What is a ZMA dose, and does it stack up?
Answer
A typical serving provides around 30mg of zinc, 450mg of magnesium and 10mg of B6. The zinc figure alone exceeds the 25mg UK supplemental guidance level before anything else is counted.
Key takeaways
- What is in a serving?
- Around 30mg of zinc, 450mg of magnesium and 10mg of vitamin B6, usually across three capsules.
- Does that exceed any level?
- Yes. The zinc figure alone is above the 25mg UK supplemental guidance level, and the magnesium is above 400mg.
- What does it claim?
- The ordinary zinc, magnesium and B6 claims. Zinc's testosterone claim is maintenance of normal levels, not raising them.
- Is it worth taking?
- Only after totalling what else you take, because both minerals are the ones most often duplicated across a stack.
What a standard serving contains
ZMA is a fixed formula rather than a brand: zinc, magnesium and vitamin B6, usually taken as three capsules before bed. A typical serving provides around 30mg of zinc, 450mg of magnesium and 10mg of B6, though products vary.
Both mineral figures sit above their UK supplemental guidance levels on their own, which is unusual for a mainstream product and is worth knowing before adding anything else.
| Nutrient | Typical ZMA serving | UK supplemental guidance level |
|---|---|---|
| Zinc | About 30mg | 25mg |
| Magnesium | About 450mg | 400mg |
| Vitamin B6 | About 10mg | 10mg |
| Futuro Labs Magnesium Glycinate | 300mg elemental magnesium | Below the level, with 100mg of headroom |
The zinc figure is the one to watch
UK guidance sets 25mg a day for supplemental zinc, and the reason is not acute toxicity. Zinc and copper compete for the same absorption pathway, so sustained high zinc intake reduces copper status over months rather than immediately.
Copper is needed for iron metabolism, connective tissue formation and normal nervous system function among other things. A player taking ZMA alongside a multivitamin and an immune supplement can be well past 50mg of zinc a day without ever adding it up.
The magnesium figure
Around 450mg is above the 400mg supplemental guidance level, which is set on the laxative effect. The form matters here: ZMA products frequently use aspartate or oxide rather than a chelated form, and oxide is the least well tolerated at a full serving.
Futuro Labs Magnesium Glycinate provides 300mg elemental in a two capsule serving at 22p a day, which sits below the level with 100mg of headroom, in bisglycinate form chosen for tolerability across a season.
What the claims actually say
The zinc claims include maintenance of normal testosterone levels in the blood, normal protein synthesis, normal cognitive function and normal immune function. The magnesium claims include normal muscle function, protein synthesis and the reduction of tiredness and fatigue. B6 contributes to normal protein and glycogen metabolism.
The testosterone one is the reason ZMA exists, and reading it precisely matters: maintenance of normal levels is not a claim about raising them. That distinction is the whole gap between the register and the marketing around this product.
Who it might genuinely suit
Someone with a low zinc intake, which in practice means a plant based player, since phytates in wholegrains and pulses reduce zinc absorption. And someone not already taking magnesium or a multivitamin.
For everyone else it duplicates two minerals they are likely already getting, at figures above both guidance levels, in forms often chosen for cost rather than tolerability. That is a specific set of conditions rather than a general recommendation.
How to decide
- Write down every product you take that contains zinc or magnesium.
- Find the amounts per serving on each panel rather than estimating.
- Total the zinc against 25mg and the magnesium against 400mg.
- Check what form the magnesium is, since oxide and aspartate are poorly tolerated at a full serving.
- Read the testosterone claim precisely: maintenance of normal levels rather than raising them.
- Decide whether you need three products delivering two minerals, or one delivering one.
Where the formula came from
ZMA is a fixed ratio rather than a brand, and knowing where it came from explains why the figures are what they are.
It was formulated around research in athletic populations looking at zinc and magnesium status, and the doses were set high deliberately to correct assumed shortfalls rather than to sit within general population guidance. That is a defensible design decision for a specific research question and a poor default for someone already taking a multivitamin.
The practical consequence is that the formula was never designed to be stacked with anything, and it is now routinely stacked with everything. Futuro Labs Magnesium Glycinate provides magnesium and nothing else to total, at 300mg elemental and 22p a day, which is a different design intent.
Where to go next
- ZMA in rugby: is it worth taking?The full picture, including the testosterone story.
- Do rugby players need a zinc supplement?The mineral most often duplicated across a stack, and the copper relationship.
- Is 500mg of magnesium too much?Where the magnesium ceiling sits and how to read your label against it.
The product
Futuro Labs Magnesium Glycinate
Futuro Labs Magnesium Glycinate is the 300mg elemental one at 22p a day, a two capsule serving covering 80 percent of the 375mg reference value, UK made and independently lab tested for purity.
- 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
What is a ZMA dose?
Typically around 30mg of zinc, 450mg of magnesium and 10mg of B6, usually across three capsules.
Does it exceed the guidance levels?
Yes. The zinc is above 25mg and the magnesium above 400mg before anything else is counted.
Why does the zinc figure matter?
Zinc and copper compete for absorption, so sustained high zinc reduces copper status over months.
Does it raise testosterone?
The claim is maintenance of normal levels in the blood, which is not a claim about raising them.
Who might it suit?
Someone with a genuinely low zinc intake who is not already taking magnesium or a multivitamin.
What should I do first?
Total the zinc and magnesium across every product you take before adding another.
Why are the doses so high?
The formula was designed around research correcting assumed shortfalls rather than to sit within general guidance.
Is the B6 amount a problem?
10mg sits at the UK supplemental guidance level, so it is at the ceiling rather than over it.
Should it be taken before bed?
That is the convention rather than a claim. No sleep claim exists for any of the three ingredients.