At the recommended doses, from 2.5 to 10 grams a day, hydrolysed collagen is considered well tolerated by healthy people, and in them there is no evidence that it harms the liver. Side effects, when they occur, are mild and mainly digestive. If you have allergies, a medical condition or are on medication, or if you are pregnant or breastfeeding, ask your doctor first.
Collagen supplements are among the most popular, and with popularity come questions too: is collagen bad for your liver? Does it make you gain weight? Does it have contraindications? In this guide we set out what is known, without scaremongering and without promises.
Is collagen safe?
Collagen is a protein. In supplements, it is usually found in hydrolysed form, meaning already broken down into peptides: smaller fragments that the body digests like the other proteins in your diet.
At the doses used in supplements, usually between 2.5 and 10 grams a day, hydrolysed collagen is considered well tolerated by healthy people. This does not mean it is suitable for everyone in every situation: as with any supplement, the dose, the source and the condition of the person taking it all matter.
Side effects of collagen: what they are
When they occur, unwanted effects are usually mild and short-lived.
- Digestive complaints: a feeling of heaviness, bloating or heartburn.
- An unpleasant aftertaste, more common with some products of marine origin.
- Allergic reactions, linked to the source of the collagen: fish, crustaceans, eggs or other raw materials stated on the label.
If you notice a problem after starting a supplement, stop taking it and talk to your doctor or pharmacist.
Is collagen bad for your liver?
It is one of the most searched questions. To date, there is no evidence that hydrolysed collagen, at the recommended doses, damages the liver of a healthy person: its amino acids are used in the same way as those of the other proteins we eat every day.
Things are different if you have a liver disease or are undergoing treatment: in these cases any supplement, not just collagen, should be assessed with your doctor.
Is collagen bad for your kidneys?
In healthy people, at the recommended doses, no kidney problems have been reported. There are, however, two situations in which you need your doctor’s advice before starting:
- chronic kidney disease, because protein intake has to be decided with your nephrologist;
- calcium oxalate kidney stones, because collagen is rich in hydroxyproline, an amino acid that the body can convert into oxalate.
Does collagen make you gain weight?
No, not in itself. Collagen is a protein and provides about 4 kcal per gram: a 5-gram dose is equivalent to about 20 kcal. Your weight depends on the overall balance between what you eat and what you burn, not on a single supplement. Check the label instead: some formulas contain added sugars or juices. To read it properly, see the guide on how to choose a drinkable collagen.
Contraindications: who should ask their doctor first
- Anyone who is allergic to the source of the collagen (fish, crustaceans, eggs) or to other ingredients in the formula.
- Anyone who is pregnant or breastfeeding.
- Anyone with a medical condition, particularly of the kidneys or liver, or who is taking medication.
- Anyone already taking other supplements: many formulas also contain vitamins and minerals, and the amounts add up.
Then there is the rule that applies to all supplements: do not exceed the recommended daily dose, do not use them as a substitute for a varied and balanced diet, and keep them out of the reach of young children.
Collagen: four myths
“The more I take, the better”
No. The reference dose is the one stated on the label: increasing it does not speed anything up and makes digestive complaints more likely.
“It works in a few days”
Studies on collagen peptides last weeks, not days: those published on Verisol® run for eight weeks. Anyone who promises immediate results is not telling you how things really are.
“All collagen is the same”
The source (bovine, marine), the type, the degree of hydrolysis and, above all, the dose per serving all vary. These are the first things to look at on the label: the differences are explained in bovine or marine collagen.
“Plant-based collagen exists”
Collagen is a protein of animal origin. Products presented as plant-based actually contain nutrients linked to its formation, such as vitamin C, not collagen.
Collagen PRO5: what to know before you start
Collagen PRO5 is a food supplement with 5 g of Verisol® collagen peptides per vial, of bovine origin. The formula also contains vitamin C, zinc, vitamin A, biotin and hyaluronic acid; it is gluten-free and lactose-free and contains no GMOs.
- The dose is one vial a day, away from meals: do not exceed it.
- During pregnancy and breastfeeding, we recommend talking to your doctor before taking any supplement.
- If you are undergoing treatment or have a medical condition, ask your doctor for advice first.
- If you miss a day, carry on the next day without doubling the dose.
For doses and timing, see the guide on how and when to take collagen. You’ll find other answers in the frequently asked questions.
In summary
At the recommended doses, hydrolysed collagen is usually well tolerated. Side effects, when they occur, are mild and mainly digestive. There is no evidence that it is bad for the liver in healthy people, and it does not make you gain weight in itself. Anyone with allergies, a medical condition or ongoing treatment, or who is pregnant or breastfeeding, should ask their doctor first.
This article is for information purposes only and is not a substitute for the advice of a doctor or healthcare professional. If you have a medical condition, are pregnant or breastfeeding, or are undergoing treatment, ask your doctor for advice before taking supplements.
