Collagen: The Youth Protein
You may have noticed that around your thirties, your skin started to change. Less bounce. A few wrinkles settling in. A luminosity that seems less obvious. And your hair, perhaps, a little less dense than before.
It's not in your head — and it's not inevitable either.
These changes have a very specific physiological cause: the progressive decrease in collagen production in your body. And the good news is that science now has concrete answers to support this process.
In this article, we explain what collagen is, where it is found in your body, why it is so important for your skin and hair — and most importantly, how to effectively supply it from within.
What is collagen?
The most abundant protein in your body
Collagen is a structural protein — in other words, a protein whose role is to provide shape, strength, and elasticity to the body's tissues. It is the most abundant protein in the human body, accounting for about 30% of total protein mass.
Its structure is unique: collagen consists of long chains of amino acids — mainly glycine, proline, and hydroxyproline — intertwined into an extremely strong triple helix. It is this helical structure that gives it its exceptional mechanical resistance.
The different types of collagen
There are over 28 types of collagen in the body, but three of them account for the vast majority:
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Type I collagen: the most abundant. It is found in skin, tendons, bones, and teeth. It gives skin its firmness and resistance.
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Type II collagen: mainly present in cartilage. It plays an essential role in joint mobility and flexibility.
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Type III collagen: associated with type I collagen in the skin and blood vessels. It contributes to tissue elasticity.
For the beauty of skin and hair, type I collagen is mainly what interests us.
Where is collagen found in your body?
Collagen is literally everywhere. It forms the structural framework of almost all your tissues:
In the skin
This is where collagen is most visible — and most felt. It accounts for approximately 75% of the dry weight of the skin and is concentrated primarily in the dermis, the deep layer of skin located beneath the epidermis.
In the dermis, collagen fibers form a dense and organized network that:
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gives skin its firmness and mechanical resistance
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maintains its thickness and density
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works synergistically with elastin to ensure elasticity — the skin's ability to return to its shape after being stretched
Dermal collagen works as a team with hyaluronic acid, which retains water in tissues, and elastin, which allows the skin to bounce back. Together, these three components form the "structural youth" of the skin.
In hair and nails
Hair and nails are not made of collagen — they are made of keratin. But collagen plays an essential indirect role: it constitutes the structural matrix of the hair follicle, the small living structure embedded in the dermis from which each hair grows.
Pioneering research has shown that collagen peptides can support hair follicle stem cells (HFSC) — the cells responsible for hair growth and renewal. By strengthening these stem cells, collagen helps maintain follicle health and support a normal hair cycle.
In bones, joints, and tendons
Collagen is also the main constituent of bones (about 90% of the organic bone matrix), cartilage, tendons, and ligaments. It gives bones their resistance to bending, and joints their ability to absorb shock.
Why collagen decreases with age — and why it's a problem
From age 25, the machine slows down
Collagen production by the body is at its maximum during childhood and adolescence. From the mid-twenties, it begins to gradually decline — at a rate of approximately 1% per year. This decline accelerates after menopause in women, with a loss of up to 30% in the first five years.
It is not only the quantity of collagen that decreases — it is also its quality. Collagen fibers fragment, become disorganized, and lose their network architecture, which directly translates into visible changes in the skin.
Visible consequences on the skin
When dermal collagen decreases, the skin:
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loses density and firmness — it becomes thinner, less plump
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dries out — hyaluronic acid, whose production is linked to that of collagen, also decreases
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loses elasticity — wrinkles and fine lines settle in, first around the eyes (crow's feet), then around the lips and forehead
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becomes less luminous — the disorganization of the fibers alters the way the skin reflects light
Factors that accelerate degradation
Certain lifestyle factors significantly accelerate collagen degradation:
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Sun exposure (UV): UV rays directly degrade collagen fibers and stimulate the production of metalloproteinases — enzymes that "digest" collagen
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Tobacco: reduces oxygen supply to tissues and generates free radicals that damage collagen
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Sugar: through a process called glycation, sugar binds to proteins and stiffens them — including collagen
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Chronic stress: cortisol inhibits collagen synthesis
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Lack of sleep: it is during the night that the body produces and repairs collagen
How to provide collagen to the body
Why creams alone are not enough
Collagen creams are everywhere — and yet, their effectiveness is limited. The reason is simple: collagen molecules are too large to cross the skin barrier and reach the dermis. They remain on the surface of the epidermis, where they temporarily moisturize — but do not act deeply on the dermal structure.
The real revolution is beauty from within. Supplying collagen orally, in the form of hydrolyzed collagen peptides, allows it to reach the deep layers of the skin where creams cannot go.
Hydrolyzed collagen peptides: how do they work?
Hydrolyzed collagen is collagen cut into smaller fragments — collagen peptides — by a process called enzymatic hydrolysis. These peptides are small enough to be absorbed by the small intestine and transported to target tissues via the bloodstream.
Once in the body, they exert their action in two ways:
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Direct stimulation: collagen peptides signal to fibroblasts — the dermal cells responsible for collagen production — that they need to produce more. This is a "biofeedback" mechanism: the body perceives the presence of collagen fragments as a signal of degradation and responds by increasing its production.
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Amino acid supply: peptides provide the necessary building blocks — glycine, proline, hydroxyproline — that the body needs to synthesize new collagen.
What science says about bioavailability
The question we are often asked: "Does swallowed collagen really get where it needs to go?" The answer is yes — and science confirms it.
Bioavailability studies using advanced tracing techniques have shown that approximately 90% of ingested collagen peptides are digested and bioavailable in connective tissues only 4 hours after ingestion. These peptides have been detected in the blood, skin, and synovial fluid after oral ingestion.
What science says about the results
Clinical studies on Peptan® collagen peptides — the hydrolyzed collagen used in the Qwell products we offer in our store — are among the most rigorous in the industry. Here's what they show:
On the skin
Randomized, placebo-controlled, double-blind studies conducted on women aged 40 to 65 have shown that daily supplementation with Peptan® collagen peptides produces measurable and significant results:
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+8% improvement in skin density on average, after 12 weeks (vs placebo)
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+7% improvement in elasticity from 4 weeks of supplementation at 5g/day
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+14% improvement in skin hydration after 8 to 12 weeks
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Visible reduction of wrinkles — particularly periorbital (crow's feet) and nasolabial wrinkles, from 4 weeks of intake, faster than with cream alone
These effects have been consistently observed in populations of Caucasian, Japanese, and Chinese women — showing that the benefits apply regardless of ethnicity and skin type.
On the hair
A pioneering study (Pappelbaum et al., 2024) showed that Peptan® collagen peptides increase the number of hair follicle stem cells while reducing their cell death — two factors directly linked to hair health and the prevention of hair loss.
The dose that makes the difference
Studies show significant results from 5g of collagen peptides per day, with faster effects at 10g/day. Regular intake is essential: the benefits accumulate over time and are noticeable from 4 weeks, with progressive optimization up to 12 weeks and beyond.
Natural allies of collagen
Collagen supplementation is more effective when accompanied by an adequate intake of nutrients that support its synthesis:
Vitamin C is essential for collagen production — it is directly involved in the synthesis of hydroxyproline, a key amino acid in the collagen structure. Without vitamin C, the body cannot properly make its collagen. Sources: citrus fruits, kiwi, bell pepper, blackcurrant.
Zinc is a cofactor for enzymes involved in collagen synthesis. It also contributes to protecting cells from oxidative stress. Sources: oysters, poultry meat, legumes.
Biotin supports the structure of structural proteins in the skin, hair, and nails. It is often associated with collagen in beauty formulas.
Antioxidants (vitamin E, polyphenols, selenium) protect existing collagen from degradation by free radicals. Sources: red fruits, green tea, nuts, olive oil.
Our recommendation: Qwell collagen water
At MerveilleNature, we have selected Qwell collagen waters because they bring together everything we look for in a serious beauty supplement:
- 5g of Peptan® collagen per bottle — the clinically validated effective dose
- Hydrolyzed collagen (peptides) — for optimal absorption and bioavailability
- Enriched with biotin, zinc, and vitamin B12 — essential cofactors to amplify the effect
- No added sugar — so as not to counteract the benefits of collagen through glycation
- 100% natural — no artificial flavors or preservatives
- Peach flavor — pleasant to drink daily, which promotes regularity of intake
One bottle a day, in the morning — a simple, sustainable, and scientifically proven way to take care of your skin from within.
👉 Discover Qwell collagen waters in our store
In summary
Collagen is not a fad ingredient — it is the fundamental structural protein of your skin, hair, bones, and joints. Its progressive decrease from your twenties is a natural phenomenon, but its consequences are not inevitable.
Supplementation with hydrolyzed collagen peptides, at an effective dose and on a regular basis, is now one of the most well-documented approaches to supporting skin beauty from within — with measurable results on density, elasticity, hydration, and wrinkle reduction.
Lasting beauty starts from within. And it is cultivated, day after day.
To go further
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Read our article: 8 medicinal plants for healthy, soothed, and radiant skin
Scientific sources
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Asserin J. et al. The effect of oral collagen peptide supplementation on skin moisture and the dermal collagen network. J Cosmet Dermatol. 2015;14(4):291-301.
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Vleminckx et al. Randomized, placebo-controlled, double-blind study on skin density, elasticity, hydration and wrinkle reduction in Chinese women. Rousselot internal data.
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Kuninty et al. Randomized, placebo-controlled, double-blind study on skin elasticity and hydration in Caucasian women. Rousselot clinical data.
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Pappelbaum et al. Revealing novel insights on how oral supplementation with collagen peptides may prevent hair loss. 2024.
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Kleinnijenhuis et al. Bioavailability of Peptan collagen peptides. Anal Bioanal Chem. 2019.
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Rousselot. The science behind skin & hair beauty from within — Peptan Science Brochure. 2025.
This article was written based on published scientific data. It is provided for informational and educational purposes only. It does not constitute medical advice.
