First of all: do we really need collagen?

Imagine your skin as a mattress.

When young, this mattress is dense, firm, and perfectly organized. This skin mattress contains firm and elastic springs, the collagens.
Over time, the springs loosen, break, and become disorganized. The result: the skin sags and hollows.

Collagen is the most abundant protein in the human body. In the skin, there are about 19 types, but the most present are collagens I, III, IV, and VII.

The problem? From age 25, we lose about 1% of collagen per year. This decline is imperceptible day-to-day but clearly visible after 10 years… especially since the drop accelerates around menopause: -30% in just 5 years.

And time is not the only thing attacking our collagen. Tobacco, pollution, sun exposure, alcohol… all these factors accelerate degradation.

Collagen intake – or molecules stimulating its synthesis – is therefore relevant both topically (cosmetics) and orally (dietary supplements).

Criterion No. 1: peptide size, the key figure.

Native collagen is a gigantic molecule: 300,000 Da. It cannot be absorbed intact. To be assimilated, it must be cut, hydrolyzed into smaller fragments: peptides.

To illustrate, collagen is a very long necklace of beads, while peptides represent groups of about ten beads.  

Today, most products on the market use peptides between 2,000 and 4,000 Da. This is better than the intact molecule, but not sufficient. Absorption is still too variable and unpredictable.

Conversely, when peptide size decreases, 500 Da for example, absorption is more complete, optimal, and much faster, 4 times faster compared to peptides of 2000 Da.

Expert advice:

Always check the molecular weight of the dietary supplement and choose peptides around 500 Da for proven effectiveness at low doses, from 1 g to 2 g per day.

The mistake to avoid:

A molecular weight that is too low, 100 Da for example, is also not ideal. Excessive hydrolysis results in isolated free amino acids (single beads), not peptides capable of restarting collagen production.

Another limitation: the more advanced the hydrolysis, the more bitter the taste becomes. Yet a supplement is only effective if taken daily, consistently.

Criterion No. 2: di- and tripeptides, the signal to trigger collagen production.

Size determines absorption. But what truly triggers effects in the skin is the exact nature of the absorbed peptides.

Collagen is based on a repeated molecular motif: Glycine, Proline, Hydroxyproline. These three amino acids alone represent 50% of the collagen molecule. They are the most abundant beads in the necklace.

To guarantee targeted action, it is therefore essential to have dipeptides (two beads = two amino acids) and tripeptides (three beads = three amino acids) containing these specific amino acids.

These precious peptides take a true VIP corridor in the intestine: a rapid and reserved absorption pathway, inaccessible to free amino acids and longer peptides. This fast route is not saturable and ensures their presence in the blood quickly after oral intake.

How does it then work in the skin? Like a signal. They do not replace lost collagen; they stimulate production. By their presence, the collagen factories – fibroblasts – understand it is time to create new collagen.

This is a biomimetic approach: triggering production through mechanisms naturally used by the skin.

Expert advice:

Demand a quantified guarantee of the percentage of di and tripeptides.

The trap to avoid:

A "low molecular weight" collagen without a guarantee of di/tripeptides lacks the major signal to restart production.

Criterion #3: quantity, less is more… provided you have the right collagen.

The effective dose is not an absolute truth. It is a variable that depends entirely on the size of the peptides.

With conventional collagen at 2,000-4,000 Da, studies are clear: 5 to 10 g per day are needed to achieve measurable effects on the skin, which means up to 20 capsules daily (Proksch E. et al., 2014). Difficult to maintain over time.

With smaller peptides, around 500 Da, enriched in GLY-PRO-HYP, everything changes: they seem to cross the digestive barrier more easily and reach the bloodstream. As a result, clinical studies observe effects from 1 to 1.65 g per day. (Kim D.U. et al., 2018; Lee E. et al., 2025). At equal doses, a pharmacokinetic study even reports a blood concentration of active tripeptide 54 times higher than that of regular collagen. (Hwang S. et al., 2026).

Expert advice:

Do not compare doses between products without considering the size of the peptides. 500 mg of well-formulated 500 Da collagen can outperform 10 g of regular collagen.

The mistake to avoid:

A very high dose is not a sign of quality. It is often a sign of poor absorption that the manufacturer compensates for by quantity. In other words: they are trying to hide the problem.

Criterion #4: Essential cofactors to create collagen once the signal is given.

Collagen peptides are good, essential to restart production… but not enough. Indeed, without cofactors, the signal arrives but production does not start. Imagine turning the key to start a car without adding fuel.

Some nutrients are essential for collagen creation; here are a few examples.

The GLYCINE. The number 1 pearl of collagen: it makes up 33% of its amino acids.

To renew the body’s collagen, glycine needs are estimated at 14.5 g per day, while average dietary intake is around 4.5 g per day. This represents an estimated deficit of 10 g per day according to scientists.

The VITAMIN C. It is the essential architect. Without it, collagen simply cannot assemble properly. Synthesis cannot start.

Important to know: unlike cats, dogs, and 99% of mammals, humans cannot produce their own vitamin C!

External intake through diet, dietary supplements, and cosmetics is therefore essential to meet needs.

The MSM. It helps stabilize the collagen structure and contributes to protecting existing fibers from degradation.

Beyond this trio, a well-thought-out formula can also offer protective nutrients like antioxidants or anti-glycation agents.

Expert advice:

Don’t just check for the presence of these essential nutrients, check their forms. Stable vitamin C, zinc bisglycinate, B vitamins in active forms: bioavailability depends as much on the chosen form as on the dose.

The mistake to avoid:

Taking only peptides without supplementing them with these essential nutrients will inevitably be disappointing, not because peptides are useless, but because the collagen factories won’t have what they need to create fibers.

Criterion #5: Clinical evidence, the only guarantee of effectiveness.

Dietary supplements are not medicines. Regulations do not require proof of effectiveness before marketing.

Result: 99% of dietary supplements have no proven benefits from clinical studies.

What you can sometimes read:

-            Or legal claims validated by EFSA: “Vitamin C contributes to normal collagen formation.” This is regulatory.

-            Either studies on ingredients tested alone by ingredient suppliers. Several brands with completely different formulas can sometimes claim the same results simply because they use the same ingredient.

The real proof, the only one done under real conditions, is the clinical study. A study conducted on the complete final formula, under medical supervision, in real usage conditions, with objective and reproducible measurements: dermis density, hydration, wrinkle depth.

Expert advice:

For each displayed result, ask an essential question: “Was the study conducted on the complete formula as sold?” If the answer refers to a supplier study on an isolated active ingredient, that is not product proof. It is ingredient proof.

The trap to avoid:

A strong bibliography is not validation. Just because the site highlights many figures doesn’t mean they relate to the finished product; it’s essential to read between the lines… and read the fine print (the references).

COLLAGÈNE+: Novexpert’s choice based on the latest scientific recommendations

For 20 years, Novexpert Laboratories have formulated products with proven efficacy.

COLLAGÈNE+ is the direct translation of the latest advances in collagen dietary supplements: a complete, targeted, demanding formula with no compromises.

The formula:

Quality:

• 600 blacklisted ingredients
• 0% controversial additives
• Quality control on ingredients and the finished product.
• 100% French manufacturing
• Protective and practical stick format  

Clinical evidence on the complete formula:

Clinical study conducted under medical supervision

These are not supplier figures. This is not a study on an isolated active ingredient. It is the effectiveness of the complete formula, tested under real conditions.

Scientific sources

Asai, T. T., Yoneda, S., & Oikawa, S. (2019). Collagen-derived di-peptide prolyl-hydroxyproline promotes fibroblast migration and proliferation. Biochemical and Biophysical Research Communications.

Barati, M., Jabbari, M., Navekar, R., Farahmand, F., Zeinalian, R., Salehi-Sahlabadi, A., & Asgharieh-Ahari, G. (2020). Collagen supplementation for skin health: A mechanistic systematic review. Journal of Cosmetic Dermatology.

Haute Autorité de Santé (HAS). Data on vitamin C deficiency and connective tissue integrity. has-sante.fr.

Hwang, S., Won, J., Kim, S., Kang, W., & Park, M. (2026). Low-molecular-weight collagen peptide supplementation improves cellulite severity, skin elasticity, and hair shaft diameter: A clinical study with pharmacokinetic evaluation. Journal of Dietary Supplements.

Iwai, K., Hasegawa, T., Taguchi, Y., Morimatsu, F., Sato, K., Nakamura, Y., & Ohtsuki, K. (2005). Identification of food-derived collagen peptides in human blood after oral ingestion of gelatin hydrolysates. Journal of Agricultural and Food Chemistry.

Kim, D.-U., Chung, H.-C., Choi, J., Sakai, Y., & Lee, B.-Y. (2018). Oral intake of low-molecular-weight collagen peptide improves hydration, elasticity, and wrinkling in human skin: A randomized, double-blind, placebo-controlled study. Nutrients, 10(7), 826.

Lee, E., Ahn, D. K., Kim, J. H., Lee, S., Kim, H. J., Lee, H. K., & Shin, J. H. (2025). Skin anti-aging and moisturizing effects of low-molecular-weight collagen peptide supplementation in healthy adults: A randomized, double-blind, placebo-controlled clinical trial. Journal of Microbiology and Biotechnology.

Liang, R., Fei, Y. J., Prasad, P. D., Ramamoorthy, S., Han, H., Yang-Feng, T. L., & Ganapathy, V. (1995). Human intestinal H+/peptide cotransporter: Cloning, functional expression, and chromosomal localization. Journal of Biological Chemistry, 270(12), 6456–6463.

Meléndez-Hevia, E., De Paz-Lugo, P., Cornish-Bowden, A., & Cárdenas, M. L. (2009). A weak link in metabolism: The metabolic capacity for glycine biosynthesis does not satisfy the need for collagen synthesis. Journal of Biosciences, 34(6), 853–872.

Proksch, E., Segger, D., Degwert, J., Schunck, M., Zague, V., & Oesser, S. (2014). Oral supplementation of specific collagen peptides has beneficial effects on human skin physiology: A double-blind, placebo-controlled study. Skin Pharmacology and Physiology, 27(1), 47–55.

Sato, K., Egashira, Y., Ono, S., Mochizuki, S., Shimmura, Y., Fukuhara, I., & Shigemura, Y. (2019). Distribution of collagen-derived amino acids and peptides in rat blood after ingestion of collagen hydrolysate. Bioscience, Biotechnology, and Biochemistry.

Schunck, M., Zague, V., Oesser, S., & Proksch, E. (2015). Dietary supplementation with specific collagen peptides has a body mass index–dependent beneficial effect on cellulite morphology. Journal of Medicinal Food.

Shigemura, Y., Akaba, S., Kawashima, E., Park, E. Y., Nakamura, Y., & Sato, K. (2014). Identification of collagen-derived peptides in human plasma after ingestion of collagen hydrolysates. Food Chemistry.

Shigemura, Y., Iwai, K., Morimatsu, F., Iwamoto, T., Mori, T., Nomura, Y., & Sato, K. (2009). Effect of prolyl-hydroxyproline (Pro-Hyp), a food-derived collagen peptide in human blood, on growth of fibroblasts from mouse skin. Journal of Agricultural and Food Chemistry.

Zague, V., de Freitas, V., da Costa Rosa, M., de Castro, G. Â., Jaeger, R. G., & Machado-Santelli, G. M. (2011). Collagen hydrolysate intake increases skin collagen expression and suppresses matrix metalloproteinase 2 activity. Journal of Medicinal Food.

*Up to +58% density: Average: Skin density increased by 10% after 63 days - Clinical study – Image analysis by UltraScan - 30 volunteers - Result after 63 days of use - 1 stick of Collagen + per day.

*up to -66% wrinkles: Average: -16% wrinkles after 84 days - Clinical study – Image analysis under dermatological control - 23 volunteers - Result after 84 days of use - 1 stick of Collagen + per day.

*83% more hydrated and comfortable skin / 100% firmer skin: Clinical study - Usage test - 30 volunteers - Results at 21, 63, and 84 days - 1 stick per day