Collagen is the main component of the skin's connective tissue and makes up around 70–80 % of the skin's dry weight¹. It gives the skin structure, provides elasticity and stores moisture. However, with increasing age, the body's own collagen production slows down. Skin collagen content falls with age; in one measurement study, women had less skin collagen than men at every age². As a result, the skin loses firmness and elasticity, wrinkles appear and the tissue sags.
Many people therefore turn to collagen supplements or pay specific attention to a diet that supports collagen formation. But what is actually known about collagen supplements and skin? What does science say? In this article, you will find out which factors speed up collagen breakdown, what you can do for your skin day to day and what studies on supplements have measured.
The role of collagen for skin health
Collagen is a main component of connective tissue and forms a kind of scaffolding for the skin. It ensures that the skin remains firm and elastic. Over time, however, this scaffolding becomes less stable: with age, collagen is broken down faster and less of it is made³.
A high collagen content is part of what makes skin look plump and youthful. At the same time, with age the collagen network in the deeper skin layer increasingly breaks into fragments, which makes the skin less mechanically resilient⁴. This causes wrinkles to appear, the skin becomes thinner and its ability to retain moisture decreases.
Why does collagen decrease with age?
One of the main reasons for collagen degradation is the natural ageing process. However, external factors also contribute to the collagen structure changing and weakening. You can learn more about collagen and ageing here.
UV radiation as a collagen killer
Sun exposure is one of the main causes of premature skin ageing. UV radiation sets off processes in the skin that switch on enzymes which break down collagen, and that slow collagen production³. In a study of 903 adults under 55, participants were assigned to two groups by chance. Over 4.5 years, skin ageing increased 24 % less with daily sunscreen than in the group that used sunscreen as they liked⁵. Skin ageing was measured from the fine texture of the skin surface, which becomes coarser over the years. Take a look at our article for more information.
Sugar and poor nutrition
High sugar consumption damages collagen through a process called glycation. In this process, sugars form firm bonds with collagen (the Maillard reaction). This goes along with connective tissue that becomes increasingly stiff⁶. The result is accelerated skin ageing and loss of elasticity.
Berries, green tea and dark chocolate are rich in polyphenols.
Smoking and environmental toxins
In the lab, tobacco smoke extract disrupted collagen production by skin cells and increased the enzymes that break down collagen⁷. In a study of 132 adults, heavy smokers were 4.7 times more likely to show premature wrinkling than non-smokers. Heavy meant more than 50 pack-years — roughly a pack a day for 50 years⁸. The study was small and shows a link; the exact size of the factor is correspondingly uncertain.
Stress and lack of sleep
Chronic stress increases the production of the hormone cortisol, which accelerates the breakdown of collagen. Sleep plays a part too. In a study of 60 women, those who slept poorly showed more signs of natural skin ageing. Their skin barrier also recovered more slowly than in women who slept well⁹. The skin barrier is the outermost layer of skin, which keeps water in and irritants out. The study shows a link, not that poor sleep is the cause.
What the skin studies on collagen peptides measured
Wrinkle depth as a measured endpoint
In one study, 114 women aged 45 to 65 took 2.5 g of specific collagen peptides or a dummy product (placebo) every day for eight weeks. Researchers measured the volume of the wrinkles around the eyes: it was measurably lower in the collagen group than in the placebo group¹⁰. Wrinkle volume describes how the skin looks; one specific product was tested in a single study. What was recorded was wrinkle depth and skin appearance against a placebo group. Fibroblasts in the dermis build the collagen scaffold, and the amino acids from collagen peptides are among the raw materials available to them for it.
Skin moisture as a measured endpoint
Collagen interacts with hyaluronic acid, another important component of the skin. In studies with a comparison group (placebo), skin hydration was measurably higher after eight weeks of taking collagen peptides daily¹¹. Skin hydration describes how much water the top layer of skin holds; dry skin holds little. The products tested were specific collagen preparations used in research.
Skin elasticity as a measured endpoint
In one study, 72 women aged 35 and over took a drink with 2.5 g of collagen peptides plus vitamin C, zinc, biotin and vitamin E for twelve weeks. A comparison group got a dummy product (placebo). For skin elasticity – how well the skin springs back after being stretched – the study found a difference from the placebo group that is unlikely to be down to chance¹². Because the drink contained several ingredients, the difference cannot be attributed to collagen alone. Elasticity there was measured with a cutometer, not judged in the mirror. You can also find our collagen peptides in our online shop.
What plays a part in collagen formation
Nutrition and skin
Certain nutrients play a decisive role in collagen formation.
- Vitamin C contributes to normal collagen formation for the normal function of skin. Good sources are citrus fruits, peppers and kiwis.
- Amino acids such as glycine and proline are the building blocks of collagen. They are found in bone broth, fish, eggs and meat.
- Antioxidants are studied in connection with oxidative stress. Berries, green tea and dark chocolate are particularly rich in them.
Skin care with collagen
Collagen molecules in creams are too large to pass the outer skin layers, so a cream containing collagen stays on the surface. Cosmetic actives are usually assessed on different criteria.
- In one study, retinol (vitamin A) was applied to the naturally aged skin of people over 80. After seven days, the skin cells that make collagen were multiplying more, and the skin was making more collagen¹³. This applies to retinol applied to the skin – not to collagen taken by mouth.
- Peptides are a common ingredient in skin care products.
- Sunscreen, which reduces the skin's UV exposure, is one of the established strategies against sun-induced skin ageing¹⁴.
Conclusion: what is known about collagen and skin
Collagen is the load-bearing structural protein of the skin. Its decline over the years is a normal process — sun protection, less sugar and not smoking are the points with the best evidence behind them. Studies of collagen peptides have recorded wrinkle depth, skin elasticity and skin moisture as their measures, over periods of four to twelve weeks.
A conscious lifestyle with plenty of exercise, low stress and an antioxidant-rich diet is good for your skin too. Take a look at our article on what destroys collagen.