Collagen and the sun: what UV radiation does to collagen in the skin

Short answer: UV radiation breaks down collagen in the skin. In UV-irradiated skin, the breakdown of type I collagen was 58% higher than in non-irradiated skin (Fisher et al., 1997). Collagen as a food supplement will not protect you from the sun and does not replace sunscreen: protection comes from sunscreen with SPF, shade and clothing. People who used sunscreen daily for 4.5 years had no measurable increase in signs of skin ageing (Hughes et al., 2013). Studies of collagen peptides and UV are small and have not shown protection from the sun.

Collagen makes up 70 to 80% of the dry weight of the skin and gives the dermis, the layer beneath the epidermis, its firmness and structure (Oikarinen, 1994). Long-term exposure to UV radiation from the sun causes premature skin ageing, known as photoageing: wrinkles, uneven pigmentation and loss of firmness (Fisher et al., 1997).

How this happens was shown by a study in the New England Journal of Medicine. Researchers irradiated the skin of 59 volunteers with UV fluorescent lamps. After just one exposure, the skin began to produce more of three enzymes from the matrix metalloproteinase group, which break down collagen, and in the irradiated skin the breakdown of type I collagen was 58% higher than in non-irradiated skin. After four exposures every other day, the activity of two of these enzymes stayed elevated for a week, 4.4-fold for collagenase and 2.3-fold for gelatinase (Fisher et al., 1997). According to the authors, repeated sunbathing thus keeps collagen breakdown going and may contribute to photoageing.

In a French study of 298 women aged 30 to 78, the authors estimated that UV radiation accounts for 80% of the visible signs of facial ageing. They compared women who seek out the sun with women who avoid it, and the study was led by researchers from the cosmetics company L’Oréal (Flament et al., 2013).

A tan is the skin’s visible reaction to UV: pigment cells start producing more melanin. Changes to collagen in the dermis are not visible straight away and only show up years later as photoageing.

What protects against UV is whatever stops the radiation before it reaches the skin: a broad-spectrum sunscreen with a high SPF, shade when the sun is strongest, clothing, a hat and sunglasses. A randomised trial in Nambour, Australia, showed that this also makes sense for skin ageing. 903 adults under 55 were divided into a group that used sunscreen daily for 4.5 years and a group that used it at their own discretion. In the daily sunscreen group, signs of skin ageing did not measurably increase, and ageing was 24% lower than in the other group. The study was funded by the Australian government agency for health research (Hughes et al., 2013).

Sunscreen does not add collagen. It does, however, reduce the dose of UV that triggers the enzymes that break down collagen. Apply enough sunscreen and reapply it during the day, especially after swimming and sweating.

The question arises whether collagen as a food supplement does anything for skin exposed to the sun. Research so far is limited, and the results need to be read with caution:

• An experiment in mice. Hairless mice given a fish collagen peptide every day (0.2 g per kilogram of body weight) had a smaller drop in skin hydration, less thickening of the epidermis and less loss of soluble type I collagen after repeated UVB irradiation than mice without the peptide (Tanaka et al., 2009). Results in animals cannot be transferred to humans.
• Collagen with astaxanthin. 44 adults with moderately sun-damaged skin took 3 g of collagen hydrolysate and 2 mg of astaxanthin daily for 12 weeks, or a placebo. The supplement group had better skin elasticity and less water loss through the skin, but DNA damage in skin artificially irradiated with UV did not differ between the groups (Yoon et al., 2014). This was a combination of two substances, so the result cannot be attributed to collagen alone.
• Marine collagen in postmenopausal women. 36 women took 5 g of marine collagen hydrolysate daily for 4 weeks, or a placebo. Skin elasticity on the cheeks, that is, on areas exposed to the sun, improved compared with placebo, and the difference lasted even 4 weeks after stopping (Sangsuwan and Asawanonda, 2021). The study was small and short, and it did not measure protection against UV.

The overall picture is sober. A meta-analysis of 23 randomised trials with 1,474 participants found improvements in hydration, elasticity and wrinkles only in studies funded by companies. Studies without such funding and high-quality studies found no effect (Myung and Park, 2025). None of the studies mentioned showed that collagen protects against sunburn, changes a tan or restores collagen damaged by the sun. What research on collagen and skin shows in general is summarised in our article Marine collagen for skin: what the science really says.

A collagen bed contains no collagen and does not deliver any into the skin. It is a bed or cabin with lamps that shine visible red light, and the name refers to what, according to the sellers, it is supposed to do to collagen in the skin. Tanning is caused by UV radiation, so red light on its own does not tan. Some tanning beds, however, combine red lamps with classic UV tubes: these then tan because of the UV, and everything UV does to collagen applies to them. Before you lie down, ask at the salon whether the bed also emits UV.

Research on red light is still modest. In a controlled study with 136 volunteers, people who completed 30 sessions, twice a week, under full-body lamps with red light, and in some of the groups near-infrared light as well, had a higher collagen density in the skin measured by ultrasound than the 23 people in the control group (Wunsch and Matuschka, 2014). The control group was small, and the first author worked for the company Medical Light Consulting.

Yes. You can take collagen as a food supplement all year round, and sunny days change nothing about that. We found no study showing that collagen in a supplement or in a cream increases the skin’s sensitivity to the sun. You can safely apply a collagen cream or serum under your sunscreen, but on their own they will not stop UV unless they contain a UV filter. Why collagen from a cream stays on the surface of the skin is explained in our article Collagen cream vs. collagen in a sachet.

Collagen is not a sunburn remedy, and we found no study in humans showing that it soothes sunburnt skin or speeds up its recovery. Cool sunburnt skin, protect it from further sun and drink plenty of fluids. If blisters form, you have a fever or chills, or a large area is burnt, see a doctor.

collalloc kolagen contains 3,300 mg of hydrolysed marine collagen types I, II and III per sachet, with a molecular weight of around 500 Da and no fillers, colourings or sweeteners. Stir it into 200 ml of a cold or lukewarm drink up to 60 °C. It does not protect against the sun. In the sun, rely on sunscreen, shade and clothing. What we know about collagen and skin is on our Collagen for skin page and in the article Collagen and skin ageing.