The Daily Foundation
Zinc
Zinc
Citrate
Small dose. Enormous reach. Essential for over 300 enzymatic processes and decades of daily supplementation research.
10mg per serving · 1.67mg per capsule · 6 capsules daily
0
Daily Dose at 100% NRV
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Enzymatic Reactions Requiring Zinc
0
Total Body Zinc Storage
0
Global Population Estimated Deficient
What It Does
Three things. All proven.
Testosterone & Hormonal Health
Zinc is required for the enzymatic conversion of androgens and the synthesis of testosterone. Deficiency directly suppresses testosterone production. Adequate zinc status is a prerequisite for normal hormonal function in both men and women.
Immune Function
Zinc is essential for the development and activation of T-lymphocytes, natural killer cells and neutrophils. It modulates the inflammatory response and is one of the most studied nutrients in immune support with consistent clinical evidence across multiple populations.
Protein Synthesis & Recovery
Zinc is a structural component of ribosomes and a required cofactor in the protein synthesis pathway. Without adequate zinc, the rate of muscle protein synthesis is impaired regardless of dietary protein intake. Recovery slows and adaptation stalls.
The Science
The trace mineral with an outsized role.
Zinc is classified as a trace mineral, meaning the body requires it in comparatively small amounts. This categorisation is frequently misread as a signal of limited importance. It is the opposite. Zinc is present in every cell of the human body, acts as a structural component of over 2,000 transcription factors, and is required as a cofactor in more than 300 enzymatic reactions spanning metabolism, immune function, DNA synthesis, wound healing and hormonal regulation.
The human body has no dedicated zinc storage system. Unlike iron, which is stored in ferritin, or calcium, which is held in bone, zinc is in constant metabolic circulation. There is a small labile pool that can buffer short-term fluctuations in intake, but this is limited to 1 to 2 grams total and depletes rapidly under conditions of inadequate intake, high training volume or elevated physiological stress. This is why consistent daily intake matters and why deficiency develops more quickly than most people realise.
The formula uses zinc citrate specifically. Bioavailability is the defining variable in zinc supplementation and the reason form selection matters considerably more than the headline dose. At 10mg elemental zinc daily, the formula delivers precisely 100% of the UK Nutrient Reference Value in the form with the strongest bioavailability evidence among the major citrate, gluconate and picolinate options available.
The deficiency most active people do not know they have.
Zinc deficiency in the clinical sense, severe enough to produce unambiguous symptoms, is relatively rare in developed countries. Subclinical zinc insufficiency, the state where zinc intake is sufficient to avoid overt deficiency but insufficient to support optimal function, is considerably more common and far harder to detect.
Standard serum zinc testing is a poor marker of functional zinc status for the same reason serum magnesium is unreliable. The body maintains serum concentration within a narrow range by drawing on intracellular stores even as those stores deplete. By the time serum zinc falls below reference range, functional deficiency has typically been present for some time.
Athletes and regularly active people face a specific and compounding problem. Zinc is lost through sweat at a rate of approximately 1mg per litre. High training volumes can produce losses of 3 to 5mg per day above baseline requirements. This elevated loss is rarely accounted for in standard dietary reference values, which are established for sedentary or lightly active populations. Training hard on a diet that theoretically meets the NRV still produces a deficit for most people who sweat consistently.
Sweat losses alone can double your daily zinc requirement. Standard dietary reference values do not account for this. Training populations are systematically underserved by general recommendations.
Oysters every day is not a strategy.
Oysters are the highest dietary source of zinc at approximately 74mg per 100g. They are also not a practical daily food for most people. Red meat, poultry and shellfish are the most bioavailable dietary sources. Plant-based sources including legumes, seeds and wholegrains contain zinc but in forms bound to phytates that significantly reduce absorption, often by 50% or more.
The practical reality is that zinc intake adequacy depends heavily on dietary pattern. Omnivores who regularly consume red meat or shellfish are in a reasonable position if their training volumes are moderate. High-volume athletes, vegetarians, vegans and anyone with a heavily processed food diet face a meaningful gap between requirement and intake.
Even for people with good dietary zinc sources, the phytate problem is underappreciated. A diet high in wholegrains and legumes, which are broadly encouraged for health reasons, simultaneously increases phytate load and reduces the bioavailability of whatever zinc those foods contain. You can eat what appears on paper to be a zinc-adequate diet and still be functionally insufficient.
Dietary zinc on paper and bioavailable zinc in your cells are different numbers. The form it comes in, and what you eat alongside it, changes the arithmetic significantly.
Not all zinc supplements are the same.
Zinc oxide is the cheapest supplemental form and has an absorption rate of approximately 50% relative to zinc citrate in comparative studies. It is widely used because it is inexpensive and has a high elemental zinc percentage by weight, making it look impressive on a label while delivering considerably less usable zinc per dose.
Zinc citrate delivers zinc bound to citric acid, which forms a water-soluble complex that dissolves readily in the gastrointestinal tract and is efficiently absorbed across the intestinal wall. A comparative study published in the Journal of the American College of Nutrition found that zinc citrate and zinc gluconate produced equivalent serum zinc responses significantly greater than zinc oxide at the same elemental dose.
Zinc picolinate is sometimes marketed as the superior form based on limited older research. More recent comparative work has not consistently confirmed its advantage over citrate. Zinc citrate remains the most practically well-supported combination of high bioavailability, good tolerability and cost-effective manufacturing, which is why it appears in this formula at the 10mg elemental dose rather than a higher dose of a cheaper, less absorbed form.
10mg of zinc citrate delivers more usable zinc than 25mg of zinc oxide. The headline number on a label tells you almost nothing without the form.
Who needs zinc the most?
01
Anyone training consistently and sweating regularly. Sweat losses compound over time. Athletes in regular training have elevated zinc requirements that standard dietary guidance does not reflect. Consistent supplementation at the NRV level closes this gap without risking excess.
02
Vegetarians and vegans. Plant-based zinc sources are primarily in phytate-bound forms with substantially lower bioavailability than animal sources. Research consistently shows lower serum and tissue zinc in vegetarian and vegan populations compared to omnivores at equivalent dietary zinc intakes.
03
Men concerned about testosterone and reproductive health. Zinc deficiency is directly associated with reduced testosterone synthesis and impaired sperm quality. Multiple randomised controlled trials have shown that correcting zinc insufficiency in deficient men improves both testosterone levels and sperm parameters.
04
Anyone prioritising immune resilience. The immune-supporting evidence for zinc is among the most robust of any single micronutrient. Meta-analyses consistently show that adequate zinc status reduces the incidence and duration of common infections. The mechanism is direct and well understood at the cellular level.
05
Anyone eating a heavily processed diet. Ultra-processed foods are largely zinc-depleted relative to whole food alternatives. A diet high in refined carbohydrates, processed meats and convenience foods simultaneously reduces zinc intake and increases phytate consumption from refined grain products, compressing bioavailability from both directions.
The benefits that go beyond training.
Zinc is essential for normal thyroid hormone metabolism, which governs metabolic rate and energy production at the cellular level. Zinc deficiency impairs the conversion of T4 to the active T3 thyroid hormone and reduces receptor sensitivity to both. The metabolic consequences of suboptimal zinc status extend well beyond what most people associate with a single mineral.
The role of zinc in skin health is well established and clinically exploited. Zinc has documented anti-inflammatory and sebum-regulating properties that make it one of the more evidence-backed nutritional interventions for acne. Beyond cosmetic effects, zinc is essential for wound healing, collagen synthesis and the maintenance of skin barrier integrity. These are not peripheral concerns for active people whose skin is under mechanical stress.
Zinc also plays an important role in cognitive function. It is one of the most abundant transition metals in the brain and is released at glutamatergic synapses where it modulates NMDA receptor activity. Low brain zinc is associated with impaired memory consolidation, reduced neuroplasticity and increased susceptibility to neuroinflammation. Adequate zinc status supports the cognitive demands that training populations place on their brains alongside their bodies.
Zinc is operating in your thyroid, your brain, your skin, your immune system and your muscles simultaneously. It is not a single-purpose nutrient.
The right dose matters more with zinc than most minerals.
Zinc is a nutrient where the therapeutic window deserves careful attention. The UK tolerable upper intake level for supplemental zinc is 25mg per day. Chronic supplementation above this level is associated with copper depletion because zinc and copper compete for the same intestinal absorption pathway. The consequence of chronic copper depletion is anaemia, neurological impairment and immune dysfunction, outcomes that directly undermine the reasons most people take zinc in the first place.
The 10mg elemental dose in The Daily Foundation is exactly at the NRV, well within the safe range, and explicitly chosen to deliver the documented benefits of adequate zinc status without approaching the threshold where copper displacement becomes a concern. This is a deliberate and defensible formulation decision. Many zinc supplements on the market are dosed at 15 to 50mg and are either ignorant of or indifferent to the copper interaction.
At 10mg daily from zinc citrate, the only population that needs to exercise additional caution is anyone already taking high-dose zinc supplements separately from this formula. Stacking zinc sources without awareness of total elemental intake is the primary risk scenario. Within The Daily Foundation as a standalone supplement, the zinc dose is safe, appropriate and calibrated to the evidence.
More zinc is not better zinc. The 10mg dose is the right number. It is not a conservative compromise. It is the correct evidence-based position.
At a glance
Form
Zinc Citrate
Dose Per Capsule
1.67mg elemental
Daily Serving
10mg elemental (6 capsules)
NRV
100%
Best Taken
With food. Avoid taking alongside high-phytate meals where possible.
Works With
Vitamin D3, Magnesium and all other ingredients in The Daily Foundation
What the Research Shows
Testosterone
Zinc restriction reduces testosterone. Repletion restores it.
Prasad et al. placed healthy men on a zinc-restricted diet for 20 weeks and documented a significant fall in serum testosterone. Supplementation in zinc-deficient elderly men produced near doubling of testosterone over six months. This is the human trial behind the EFSA-approved health claim for zinc and normal testosterone maintenance.
Immunity
Even mild zinc deficiency measurably impairs immune function.
A review in the Proceedings of the Nutrition Society found that zinc supplementation in individuals with suboptimal status significantly improved T lymphocyte proliferation, natural killer cell activity and interleukin-2 production. Immune impairment caused by mild deficiency was reversed rapidly with supplementation.
Bioavailability
Zinc citrate absorbs significantly better than the oxide form found in most supplements.
A direct comparison study in the Journal of Nutrition found zinc citrate produced absorption rates equivalent to zinc gluconate and significantly higher than zinc oxide. Zinc oxide is in most budget supplements because it is cheap to produce. It is not in this formula.
Plant-Based
Vegetarians and vegans absorb up to 50% less zinc from the same nominal intake.
Phytates in legumes, grains, nuts and seeds bind to zinc and reduce intestinal absorption by up to 50% compared to animal-source forms. Someone eating the same nominal zinc intake on a plant-based diet is absorbing meaningfully less. The recommendation for plant-based eaters is 50% higher intake than standard reference values to compensate.
Dose logic
The dose is 10mg. That is not a coincidence and it is not a compromise.
The EFSA tolerable upper intake level for supplemental zinc is 25mg per day. Zinc is one of the few trace minerals where the margin between adequate and excessive intake is narrow enough to matter. 10mg delivers 100% of the adult NRV at the bioavailable citrate form. It closes the gap that training and dietary patterns create without pushing into the territory where zinc interferes with copper absorption. This is the right dose and it is on the label because that is how this brand operates.
One mineral. Three hundred enzymes. One hundred percent of your daily requirement.
