Collagen supplements may make your skin more elastic – but the evidence for this is quite thin.
There's been a lot of hype around collagen.
This protein, which is important for the structure of skin and joints, is being touted as a miracle cure for everything from wrinkles to poor sleep.
The production of collagen, the body's most abundant protein, naturally slows down with age – whether you protect your skin from the sun or not.
To replace it, collagen supplements suddenly became big business.
One big fan is Brian Johnson, a tech entrepreneur turned walking experiment on how to extend life, who says he takes 25 grams of collagen peptides every day.
But collagen is not always well understood.
Although there is some evidence that supplementation with this molecule provides some health benefits, research is limited.
The main risk of taking it as a supplement could be that it's a waste of money – there are very few known side effects – but does the scientific evidence keep up with the marketing claims?
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Why collagen is confusing
To start with the basics, "collagen can only be found in animal connective tissue," says Andrea Soares, a registered dietitian in Georgia, USA, who is part of the Top Nutrition Coaching Network, a company that helps connect people with dietitians in their area.
Collagen products come from a variety of animals: cows, pigs, chickens, and fish.
Gelatin, which is used to make candy, jellies, and capsules for pharmaceutical products, is a form of collagen.
"Some plant-based supplements claim to be 'vegan collagen,' but what they actually contain are collagen-boosting ingredients like vitamin C, amino acids, and minerals that help your body make its own collagen," says Soares.
"If you're vegan, you may want to spend your money on a well-rounded diet rather than on herbal 'collagen' supplements that don't actually contain collagen."
Different types of collagen seem to function differently.
Hydrolyzed collagen (collagen hydrolysate) is collagen that has been broken down into short chains of amino acids known as peptides.
They are further broken down as they move through the digestive system.
On the other hand, undenatured (raw) type II collagen is a component of the cartilage that lines the joints.
In theory, it could help replenish collagen around joints, says David Hunter, a clinical rheumatology researcher at the University of Sydney, who specializes in osteoarthritis.
Type II collagen is also broken down into amino acids in the stomach, although the body usually absorbs hydrolyzed collagen better.
In addition to the wide range of sources and types of collagen, this substance is packaged in many different forms, from chocolate bars to drinks.
Compared to powders and liquids, "tablets and gummies often have less collagen per serving and may contain added sugars or fillers," says Soares.
While eating foods rich in protein and vitamin C usually helps our bodies make collagen, the amount present in foods like bone broth varies.
She advises those taking collagen as a supplement to opt for a powder or liquid, with at least 5-10 grams of collagen per serving.
Overall, many marketing claims regarding oral collagen products do not stand up to scrutiny.
In the European Union, "no health claims related to collagen supplements have been given the green light," explains Leng Heng, senior scientific officer for human nutrition at the European Food Safety Authority (EFSA).
EFSA is the European Union agency that assesses the risks associated with novel foods.
When they studied collagen, they concluded that the health claims made about it have not yet been supported by a sufficient amount of high-quality evidence.
They were "not well-defined, lacked human studies, or relied on evidence from animal or laboratory studies, which cannot predict effects in humans," Heng says.
He points out that claims such as the idea that collagen helps preserve skin elasticity or improves joint function are not yet sufficiently supported by scientific research.
Potential industry bias is a key concern for the rigor of the assessment, says Hunter.
Many studies on collagen are funded by supplement companies or written by employees of these companies.
Conflicts of interest must be declared in academic studies, but this does not always happen.
For example, one published study contains five to seven authors who have stated affiliations with supplement companies, but no additional information is provided in the conflicts of interest section.
(In response to a BBC request, the study's publisher, Elsevier, said the study was now under investigation.)
"The reality of many of these studies is that it's hard to find any studies that are completely independent of industry," Hunter says.
Influencers sometimes praise poor-quality research and promote higher doses of supplements than recommended by health authorities.
Even systematic reviews and meta-analyses – massive reviews of evidence, which bring together the results of multiple studies in one place – can be compromised by the quality of the included studies.
Hunter and his co-authors assess the risks of bias in such studies, including the involvement of industry itself.
But he says it can be difficult to account for bias when there simply aren't enough independent studies, as in the case of collagen.
Collagen helps form connective tissue and plays a key role in the skin, bones, and cartilage in the body.
While the individual health risks of collagen supplements appear low, there are some larger potential consequences of the growing appetite for collagen.
For example, collagen supplements from cattle have been linked to deforestation in Brazil.
Meanwhile, the European Commission has commissioned research into the possibility that collagen or gelatin could lead to new cases of transmissible spongiform encephalopathy (TSE, or prion diseases).
EFSA assessed the oral exposure of humans to contaminated gelatin under a hypothetical worst-case scenario and concluded that there was no risk or that it was negligibly small.
Collagen for skin, tissue and joints
One key problem with any claims regarding the benefits of collagen is what happens when this molecule is ingested.
As London-based dermatologist Anjali Mahto told the BBC in 2019, there is "little hard evidence that it survives digestion, travels through the bloodstream, and even reaches your skin."
Moreover, when any protein reaches the stomach – including collagen – it is usually rapidly broken down into amino acids, which are then reassembled into the proteins the body needs at that moment.
So, if the body needs collagen, it could reassemble those amino acids into collagen, but there are no guarantees.
Another problem is the formation of collagen supplements.
In many dermatological studies of collagen products, these products also contain other ingredients that may be good for skin health, making it difficult to isolate the effects of collagen itself.
However, many users swear by the effects of collagen on the look and feel of their skin.
A systematic review and meta-analysis showed that hydrolyzed collagen may have positive effects on the skin, such as improving hydration and elasticity.
However, the authors concluded that further research is needed to truly confirm this.
Other industry-funded studies have shown that oral products with high amounts of the collagen peptides, prolylhydroxyproline and hydroxyprolylglycine, can improve skin moisture and appearance.
"Consistent use is key," says Soares.
There are certain strategies to enhance the potential benefits of collagen supplements, for example for tendons.
Robert Erskine, associate professor of neuromuscular physiology at Liverpool John Moores University, suggests that exercise could stimulate the body's tissues to regenerate collagen more than usual.
In turn, this could strengthen the tendons, allowing someone to move faster and be less likely to fall.
In one study, Erskine and colleagues from universities across the UK tested whether taking hydrolyzed collagen could boost the amount of collagen the body makes after high-intensity resistance exercise.
The study, conducted on a small sample of young, healthy men, showed that the men produced significantly more new collagen when they drank a mixture of vitamin C and 30 grams of hydrolyzed collagen before exercise.
This was a stronger dose than what had been previously studied or what is typically packaged for consumers.
In another study involving Erskine, the team tested the same effects in healthy middle-aged men.
They found that there was still an effect of collagen supplementation, but it was smaller.
So, age is a factor in collagen production, just like gender.
There are links between estrogen and collagen synthesis, for example.
Collagen supplements are extracted from the skin, cartilage, and bones of animals such as chickens and cows.
"I'm really interested in trying to explore how we can improve the health and performance of athletes, especially female athletes," says Erskine.
"I think collagen will play a big role in that," not only to improve their performance, but also to reduce the risk of injury.
While such research is relatively new and conducted on a small sample, it is already being integrated into the nutritional habits of elite athletes.
"I think the evidence is strong enough to make these suggestions," he says.
Moreover, although collagen supplements are often associated with young and athletic types or those who care about their image, they are increasingly being investigated as a possible way to treat chronic conditions associated with age.
For example, there is mixed evidence on whether collagen helps with symptoms of rheumatoid arthritis.
A recent meta-analysis found that the overall quality of research in this area was poor, so it was not possible to determine whether collagen supplements could help.
However, the authors noted that some studies have reported adverse effects.
Regarding osteoarthritis, Hunter and colleagues conducted a systematic review of studies, finding that collagen supplements appear to reduce osteoarthritis pain in the short term.
However, Hunter points out that the evidence base is limited.
The collagen studies the team used were limited in both quantity and quality (such as small samples).
For this reason, he and his colleagues did not include collagen in a new clinical trial of complementary medicines that appear to show more promise for osteoarthritis: pine bark extract, frankincense oil extract, and curcumin.
Should you take collagen supplements?
As with any supplement, there is a risk of interactions with other medications people are taking, so Hunter advises anyone considering taking supplements to consult a healthcare professional first.
Increased intake of proteins like collagen can be a problem for people with chronic kidney or liver conditions that affect protein metabolism, says Erskine.
Many of Hunter's patients are interested in supplements after hearing about them through advertisements, the media or people they know, he says.
"It's very important that people, especially healthcare professionals, are open to these conversations," he says.
"If you reject them up front, I think it's very likely that many patients will just go away and buy them anyway."
In his own practice, Hunter tells patients who express interest in supplements that some are worth trying for three to four weeks.
As with skin appearance, some studies show that the benefits of supplements for joints don't start to be felt for two to three months, if even then.
However, Hunter points out that many people living with osteoarthritis will find it difficult to continue taking the supplement if they don't see effects within about a month.
Overall, given the many reasons people may have to seek out collagen, there is no single answer to whether a collagen supplement is worth the effort.
It will depend on why you want to take it, how long you can continue taking it, how accessible it is to you, whether the collagen combines with other ingredients, and how it might affect other aspects of your health.
"Not everyone will respond to collagen supplements the same way," Erskine points out.
Ultimately, scientists point out that the hundreds of euros spent annually on collagen supplements could instead be spent on a more balanced diet, which would improve health in many different ways.
In addition to a nutritious and varied diet, exercise, sleep, and sun protection all have well-known benefits for skin appearance and health, for example.
It may seem boring, but it could save you some serious money in the long run.
*All content in this article is provided for general information purposes only and should not be treated as a substitute for medical advice from a doctor or other healthcare professional.
The BBC is not responsible for any diagnosis made by a user based on the content on this site.
The BBC is not responsible for the content of any external websites referenced in the text, nor does it endorse any commercial products or services mentioned or advertised on any of those sites.
Always consult your general practitioner if you are concerned about your health in any way.
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