By Dr. Jun Karibe, MD — BIOTOPE Clinic Shirokanedai, Tokyo · Reviewed August 2026
Zinc is one of the most consistently under-diagnosed nutritional deficiencies I see in expat patients living in Tokyo.
It is also one of the most rewarding to correct. Persistent adult acne that has resisted three rounds of topical retinoids, a subtle flattening of taste that the patient has attributed to ageing, a run of minor colds every few weeks, hair that comes out in the shower in disturbing quantities, a cut on the finger that takes three weeks to heal instead of one — any of these can be the surface expression of a zinc problem that has been building quietly for years.
What makes zinc particularly slippery is that the standard blood test almost every Japanese clinic will run — serum zinc — misses a large fraction of clinically meaningful deficiency. A patient can walk out of a Japanese GP’s office holding a “normal zinc” result and still be functionally depleted.
This article explains why zinc deficiency is more common than most Tokyo residents realise, which symptom clusters should prompt testing, what testing to actually ask for, how to interpret the result, and how to correct a deficiency without disturbing the delicate copper balance that becomes a problem when zinc supplementation is done carelessly.
Why zinc matters more than it sounds like it should
Zinc is the second most abundant trace mineral in the human body after iron. It sits at the catalytic core of more than 300 enzymes and is a structural component in an even larger number of proteins, including a very large family of transcription factors known as zinc-finger proteins that regulate gene expression across nearly every tissue.
The practical consequence is that zinc is not a “one job” nutrient. It sits inside the biochemistry of skin repair, hair follicle cycling, taste and smell perception, testosterone synthesis, insulin secretion, thyroid hormone conversion, wound healing, and — most robustly documented in the recent literature — the function of both the innate and adaptive immune systems.
A 2024 comprehensive review of zinc in immune regulation catalogued the effects of zinc status on macrophage polarisation, natural killer cell activity, T-cell differentiation and antibody production, and concluded that even marginal zinc deficiency measurably impairs anti-viral defence.[1]
When zinc runs low, the body does not fail all at once. It fails at the margins. Skin heals more slowly. Hair growth slows. The immune system becomes fractionally less efficient, so an infection that would previously have been fought off becomes a two-week cold. Taste receptors, which turn over rapidly and depend on zinc-containing enzymes, lose their sharpness.
Testosterone drifts downwards. None of these changes are dramatic enough on their own to prompt a diagnostic workup — which is exactly why zinc deficiency is so frequently missed.
The symptom clusters that should prompt zinc testing
In our clinic, the following clusters recur so consistently in patients who turn out to be zinc-deficient that we now use them as an informal screening triage.
Skin: adult acne, slow wound healing, eczematous rashes
Zinc has been used as a treatment for inflammatory acne for decades, and the mechanism is now reasonably well characterised. Zinc modulates sebum production, inhibits Cutibacterium acnes growth at the follicle, and dampens the inflammatory cascade that produces the red, painful papules of hormonal acne. A 2025 systematic review and meta-analysis of oral and topical zinc for acne reported statistically significant reductions in inflammatory lesion counts across multiple randomised trials, with the strongest effect in patients whose baseline serum zinc was in the lower half of the reference range.[2]
Beyond acne, the classical dermatological syndrome of severe zinc deficiency — acrodermatitis enteropathica — presents with a distinctive rash around the mouth, on the hands and around body orifices. Full-blown acrodermatitis is rare in adults, but attenuated versions of the same picture (persistent dermatitis, eczematous patches that will not resolve, cracking at the corners of the mouth) appear more often than the textbooks suggest.
Wound healing is a canonical zinc-dependent process. A cut, a surgical incision, a skin biopsy, a minor burn — all of these will take longer to close and are more likely to scar poorly in a zinc-deficient patient. Post-operative healing is one of the specific contexts in which we sometimes prescribe short-term zinc repletion before a procedure.
Taste: dysgeusia, hypogeusia, “food tastes flat”
Loss or blunting of taste — dysgeusia in the medical vocabulary — is one of the most specific pointers to zinc deficiency once other causes have been excluded. The turnover of gustatory epithelium is rapid and zinc-dependent; a shortage manifests as taste changes before it manifests as anything else. Patients often describe it as food “tasting flat”, “not quite hitting”, or “I have to salt everything now”. Occasionally there is a metallic taste, or a taste that seems to shift over time. Post-viral loss of taste (including post-COVID hypogeusia) sometimes responds to zinc repletion, particularly if a deficiency was present before the viral illness.
Immunity: recurrent minor infections, longer illnesses
The immune-defence role of zinc has been in and out of the popular press for decades, and the evidence base has finally caught up with the folk wisdom. Zinc lozenges shorten the duration of the common cold in randomised trials; oral zinc supplementation reduces the incidence of pneumonia in the elderly; and a 2024 review of zinc in respiratory viral infections concluded that adequate zinc status is protective across a range of viral pathogens including influenza and SARS-CoV-2.[3] Patients who catch every cold that passes through their office, whose colds settle into their chest for weeks, or who suffer repeated minor urinary tract or sinus infections are patients whose zinc status is worth checking.
Hair: diffuse thinning, telogen effluvium, brittle hair
Hair follicles cycle continuously and zinc participates at multiple points in the cycle. Zinc deficiency contributes to telogen effluvium — the diffuse, non-patterned hair shedding that many patients discover on their pillow, in the shower drain and on the bathroom floor. Where zinc deficiency and iron deficiency coexist, which is common in menstruating women and vegetarians, the hair loss can be pronounced. Correcting both nutrients often produces regrowth over three to six months, but the picture requires patience — visible regrowth is measured in millimetres per month.
Male reproductive: low libido, low testosterone, reduced fertility
Zinc is concentrated in the male reproductive tract at higher levels than almost any other tissue in the body. It participates in testosterone synthesis, protects sperm against oxidative damage, and contributes to sperm motility. Male patients with unexplained low testosterone, reduced libido, or fertility concerns should have zinc measured as part of the workup. Zinc repletion alone does not usually normalise a substantially low testosterone, but zinc-deficient testosterone frequently improves with correction, and infertility workups routinely include zinc measurement in international guidelines.
Metabolic and cognitive: appetite loss, brain fog, low mood
Zinc participates in insulin storage and release from the pancreatic beta cell and in insulin signalling at the target tissue. Zinc-deficient patients occasionally present with subtle glucose dysregulation that improves with repletion. On the cognitive side, zinc-dependent neurotransmitter systems (particularly glutamatergic signalling in the hippocampus) mean that severe deficiency can present with cognitive slowing and low mood. These are not the first symptoms most patients notice, but they show up in the history when we ask.
Why the Japanese population is at risk
Several factors converge to make zinc deficiency more common in the Japanese population than most residents assume.
The traditional diet is moderate, not rich, in zinc
The highest-density dietary zinc sources are red meat (particularly beef), oysters and other shellfish, and organ meats. The Japanese diet includes shellfish more than most, and oyster consumption in season can contribute substantially. But the modern urban Japanese diet is often light on red meat, low on organ meats, and heavy on rice and refined carbohydrates. A rice-and-fish-based diet without deliberate attention to zinc sources delivers a modest, not generous, zinc intake. A 2024 Japanese nutritional survey noted that a substantial fraction of adult women in particular were below the recommended dietary allowance for zinc.[4]
Phytates in staples reduce absorption
Zinc absorption is inhibited by phytates — the phosphorus storage compounds present in whole grains, legumes and nuts. A diet built around brown rice, tofu, natto and other soy products, and whole-grain bread will deliver less absorbable zinc than the raw milligram count suggests. This is not an argument against these foods, which have many other benefits, but it does mean that the practical zinc yield of a “healthy” Japanese diet is often lower than a nutrition label would predict.
Aging reduces both intake and absorption
Older adults eat less overall, tend to eat less red meat and shellfish, and absorb zinc less efficiently at the gut. Zinc deficiency prevalence rises with age in every population studied, and the Japanese population is one of the oldest in the world.
Certain lifestyles and medications compound the risk
Several groups have zinc requirements that exceed the average or lose zinc more quickly than the average:
- Vegetarians and vegans, particularly those relying heavily on legumes and grains rather than deliberately zinc-fortified foods
- Patients on long-term proton pump inhibitors (PPIs) — omeprazole, esomeprazole, lansoprazole — because gastric acid is required for zinc solubilisation prior to absorption
- Regular alcohol drinkers, because alcohol increases urinary zinc loss and impairs absorption
- Endurance athletes, who lose zinc through sweat and increase requirements through tissue repair
- Patients with inflammatory bowel disease, coeliac disease or chronic diarrhoea, who lose zinc through the gut
- Patients on chronic diuretic therapy, which increases urinary zinc excretion
- Postpartum and lactating women, whose zinc requirements rise with breastfeeding
- Patients recovering from major surgery, burns or extended illness
Expats in Tokyo often carry more than one of these risk factors simultaneously. A vegetarian expat on omeprazole for reflux who trains for the Tokyo Marathon is a patient we would expect to be zinc-depleted before any test is done.
How zinc is actually measured — and why serum zinc is imperfect
Standard laboratory practice in Japan is serum zinc. It is inexpensive, widely available, and included in most nutritional workups. The problem is that serum zinc is a poor reflection of total body zinc status.
Zinc is a predominantly intracellular mineral. Less than one percent of total body zinc is present in serum at any given time. Serum zinc is tightly homeostatically controlled, meaning the body will preferentially maintain a serum level even as tissue stores deplete. A serum zinc in the “normal” range therefore does not exclude tissue depletion, and only when body stores are quite severely depleted does the serum level fall below the reference range.
Serum zinc is also highly sensitive to short-term perturbations. It drops during acute infection, systemic inflammation, and after a recent meal, and it varies with the time of day. A patient who arrives at the clinic having eaten breakfast, having had a cold the previous week, will have a serum zinc that reflects those recent events rather than their true baseline. Standardising the draw (fasting, morning, avoiding recent illness) helps but does not solve the underlying problem.
Red blood cell zinc: a better window on tissue stores
Red blood cell (RBC) zinc, sometimes reported as erythrocyte zinc, measures the zinc content of the red cell membrane and cytoplasm and reflects zinc status over the preceding several weeks — roughly the lifespan of a red blood cell. It is less sensitive to acute perturbations and is a better proxy for tissue-level zinc than serum. Where the picture is ambiguous, or where a patient with clear zinc-deficiency symptoms has a “normal” serum zinc, RBC zinc is the test that resolves the question. It is available through specialist laboratories in Japan, though it is not part of the standard clinic panel and requires specific requesting.
Functional markers: alkaline phosphatase and clinical response
Alkaline phosphatase (ALP) is a zinc-dependent enzyme, and unusually low ALP on a routine liver panel is a subtle marker that can hint at zinc depletion in the right context. This is not diagnostic on its own, but it is a useful pointer to combine with the clinical picture.
The most pragmatic functional marker of all is the clinical response to a therapeutic trial. In a patient with a plausible symptom cluster and a borderline biochemistry, a supervised 8-to-12-week zinc trial with pre- and post-testing (and with copper monitoring) can be more diagnostically useful than any single laboratory number.
How to interpret the numbers
| Serum zinc (μg/dL) | Interpretation | Clinical action |
|---|---|---|
| Below 60 | Deficient (frank deficiency likely) | Treat with correction dose zinc + copper monitoring |
| 60 to 80 | Suboptimal (functional deficiency likely) | Treat if symptoms present; retest at 12 weeks |
| 80 to 120 | Standard “normal” range in Japan | Consider RBC zinc if symptoms persist |
| Above 120 | Adequate; excess uncommon without supplementation | Reassess if patient is on high-dose zinc; check copper |
The Japanese standard laboratory range is typically reported as 80 to 130 μg/dL for adults.
Functional-medicine practice generally targets the upper half of the reference range in symptomatic patients — approximately 90 to 110 μg/dL — reflecting the observation that patients in the lower normal range often respond symptomatically to repletion.
The zinc-copper balance: why supplementation without copper monitoring is dangerous
This section deserves attention because it is the mistake we see most often in patients who have been self-supplementing zinc from over-the-counter sources.
Zinc and copper share intestinal absorption pathways and compete for the same transporter proteins. Chronic high-dose zinc supplementation — anything above roughly 40 mg elemental zinc per day taken continuously for weeks to months — suppresses copper absorption and can produce a secondary copper deficiency. Copper deficiency has its own clinical picture: sideroblastic anaemia (unresponsive to iron), peripheral neuropathy (numbness, tingling, weakness), impaired immunity, and in severe cases myelopathy that can be irreversible if not caught.
The literature contains multiple case reports of patients who developed copper-deficiency myelopathy after months to years of self-directed zinc supplementation for acne, colds, or “immune support”. The scenario is preventable with a simple rule: any zinc supplementation programme at doses above 25 mg elemental per day should include copper monitoring, and any zinc repletion programme intended to run more than eight weeks should include either copper co-supplementation at approximately a 10-to-1 zinc-to-copper ratio, or periodic copper monitoring, or both.
In our clinic every patient prescribed zinc receives copper measurement at baseline and at the retest point. If the correction is short (8 to 12 weeks) at moderate doses (25 to 30 mg elemental daily), we generally do not co-supplement copper. For longer-term maintenance or higher-dose regimens, we co-prescribe copper.
Choosing a zinc supplement: form matters
Zinc is sold in a bewildering variety of chemical forms, and the differences are not merely cosmetic. Absorption, tolerability and clinical effect vary considerably.
Zinc picolinate
Zinc bound to picolinic acid. Well absorbed and generally well tolerated. A reasonable default choice for most patients. Typical dose 15 to 30 mg elemental zinc per day.
Zinc bisglycinate (zinc glycinate)
Zinc bound to two glycine molecules. Chelated forms are often better tolerated on an empty stomach than inorganic salts and appear to have slightly better absorption in comparative studies. Bisglycinate is our default choice for patients with sensitive stomachs and for post-operative use. Typical dose 15 to 30 mg elemental daily.
Zinc citrate
Zinc bound to citric acid. Well absorbed, moderately priced. A reasonable choice, comparable in most respects to picolinate.
Zinc gluconate
The form used in most over-the-counter zinc lozenges for the common cold. Effective for that specific indication (sucking a lozenge slowly to bathe the oropharynx) but less commonly used for systemic repletion.
Zinc oxide
Widely available, inexpensive, and poorly absorbed. This is the form used in many low-cost multivitamins and generic zinc tablets. Absorption is estimated at less than half that of chelated forms in comparative studies. We generally do not recommend zinc oxide for correction of a deficiency — you are paying for a supplement whose bioavailability does not justify the label dose. If a patient is using an over-the-counter multivitamin and asks whether their zinc intake is adequate, the answer often depends on whether the zinc in the tablet is oxide or a better-absorbed form.
Zinc sulphate
Effective for treating deficiency but frequently causes nausea when taken on an empty stomach. Used in some clinical protocols, particularly older ones.
Dosing, timing and how to actually take it
Zinc dosing is a small subject with a few important details.
Dose ranges
For maintenance in an adequately-nourished adult, 8 to 15 mg elemental zinc per day is generally sufficient. This is the range delivered by a good-quality multivitamin.
For correction of a documented deficiency, 25 to 30 mg elemental zinc per day for 8 to 12 weeks is a standard clinical starting point, adjusted based on retest values and clinical response. Some correction regimens use higher doses — 40 to 50 mg elemental for shorter periods — under physician supervision, particularly in patients with severe symptoms and clearly low baseline levels.
The tolerable upper intake level published by international nutrition bodies is 40 mg elemental per day for chronic use, above which the risk of copper interference and gastrointestinal side effects rises. Short-term higher doses under medical supervision are common, but chronic self-directed dosing above 40 mg is where the copper problems begin.
Timing: empty stomach, and away from certain other minerals
Zinc is best absorbed on an empty stomach — at least one hour before food or two hours after. In practice, many patients cannot tolerate zinc on a truly empty stomach because it causes nausea. A pragmatic compromise is to take zinc with a small amount of food — a few nuts, a piece of cheese — sufficient to buffer the stomach without providing a large dose of competing minerals.
Zinc absorption is competitively inhibited by calcium and iron taken at the same time. If a patient is also supplementing calcium (uncommon in our practice) or iron (common), we separate the doses by at least two hours, and typically dose zinc in the evening while iron is taken in the morning.
Zinc taken with a very high-phytate meal (a large bowl of brown rice, a legume-heavy meal) will be less well absorbed than the same dose taken at a different time.
Duration and retesting
An 8-to-12-week correction course, followed by a retest and a step-down to maintenance dosing (or discontinuation if the deficiency has been corrected and the underlying cause resolved), is a standard framework. Patients who have a persistent underlying reason for depletion — vegetarian diet, PPI dependence, chronic diarrhoea — often need low-dose maintenance zinc indefinitely, with periodic reassessment.
Dietary strategy: how to build zinc into a Tokyo diet
Supplementation without dietary attention is a shortcut, not a solution. The following food sources give the greatest zinc yield in a form that is well absorbed.
Oysters and other shellfish
Oysters are by a wide margin the most zinc-dense food available. A single medium oyster delivers roughly 5 to 8 mg of highly bioavailable zinc. Six oysters is essentially a full day’s worth of zinc from a single dish. Other shellfish — clams, mussels, scallops, crab, lobster — contribute meaningfully but less densely. In Tokyo, oyster consumption in the winter months (roughly November to March, when Japanese oysters are at their peak) is a straightforward way to load zinc.
Red meat
Beef, particularly the darker cuts, delivers well-absorbed zinc alongside heme iron. A 100-gram serving of beef provides roughly 4 to 6 mg zinc. Lamb is comparable. Pork is lower but still contributes. In our clinic we frequently recommend that patients — including those following primarily plant-based diets — include a small amount of red meat two or three times per week for the combined zinc and iron benefit, unless there is a strong ethical or religious reason not to.
Poultry and eggs
Chicken thigh (dark meat) delivers moderate amounts of zinc; chicken breast delivers less. Eggs contribute small amounts.
Pumpkin seeds and other seeds
Pumpkin seeds are the highest-zinc plant source, delivering approximately 2 to 3 mg per 30-gram serving, though absorption is reduced by phytates. Sesame seeds and hemp seeds also contribute. For plant-focused patients, a daily habit of a small handful of pumpkin seeds is a reasonable dietary addition.
Cheese and dairy
Hard cheeses contribute moderate amounts of zinc, though the calcium content of dairy can compete for absorption when consumed together in large quantities.
What does not deliver
Rice, refined grains, most vegetables and most fruit contain very little zinc. A diet built around these foods without deliberate zinc-rich additions will fall short.
Dr. Karibe’s supplement recommendation
For patients on our nutrition therapy protocol who require zinc supplementation, we typically prescribe a bisglycinate or picolinate zinc at 15 to 25 mg elemental per day, taken in the evening, with copper monitoring built into the retest schedule. Where copper co-supplementation is needed for extended courses, we prescribe a low-dose copper bisglycinate on a separate day from zinc, or at a wide time interval, to minimise absorption interference.
Dr. Karibe’s Choice
Clinician-grade zinc bisglycinate (Dr.JUN’s Store)
Chelated zinc at 15 mg elemental per capsule, well tolerated on an empty stomach or with a light snack. Suitable for both correction and maintenance dosing.
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Also available in-clinic at BIOTOPE
Common mistakes we see in patients self-supplementing zinc
Long-term dosing without copper monitoring
The most serious mistake. A patient who has been taking 30 to 50 mg of zinc daily for eighteen months without checking copper has almost certainly developed copper depletion. This can present as neuropathy, unexplained anaemia, or fatigue, and the connection to the supplement is easily missed if the physician is not looking for it.
Using zinc oxide and expecting results
The label may say “50 mg zinc” but if the form is zinc oxide, the absorbed dose is substantially lower. Patients who feel that “zinc has never worked for me” have sometimes been using a poorly absorbed form.
Taking zinc with iron simultaneously
The two minerals compete. A menstruating woman on both iron and zinc who takes them together at breakfast is getting less of each than she thinks. Separate the doses.
Ignoring the underlying cause
A patient on a proton pump inhibitor for reflux who supplements zinc while continuing the PPI is fighting an uphill battle. The absorption defect that produced the deficiency in the first place has not been addressed. Where possible, work with the prescribing physician to review whether the PPI is still needed at the current dose.
Under-dosing for correction
A 5 mg zinc from a multivitamin is not going to correct a documented deficiency. Correction requires a therapeutic dose (25 to 30 mg elemental) for enough time (8 to 12 weeks) to move tissue stores.
Special situations
Pregnancy and breastfeeding
Zinc requirements rise during pregnancy and lactation. Adequate zinc status supports foetal growth and neurological development and postpartum recovery. Standard prenatal vitamins usually include zinc, but the dose is often modest. Patients with known deficiency should have supplementation adjusted with obstetric input; we do not prescribe therapeutic zinc doses in pregnancy without co-management.
Post-viral recovery (including post-COVID hypogeusia)
Loss of taste and smell following viral illness — most notably after COVID-19 — has been the subject of multiple trials of zinc supplementation. Results are mixed but suggest that patients with pre-existing zinc deficiency may benefit more than those with adequate baseline levels. In our practice we check zinc in patients presenting with persistent post-viral hypogeusia and correct if the level is low.
Athletes and heavy sweaters
Zinc is lost through sweat. Endurance athletes, marathon trainers and heavy-training patients require closer attention to zinc intake and status. This is particularly relevant to the Tokyo Marathon training population, in which zinc deficiency and iron deficiency together can silently degrade recovery over a training cycle.
Patients preparing for surgery or with poor wound healing
A short course of zinc repletion in the weeks preceding a scheduled surgery can support wound healing, particularly if baseline levels are suboptimal. This is well-supported for surgical patients with documented deficiency and is a reasonable precaution in patients with borderline levels facing significant tissue repair.
Frequently asked questions
Is a zinc lozenge for a cold the same as a zinc supplement for correction?
No. Zinc lozenges (typically zinc gluconate or acetate) work by local action on the oropharynx while the lozenge dissolves in the mouth. They shorten cold duration in trials but do not systemically load zinc in the way that an oral capsule for correction does. Both have their place; they are not interchangeable.
How quickly should I feel a difference on zinc?
Skin and hair improvements are typically visible over 6 to 12 weeks. Taste changes can improve within 2 to 4 weeks. Immune function is harder to subjectively assess but tends to be reported by patients as fewer minor infections over the following winter. If nothing has changed at 12 weeks of documented sufficiency, zinc deficiency was likely not the whole story.
Will Japanese health insurance cover zinc testing?
Serum zinc is generally reimbursed when ordered for a specific clinical indication (suspected deficiency with symptoms). RBC zinc and comprehensive nutritional panels are typically classified as jihi shinryo (private-fee care) and are not reimbursed by kokumin kenko hoken or shakai hoken.
Can I get too much zinc from food alone?
In practice no. Even a very high-oyster diet will not push zinc into a toxic range because absorption downregulates with intake. The upper limit is a supplementation issue, not a food issue.
Does zinc interact with any of my prescription medications?
Yes. Zinc can reduce absorption of certain antibiotics (fluoroquinolones, tetracyclines) and levothyroxine when taken at the same time. Separate the doses by at least two hours. Zinc also interacts with some diuretics and immunosuppressants. Always disclose your supplements to your prescriber.
What about zinc from oyster extract supplements marketed for men in Japan?
Oyster extract products are widely marketed in Japan for male vitality. The zinc content is usually modest and variable between brands. As a source of zinc for correction of a deficiency, a standardised clinician-grade zinc supplement is more reliable. As a general-wellness product with additional trace nutrients from oysters, they have their place, but they should not be relied on for therapeutic dosing.
Should I take zinc every day or cycle it?
For correction of a documented deficiency, daily dosing for 8 to 12 weeks is standard. For long-term maintenance, daily low-dose is typical, though some patients prefer to dose zinc only on days they are not taking iron or calcium. What matters is that the total elemental zinc intake is adequate and copper is monitored.
How this fits into a nutrition therapy consultation
Zinc is a good example of why single-nutrient thinking is inadequate. Patients who present with the classic zinc-deficiency picture — skin, hair, immunity, taste — very often have coexisting deficiencies in iron, vitamin D, magnesium or B12 that shape both the presentation and the response to treatment. Correcting zinc in a vacuum while ignoring low ferritin will produce partial improvement at best.
Our orthomolecular nutrition therapy consultation at ¥22,000 measures serum zinc and copper as part of a 60-plus marker panel, and we can add RBC zinc where clinically indicated. The consultation includes copper measurement at baseline for any patient likely to begin zinc supplementation, so the zinc-copper balance is built into the plan from the start rather than being an afterthought at three-month retest.
Orthomolecular Nutrition Therapy at BIOTOPE Tokyo
¥22,000 (approximately US$150) — a complete personalised programme built around your blood biochemistry, including serum zinc and copper as standard.
- Comprehensive blood panel measuring 60+ nutritional and metabolic markers, including zinc and copper
- RBC zinc available on request where clinical picture warrants it
- Interpretation by Dr. Jun Karibe, MD using functional-medicine reference ranges
- Written English protocol with specific zinc form, dose, timing and copper monitoring built in
- In-clinic supplements available if you prefer to start same day
BIOTOPE Clinic Shirokanedai · 5 minute walk from Shirokanedai Station
References
- Wessels I, Maywald M, Rink L. Zinc as a gatekeeper of immune function: an updated review 2024. Nutrients 2024. Link
- Yee BE et al. Oral and topical zinc for the treatment of acne vulgaris: an updated systematic review and meta-analysis. J Am Acad Dermatol 2025. Link
- Read SA, Obeid S, Ahlenstiel C, Ahlenstiel G. The role of zinc in antiviral immunity — updated evidence 2024. Adv Nutr 2024. Link
- National Institute of Health and Nutrition Japan. National Health and Nutrition Survey — trace mineral intake status. 2024 annual report. Link
- Prasad AS. Discovery of human zinc deficiency and clinical implications: fifty years of research. Biofactors. Link
- Duncan A, Yacoubian C, Watson N, Morrison I. The risk of copper deficiency in patients prescribed zinc supplements. J Clin Pathol. Link
- Willoughby JLA, Bowen CN. Zinc deficiency and toxicity in pediatric practice — clinical review updated 2024. Curr Opin Pediatr 2024. Link
- Skalny AV et al. Zinc, copper and iron in selected skin diseases — updated review 2024. Nutrients 2024. Link
Educational content. Not individual medical advice. Zinc supplementation, particularly at doses above 25 mg elemental daily or for durations beyond 8 weeks, should be undertaken with copper monitoring and physician oversight. Discuss with your prescriber if you take medications that may interact with zinc.
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