Inmunoferón in Spain: What It Is and Does It Work?

Inmunoferón is a brand sold in Spain today as a food supplement to "support your defences". It contains AM3, an extract of yeast and soy, plus zinc. Only the zinc has an approved health claim. There is no good proof that it prevents colds or flu in healthy people. This guide is by Dr. Pedro Yelamo Vera, a GP licensed in Spain (Colegiado No. 484814280).

What is Inmunoferón?

It is a brand made by the Spanish firm Cantabria Labs. For years it was sold in Spain as a medicine, with the active substance glicofosfopeptical (AM3). The Inmunoferón products you find in Spanish pharmacies today are labelled as food supplements (complementos alimenticios). There are capsules, sachets and a children's syrup (Inmunoferón Junior).

A food supplement does not go through the checks that the Spanish medicines agency (AEMPS) needs for a medicine. It may only make claims that the EU has approved for its ingredients.

What is Inmunoferón used for?

The label says it helps the immune system work normally, thanks to its zinc. This is an EU-approved claim for zinc. It only means the body needs zinc for its defences. It does not mean that extra zinc on top of your diet stops colds.

It is not meant to cure an infection, and it does not replace any treatment.

What is in Inmunoferón?

• AM3: a sugar from the yeast Candida utilis joined to a soy protein. The maker calls it an immune modulator.
• Zinc: a mineral the immune system needs.

As it contains soy protein, it is not suitable if you are allergic to soy.

Does Inmunoferón work?

There are few studies on AM3. Most are small, old and in narrow groups, such as people with chronic bronchitis. There are no large, independent trials showing it prevents colds or flu in healthy adults or children.

A Cochrane review looked at immune boosters in children who keep getting chest and throat infections. It found this group of products might cut infections, but the studies were poor. That review tells us nothing firm about Inmunoferón itself.

What about other immune supplements?

• Zinc: some studies suggest zinc lozenges or syrups shorten a cold a little if started in the first days. More data are needed. Too much zinc can lower copper and make you feel sick.
• Vitamin C: does not prevent colds in most people.
• Vitamin D: only worth taking if you are low. See our guide to low vitamin D.
• Echinacea and propolis: results are mixed, and they can cause allergies.

No supplement replaces vaccines. Read who should get the flu jab in Spain.

What really helps your immune system?

• Routine vaccines and, if you qualify, the flu jab and other advised vaccines.
• Washing your hands often and letting fresh air in.
• Enough sleep.
• Not smoking, and keeping alcohol low.
• A varied diet with fruit, vegetables, pulses and protein.
• Keeping illnesses such as diabetes under control.

Young children at nursery can catch many colds a year. This is usually normal, and it gets better with age.

Who should ask before taking it?

• People allergic to soy or yeast.
• Women who are pregnant or breastfeeding. There is not enough safety data.
• Children: ask their doctor first.
• People with an autoimmune disease, a transplant, or treatment that weakens the immune system.

This guide does not give supplement doses. Follow the label and ask your pharmacist.

When should repeated infections be checked?

See a doctor if infections are more frequent than normal for your age, take a long time to clear, or are severe, such as repeated pneumonia. Also see one if they come with weight loss, or if they are unusual infections. A doctor may order blood tests before any supplement is considered.

In English: what is the equivalent?

There is no direct UK or US version. In those countries AM3 products are not widely sold. In Spanish pharmacies, ask for Inmunoferón by name; zinc on its own is zinc or suplemento de zinc. None of these needs a prescription in Spain.

When to call 112

• Trouble breathing or blue lips.
• Chest pain.
• Confusion or deep drowsiness.
• Swelling of the face, lips or tongue after taking a product.

Frequently asked questions about Inmunoferón

Getting a medical assessment

If infections keep coming back or a cold is not getting better, you can book a video consultation with Dr. Pedro Yelamo Vera, a physician registered in Spain. You can also read about colds, how long a cold lasts and flu. A prescription is never guaranteed: it is issued only where clinically appropriate after a genuine evaluation, as a private electronic prescription under Spanish law. This service is for urgent, non-emergency care. In an emergency, call 112.

This guide is general information. It does not replace the package leaflet or the advice of your doctor or pharmacist.