effect for only about a quarter of their ingredients, and some contained vitamins and minerals above safe upper limits.
• Fat burners. Usually caffeine plus a long list of extras. The caffeine does the work, and the extras add cost and risk. A calorie deficit, protein and training are what burn fat.
• Glutamine, greens powders and detox teas. No meaningful benefit for building muscle or losing fat. Vegetables beat greens powders, and "detox" teas are often laxatives.

How to buy safely

Because supplements are regulated as food, quality varies. The IOC consensus statement warns that some products are contaminated with substances that are not on the label, including banned ones. That matters for anyone who is drug tested, and for everyone else it matters because you do not know what you are taking.

• Choose products that are batch-tested by a third party, such as those certified by Informed Sport.
• Be wary of anything promising rapid fat loss, huge strength gains or "hormone" effects.
• Avoid anything sold as a "research chemical" or "not for human consumption". That includes grey-market peptides.
• Check with your GP or pharmacist before starting a supplement if you take medication, are pregnant or have a health condition.

A simple, cheap stack

For most people who lift, this covers almost everything the evidence supports:

1. Creatine monohydrate, 3-5 g every day.
2. Vitamin D, 10 micrograms a day from October to March.
3. Protein powder only if you struggle to hit your protein target from food.
4. Caffeine before training if you like it and it does not affect your sleep.

Everything else is a nice-to-have at best. Spend the money you save on good food instead. The full verdicts on 22 popular supplements, with the doses used in the research, are in our free Supplement Truth Guide.

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