In skin samples from women, hyaluronic acid content was halved at age 60 and decreased more than fourfold at age 75, compared to ages 19 to 47. Collagen follows the same pattern: in culture, fibroblasts from people over 80 years old produce approximately one-third less type I procollagen than those from young adults. The two decline together, but they are neither the same molecules, nor the same roles, nor the same evidence.
This guide brings together studies identified via PubMed: the nature of each, trials on skin and knee, associated formulas, the role of vitamin C, the effect of a cream, studied doses compared to our two formats, and precautions.
Two complementary molecules : collagen is a protein that forms the framework of the dermis, tendons and cartilage. Hyaluronic acid is a glycosaminoglycan, a long-chain sugar that retains water between these fibers; the skin concentrates half of the body's total supply. Both decline with age.
What the trials show : collagen peptides, from 2.5 to 10 g per day for 8 to 12 weeks, improve hydration and elasticity with a moderate effect, but a 2025 analysis no longer finds an effect in trials without industrial funding. Oral hyaluronic acid, from 120 to 240 mg per day, improved hydration in smaller trials. The only identified trial that compared collagen alone and collagen plus 30 mg of hyaluronic acid found no additional benefit.
- Collagen and hyaluronic acid: two molecules, two roles
- What age and sun change
- What becomes what you swallow
- Collagen peptides and skin: results and debate
- Oral hyaluronic acid and skin
- Should you combine them? Trials of combined formulas
- Joints: what we know about the knee
- On the skin: serum, cream and what truly penetrates
- Which to choose based on your goal
- Studied doses and our two formats
- How to take them, and for how long
- Tolerance and precautions
- Frequently asked questions
A protein that maintains structure, a giant sugar that retains water.
is the most abundant protein in the animal kingdom. In humans, it represents one-third of all proteins in the body and three-quarters of the dry weight of skin. Three chains wind together in a triple helix, rich in glycine, proline and hydroxyproline, then assemble into fibrils that give tissues their strength. Type I forms the fibrils of all fibrous tissues, skin and tendons included, except cartilage, where Type II predominates; in skin, Type III accompanies Type I, and this mixture gives it resilience and suppleness. Hyaluronic acid is not a protein but a glycosaminoglycan: a very long chain of two repeated sugars, D-glucuronic acid and N-acetyl-D-glucosamine, capable of binding and retaining water. The skin alone contains 50% of the body's hyaluronic acid, much more in the dermis than in the epidermis; it also lubricates joints. It renews very quickly: its half-life is less than one day in skin and 1 to 3 weeks in cartilage.
CriterionCollagen Hyaluronic acid
| Nature | Protein in triple helix | Glycosaminoglycan, long unsulfated sugar |
|---|---|---|
| Main role | Strength and tissue integrity | Water retention, volume, lubrication |
| Where to find it | Types I and III in skin, Type II in cartilage | Skin, which contains 50% of it, synovial fluid |
| With age | Slowed synthesis | Peau, qui en contient 50 %, liquide articulaire |
| Avec l'âge | Synthèse ralentie | Disappears from the epidermis, shorter chains |
| Oral doses studied | 2.5 to 10 g of peptides per day most commonly | 120 to 240 mg per day most commonly |
What age and sun change
With chronological aging alone, the skin produces less collagen types I and III. In culture, fibroblasts from people over 80 years old produced 56 ng/mL of type I procollagen, compared to 82 ng/mL for those from young people aged 18 to 29, approximately 32% less, and these cells are less mechanically stimulated in aged skin.
In the skin of women distributed across five age groups, hyaluronic acid represented 0.030% of skin weight from 19 to 47 years, then 0.015% at 60 years and 0.007% at 75 years. The remaining molecules were also chemically modified in the oldest age group.
Longas MO, Russell CS, He XY. Carbohydr Res 1987;159(1):127-136. DOI: 10.1016/s0008-6215(00)90010-7
In aged skin, hyaluronic acid almost disappears from theepidermis but persists in the dermis, and its chains shorten. The epidermis thus loses the molecule that retained water best, which contributes to dryness, thinning, and loss of elasticity.
Sun adds to time: approximately 80% of facial aging is attributed to ultraviolet rays. Sun-exposed skin contains more small-sized hyaluronic acid, a sign of degradation, and repeated exposures deposit type I collagen similar to that of a scar. Our article on collagen loss after 25 years details these changes.
Sun protection remains the first step to preserve both.
What becomes what you swallow
Swallowed collagen is digested, but in hydrolyzed form—that is, already broken down into peptides—it leaves measurable fragments in the blood. In fasting volunteers who took 9.4 to 23 g of gelatin hydrolysate, peptides containing hydroxyproline reached their peak 1 to 2 hours after intake, then half that level at 4 hours; the main one was prolyl-hydroxyproline, a dipeptide derived from collagen. On human skin explants, collagen peptides increased the production of collagen and glycosaminoglycans, the hyaluronic acid family. Oral collagen would thus provide building blocks and signals to fibroblasts, rather than ready-to-use collagen.
Hyaluronic acid, meanwhile, resists digestive juices, and its fate has been studied mainly in animals. In rats, it is broken down not by gastric and intestinal juices but by the cecal contents, rich in bacteria, into fragments of a few sugars that cross the large intestine wall; after intake of 300 kDa hyaluronic acid, fragments of various sizes were found in the skin.
Neither hyaluronic acid nor collagen swallowed arrive intact in the skin: only clinical trials allow us to judge a supplement.
Collagen peptides and skin: results and a debate
A 2023 meta-analysis pooled 26 randomized trials and 1,721 participants, with doses ranging from 372 mg to 12 g per day for 2 to 12 weeks, including 14 trials on fish collagen. Compared to placebo, hydration improved with an effect size of 0.63 and elasticity of 0.72, and treatments lasting more than 8 weeks performed better than shorter ones. A 2021 meta-analysis of 19 trials and 1,125 participants found favorable effects on hydration, elasticity, and wrinkles.
Effect size compares the difference between two groups to the spread of measurements: 0.2 corresponds to a small effect, 0.5 to a medium effect, 0.8 to a large effect. Values of 0.63 and 0.72 fall between medium and large.
In 23 randomized trials and 1,474 participants, collagen supplements overall improved hydration, elasticity, and wrinkles. But trials without company funding showed no effect on these three parameters, unlike funded trials, and high-quality trials did not find significant effects.
Myung SK, Park Y. Am J Med 2025;138(9):1264-1277. DOI: 10.1016/j.amjmed.2025.04.034
The authors conclude that no clinical evidence yet supports recommending these supplements against skin aging. Here are the most relevant trials, to be read with this caveat.
2.5 g per day. In 114 women aged 45 to 65, 2.5 g of bioactive collagen peptides for 8 weeks reduced the volume of crow's feet wrinkles by 20% compared to placebo; in a biopsied subgroup, type I procollagen content was 65% higher and elastin content was 18% higher.
10 g per day. In two controlled trials in women aged 40 to 65, 10 g of pork or fish collagen peptides increased hydration after 8 weeks and dermal collagen density as early as 4 weeks, while reducing its fragmentation, with effects still present at 12 weeks.
Around 1 g per day. In 64 people, 1,000 mg of a low molecular weight collagen peptide, rich in tripeptides, improved hydration as early as 6 weeks, then wrinkles and two out of three elasticity parameters at 12 weeks, with no adverse effects; several authors work for companies in the sector. In 99 Japanese women, in a trial conducted by a cosmetics group, 1 or 5 g per day for 12 weeks increased skin water content, without changing elasticity; the abstract does not detail the effect of each dose. Our article collagen, skin and wrinkles revisits these trials.
Oral hyaluronic acid and skin
In Japan, in people with dry skin, a 2014 review written in part by researchers from a manufacturer compiles four placebo-controlled trials of 22 to 42 participants: 120 or 240 mg per day for 4 to 6 weeks increased hydration, with equivalent effects at both doses according to the authors. In Taiwan, in 40 adults aged 35 to 64, 120 mg per day for 12 weeks improved facial hydration, water loss through the skin, elasticity and wrinkles compared to placebo, with no adverse effects, and visible differences from week 8 onwards; researchers from the ingredient manufacturer signed the study.
In 150 Caucasian adults aged 18 to 60, 60 or 120 mg per day of 1.8 MDa sodium hyaluronate for 12 weeks, from autumn to winter, increased cheek hydration by 9.1% and 11.5% compared to placebo. At 120 mg, elasticity, epidermal thickness and dermal density also improved, and the depth of crow's feet wrinkles decreased; skin tone and pores did not change. The trial was conducted at the ingredient manufacturer's facilities.
Dolečková I, Kušnierik P, Berka V, et al. Sci Rep 2025;16(1):2941. DOI: 10.1038/s41598-025-32758-5
À 200 mg per day, in 60 women presenting mild to moderate signs of skin aging, with a biofermentation hyaluronic acid covering a wide range of molecular weights, hydration increased by 10.6% and wrinkle depth decreased by 18.8% in 28 days in the supplemented group, compared to the start of the trial; the abstract does not quantify the difference from placebo. A 2025 meta-analysis of 7 randomized trials confirms an improvement in hydration, elasticity and wrinkle depth, on small sample sizes. Each trial used its own ingredient: a result does not automatically transfer to another. Our article hyaluronic acid: serum or capsules? compares the two routes.
Should you combine them? Trials of combined formulas
Combining them seems logical, since they don't work the same way; however, you need to compare the complete formula to its individual ingredients, which only one identified trial did.
In 87 women aged 40 to 65, a syrup providing 5 g of hydrolyzed bovine collagen and 80 mg of vitamin C per day for 16 weeks increased dermal density by 16.3% compared to placebo, reduced skin roughness by 9.6% and wrinkle volume by 13.8%. Enriched with 30 mg of hyaluronic acid, it produced comparable results, with no significant difference: +16.0%, −9.9% and −13.9%. Neither significantly improved hydration or elasticity, and no adverse effects were reported.
Žmitek K, Žmitek J, Hristov H, et al. Nutrients 2024;16(12):1908. DOI: 10.3390/nu16121908
Limitation highlighted by the authors: 30 mg of hyaluronic acid is less than in most trials where it was tested alone. A combination at a higher dose was therefore not evaluated. They also report a previous trial from their team where 10 g of hydrolyzed collagen with 80 mg of vitamin C for 12 weeks improved dermal density, roughness and wrinkles, with no significant effect on thickness, elasticity or hydration.
In 120 people, a 50 mL drink combining notably 5 g of hydrolyzed collagen, hyaluronic acid, N-acetylglucosamine, vitamins and minerals, taken for 90 days, was accompanied by a 7.5% increase in skin elasticity. Authored by the manufacturer, the study measures the effect of an entire formula, without being able to attribute it to a single ingredient.
Vitamin C has an established role: it is the cofactor of enzymes that stabilize the collagen triple helix and stimulates collagen production by fibroblasts. Its severe deficiency, scurvy, makes skin fragile and wound healing difficult. According to a review, supplementary intake should only increase its content in the skin if the blood is not already saturated with it.
Our two formulas combine these three ingredients: the powder provides 10 g of Naticol® marine collagen, 210 mg of hyaluronic acid and 80 mg of vitamin C per day, the capsules 1,208 mg of Naticol® marine collagen, 200 mg of hyaluronic acid and 160 mg of vitamin C. No published trial has tested exactly these combinations. For a collagen without hyaluronic acid, our Novagen provides 5 g of Naticol x3Peptide, including 1,250 mg of tripeptides, and 120 mg of vitamin C; it is reserved for adults, excluding pregnancy, breastfeeding and fish allergy. Our guide toacerola presents a natural source of vitamin C.
Joints: what we know about the knee
In the knee, type II collagen forms the framework of cartilage and hyaluronic acid lubricates the joint. A 2024 meta-analysis covering 35 trials and 3,165 patients with osteoarthritis shows that collagen derivatives, in all forms combined, reduce pain (effect size of −0.35) and improve function (−0.31): a small to moderate effect, with no more adverse effects or dropouts than control.
In athletes, 147 student athletes took 25 mL of a beverage providing 10 g of collagen hydrolysate or placebo for 24 weeks: among the 97 analyzed, joint pain at rest assessed by the physician decreased by 1.37 points versus 0.90, with a more marked difference at the knee. In another trial, 139 athletes with knee pain during exercise took 5 g of bioactive collagen peptides or placebo for 12 weeks: pain during exercise decreased by 19.5 points versus 13.9 on a visual scale, with no difference at rest. Our Drinkable Marine Collagen also provides 5 g of collagen per shot, but Naticol® marine collagen and not the peptides tested in that trial, with other ingredients and in a 20-day course, shorter than the trial; it is not recommended for children, pregnant or breastfeeding women and in case of allergy to salicylate derivatives.
For oral hyaluronic acid, the longest trial followed 60 people with stage 2 or 3 knee osteoarthritis for 12 months, with 200 mg per day or placebo and daily quadriceps strengthening exercises in both groups. All improved; the advantage of hyaluronic acid was significant only in those 70 years and under, at the 2nd and 4th month. A 2024 systematic review lists 11 studies and 597 patients, almost all on knee osteoarthritis, one on low back pain, at 30 to 300 mg per day: 9 report an improvement, with rare and mild adverse effects.
In the 12-month trial, the placebo group also improved thanks to the exercises. Supplements add to physical activity without replacing it, and hyaluronic acid injections in the knee are a distinct medical procedure, to be discussed with your doctor. Our articles on collagen and joints and onosteoarthritis go further.
On skin: serum, cream and what truly penetrates
Native collagen, which weighs approximately 300 kDa, cannot cross the stratum corneum, the superficial barrier of the epidermis. Even hydrolyzed into peptides of 1 to 10 kDa, it penetrates little, and the larger a peptide exceeds six or seven amino acids, the less chance it has of reaching the deeper layers. When applied, collagen acts mainly as a good humectant for the stratum corneum: a collagen cream hydrates the surface without reconstituting the collagen of the dermis, as explained in our article on collagen mask.
For hyaluronic acid, everything depends on size. On sections of human skin analyzed by Raman spectroscopy, hyaluronic acid of 20 to 300 kDa crossed the stratum corneum, unlike hyaluronic acid of 1,000 to 1,400 kDa. According to a review written by cosmetic industry researchers, the large remains on the surface, where it forms a film that limits water loss, and the small penetrates deeper. In a 2011 randomized trial it cites, formulas at 0.1% sodium hyaluronate of different sizes, applied for 60 days around the eyes, improved hydration and elasticity compared to placebo, and only the smallest reduced wrinkle depth.
Our Hyaluronic Acid Serum combines sodium hyaluronate, aloe vera and glycerin, to be applied morning and evening on clean skin, before cream. Our Caviar Cream contains hydrolyzed marine collagen, caviar extract, grapeseed oil and vitamin E, for the face and neck. As for hyaluronic acid injections, they are in the realm of a physician: no serum, no cream nor any supplement can replace them.
Which to choose according to your objective
| Objective | Most studied | Trial doses | Level of evidence |
|---|---|---|---|
| Wrinkles and elasticity | Collagen peptides | 2.5 to 10 g per day, 8 to 12 weeks | Numerous trials, moderate effect, debated according to funding |
| Hydration | Oral hyaluronic acid and collagen | 120 to 240 mg of hyaluronic acid, 4 to 12 weeks | Several favorable trials, small, short and often industry-sponsored |
| Dermis density | Collagen peptides | 5 to 10 g per day, 4 to 16 weeks | Several consistent trials |
| Knee | Collagen derivatives | 5 to 10 g of hydrolysate in athlete studies | Meta-analysis of 35 trials, small to medium effect |
| Nails | Collagen peptides | 2.5 g per day, 24 weeks | One uncontrolled trial of 25 people |
| Hair | Neither one solidly established | Not established | No solid controlled trial identified |
For nails, an open trial in 25 people taking 2.5 g of peptides per day for 24 weeks measured 12% faster growth and 42% fewer broken nails, a signal more than proof; our article on collagen for hair and nails details this point. For multiple objectives at once, a formula combining both brings together the two ingredients, without the only comparative trial identified measuring additional benefit. Our comparison best collagen: which one to choose? helps distinguish between sources, forms and dosages.
Studied doses and our two formats
Comparing a product to a trial only makes sense at equal quantity, and each trial tested its own ingredient.
| Ingredient | Trial doses | Powder, 1 scoop | Capsules, 4 per day |
|---|---|---|---|
| Collagen | 2.5 to 10 g in most skin trials; 1 g in a few | 10 g of Naticol® marine collagen | 1,208 mg of Naticol® marine collagen |
| Hyaluronic acid | 120 to 240 mg for skin; 200 mg in the 12-month knee trial | 210 mg | 200 mg |
| Vitamin C | 80 mg with 5 g of collagen in the 2024 Slovenian trial, with 10 g in an earlier trial they report | 80 mg | 160 mg |
The powder. Its 10 g of collagen matches the 10 g trials: the two 2015 trials in women aged 40 to 65 (hydration and dermal density), the 24-week trial in athletes and the previous Slovenian trial, reported by the authors of the 2024 trial, which combined 10 g of collagen with 80 mg of vitamin C, like our powder. These trials used collagens other than Naticol: the comparison is based on quantities, not results specific to our formula.
The capsules. Their 1,208 mg of collagen is below the 2.5 to 10 g in most skin trials, roughly eight times less than the powder, but close to the 1,000 mg from the 12-week trial in 64 people, which focused on a low molecular weight peptide rich in tripeptides, and to the 1 g dose from the Japanese trial, whose abstract does not detail the effect. To match the quantities in most trials, the powder is the appropriate format; capsules prioritize convenience.
Hyaluronic acid. The 210 mg in the powder and 200 mg in the capsules fall within the range of skin trials, 120 to 240 mg, and match the 200 mg from the 28-day trial and the 12-month knee trial. The quantity is comparable, but each result remains tied to the tested ingredient.
To choose between powder, capsules and shots, our guide collagen: which format to choose? compares their benefits.
How to take them, and for how long
In the meta-analysis of 26 trials, courses longer than 8 weeks perform better than shorter ones; in the Taiwanese trial, differences from placebo appeared at week 8; in the Slovenian trial, dermal density continued to improve between weeks 8 and 16. Counting at least three months before judging is therefore reasonable, that is three containers of powder or three pill organizers of capsules.
The time of day is a matter of comfort: no trial presented here compares dosing schedules. The tips below are practical; our article when to take collagen provides more information, and our 5 ways to consume collagen powder offer recipe ideas.
Tolerance and precautions
In trials, both ingredients are well tolerated. The meta-analysis of 35 trials on osteoarthritis finds no more adverse effects with collagen derivatives than with control, and the 16-week Slovenian trial reported none. For oral hyaluronic acid, the Taiwanese trial reports none related to the product, and the 2014 review reports no blood abnormalities with intakes from 12 weeks to 12 months.
The main precaution concernsfish allergy. In 101 fish-allergic patients, 21% were sensitized to type I collagen from salmon, barramundi, or tuna, capable of triggering allergic reaction in laboratory testing. Marine collagen should therefore be avoided in case of fish allergy, unless otherwise advised by an allergist.
For pregnancy and breastfeeding, trials provide no data, and the 2025 trial excluded pregnant or breastfeeding women. For both our formulas, consult a healthcare professional before use; our Novagen and our Marine Collagen drink are not recommended in these situations. Finally, collagen is of animal origin, marine in our formulas, and is not suitable for a vegan diet. Our article on the dangers of marine collagen details these points.
Fish allergy : no marine collagen without medical advice. Pregnancy and breastfeeding : consult a healthcare professional before any intake. Chronic illness or ongoing treatment : discuss with your doctor or pharmacist. Joint pain : a warm, red, or swollen knee, or pain after trauma, requires a consultation. Hyaluronic acid injections : a medical decision that no supplement or care can replace.
10 g of type 1 marine collagen Naticol, 210 mg hyaluronic acid and 80 mg vitamin C in a measuring spoon per day, to be dissolved in water, juice or coffee, or mixed into yogurt. One jar covers one month.
See the Marine Collagen powderPrefer capsules? Our Marine collagen and hyaluronic acid in capsules Provides 1,208 mg of marine collagen and 200 mg of hyaluronic acid per 4 capsules.
Frequently asked questions
What is the difference between collagen and hyaluronic acid?
Collagen is a triple helix protein that forms the framework of skin, tendons, and cartilage. Hyaluronic acid is a long-chain sugar that retains water between these fibers; the skin contains half of the body's supply. One provides structure, the other provides hydration and volume.
Collagen or hyaluronic acid: which one to choose?
For wrinkles, elasticity, and joints, collagen is the most studied, typically at 2.5 to 10 g per day for 8 to 12 weeks. For dry skin, oral hyaluronic acid at 120 to 240 mg per day improved hydration in several trials, often small and manufacturer-linked. A formula combining both provides both ingredients, though the only comparative trial identified did not measure additional benefit.
Can you take collagen and hyaluronic acid at the same time?
Yes, and the combination was well tolerated in trials. The only comparative trial identified, in 87 women over 16 weeks, obtained comparable effects with 5 g of collagen and 80 mg of vitamin C, with or without 30 mg of hyaluronic acid: the specific benefit of the combination remains to be demonstrated.
Marine collagen and hyaluronic acid: what effects on the skin?
In meta-analyses, collagen peptides, mostly from fish, improve hydration and elasticity with a moderate effect. Oral hyaluronic acid increased hydration by 9.1 to 11.5% in a trial of 150 adults. A 2025 analysis notes that trials without industrial funding do not find an effect.
What dose of collagen and hyaluronic acid per day?
Skin trials most often use 2.5 to 10 g of collagen peptides per day, some around 1 g. For hyaluronic acid, studied doses range from 120 to 240 mg per day for skin, and 200 mg in the main knee trial.
How long should you take collagen and hyaluronic acid?
At least 8 to 12 weeks. Courses longer than 8 weeks perform better in a meta-analysis of 26 trials. With oral hyaluronic acid, differences in wrinkles appeared at week 8 in the Taiwanese trial, as early as the first month in the 2025 trial. Dermal density continued to improve at 16 weeks in a 2024 trial.
Are collagen and hyaluronic acid capsules dangerous?
Trials report no more adverse effects than with placebo. The real precaution concerns fish allergy: 21% of fish-allergic individuals tested in a study were sensitized to fish collagen. During pregnancy or breastfeeding, ask for advice from a healthcare professional.
What is the best collagen with hyaluronic acid?
One whose collagen dose corresponds to trials, most often 2.5 to 10 g per day, with a quantity of hyaluronic acid close to the 120 to 240 mg studied; vitamin C participates in collagen production, without demonstrated specific benefit in these trials. A powder allows reaching 10 g of collagen, which capsules can hardly achieve.
Is a cream with collagen and hyaluronic acid effective?
It hydrates the skin surface. Applied collagen is too large to cross the stratum corneum. Large hyaluronic acid forms a film that limits water loss, while small hyaluronic acid penetrates deeper. A cream does not replace oral intake or injection.
Why combine vitamin C with collagen and hyaluronic acid?
Vitamin C is the cofactor for enzymes that stabilize the triple helix of collagen, and it stimulates its production by fibroblasts; its severe deficiency, scurvy, makes skin fragile and slows wound healing.
Are collagen and hyaluronic acid effective for joints?
For collagen, a meta-analysis of 35 trials and 3,165 osteoarthritic patients shows a small to moderate effect on pain and function. For oral hyaluronic acid, 200 mg per day for 12 months performed better than placebo only in those 70 years old and younger, and only at months 2 and 4. A swollen or warm knee warrants medical advice.
Can you take collagen and hyaluronic acid during pregnancy?
Trials do not provide data in pregnant or breastfeeding women, which a 2025 trial excluded for example. Before any intake, seek advice from your doctor or midwife.
Sources
The studies cited below were identified via PubMed.
- Longas MO, Russell CS, He XY. Evidence for structural modifications of dermatan sulfate and hyaluronic acid with age. Carbohydrate Research, 1987;159(1):127-136. DOI
- Varani J, Dame MK, Rittie L, et al. Decreased collagen production in aged skin: roles of age-related alterations in fibroblast function and insufficient mechanical stimulation. The American Journal of Pathology, 2006;168(6):1861-1868. DOI
- Shoulders MD, Raines RT. Collagen structure and stability. Annual Review of Biochemistry, 2009;78:929-958. DOI
- Papakonstantinou E, Roth M, Karakiulakis G. Hyaluronic acid: a key molecule in skin aging. Dermato-Endocrinology, 2012;4(3):253-258. DOI
- Pullar JM, Carr AC, Vissers MCM. The roles of vitamin C in skin health. Nutrients, 2017;9(8):866. DOI
- Iwai K, Hasegawa T, Taguchi Y, et al. Identification of food-derived collagen peptides in human blood after ingestion of gelatin hydrolysates. Journal of Agricultural and Food Chemistry, 2005;53(16):6531-6536. DOI
- Asserin J, Lati E, Shioya T, Prawitt J. Effect of oral supplementation with collagen peptides on skin hydration and dermal collagen network: data from an ex vivo model and randomized placebo-controlled clinical trials. Journal of Cosmetic Dermatology, 2015;14(4):291-301. DOI
- Kawada C, Yoshida T, Yoshida H, et al. Ingested hyaluronic acid hydrates dry skin. Nutrition Journal, 2014;13:70. DOI
- Kimura M, Maeshima T, Kubota T, et al. Absorption of orally administered hyaluronic acid. Journal of Medicinal Food, 2016;19(12):1172-1179. DOI
- Pu SY, Huang YL, Pu CM, et al. Effects of oral collagen against skin aging: systematic review and meta-analysis. Nutrients, 2023;15(9):2080. DOI
- de Miranda RB, Weimer P, Rossi RC. Effects of hydrolyzed collagen supplementation on skin aging: systematic review and meta-analysis. International Journal of Dermatology, 2021;60(12):1449-1461. DOI
- Myung SK, Park Y. Effects of collagen supplements on skin aging: systematic review and meta-analysis of randomized trials. The American Journal of Medicine, 2025;138(9):1264-1277. DOI
- Proksch E, Schunck M, Zague V, et al. Oral intake of specific bioactive collagen peptides reduces wrinkles and increases dermal matrix synthesis. Skin Pharmacology and Physiology, 2014;27(3):113-119. DOI
- Kim DU, Chung HC, Choi J, et al. Oral intake of low molecular weight collagen peptides improves hydration, elasticity and wrinkles in human skin: randomized double-blind placebo-controlled study. Nutrients, 2018;10(7):826. DOI
- Miyanaga M, Uchiyama T, Motoyama A, et al. Oral collagen peptide supplementation improves skin hydration by increasing natural moisturizing factors in the stratum corneum: randomized double-blind placebo-controlled trial. Skin Pharmacology and Physiology, 2021;34(3):115-127. DOI
- Hsu TF, Su ZR, Hsieh YH, et al. Oral hyaluronic acid attenuates wrinkles and improves dry skin: 12-week double-blind placebo-controlled study. Nutrients, 2021;13(7):2220. DOI
- Dolečková I, Kušnierik P, Berka V, et al. Oral sodium hyaluronate improves hydration, barrier function and signs of skin aging: randomized double-blind placebo-controlled trial in 150 healthy adults. Scientific Reports, 2025;16(1):2941. DOI
- Michelotti A, Cestone E, De Ponti I, et al. Oral intake of a novel full-spectrum hyaluronic acid improves skin profilometry and aging: randomized double-blind placebo-controlled clinical trial. European Journal of Dermatology, 2021;31(6):798-805. DOI
- Amin P, Sarabi A, Choe S, et al. Oral hyaluronic acid supplement: efficacy on hydration, elasticity and wrinkle depth. Journal of Drugs in Dermatology, 2025;24(9):910-919. DOI
- Žmitek K, Žmitek J, Hristov H, et al. Effects of collagen and vitamin C supplementation, alone or combined with hyaluronic acid, on skin density, texture and other skin parameters: randomized double-blind placebo-controlled trial. Nutrients, 2024;16(12):1908. DOI
- Genovese L, Corbo A, Sibilla S. Evolution of skin texture and properties following nutritional intervention with a nutricosmetic combining bioactive collagen peptides and antioxidants. Skin Pharmacology and Physiology, 2017;30(3):146-158. DOI
- Liang CW, Cheng HY, Lee YH, et al. Efficacy and safety of collagen derivatives in osteoarthritis: sequential meta-analysis of trials. Osteoarthritis and Cartilage, 2024;32(5):574-584. DOI
- Clark KL, Sebastianelli W, Flechsenhar KR, et al. 24-week study of collagen hydrolysate as a dietary supplement in athletes with activity-related joint pain. Current Medical Research and Opinion, 2008;24(5):1485-1496. DOI
- Zdzieblik D, Oesser S, Gollhofer A, König D. Improvement of knee joint discomfort related to activity following supplementation with specific collagen peptides. Applied Physiology, Nutrition, and Metabolism, 2017;42(6):588-595. DOI
- Tashiro T, Seino S, Sato T, et al. Oral administration of polymer hyaluronic acid alleviates symptoms of knee osteoarthritis: a 12-month double-blind placebo-controlled study. The Scientific World Journal, 2012;2012:167928. DOI
- de Carvalho JF, Davidson J. Oral hyaluronic acid in osteoarthritis and lower back pain: systematic review. Mediterranean Journal of Rheumatology, 2024;35(4):557-562. DOI
- Aguirre-Cruz G, León-López A, Cruz-Gómez V, et al. Collagen hydrolysates for skin protection: oral administration and topical formulation. Antioxidants, 2020;9(2):181. DOI
- Essendoubi M, Gobinet C, Reynaud R, et al. Penetration of hyaluronic acid of different molecular weights into human skin, studied by Raman spectroscopy. Skin Research and Technology, 2016;22(1):55-62. DOI
- Bravo B, Correia P, Gonçalves Junior JE, et al. Benefits of topical hyaluronic acid for skin quality and signs of skin aging: from literature review to clinical data. Dermatologic Therapy, 2022;35(12):e15903. DOI
- Hexsel D, Zague V, Schunck M, et al. Oral supplementation with specific bioactive collagen peptides improves nail growth and reduces symptoms of brittle nails. Journal of Cosmetic Dermatology, 2017;16(4):520-526. DOI
- Kalic T, Kamath SD, Ruethers T, et al. Collagen, an important fish allergen for improved diagnosis. The Journal of Allergy and Clinical Immunology: In Practice, 2020;8(9):3084-3092.e10. DOI
