Two pooled analyses say yes for skin: one for hydration and elasticity against placebo, the other for wrinkles, elasticity and hydration after 90 days. Single placebo-controlled trials add wrinkles, collagen density in the dermis and hair thickness.
- 26 trials, 1,721 participants: a 2023 meta-analysis found oral collagen significantly improved skin hydration and elasticity compared with placebo.
- 19 trials, 1,125 participants: a 2021 meta-analysis concluded that 90 days of hydrolysed collagen reduced wrinkles and improved skin elasticity and hydration.
- Eye-wrinkle volume about 20% lower than placebo after 8 weeks, in a placebo-controlled trial of 114 women aged 45 to 65 that tested 2.5 g of collagen peptides a day.
of 106 women felt the appearance of their skin improved after 8 weeks on our liquid marine collagen.
- 89%reported more moisture and glow
- 87%noticed fewer fine lines and wrinkles
- 81%reported firmer skin
Do collagen supplements work?
For skin, the largest body of evidence says yes, which matters because one study on its own is easy to wave away. Two research teams have gathered randomised trials of collagen taken by mouth and added their results together. The 2023 analysis found oral collagen significantly improved skin hydration and elasticity compared with placebo.1 The 2021 analysis concluded that 90 days of hydrolysed collagen reduced wrinkles and improved skin elasticity and hydration.2
"Work" needs a target, though. A supplement is tested against one measurement at a time: water in the skin, how it springs back, the size of a wrinkle, the width of a hair. We therefore go outcome by outcome and tell you who was studied, how much they took and for how long. That way you can hold each result up against your own reason for asking.
What do the pooled analyses say?
Both pooled analyses of skin found in collagen's favour: one of 26 randomised controlled trials found oral collagen significantly improved skin hydration and elasticity compared with placebo, and one of 19 trials concluded that 90 days of hydrolysed collagen reduced wrinkles and improved skin elasticity and hydration. A meta-analysis pools many trials into one calculation, the widest view the research offers.
Hydration and elasticity better than placebo
Pu and colleagues combined 26 randomised controlled trials in 2023. Oral collagen significantly improved skin hydration and elasticity compared with placebo, and the hydration effect was larger when collagen was taken for more than 8 weeks. The authors described fish as the optimal source of collagen for improving skin hydration.1
26 randomised controlled trials · 1,721 participants
90 days: wrinkles, elasticity and hydration
De Miranda and colleagues pooled 19 randomised double-blind trials in 2021. They concluded that 90 days of hydrolysed collagen reduced wrinkles and improved skin elasticity and hydration. About 95% of the people in those trials were women.2
19 randomised double-blind trials · 1,125 participants aged 20 to 70
In the first card, the larger hydration effect went with taking collagen for more than 8 weeks, a detail that returns in the last section.
What did single trials measure?
Single trials measured skin hydration, skin elasticity, wrinkles, collagen density in the dermis, hair thickness and nail growth, on faces, scalps and fingertips. The table has one study for each outcome, with its own dose, people and date.
One study per outcome
Each row is a separate study with its own participants and daily amount.
| Outcome | Study | Daily amount | Result | When |
|---|---|---|---|---|
| Skin hydration | 64 women aged 40 to 60, randomised, double-blind, placebo-controlled3 | 1,000 mg of low-molecular-weight fish collagen peptide | Skin hydration significantly higher than placebo | Week 6 and week 12 |
| Skin elasticity | 36 postmenopausal women, randomised, double-blind, placebo-controlled4 | 5 g of marine collagen hydrolysate | Cheek skin elasticity improved compared with placebo | Week 4, and still there four weeks after stopping |
| Wrinkles | 114 women aged 45 to 65, randomised, double-blind, placebo-controlled5 | 2.5 g of collagen peptides | Eye-wrinkle volume significantly lower than placebo, about 20% at 8 weeks | Week 4 and week 8, and still there four weeks after stopping |
| Collagen in the dermis | One of two placebo-controlled trials in the same paper6 | Collagen peptides, daily | Collagen density in the dermis significantly increased | Week 4, still present at week 12 |
| Hair | 44 healthy women aged 39 to 75, randomised, placebo-controlled7 | 2.5 g of collagen peptides | Hair thickness up 1.93 micrometres on average with collagen, against a slight dip of 0.99 micrometres with placebo | Week 16 |
| Nails | 25 participants, an open-label study8 | 2.5 g of collagen peptides | Nail growth rate up 12%, frequency of broken nails down 42% | Week 24 |
Two rows deserve a second look, because they go beneath the surface. In the wrinkle trial, skin samples were taken as well. After 8 weeks the collagen group had 65% more procollagen type I and 18% more elastin in the skin than the placebo group.5 In the dermis row, the reading was collagen density itself, higher after 4 weeks of daily collagen peptides.6
The hair result was a physical measurement too. The between-group difference in thickness was significant in that trial of 44 healthy women.7 In the nail study, a physician judged brittle nails clinically improved in 64% of participants at the end, and in 88% four weeks after they stopped. 80% agreed their nails looked better.8
Each outcome has its own article if you want the full account, and the table links to them.
assets/img/blog/dw-notes.webpDoes the collagen even reach your blood?
Yes: in a 2024 randomised, double-blind crossover study, blood levels of free hydroxyproline and collagen-derived peptides rose after six healthy adults took a single 10 g dose of collagen hydrolysate. The peptides included Pro-Hyp and Hyp-Gly, and the rise held for all sources and molecular weights tested.9
The authors describe collagen hydrolysates as digested and absorbed both as free amino acids and in peptide-bound form.9 That study is about blood, and skin was measured in the separate trials in the table above. For the longer story, read how collagen is absorbed.
What did 106 women report on our liquid marine collagen?
In a user trial of our liquid marine collagen, 95% of the women felt the appearance of their skin improved and 89% reported more moisture and glow. Published trials test other people's formulas, so we add our own data. In that trial, 106 women took our liquid marine collagen daily for 8 weeks and then reported what they had noticed.10 These figures are shares of women, not measurements of skin.
felt the appearance of their skin improved.
reported more moisture and glow.
noticed a reduction in fine lines and wrinkles.
reported healthier hair.
reported firmer skin.
reported stronger nails.
User trial of our liquid marine collagen: 106 women, daily intake, 8 weeks. Self-reported.
Women in that trial reported visible results in as little as 4 weeks, with further improvement by week 8. In the same trial, 99% found it easy to include in their daily routine, which matters because a supplement can only be judged if it is taken.10
What did the skin imaging show?
The skin imaging showed a visible reduction in eye wrinkles, forehead wrinkles, spots, pigmentation and redness, and improved skin texture, in a separate clinical study in which 10 women took our liquid marine collagen daily for 8 weeks.10 Self-report is one kind of evidence and a camera is another, and here the skin was analysed before and after.
Clinical study of 10 women after daily intake of our liquid marine collagen for 8 weeks.
Then there are the people who expected nothing. Two of the accounts below come from writers who said so in print.
“And truthfully? My skin looks better than ever.”
She calls herself a sceptic. After taking marine collagen every day for two months she found her skin plumper, healthier and noticeably more radiant.
Shannon LawlorBeauty editor, writing in Marie Claire UK11
“To my surprise, these worked.”
After around six months on 10,000 mg of marine collagen a day she reported glowier, more even skin that held on to hydration for longer, and nails that were less brittle.
Charlotte BitmeadWriting in Stylist12
“I can really see the visible changes in my skin and nails.”
Check4YouVerified purchase · Amazon, Germany · 27 December 2023
Independent first-person accounts of marine collagen published by the outlets named, and a verified buyer review of our liquid marine collagen as sold under our manufacturer's own label.
How do you give collagen a fair trial?
Take it daily for 8 weeks or more, know your daily amount and pick your outcome first, copying what the studies above did.
- Take it daily. Each study in the table above used a daily amount, and so did both of ours.
- Give it 8 weeks or more. In the 2023 meta-analysis the hydration effect was larger when collagen was taken for more than 8 weeks.1 Our own trial ran for 8 weeks.
- Know your daily amount. The clinical trials we draw on used between 1 g and 10 g of collagen peptides a day. One portion of Core™ holds 11,000 mg of hydrolysed marine collagen, just above that range.
- Make it easy. Shake, pour into the cap, drink it straight or stir it into water or a smoothie.
- Pick your outcome first. Decide what you are watching: moisture, lines, hair or nails. Take a photo in the same light on day one.
Different outcomes were read at different points, from week 4 for cheek elasticity to week 24 for nails. Our guide to how long collagen takes to work sets those dates out.
Questions about whether collagen works
Does collagen actually work?
For skin, two pooled analyses say yes. One combined 26 randomised controlled trials with 1,721 participants and found oral collagen significantly improved skin hydration and elasticity compared with placebo. The other combined 19 trials and concluded that 90 days of hydrolysed collagen reduced wrinkles and improved skin elasticity and hydration.
Is collagen worth taking?
If skin appearance is your goal, the user trial of our liquid marine collagen is the closest guide: after 8 weeks, 95% of 106 women felt the appearance of their skin improved and 99% found it easy to include in their daily routine. Look at what was measured and decide if it matches what you want.
How long should you take collagen before judging it?
Allow 8 weeks or more. A meta-analysis of 26 trials found the skin hydration effect was larger when collagen was taken for more than 8 weeks, and our own trial lasted 8 weeks.
Does collagen work for hair and nails as well as skin?
Hair and nails have both been studied: in a randomised, placebo-controlled trial of 44 healthy women, hair thickness rose by 1.93 micrometres on average in the group taking 2.5 g of collagen peptides a day for 16 weeks, a significant difference from placebo. In an open-label study of 25 participants on the same daily amount for 24 weeks, nail growth rate rose 12%.
Does it matter which collagen you take?
It can: the authors of the 26-trial meta-analysis described fish as the optimal source of collagen for improving skin hydration. The studies here used fish collagen, marine collagen hydrolysate and collagen peptides, and each reported its own result. Core™ is hydrolysed marine collagen, types I and III.
Is collagen you swallow absorbed?
The authors of a 2024 study in six healthy adults describe collagen hydrolysates as digested and absorbed both as free amino acids and in peptide-bound form. After a single 10 g dose of collagen hydrolysate, blood levels of free hydroxyproline and of collagen-derived peptides rose. That finding is about blood levels.
