Zinc is involved in more than 300 enzyme reactions in the body and, according to the EFSA, is officially involved in the normal function of the immune system, the maintenance of normal skin, hair, and nails, as well as cell division. A mild deficiency is more common in Germany than many think—but the symptoms are non-specific and often misinterpreted. This article contextualizes what is actually proven by studies and official reference values, where zinc is overestimated, and what an sensible intake looks like.

What is zinc and why can't the body store it?

Zinc is an essential trace element that the body cannot produce itself and does not store in significant amounts. This means: Intake must be regular via diet or, if necessary, via a dietary supplement. Zinc is a component of numerous enzymes and is therefore involved in fundamental processes such as cell division, wound healing, protein synthesis, and the protection of cells from oxidative stress. Good sources of zinc include beef, cheese, whole grain products, legumes, nuts, and pumpkin seeds.

Zinc in food: The best sources compared

Animal-based foods generally provide zinc in a more bioavailable form than plant-based sources, as plant foods often simultaneously contain phytates, which inhibit absorption in the gut. The following overview shows the zinc content of selected foods per 100 grams.

Those who eat a vegan or vegetarian diet can improve zinc absorption from legumes, grains, and nuts by soaking, sprouting, or—in the case of grains—using sourdough for preparation. This breaks down a portion of the phytates contained.

The EFSA-approved functions of zinc at a glance

The European Food Safety Authority (EFSA) has established a list of permitted health-related claims based on Regulation (EU) No. 432/2012. A total of 18 claims are approved for zinc—the following table shows the nine claims most relevant to this guide in their exact wording.

These statements are legally permitted, EFSA-verified statements regarding normal function—not medical claims and not statements regarding the treatment or prevention of diseases.

The remaining nine approved claims relate, among other things, to the maintenance of normal bones, normal protein, DNA, carbohydrate, and fatty acid synthesis, normal acid-base metabolism, the normal metabolism of macronutrients, as well as the maintenance of normal testosterone levels in the blood and normal vision. Overall, the list shows how deeply anchored zinc is in metabolism—at the same time, these are legally defined formulations for normal function and not statements about therapeutic effects on existing diseases.

Zinc and the immune system: What does the current study situation show?

Zinc plays a proven role in the normal function of the immune system. Things get interesting when asking whether zinc also helps with an acute cold. A current Cochrane analysis evaluated 34 studies with a total of 8,526 participants in this regard. The result is nuanced:

Prevention: Preventive zinc intake could neither demonstrably reduce the risk of catching a cold nor the subsequent duration or severity of a cold.

Treatment: If zinc is taken during an already existing cold, it can shorten the duration of the cold by about two days according to the analysis. Mild gastrointestinal discomfort was observed as a possible side effect.

Important for context: The exact dosage and dosage form (e.g., lozenges vs. capsules) varied between the included studies, so no blanket dosage recommendation for colds can be derived from them. In case of doubt, those with a cold should seek advice from a pharmacy or doctor regarding appropriate use.

Zinc for hair, skin, and nails: When it really helps—and when it doesn't

Zinc is involved in keratin formation and skin repair processes, which is why a deficiency can have a visible effect on hair, skin, and nails. This is precisely where a logical error occurs in many guidebooks: Not every type of hair loss responds to zinc.

Hereditary hair loss (androgenetic alopecia): This by far most common form of hair loss in women and men is primarily triggered by genetic predisposition and the hormone sensitivity of the hair follicles. Zinc intake alone does not change this mechanism—even with normal zinc levels, the hair loss remains.

Deficiency-related or diffuse hair loss: If a zinc deficiency actually exists, it can manifest itself, among other things, in increased hair loss. In this case, normalizing zinc supply is sensible and can contribute to the recovery of hair growth.

The practical consequence: Zinc is not a blanket remedy for hair loss, but is primarily relevant if a deficiency actually exists or is impending. Anyone who notices severe, sudden hair loss should have the cause clarified by a doctor instead of dosing highly without control—also because an iron deficiency is a very common, often overlooked co-trigger (more on this in our guide on iron for women).

And for blemished skin? Zinc is often discussed in connection with acne. Older, sometimes smaller clinical studies from the 1980s and 1990s investigated oral zinc gluconate with around 30 mg of zinc per day over several weeks and observed an improvement in skin appearance—in one study comparable to a low-dose tetracycline treatment. Important for context: A noticeable effect in these studies only appeared after about four weeks, around one-third of participants reported mild gastrointestinal complaints, and the dose of 30 mg used is already above the safe upper limit of 25 mg per day defined by the DGE. Use for acne is not an officially approved indication for zinc supplements in Germany and should therefore only take place in consultation with a physician or dermatologist—not high-dosed on one's own initiative.

Zinc daily requirement: The DGE reference values at a glance

The German Nutrition Society (DGE) revised its reference values for zinc in 2019. What is new is that the recommended amount is no longer a flat rate, but is stated depending on the phytate intake of the diet. Phytates come primarily from whole grain cereals and legumes and inhibit zinc absorption in the gut.

Those whose diet consists mainly of animal protein have a low phytate intake; a wholesome diet rich in whole grains and legumes counts as high phytate intake – in this case, more zinc tends to be necessary as less of it is absorbed. The DGE (German Nutrition Society) sets its own higher reference values for pregnant and breastfeeding women; since these vary depending on the trimester and individual situation, we recommend discussing your exact requirements with your gynecologist instead of taking higher doses across the board.

Am I affected by a zinc deficiency? Symptoms and risk groups

There is no classic warning sign for zinc deficiency – the DGE expressly points out that none of the known symptoms are specific to a zinc deficiency. According to the DGE, possible signs include impaired longitudinal growth (in children), skin eczema, diarrhea, wound healing disorders, problems with perception and memory, and an increased susceptibility to infectious diseases. In professional literature, taste and smell disorders, decreased appetite, and hair loss are also frequently mentioned as additional symptoms.

Risk groups for inadequate zinc supply are considered to be in particular:

• Vegans and vegetarians: plant-based zinc sources often simultaneously contain phytates, which inhibit absorption.
• People with chronic inflammatory bowel diseases (e.g., Crohn's disease, ulcerative colitis), as intestinal absorption can be impaired.
• Individuals after bariatric surgery (e.g., gastric bypass), due to altered nutrient absorption.
• People with genetically determined absorption disorders, where zinc intake is fundamentally restricted.

An actual deficiency cannot be reliably determined by symptoms alone, but only through a medical blood test. In the case of persistent, unclear symptoms, this approach is preferable to simply opting for a high-dose supplement on suspicion.

How does a zinc deficiency test work at the doctor's office?

A zinc deficiency is determined via a blood draw with subsequent measurement of the zinc level in the serum or plasma. Since the zinc level in the blood can also be influenced by the time of day, acute inflammation, and the last meal, doctors always interpret the value in the context of the individual's symptoms. If there is a well-founded suspicion – for example, in the risk groups mentioned above or with persistent, unclear symptoms – testing via a primary care physician is the most sensible first step before supplementing independently with high doses.

Zinc for athletes and in old age

Two groups deserve special attention regarding zinc supply, even if they are not always explicitly mentioned in the official risk groups of professional literature:

Very athletic people: Zinc can be lost through heavy sweating and intensive physical exertion. Those who train intensively on a regular basis should therefore pay special attention to a balanced, varied diet that meets their needs, rather than relying exclusively on one-sided protein sources.

Older people: With increasing age, the amount of food consumed as well as the variety of the diet decreases for many, which can make zinc intake through food more difficult. At the same time, some medications that are taken more frequently in old age influence the mineral balance. In case of doubt, a doctor should also consider a needs-based supply here.

Comparison of zinc forms: Bisglycinate, citrate, gluconate, picolinate, and oxide

Not every zinc compound is absorbed equally well by the body. Different zinc compounds are used in food supplements, which can differ in bioavailability and tolerability.

• Zinc bisglycinate (amino acid chelate): considered particularly well-tolerated because the zinc is bound to the amino acid glycine; often recommended for sensitive stomachs.
• Zinc citrate and zinc gluconate: widely used organic zinc compounds with good absorption, often contained in liquid and effervescent preparations.
• Zinc picolinate: also an organic compound, which is attributed good bioavailability in individual studies.
• Zinc oxide: an inorganic, cost-effective compound with a tendency for lower solubility compared to organic zinc compounds.

For basic daily supply, the exact compound is usually secondary to the question of whether the total dose is within the recommended range and is taken regularly.

Taking zinc correctly: Timing and interactions

In the gut, zinc competes with other minerals for the same transport pathways. This is relevant for intake:

• Copper: A permanently high zinc intake can inhibit copper absorption. For long-term, higher-dose zinc intake, professional literature suggests a ratio of approximately 1 mg of copper per 8–15 mg of zinc.
• Iron and calcium: If high doses of iron, calcium, and zinc are taken at the same time, they can hinder each other's absorption in the gut. A gap of a few hours is sensible here.
• Phytates: Whole grains, legumes, and other phytate-rich foods reduce zinc absorption from the same meal; soaking, sprouting, or sourdough fermentation can reduce the phytate content.
• Certain antibiotics: Zinc can impair the absorption of some antibiotics (e.g., tetracyclines, quinolones). Anyone taking such medications should maintain an interval of several hours and consult their pharmacist.

In cases of individual illnesses, pregnancy, breastfeeding, or when taking medications, zinc intake should fundamentally be coordinated with a doctor or a pharmacist.

Can you overdose on zinc?

Yes. According to the DGE, the tolerable total intake (Upper Level) for adults is 25 mg of zinc per day – combined from food and food supplements. If this amount is permanently exceeded, this can, among other things, impair copper absorption and lead to nausea, and in some studies, even to a weakening of immune function. Short-term high-dose intake should therefore be avoided and only occur after medical consultation.

Meeting your daily zinc requirement

The majority of zinc requirements can be met through a varied diet containing meat, cheese, whole grain products, legumes, and nuts. Those who wish to specifically supplement their diet – for example, during cold season or if they have an increased requirement – can make use of a combination preparation that links zinc with other nutrients for the immune system.

Frequently asked questions about zinc

Sources: German Nutrition Society (DGE) – FAQ Zinc, Regulation (EU) No. 432/2012 – List of permitted health claims, Cochrane Blogshot – Zinc for colds, Orthomol – Zinc content in food, PTA-Forum – Zinc as a therapy option for acne. This article is not a substitute for individual medical advice.