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Collagen is wonderful.
Put the word “collagen” on almost anything, however, and apparently it becomes even more wonderful.
Collagen drinks.
Collagen powders.
Collagen gummies.
Collagen coffee.
Collagen jelly.
And invariably, somewhere on the packaging, there will be beautiful glowing skin.
From a marketing perspective, I completely understand it.
We lose collagen as we age. Therefore, surely if we eat collagen, we replace collagen.
It’s wonderfully intuitive.
There is just one problem.
That isn’t how human digestion works.
And while I wouldn’t go so far as to say oral collagen definitely does nothing—the research is more nuanced than that—I remain unconvinced enough by the current evidence that I don’t routinely recommend collagen supplements to my patients for skin ageing.
Here’s why.
Let’s start with the digestive system.
Collagen is a protein.
And when we eat proteins, our digestive system doesn’t generally take the whole protein molecule, pass it intact through our intestine, and deliver it to whichever organ we would like it to improve.
Protein is progressively broken down by digestion.
By the time dietary protein reaches the small intestine, much of it is being absorbed as free amino acids, dipeptides and tripeptides.
There is a specific intestinal transporter called PepT1 that efficiently transports di- and tripeptides into intestinal cells. Larger intact dietary proteins and peptides generally do not cross the healthy adult intestinal barrier in physiologically meaningful quantities.
So the idea that you drink marine collagen and that collagen somehow travels intact from your intestine to your cheek is incorrect.
You do not absorb a collagen fibre and deliver it to a wrinkle.
I used to hear this argument:
“Collagen doesn’t work because all protein is completely broken down into amino acids anyway.”
That isn’t entirely correct either.
Some small collagen-derived peptides survive digestion and are absorbed intact.
Human studies have detected hydroxyproline-containing di- and tripeptides in the bloodstream after people consume hydrolysed collagen. One of the most commonly detected is prolyl-hydroxyproline, or Pro-Hyp.
A more recent randomised crossover bioavailability study similarly found substantial absorption of hydroxyproline-containing di- and tripeptides following collagen hydrolysate consumption.
So scientifically, the correct statement is:
Oral collagen is digested predominantly into amino acids and small peptides. Some collagen-derived di- and tripeptides can enter the circulation intact.
And that raises the much more interesting question.
This is where collagen supplementation becomes biologically plausible.
Certain collagen-derived peptides have been studied for potential biological signalling effects. The theory is that some of these peptides may reach peripheral tissues and influence fibroblast activity or extracellular matrix metabolism.
In other words, the proposed mechanism isn’t:
Drink collagen → collagen travels to skin → fills wrinkle.
It is closer to:
Hydrolysed collagen → digestion → amino acids + bioavailable small peptides → possible biological signalling → potentially altered fibroblast/ECM activity.
That mechanism is certainly more credible.
But biological plausibility and meaningful clinical benefit are two different things.
And this is where I become much more cautious.
There are.
And I think it is important that I say this clearly rather than cherry-picking evidence that supports my opinion.
Several systematic reviews and meta-analyses have concluded that hydrolysed collagen supplementation is associated with improvements in measures such as skin hydration and elasticity.
A meta-analysis of 26 randomised controlled trials involving 1,721 participants, for example, found statistically significant improvements in hydration and elasticity with hydrolysed collagen compared with placebo. The authors nevertheless highlighted biases in the available trials and called for larger studies.
Another meta-analysis has similarly reported apparent improvements in hydration and elasticity.
If we stopped reading there, the conclusion would be easy:
Take collagen.
But then came a particularly interesting analysis.
A 2025 systematic review and meta-analysis examined 23 randomised controlled trials involving 1,474 participants.
When all the studies were pooled together, collagen supplementation appeared to improve:
So far, so good.
But the researchers then separated the studies according to funding source and study quality.
And the picture changed.
In studies not funded by pharmaceutical companies, collagen supplementation showed no significant benefit for hydration, elasticity or wrinkles.
Similarly, when the researchers looked at high-quality studies, they found no significant benefit across those outcomes.
The positive results were concentrated disproportionately among industry-funded and/or lower-quality studies.
That doesn’t prove that collagen supplements don’t work.
Industry funding does not automatically invalidate research.
But it absolutely changes how confident I am in the conclusion.
And for me, that distinction matters.
This is probably the most accurate way to describe my position.
I don’t believe the current evidence is strong enough for me to routinely recommend oral collagen specifically to improve skin ageing.
That is different from saying:
“Collagen supplements have been proven not to work.”
They haven’t.
There is biological plausibility.
There are positive trials.
There are meta-analyses reporting benefits.
But there are also significant questions around study quality, heterogeneity, conflicts of interest and whether statistically measurable improvements translate into meaningful visible differences for patients.
A dermatology review looking specifically at collagen claims on social media reached a similar conclusion: some studies demonstrate improvements in skin parameters, but commercial and social-media claims frequently go substantially beyond what the evidence actually supports.
And that is where I have a problem.
This is another reason collagen drinks can be difficult to evaluate.
Turn the bottle around.
Very often, collagen isn’t the only thing inside.
Depending on the formulation, there may also be:
Vitamin C.
Vitamin E.
Zinc.
Biotin.
Hyaluronic acid.
Polyphenols.
Plant extracts.
Various antioxidants.
And sometimes quite a lot of sugar.
If a study uses a multi-ingredient formulation and skin measurements improve, it becomes much harder to say:
“The collagen did that.”
Vitamin C, for example, has a genuine biological role in collagen synthesis. Antioxidant compounds may influence oxidative pathways relevant to skin biology.
But I would not make the claim that the antioxidants are “what actually works” in most collagen drinks.
We simply don’t have the evidence to say that.
A better question is:
If your collagen drink contains six potentially active ingredients and your skin improves, which ingredient deserves the credit?
Often, we don’t know.
Suppose collagen peptides really do provide amino acids and signalling peptides that support collagen synthesis.
Why should those building blocks preferentially go to your face?
Your body contains collagen everywhere.
Skin.
Tendons.
Ligaments.
Cartilage.
Bone.
Blood vessels.
Connective tissue throughout the body.
The body does not receive a packet of hydroxyproline and read the label:
“For crow’s feet.”
Nutrients enter a shared metabolic pool and are distributed according to physiology.
That doesn’t mean collagen-derived peptides cannot exert tissue-specific signalling effects—this remains an area of research.
But it is another reason I dislike the simplistic marketing image of drinking collagen and somehow “replenishing the collagen in your skin.”
Human physiology is much more interesting than that.
This distinction is fundamental.
Your fibroblasts manufacture collagen.
To do that, they require amino acids and appropriate micronutrients, and collagen synthesis involves a complex series of intracellular and extracellular steps.
But simply providing more substrate doesn’t necessarily mean the body will make unlimited amounts of collagen.
Think about building a house.
Having more bricks is useful if you don’t have enough bricks.
But once enough bricks are sitting on the construction site, delivering another truckload doesn’t necessarily make the builders work faster.
The regulatory signals matter.
The cells matter.
The extracellular environment matters.
Age matters.
Hormones matter.
UV exposure matters enormously.
And this is why I think the conversation around skin collagen needs to move beyond:
“Consume collagen = make collagen.”
If someone asks me:
“Should I spend money on collagen drinks for my skin?”
My answer is generally that I would prioritise things for which we have stronger evidence or greater overall health benefit.
Your body needs amino acids to synthesise proteins—including collagen.
Rather than obsessing over whether those amino acids came specifically from fish collagen, I am much more interested in whether you are consuming adequate high-quality dietary protein overall, particularly as you age.
And from a healthy-longevity perspective, adequate protein becomes even more important because I care about something besides your skin:
your muscle.
Maintaining muscle mass and physical function as we age has consequences far beyond whether our skin looks good.
Collagen synthesis requires more than protein.
Vitamin C is an essential cofactor in collagen biosynthesis. Adequate nutrition also supplies the micronutrients and phytochemicals required for normal cellular function.
This is a very different message from:
“Take an antioxidant beauty drink and your wrinkles disappear.”
I would rather think about dietary quality as part of whole-body health.
This is perhaps the least glamorous but most important part.
We spend enormous amounts of money trying to manufacture new collagen while simultaneously destroying existing collagen through UV exposure and smoking.
If preserving skin collagen is your objective, consistent photoprotection is one of the most rational things you can do.
Again:
Not sexy.
Not new.
Not $180 a box.
But biology doesn’t particularly care about marketing.
This is where I make a distinction between systemic nutritional supplementation and local biological stimulation.
If I use Ultherapy PRIME, for example, I know where I am delivering ultrasound energy and which tissue depth I am targeting.
If I use an appropriate laser, I am creating a controlled stimulus within the skin.
If I use a collagen biostimulator such as CaHA, I am placing a regenerative scaffold directly into the tissue where I want a biological response.
These interventions are not perfect, and they don’t stop ageing.
But conceptually, the target is very different.
We are delivering a stimulus to the tissue we actually want to change.
That makes more biological sense to me than assuming that drinking collagen will preferentially rebuild facial dermal collagen.
Absolutely.
This is an important part of medicine.
I don’t want to become emotionally attached to being against collagen supplements any more than I want to become emotionally attached to selling them.
If we eventually have large, well-designed, independently funded randomised trials showing clinically meaningful improvements in skin outcomes—and we understand which peptides, at what dose, in which patients, for how long—I would happily change my position.
In fact, a 2024 human bioavailability study concluded that although collagen-derived metabolites clearly appear in the circulation, larger studies are still needed to determine what circulating concentrations are required to produce physiological effects in target tissues.
That, to me, sums up the current situation rather nicely.
The biology is interesting.
The hypothesis is plausible.
The clinical evidence is conflicting.
The marketing is considerably more confident than the science.
This is probably my biggest takeaway.
When something says COLLAGEN in beautiful gold lettering on the front of the box, don’t immediately assume that consuming it means replacing the collagen you’ve lost.
Turn the box around.
Ask:
What exactly is in it?
What dose?
What type of hydrolysed collagen?
What else is in the formulation?
Was the specific product actually studied?
Was the study randomised and placebo-controlled?
How many people were studied?
How long were they followed?
Who funded it?
And was the improvement something patients could actually see—or simply a statistically significant change measured by a machine?
Those questions are much less exciting than a before-and-after photograph.
But they’re the questions I increasingly want us to ask at VIDASKIN.
Because “supports collagen” and “meaningfully improves ageing skin” are not the same scientific statement.
And until the evidence becomes more convincing, I’ll continue spending my money on good food.
Founded in 2015, Dr Vicki has grown with the clinic, to become one of the leading aesthetic clinicians in Singapore. She is an appointed key opinion leader and trains other aesthetic doctors on how to best use prestigious brands and treatments.
