Supplements That Actually Work

Overview

The supplement industry is large, lightly regulated, and built on the gap between what people hope works and what has been shown to.

The genuinely useful list is short enough to fit in a paragraph. Everything else ranges from mildly promising to actively pointless.

Quick Answer

The supplements with the strongest evidence for training are creatine monohydrate, caffeine, protein powder as a food convenience, and vitamin D where a deficiency exists. Most other performance supplements, including BCAAs, testosterone boosters and fat burners, have little or no supporting evidence.

Key Points

Creatine and caffeine are the only two with strong performance evidence.
Protein powder is convenient food, not a performance supplement.
Vitamin D matters only if you are deficient, which many people in northern climates are.
BCAAs are redundant if you eat enough total protein.
Fat burners produce trivial effects at best.

The short list

Supplement	Evidence	Typical dose
Creatine monohydrate	Strong	3 to 5g daily
Caffeine	Strong	3 to 6mg per kg, 45 to 60 min before
Protein powder	Strong as food, neutral as a supplement	As needed to hit protein target
Vitamin D	Strong if deficient	10 to 25 micrograms daily in winter
Omega 3	Moderate, mainly general health	1 to 2g combined EPA and DHA

Public health advice in the UK is to consider a daily vitamin D supplement during autumn and winter, since sunlight is insufficient to produce enough at those latitudes.

The long list of things that do not do much

Supplement	The claim	The reality
BCAAs	Muscle growth, reduced soreness	Redundant if total protein is adequate
Testosterone boosters	Raise testosterone	No meaningful effect in healthy men
Fat burners	Accelerate fat loss	Effects are trivial, mostly caffeine
Glutamine	Recovery, immunity	No benefit in healthy trained people
Mass gainers	Muscle gain	Expensive calories, food is cheaper
Detox products	Remove toxins	Your liver and kidneys already do this
Pre-workout blends	Multiple benefits	Usually caffeine plus expensive filler

Most pre-workout products are caffeine with additions that either do nothing or are present at doses too low to matter. Caffeine alone is far cheaper and equally effective.

Caffeine, used properly

Aspect	Guidance
Dose	3 to 6mg per kg bodyweight
Timing	45 to 60 minutes before training
Tolerance	Builds within one to two weeks of daily use
Cut-off	At least 8 hours before bed
Caution	Sleep loss will cost you more than caffeine gains

Caffeine improves endurance, perceived effort and, to a smaller degree, strength output. If you use it every day for every session, you lose most of the acute benefit and keep the sleep disruption.

How to judge a claim yourself

-Is there human research, or only cell and rodent studies?
-Is the dose in the product the same as the dose in the studies?
-Was the research funded by the company selling it?
-Does the marketing rely on a mechanism rather than an outcome?
-Would the effect be visible without the supplement, given good training and food?

The final question filters most of the market. No supplement compensates for inconsistent training, inadequate protein or insufficient sleep.

Common Mistakes

Mistake	Why it causes problems	Better approach
Buying supplements before fixing sleep and food	Small effect chasing large problems	Fix the basics first
Proprietary blends	Doses are hidden, usually because they are low	Buy single ingredients
Daily high dose caffeine	Tolerance plus sleep disruption	Use it strategically
BCAAs alongside a high protein diet	Paying for amino acids you already eat	Skip them
Believing before and after photos	Marketing, not evidence	Look for controlled studies

Frequently Asked Questions

What supplements should a beginner take?

Realistically, none are needed. If you want to start somewhere, creatine and vitamin D in winter are the two most defensible.

Are BCAAs useless?

For anyone eating adequate total protein, essentially yes. They may have a small role for people training fasted on very low protein intakes, which describes very few people.

Do fat burners work?

The measurable effects are very small, and mostly attributable to the caffeine content. They are not a substitute for a calorie deficit.

Should I take a multivitamin?

It is inexpensive insurance if your diet is restricted or you eat few vegetables. It is not necessary for someone eating a varied diet.