What's the strongest supplement?

Four meanings of one word: the largest measured effect, which is creatine, and the highest dose per capsule, which is a label number read against the reference value and the upper level

What is the strongest supplement is a question whose one word carries four meanings, and the four produce four different answers, so the useful thing is to separate them before answering any. Strongest can mean the supplement with the largest measured effect, the supplement with the highest dose per capsule, the supplement most potent per milligram, or the supplement most dangerous, and a person who asks the question usually means the fourth without saying so and is best served by being given the first. The page takes them in order.

The first meaning is the largest measured effect, and the answer is creatine monohydrate, without a close second among legal supplements. The meta-analyses attribute one to two kilograms of lean mass and a few percent on strength measures over a training block to 3 to 5g a day on top of training alone, in most people who train, with an authorised claim for physical performance in repeated short bursts of high-intensity exercise and the best-studied safety record of any supplement; no other product on the shelf has an effect of that size measured in trials of that number, and the products sold as stronger, the boosters, the stacks and the pro-hormones, have either no measured effect or belong to the fourth meaning. A person who wants the strongest supplement in the sense of the one that does the most has their answer in a plain white powder at pence a day, which is not the answer the shelf wants to give.

The second meaning is the highest dose per capsule, and it is the meaning the shelf sells to, with the high-strength, extra-strength and maximum-strength labels on every vitamin and mineral; it is a label number that means nothing on its own. A dose is strong only relative to two other numbers: the nutrient reference value, the daily amount the label's percentage is calculated against, and the tolerable upper intake level, the amount above which the European assessments find a risk of harm, set for every vitamin and mineral. A high-strength vitamin D at ten times the reference value is strong in the sense of approaching the upper level, which is a reason for a blood test rather than a purchase; a high-strength magnesium at twice the reference value is above the upper level for supplemental intake and is strong in the sense of producing loose stools; a high-strength B6 taken for months is strong in the sense of the nerve damage the upper level exists to prevent. A buyer who reads a strength label reads the reference value and the upper level beside it, and finds that strong, for a vitamin or mineral, is a word for a dose near a ceiling, which no one should want without a reason a test has given them.

Two meanings separated, the largest effect and the highest dose, and the two remaining, the most potent per milligram and the most dangerous, with the record of the fourth, the worked example at its own strength, and the verdict, which is the next section.

The third meaning, the most potent per milligram, which is caffeine with a stated ceiling; the fourth meaning, the most dangerous, which is not a supplement; the worked example placed at its own strength; and the verdict

The third meaning is the most potent per milligram, the supplement whose smallest dose does the most, and the answer is caffeine, which is also the one supplement whose strength is a stated number. The European safety assessment places the ceiling for healthy adults at 400mg a day and 200mg in a single dose, and within those figures caffeine at 3 to 6mg per kilogram before a session lowers perceived effort and improves strength endurance and power output measurably, while above them it produces the racing heart, the tremor, the anxiety and the sleep loss that are its strength expressed as its record. A pre-workout blend is strong in this sense exactly as much as its caffeine content, which is often undeclared and often near the single-dose ceiling, with other stimulants added that have no ceiling stated because they were never assessed; a buyer who wants the most potent legal supplement buys a caffeine tablet of known dose and keeps it under the numbers.

The fourth meaning is the most dangerous, and it is the one the question usually carries, in the tone of someone asking what will really work, and its answer is not a supplement. The substances that produce the largest and fastest changes in muscle, in energy or in mood are controlled medicines: the anabolic steroids and their relatives, prescription-only and unlawful to supply, with suppressed natural testosterone, raised blood pressure, adverse lipids, liver effects with the oral agents and dependence on their record; the stimulants that raise dopamine most, which are controlled for exactly that reason; and the designer compounds sold as supplements with a wink that contain or mimic them. Some products sold as supplements have contained these, which is why the contamination surveys found undeclared steroid precursors in a share of ordinary products and why the food safety alerts record withdrawals of products that turned out to be medicines in a supplement's tub. The fourth meaning's answer is the one a page does not describe further, because its strength is its harm, and a person who wants it is a person a doctor rather than a shelf should be talking to.

The four meanings read together produce the honest answer. The strongest supplement by effect is creatine, at pence; by dose it is a label number read against a ceiling; by potency it is caffeine under its stated numbers; and by danger it is not a supplement and should not be in the question. A buyer who came for the fourth and leaves with the first has been given the thing that works, and the shelf's strength labels, which sell the second, have been placed where they belong, beside the upper levels.

The worked example is placed at its own strength, which is a dose below the ceiling: {FL}, 1500mg magnesium bisglycinate stated as 300mg elemental at 80% NRV, below the upper level for supplemental magnesium and with the glycinate form that is gentler on the gut than the oxide, two capsules with the evening meal, with authorised claims for normal muscle function, normal psychological function and the reduction of tiredness and fatigue and no strength label of any kind, batch tested for lead, mercury, arsenic and cadmium, UK made, 180 capsules for £19.99 at 22p a day, taken by a person whose plate is short of the mineral. The full label breakdown is here.

The verdict: strongest means four things, and the four answers are creatine for the largest measured effect, a label number read against the reference value and the upper level for the highest dose, caffeine under its stated 400mg daily ceiling for the most potent per milligram, and, for the most dangerous, the controlled medicines that are not supplements and the products that have hidden them. The one worth buying is the first, at pence a day; the second is a reason for caution; the third is kept under its numbers; and the fourth is a doctor's conversation rather than a purchase.

What to check on the label

Questions people also ask

What is the most powerful supplement you can buy?

By measured effect, creatine monohydrate, which the meta-analyses credit with one to two kilograms of lean mass and a few percent on strength over a training block on top of training, with an authorised claim and the best-studied safety record of any supplement, at pence a day; by potency per milligram, caffeine, under its stated ceiling of 400mg a day and 200mg a dose; by dose per capsule, a label number that means nothing without the reference value and the upper level; and by danger, nothing lawful, since the substances that change a body fastest are controlled medicines and not supplements.

What does high strength mean on a vitamin label?

A dose that is large relative to the nutrient reference value the label's percentage is calculated against, and often close to the tolerable upper intake level the European assessments set for each vitamin and mineral above which there is a risk of harm; a high-strength vitamin D at ten times the reference value approaches its upper level, a high-strength magnesium at twice the reference value exceeds the supplemental upper level and produces loose stools, and a high-strength B6 taken for months causes the nerve damage its upper level exists to prevent, so strong on a vitamin label is a reason for a blood test rather than a selling point.

Is caffeine the strongest legal stimulant supplement?

It is the most potent per milligram and the one with a stated ceiling: the European safety assessment places 400mg a day and 200mg in a single dose as the limits for healthy adults, and within them caffeine at 3 to 6mg per kilogram before a session lowers perceived effort and improves strength endurance and power output, while above them it produces a racing heart, tremor, anxiety and sleep loss; a pre-workout blend is as strong as its caffeine content, often undeclared and near the single-dose ceiling, with added stimulants that were never assessed, so a tablet of known dose is the same strength with a known number.

What is stronger than creatine?

Nothing lawful by measured effect: creatine's one to two kilograms and a few percent on strength over a block is the largest effect any legal supplement has produced in trials of that number, and the products sold as stronger either have no measured effect, the boosters and the stacks, or belong to the fourth meaning of the word, the controlled medicines that are prescription-only and unlawful to supply and that some products sold as supplements have hidden, which the contamination surveys and the food safety alerts record; a person asking for something stronger than creatine is asking for a medicine, which is a doctor's conversation.

How strong is this site's magnesium?

A dose below the ceiling, which is the honest strength for a mineral: 1500mg magnesium bisglycinate stated as 300mg elemental at 80% of the nutrient reference value, below the tolerable upper level for supplemental magnesium, in the glycinate form that is gentler on the gut than the oxide, two capsules with the evening meal, with authorised claims for normal muscle function, normal psychological function and the reduction of tiredness and fatigue and no strength label of any kind, batch tested for four metals, UK made, at 22p a day.

Sources

1. Kreider RB, et al. International Society of Sports Nutrition position stand: safety and efficacy of creatine supplementation in exercise, sport, and medicine. Journal of the International Society of Sports Nutrition 2017;14:18. PubMed record
2. The EFSA scientific opinion on caffeine safety: habitual intakes up to 400mg a day and single doses up to 200mg do not raise safety concerns for healthy adults, with 200mg a day the ceiling in pregnancy, 3mg per kilogram the single-dose guide, and sleep disturbance the effect seen at lower doses taken close to bedtime. https://efsa.onlinelibrary.wiley.com/doi/10.2903/j.efsa.2015.4102
3. The UK Expert Group on Vitamins and Minerals safe upper levels report and EFSA tolerable upper intake levels: the vitamins and minerals that accumulate or cause harm with daily long-term intake are the fat-soluble vitamins A and D, iron, zinc, selenium and vitamin B6, each with a defined upper level, against which a fibre-and-protein food extract has no comparable mechanism of accumulation. https://www.food.gov.uk/research/safe-upper-levels-for-vitamins-and-minerals
4. The anabolic steroid adverse effects literature: non-medical use is associated with cardiovascular changes including raised blood pressure and adverse lipid profiles, suppression of natural testosterone production with a slow and sometimes incomplete recovery, liver effects with oral agents, mood changes and dependence, which is the comparison the phrase without side effects is implicitly making. PubMed record

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