Collagen

2005: finding peptides in the blood

In 2005, Iwai and his collaborators identified peptides from collagen in the blood after ingestion of gelatin hydrolysates. This work shows that some of the fragments can be found after digestion.

2014: testing specific peptides

A trial published in 2014 compared a specific hydrolyzate to a placebo in 69 women aged 35 to 55, with daily intakes of 2.5 or 5 g for eight weeks. Researchers measure several properties of the skin, including its elasticity. This type of study contributes to current cosmetic promises, but the results of a specific ingredient do not constitute validation of all the powders sold.

2023: consolidate the results

A meta-analysis published in 2023 found on average improvements in hydration and elasticity in the included trials. Grouping studies together makes it possible to look for a trend, but does not eliminate their limitations: different formulations and measurements, sometimes small samples and relatively short durations. A difference measured by a device does not necessarily correspond to a significant visible transformation for the user.

2025: looking at quality and financing

A 2025 meta-analysis also examines outcomes by funding and trial quality. The benefits are not found in study subgroups without industrial or better quality funding. This does not prove that any effect is impossible, but reduces confidence in general promises. The sheet therefore makes a reserved recommendation, rather than an essential supplement against aging.