Zinc forms compared

The compound can affect solubility, absorption, the amount of elemental Zinc and tolerability. However, it is not possible to identify one form of Zinc as the best in every situation. Scientific comparisons between the different forms are limited, and absorption also depends on diet, dosage and a person’s individual Zinc status.

Why is Zinc bound to another substance?

In supplements, Zinc is provided as a compound. The mineral is bound to, for example, an organic acid or an amino acid. This creates names such as Zinc citrate and Zinc bisglycinate.

The binding:

• makes it possible to process Zinc into a tablet, capsule or lozenge;
• determines how much elemental Zinc the compound contains;
• can affect solubility and absorption;
• can affect taste and tolerability.

After absorption, our body uses the released Zinc. The authorised health claims therefore apply to Zinc and not exclusively to one specific compound.

Elemental Zinc versus the complete compound

This is the most important difference to recognise on a product label.

A Zinc compound does not consist entirely of Zinc. Part of its weight comes from the substance to which the Zinc is bound. The amount of the complete compound can therefore be much higher than the amount of elemental Zinc.

A specific example is a product containing 40 mg of Zinc orotate. This does not necessarily provide 40 mg of Zinc. A product in our range containing 40 mg of Zinc orotate provides 6.4 mg of elemental Zinc according to its composition.

Always check the composition carefully:

• Zinc orotate: the amount of the complete compound;
• of which Zinc: the amount of elemental Zinc.

When comparing products, the amount of elemental Zinc is the determining factor.

The main forms of Zinc compared

Zinc is available in organic and inorganic compounds.

• Organic Zinc compounds (chelates) are bound to amino acids or organic acids.
• Inorganic Zinc compounds are bound to Minerals or salts.

The main differences relate to solubility, absorption and tolerability.

Zinc acetate

Zinc acetate is Zinc bound to acetic acid. It is an inorganic compound that dissolves well in water.

Characteristics of Zinc acetate include:

• used in single-ingredient supplements;
• used by various international brands;
• good solubility in water.

Zinc acetate is a less common choice than organically bound forms such as bisglycinate or citrate, but it does not have a separate health effect compared with other forms of Zinc.

Zinc ascorbate and Zinc orotate

Ascorbate and orotate are less commonly used forms of Zinc.

In Zinc ascorbate, Zinc is bound to ascorbic acid. This can be a practical way of including Zinc and Vitamin C in one product. It does not automatically mean that Zinc ascorbate is absorbed better than every other compound. As with other compounds, the composition determines how much elemental Zinc and Vitamin C you actually obtain. With products containing Zinc ascorbate, therefore, check both amounts separately.

With Zinc orotate, the difference between the amount of the complete compound and the amount of elemental Zinc is often substantial. Read the composition carefully.

Zinc aspartate

Zinc aspartate is Zinc bound to aspartic acid, an amino acid that occurs naturally in the body.

Characteristics:

• available as a single-ingredient Zinc supplement;
• known for generally good tolerability.

Zinc aspartate is an organic compound. Always check how much elemental Zinc the product provides per daily dose.

Zinc bisglycinate

In Zinc bisglycinate, Zinc is bound to two molecules of the amino acid glycine. This is also referred to as an amino acid chelate.

Bisglycinate is often chosen because of:

• its amino acid-bound form;
• its solubility;
• its generally good tolerability;
• its use in capsules and tablets.

Some studies show good absorption, but this does not mean that bisglycinate is demonstrably better than every other form for everyone.

On product labels, you may also encounter the terms Zinc glycinate, Zinc bisglycinate or Zinc chelate.

Always check how much elemental Zinc the product provides. A well-known patented ingredient in this category is Albion’s TRAACS®, which uses a standardised manufacturing process for amino acid chelates.

Zinc carbonate

Zinc carbonate is Zinc bound to carbonate. It is an inorganic compound with a neutral taste.

Characteristics of Zinc carbonate include:

• used in basic formulas and budget-friendly supplements;
• has a stable structure.

As with Zinc oxide, the amount displayed on the label does not provide the complete picture. Always check the amount of elemental Zinc per daily dose.

Zinc citrate

Zinc citrate is Zinc bound to citric acid. It is a readily soluble organic compound that is widely used in food supplements.

Characteristics of Zinc citrate include:

• widely available;
• suitable for use in tablets and capsules;
• generally good solubility;
• available in different dosages.

Zinc citrate is a practical form for general use, but it does not have a separate health effect compared with other forms of Zinc.

Zinc gluconate

Zinc gluconate is Zinc bound to gluconic acid. This form is used in standard tablets, but it is also frequently used in lozenges.

Gluconate is chosen for these products partly because of its solubility and ease of formulation. However, the effect of a lozenge cannot be directly compared with that of a capsule that is swallowed. The dosage, composition, contact time in the mouth and duration of use differ.

Pay particular attention to the daily dose of products containing Zinc gluconate. Some products provide 50 mg of Zinc per tablet and are therefore not automatically suitable for long-term daily use.

Zinc HVP chelate

Zinc HVP chelate is an organic chelated form in which Zinc is bound to hydrolysed vegetable proteins.

Characteristics:

• used by brands such as New Roots Herbal;
• available as a single-ingredient supplement;
• known for the high stability of the chelate bond.

A chelate bond means that the Zinc is firmly incorporated into a molecule, similar to the approach used for other amino acid chelates. Always check how much elemental Zinc the daily dose provides.

Zinc methionine

Zinc methionine is Zinc bound to the amino acid methionine. A well-known patented ingredient is L-OptiZinc, in which Zinc is provided as Zinc mono-L-methionine sulphate.

This form is used in single-ingredient supplements and in products containing several compounds.

Characteristics:

• amino acid-bound form;
• available as a patented ingredient;
• often provided in capsules;
• regularly combined with other forms of Zinc.

A branded ingredient such as TRAACS® or OptiZinc® represents a specific patented manufacturing process with established quality controls. This provides information about its origin and composition, but does not automatically mean that the underlying compound has a different effect from the same compound produced by another brand.

Zinc oxide

Zinc oxide is an inorganic compound. This form contains a relatively high amount of elemental Zinc per gram of raw material, but is less soluble than various organic compounds.

This makes it possible to state a relatively high amount of Zinc on the label while using only a small amount of raw material. However, the amount on the label does not tell the whole story. Solubility, product formulation and intended use also play a role.

Zinc oxide is also used externally in skincare products such as sunscreens and protective creams. Zinc oxide applied to the skin does not contribute to your dietary Zinc intake.

Zinc picolinate

In Zinc picolinate, Zinc is bound to picolinic acid. This organic compound is used in various single-ingredient supplements and combination products.

Practical characteristics:

• available as a single-ingredient Zinc supplement and as part of combination products;
• often provided in capsules;
• regularly available in higher dosages;
• also included in products containing several forms of Zinc.

With products containing 30 or 50 mg of Zinc, the dosage is more important than the choice of picolinate.

Zinc pidolate

Zinc pidolate is Zinc bound to pidolic acid. Pidolic acid is an organic compound that occurs naturally in the body.

Characteristics:

• used in single-ingredient supplements and combination products;
• has good solubility and is often chosen for multi-form formulas.

Zinc pidolate is less common in the Dutch supplement market than bisglycinate or citrate. Always check the amount of elemental Zinc per daily dose.

Zinc sulphate

Zinc sulphate is Zinc bound to sulphate. It is an inorganic compound that occurs naturally in mineral water and liquid Mineral preparations.

Characteristics of Zinc sulphate include:

• used in liquid Mineral products such as CMD products;
• provides a high concentration per drop or capsule.

Liquid Zinc preparations based on Zinc sulphate require accurate dosing. Carefully check how much elemental Zinc a daily dose provides and keep the safe upper intake level of 25 mg of Zinc per day from food and supplements combined in mind.

One form of Zinc or a combination of several forms?

Some supplements contain one Zinc compound. Others combine, for example, citrate, gluconate, picolinate, bisglycinate and methionine.

A combination may suit someone who:

• does not specifically want to choose one compound;
• prefers to obtain several forms in a single daily dose;
• is looking for a comprehensively formulated product.

Several compounds do not automatically make a supplement more effective. Pay particular attention to:

• the total amount of elemental Zinc;
• how much each form contributes to that total;
• whether Copper has been added;
• other ingredients that may promote absorption;
• the recommended duration of use.

If five forms together provide 25 mg of Zinc, the total amount remains 25 mg.

Which form of Zinc is absorbed best?

There are indications that soluble organic and amino acid-bound forms can be absorbed well.

However, actual absorption also depends on:

• the amount of Zinc;
• the individual Zinc status;
• whether the product is taken with or without food;
• the amount of phytate in the meal;
• intestinal health;
• other Minerals;
• the product formulation.

A well-tolerated product with an appropriate amount that is used consistently may be more practical than a theoretically favourable form with an unnecessarily high dosage.

Which form is suitable for a sensitive stomach?

Zinc can cause nausea in some people, particularly when taken in a high dose or on an empty stomach. This can occur with several Zinc compounds.

Bisglycinate is often chosen because of its tolerability, but individual responses vary. If you experience stomach discomfort, you can:

• take the product during or immediately after a meal;
• choose a lower amount;
• try a different compound;
• check the daily dose;
• ask a qualified professional for advice.

Do not look only at terms such as “highly absorbable”, “chelated” or “multiple Zinc forms”. The complete composition determines whether a product is suitable for you.

View our complete range of Zinc products in our webshop.

Are you deciding between two Zinc products? Our qualified druggists and orthomolecular therapists can compare the amount, form, excipients and other ingredients for you.

Sources

• NIH Office of Dietary Supplements – Zinc fact sheet for health professionals
• EFSA – Dietary reference values for Zinc
• EFSA – Tolerable upper intake levels for Vitamins and Minerals
• Nutrients (2024) – Comparative absorption and bioavailability of various chemical forms of Zinc in humans