Collagen side effects have increased due to the popularity of collagen supplements. What gets studied is mostly the skin and the tissues around the joints. Nails, by contrast, are made of keratin, not collagen — collagen peptides only supply amino acids the body also uses to form keratin. However, as with any dietary supplement, it is possible to experience side effects from collagen.
Although collagen is generally considered safe, some people may experience unwanted side effects. Common collagen side effects relate to digestion, including gas, heartburn and bloating. People with fish or egg allergies should be particularly cautious, as many collagen supplements are derived from these sources.
Some users also report a lingering aftertaste or bad breath after taking collagen. These side effects are usually temporary, but can vary depending on individual tolerance.
Before integrating a new collagen supplement into your diet, it is advisable to consult a doctor or nutritionist - especially if you suffer from pre-existing conditions or regularly take medication. A sound knowledge of possible collagen side effects will help you make the right decision.
What are the common collagen side effects?
Dyspepsia and digestive problems
Dyspepsia and indigestion are possible side effects of collagen. These symptoms are manifested by discomfort in the upper abdominal area, accompanied by flatulence, nausea and a rapid feeling of fullness during meals.
As collagen is a protein-rich food supplement, it can stimulate stomach acid production, which can lead to these symptoms. To avoid digestive problems, it is advisable to take collagen with a meal, spread the dose throughout the day or switch to hydrolyzed collagen, which is easier to digest. If the symptoms persist, it is advisable to consult a doctor to clarify possible underlying causes.
Unpleasant aftertaste or bad breath
Some people report an unpleasant aftertaste or bad breath after taking collagen supplements. Collagen from fish or beef in particular can taste more intense. Certain additives in collagen products can also increase this effect.
To reduce this side effect, it can be helpful to mix collagen with a flavored drink or smoothie. Alternatively, unflavored powders or collagen capsules can be used. Good oral hygiene, including regular tooth brushing and the use of mouthwash, can also help to neutralize the taste.
Headaches after taking collagen
Headaches are a rare but possible side effect of collagen. They can be triggered by various factors such as dehydration, a change in diet or sensitivity to certain ingredients.
It is unlikely that collagen directly causes headaches. Rather, the body's adaptation to a new dietary supplement can cause such symptoms. Drinking enough water, keeping to a balanced diet and choosing collagen products without artificial additives are sensible steps in any case. If the headaches persist, it is advisable to seek medical advice.
Dizziness after taking collagen
Some people experience dizziness after taking collagen supplements. This can occur when the body has to adapt to the increased protein intake or, in rare cases, when collagen affects blood pressure or blood sugar levels.
If you are prone to dizziness, you should start with a low dosage and gradually increase the amount. Adequate fluid intake and a balanced diet also help to minimize side effects. If dizziness persists, it is advisable to take a break and consult a doctor.
Insomnia due to collagen?
Collagen contains glycine, one of its main amino acids. Individual responses to it differ from person to person. Especially if collagen is taken late in the evening or in high doses, it could affect sleep.
Anyone who notices that collagen affects sleep quality should preferably take it in the morning or at lunchtime. Good sleep hygiene, including a regular bedtime and a quiet environment, can help reduce sleep problems. If insomnia persists, it may be useful to seek medical advice.
Rash and allergic reactions to collagen
Allergic reactions to collagen are rare, but can occur in people who are sensitive to the collagen source. People with allergies to fish, shellfish or beef products in particular should check the ingredients carefully before taking the product.
Possible symptoms of an allergic reaction are
- Reddening of the skin
- Itching
- Swelling
Anyone who is prone to allergies can carry out a patch test on the skin before taking a new collagen preparation for the first time in order to detect possible reactions at an early stage. If skin reactions or other allergic symptoms occur, use should be stopped immediately and a doctor consulted.
Potential effects of collagen on the body
The following possible side effects of collagen may cause discomfort in sensitive individuals. If discomfort occurs after taking the supplement, you should stop taking it for the time being and consult a doctor to avoid possible complications.
Effects on the liver
Excessive intake of collagen can put a strain on the liver, as it is responsible for processing additional proteins. In rare cases, this can lead to an increase in liver enzymes, which could impair liver function in the long term. People with existing liver disease should therefore seek medical advice before taking collagen supplements.
Stress on the kidneys
A high protein intake from collagen can potentially put a strain on the kidneys. People with impaired kidney function in particular should be careful to monitor their protein intake, as excessive protein intake can increase the risk of kidney stones or reduced kidney function. Anyone suffering from chronic kidney problems should consult a doctor before taking a collagen supplement.
Possible gastrointestinal problems
The most common side effects of collagen include digestive problems such as flatulence, indigestion and occasional diarrhea. Long-term intolerance can lead to reduced nutrient absorption and affect general well-being. To avoid digestive problems, it is best to take collagen with a meal. Adjusting the dosage or switching to hydrolyzed collagen can also help to reduce stomach problems.
Influence on the cardiovascular system
Although rare, there are reports of changes in heart rate or blood pressure after taking collagen. These effects usually only occur in people with pre-existing cardiovascular disease. Anyone suffering from high blood pressure or other heart conditions should watch out for possible changes when taking collagen and seek medical advice if in doubt.
Recommended dosage for safe use
To avoid possible side effects, it is important to stick to the recommended intake. The ideal dosage is around 5 g of collagen per day, as recommended by the Kollagen Institut.
A healthy person needs around 0.8 to 1 g of protein per kilogram of body weight per day. Within this range, a daily intake of 5 g of collagen is considered safe and harmless. Those who already cover their protein intake through their normal diet should be careful not to increase the total amount of protein excessively.
Sticking to the recommended amount and taking it deliberately keeps possible side effects to a minimum.
Types of collagen and their functions
Type I collagen - The most common collagen in the body
Collagen type I is the most widespread type of collagen in the human body. It is found in skin, bones, tendons, ligaments and teeth and ensures the strength, elasticity and resilience of tissue.
This collagen plays a decisive role in wound healing and in the regeneration of skin and bones. In the skin, type I forms the fibre network of the dermis that gives it firmness and elasticity. That this network loosens over the years is a normal process. The stability of the bone structure and the strength of the teeth are also significantly supported by type I collagen.
Because type I is so widespread in the body, it is often processed into skin care products, food supplements and medical applications.
Collagen type II - the collagen of cartilage tissue
Type II collagen is the main component of cartilage tissue. It gives the cartilage both strength and elasticity and enables it to absorb compressive forces and cushion impacts. It therefore contributes significantly to the stability and resilience of the joints.
Cartilage cells, the chondrocytes, build the cartilage matrix out of type II collagen; collagen peptides supply the amino acids that serve as the raw material. Studies on type II collagen have recorded self-reported joint mobility and load tolerance by questionnaire — usually over 12 to 24 weeks and in small groups.
Collagen type III – in skin, muscles and blood vessels
Collagen type III is an essential structural protein found in skin, muscles and the walls of blood vessels. It works closely with collagen type I to ensure the elasticity and firmness of the tissue. It is particularly important for maintaining firm skin, supporting muscles and the stability of blood vessel walls.
In addition, collagen type III plays an essential role in wound healing and tissue regeneration. It is also found in the walls of newly formed blood vessels and in the connective tissue of the heart. Especially during growth and after injuries, collagen type III is crucial for the formation of new cells and tissue repair.
Collagen type IV - structural support and protective barrier
Collagen type IV is an essential component of the basement membrane, a thin layer of tissue that connects and protects different cell types. It supports both epithelial and endothelial cells and plays a central role in regulating the passage of cells and molecules between tissues. This collagen is particularly important for tissue repair and is required for filtration in the kidneys. It also ensures the stability and functionality of many organs and tissues, including the skin, lungs and blood vessels.
As it acts as a barrier between different layers of tissue, collagen type IV contributes to the maintenance of skin structure and the regeneration of damaged tissue.
Collagen type V - in bones, organs and the follicle sheath
Collagen type V occurs in bone, placenta, liver and lung tissue, and in the connective-tissue sheath around the hair follicle. The hair itself is made of keratin. It regulates the formation of collagen fibrils and contributes to the stability and elasticity of connective tissue. In the bones it provides strength and structure, while in the placenta it supports the growth of the fetus. Collagen type V also plays a decisive role in the function of the lungs and liver. It helps to maintain organ structure and supports regenerative processes in the tissue.
The hair follicle sits in a connective-tissue sheath that type V helps build. In the hair matrix itself the body forms keratin — collagen peptides supply amino acids as the raw material for that, and nothing more.
Precautions when taking collagen
Collagen supplements are generally well tolerated, but it's important to be aware of potential side effects and take appropriate precautions. Before adding a new supplement to your routine, consult a doctor to ensure it is suitable for your individual health needs.
Pay attention to how your body reacts to collagen and adjust the dosage if necessary to avoid unwanted side effects. To reduce digestive discomfort, it is advisable to take collagen with a meal and ensure adequate hydration.
If severe side effects such as allergic reactions, persistent headaches or dizziness occur, the intake should be stopped immediately and medical advice sought. Conscious use and the choice of a high-quality product keep undesirable side effects to a minimum.