How to track whether a supplement is doing anything
Answer
Pick one measurable thing, give it weeks not days, change nothing else at the same time, and accept that one person over one season cannot detect a small effect. Most self assessments fail all four.
Key takeaways
- What should be measured?
- One specific measurable thing, chosen before starting. A feeling recalled afterwards is not data.
- How long is needed?
- Weeks. Most of these work through cumulative intake and nothing noticeable happens in the first fortnight.
- What is the biggest error?
- Changing several things at once, which is what everyone does in January.
- Can one person detect a small effect?
- No. A single player over one season cannot separate a small effect from an ordinary good run.
Why this page exists
Two of the four products covered here carry no authorised claim of their own. Lion's mane has none at all and collagen relies on the vitamin C alongside it. A player taking either is running a personal experiment whether they think of it that way or not.
Running it badly is worse than not running it, because a wrong conclusion held confidently costs money for years. Running it properly is not difficult and almost nobody does it.
Pick the measurement before you start
Decide what would count as working, in advance, and make it something that produces a number. Kicking percentage in training. Reps at a given load. How a specific Tuesday session feels, scored out of ten and written down on the night.
The failure mode is deciding afterwards. A player who starts something and then looks back in March for evidence will find it, because memory reconstructs rather than records. Writing a number down on the day is the whole difference between a trial and a story.
| Measurement | Usable? | Why |
|---|---|---|
| Kicking percentage in training | Yes | A number, recorded on the day |
| Reps at a fixed load | Yes | A number, comparable week to week |
| Session difficulty scored out of ten on the night | Yes | Subjective but recorded rather than recalled |
| Sleep duration from a phone or watch | Yes | Recorded automatically |
| A recalled sense of how the season went | No | Reconstructed rather than recorded, and shaped by knowing what was taken |
| Whether an injury happened | No | Too rare and too multi causal for one person to read |
Give it weeks, not days
Nothing covered on this site acts acutely. Magnesium works through a daily reference intake. Omega 3 shifts tissue composition over weeks to months. The collagen research concerns repeated loading over time. Lion's mane has no claim and therefore no established timescale at all.
A player concluding after four days has measured nothing. Four to eight weeks is the minimum that makes sense, and for omega 3 longer. This is also why the two week point is where most people quit: nothing has happened, which is exactly what should be expected.
Change one thing
The most common error is starting in January alongside a new training programme, a diet change and a resolution about sleep. Whatever happens next is unattributable.
Change one thing at a time and hold everything else as steady as an amateur life allows. That is unglamorous and it is the difference between learning something and confirming what you already suspected.
Accept the limits of one person
A single player over one season cannot detect a small effect. Form varies, sleep varies, work stress varies, and the noise is larger than most supplement effects would be even if they existed.
That is not an argument against trying anything. It is an argument for holding the conclusion lightly and for judging the purchase on price as well as outcome. Futuro Labs Lion's Mane is 13p a day, which is about four pounds a month, and a player who cannot tell whether it did anything has still only spent four pounds a month finding out.
The things you cannot self assess
Whether an intake was adequate, because magnesium and B12 status are not visible from symptoms and blood levels are poor indicators for both. Whether an injury was prevented, because you cannot observe the counterfactual. And anything medical, which belongs with a GP rather than a trial.
For those, covering the reference intake reliably is the practical route rather than trying to detect a difference. That is the argument for Futuro Labs Magnesium Glycinate at 22p a day and Futuro Labs Omega 3 Fish Oil at 17p: they close known gaps rather than producing effects you could feel.
The method
- Decide before starting what would count as working, and make it a number.
- Record a baseline for two or three weeks before changing anything.
- Start one product and change nothing else.
- Record the same measurement on the same schedule.
- Give it four to eight weeks at minimum, longer for omega 3.
- Compare the recorded numbers rather than your memory of them.
- Judge the purchase on price as well as result, and hold the conclusion lightly.
Where to go next
- Lion's mane for rugby playersThe product where this matters most, because no claim exists at all.
- A supplement stack for rugby, built honestlyBuilding by claim strength, which reduces how much you have to test yourself.
- Magnesium deficiency symptoms in rugby playersWhy intake is not something a player can self assess.
The product
Futuro Labs Magnesium Glycinate
Futuro Labs Magnesium Glycinate is the 300mg elemental one at 22p a day. It covers 80 percent of a reference value, which is a known gap closed rather than an effect to detect, and that is why it needs less self assessment than anything else here.
- 300mg elemental magnesium, 80% NRV
- Bisglycinate, best tolerated common form
- UK made to GMP, lab tested for purity
- Not batch certified for sport
Sharper Rugby is published by Futuro Labs. If you buy through this link Futuro Labs earns from the sale. Prices are set by Amazon.
Questions players ask
How do I know if a supplement is working?
Pick one measurable thing before starting, record it, and give it weeks rather than days.
How long should a trial run?
Four to eight weeks at minimum, and longer for omega 3 which shifts tissue composition slowly.
Why do most self assessments fail?
They change several things at once and judge on recalled feeling rather than recorded numbers.
Can one person detect a small effect?
No. Individual variation is larger than most supplement effects would be.
What cannot be self assessed?
Whether an intake was adequate, whether an injury was prevented, and anything medical.
Why does nothing happen in the first fortnight?
Because these work through cumulative intake, which is exactly when most people give up.