How to choose vitamin C, vitamin D and zinc: label, doses and forms

Vitamin C, vitamin D and zinc are sold on their own, in pairs and in complexes – as capsules, tablets, sprays and drinks. That makes it easy to get lost in the units and to take the same nutrient twice without noticing. Below: how to read the label, how the product forms differ, which upper levels apply in the EU and what to choose from our catalogue.

Contents

1. Vitamin C, vitamin D and zinc: what they are and what may be said about them
2. How to read the label
3. Product forms: choose by convenience
4. Safety: upper levels and when to ask a doctor
5. Single nutrient or complex, ingredients and allergens
6. Vitamin C, vitamin D and zinc in the Vitateka catalogue
7. Frequently asked questions

Vitamin C, vitamin D and zinc: what they are and what may be said about them

Vitamin C (ascorbic acid) is a water-soluble vitamin. Vitamin D is fat-soluble; in supplements it is usually D3 (cholecalciferol). Zinc is a mineral; in supplements it comes as a salt: gluconate, picolinate, bisglycinate.

In the EU, the benefits of vitamins and minerals may only be described in the wording of the register of authorised claims (Regulation 432/2012). For these three nutrients it includes, for example:

• Vitamin C contributes to the normal function of the immune system.
• Vitamin C contributes to the reduction of tiredness and fatigue.
• Vitamin D contributes to the normal function of the immune system.
• Vitamin D contributes to the maintenance of normal bones.
• Zinc contributes to the normal function of the immune system.
• Zinc contributes to the maintenance of normal skin.

These claims apply to a product whose daily portion provides at least 15 % of the nutrient reference value (NRV). For adults the NRV is 80 mg of vitamin C, 5 µg of vitamin D and 10 mg of zinc (Regulation 1169/2011, Annex XIII), so the threshold is 12 mg, 0.75 µg and 1.5 mg. Every product in our selection is above it.

How to read the label

Units. Vitamin C and zinc are given in milligrams (mg), vitamin D in micrograms (µg) or international units (IU). By the EFSA conversion, 1 µg of vitamin D = 40 IU: 25 µg = 1,000 IU, 50 µg = 2,000 IU, 100 µg = 4,000 IU.

% NRV shows what share of the adult reference value the daily dose provides. For example, 100 µg of vitamin D is 2,000 % NRV and 1,000 mg of vitamin C is 1,250 % NRV.

The daily dose is not always one tablet. The amount is stated per portion, and a portion is 1–2 tablets or 15–25 ml. Compare the daily dose. For example, the VITATEKA C+D3+Zn liquid gives 300 mg of vitamin C, 30 µg of D3 and 6 mg of zinc at 15 ml a day, and 500 mg, 50 µg and 10 mg at 25 ml.

The salt and the zinc itself. Compare the amount of zinc itself, not the weight of the salt: in a VitalHarmony capsule, 54.5 mg of zinc bisglycinate gives 15 mg of zinc. Magnesium works the same way – see our magnesium buying guide.

Price per day = pack price ÷ number of daily doses. An example at the prices of 07.10.2026 (delivery to Estonia, VAT included): ALG Pharma zinc costs 4.50 € for 30 tablets of 15 mg, i.e. 0.15 € a day; OstroVit zinc picolinate costs 7.50 € for 150 tablets of 15 mg, i.e. 0.05 € a day. The dose is the same, but the more expensive pack is three times cheaper per day. Many product pages show a "Daily doses per pack" line – with it the price per day is easy to work out.

Product forms: choose by convenience

• Capsules and tablets give an exact dose and are easy to carry. The capsule shell is gelatine (often bovine) or plant-based – this is stated in the ingredients.
• Chewable tablets and dragées need no water; they usually contain sugar, glucose or sweeteners.
• Sprays suit those who find swallowing uncomfortable: the dose is set by the number of sprays. One spray of the VITATEKA D3 spray gives 100 µg (4,000 IU).
• Liquid complexes are measured with a cap; the VITATEKA C+D3+Zn ingredients include fruit juices and sucrose.

There are no authorised EU claims that one form is "better absorbed", so choose by convenience and ingredients. In the Immune system category you can filter straight away by capsules, tablets or liquid forms.

Safety: upper levels and when to ask a doctor

The tolerable upper intake level (UL) is the highest daily intake from all sources, food included, at which EFSA does not expect harm with long-term use.

• Do not add 4,000 IU to other products with vitamin D. The VITATEKA D3 spray and the VITATEKA D3 4,000 IU capsules give 100 µg a day – exactly the adult upper level. A complex, fish oil or multivitamin with vitamin D on top of that is already more.
• Count zinc in all your products. 15 mg in a single-nutrient supplement, zinc in a skin and hair complex and zinc from food easily come close to 25 mg together.
• For children, only products whose label states a children's age and dosage. Adult D3 doses (50–100 µg) equal or exceed the children's upper level.

Ask a doctor before use if you are pregnant or breastfeeding, take medicines or are under medical supervision. Do not take supplements with vitamin K (often D3 + K2 pairs) without a doctor's advice if you use blood-thinning medicines (vitamin K antagonists such as warfarin).

Single nutrient or complex, ingredients and allergens

A single-nutrient supplement gives one substance and a clear dose and is easier to combine with others. A complex is convenient if you want one product instead of three, but before buying check what you already take: vitamins C and D and zinc are in many multivitamins and skin and hair complexes.

• Sugar and sweeteners. The Evalar D3 2000 chewable tablets contain glucose and sorbitol; the label warns that excessive consumption of sorbitol may have a laxative effect. The VITATEKA liquid complex contains fruit juices and sucrose.
• Carrier oil. Vitamin D is fat-soluble, so it is dissolved in oil: olive, safflower, MCT or shark liver oil. Rekinol Extra D3 with shark liver oil is a fish product – this matters if you are allergic to fish.
• Capsule shell. Gelatine (bovine or porcine) or a plant shell of hydroxypropyl methylcellulose – this matters for vegetarians.
• Origin of D3. Cholecalciferol can be of animal origin or vegan: the VITATEKA C+D3+Zn liquid states vegan cholecalciferol.

Vitamin C, vitamin D and zinc in the Vitateka catalogue

All products below were in stock on 07.10.2026; the doses are taken from the labels on our website. More options are in the Immune system category (with the "How to choose" and "Our pick" panel) and in the Vitamin C and Vitamin D sections.

• Vitamin C: OstroVit Vitamin C 1000 – 1,000 mg per capsule, 120 daily doses.
• Vitamin D3, 100 µg (4,000 IU): VITATEKA spray – one spray a day, in MCT oil; VITATEKA capsules with olive oil – 90 capsules, bovine gelatine shell.
• Vitamin D3, 50 µg (2,000 IU): ALG Pharma D3 2000 – 60 capsules in safflower oil; Evalar D3 2000 – 60 chewable tablets; Oleofarm Rekinol Extra D3 – 60 capsules with shark liver oil.
• D3 + K2: ALG Pharma VitalGold D3+K2 – 50 µg of D3 and 100 µg of K2 per tablet, 40 tablets.
• Zinc, 15 mg: ALG Pharma, gluconate – 30 tablets; OstroVit, picolinate – 150 tablets; VitalHarmony, bisglycinate – 90 capsules.
• All in one: VITATEKA C+D3+Zn, 500 ml – 15–25 ml a day; at 15 ml the bottle lasts 33 days.

Zinc and selenium are collected in our Zinc and Selenium selections. Rosehip syrups and teas are in the Rosehip selection: these are plant products, so compare the amount of vitamin C in mg if the label states it.

In short

• Compare the daily dose, not the pack size; convert vitamin D to micrograms: 40 IU = 1 µg.
• 4,000 IU (100 µg) of vitamin D is the EFSA upper level for adults; do not add it to other products with vitamin D.
• For zinc, look at the amount of zinc itself, not the weight of the salt, and keep the total from all products below 25 mg.
• Work out the price per day: pack price ÷ number of daily doses.
• Choose the form by convenience and ingredients: sugar, sweeteners, carrier oil, capsule shell.
• Pregnant or breastfeeding women, people taking medicines, and children – ask a doctor first.

Frequently asked questions

How many IU are in 1 µg of vitamin D?

40 IU. So 10 µg = 400 IU, 25 µg = 1,000 IU, 50 µg = 2,000 IU and 100 µg = 4,000 IU. This conversion is given by EFSA.

Can I take vitamin D on its own and in a complex at the same time?

Yes, if the daily total stays within the upper level: for adults that is 100 µg (4,000 IU) from all sources (EFSA, 2023). If one product already gives 100 µg, do not add a second product with vitamin D without a doctor's advice.

How much zinc a day is already a lot?

The reference value for adults is 10 mg and the upper level is 25 mg a day from all sources, food included (SCF, 2002). A 15 mg supplement gives 150 % NRV; if you also take a complex with zinc, add the doses up.

Why does one zinc pack say 15 mg and another 54.5 mg?

54.5 mg is the weight of the salt (zinc bisglycinate), of which 15 mg is zinc itself. Compare the line "zinc – … mg" in the table of the content per daily dose.

Isn't 1,000 mg of vitamin C too much?

It is 1,250 % NRV. EFSA has not set an upper level for vitamin C (EFSA, 2004). Stick to the dose on the label and do not combine several products with vitamin C without a reason.

Which form should I choose for a child?

Only a product whose label states a children's age and dosage. Adult vitamin D3 doses (50–100 µg) equal or exceed the children's upper level (50 µg for ages 1–10). Ask a doctor before giving a supplement to a child.

Important information

A food supplement is not a substitute for a varied and balanced diet and a healthy lifestyle. Do not exceed the recommended daily dose. If you are pregnant, breastfeeding, taking medicines or under medical supervision, ask a doctor before use. Keep out of the reach of children.

Read also

• How to choose calcium, vitamin D and collagen
• VITATEKA vitamin D3 4,000 IU spray: ingredients and use