the gut question, and where that research actually sits

The gut claim is the one I get asked about most and the one I am most careful with, because it is where this category sometimes gets ahead of itself.

So here is a straight account of what is underneath it.

the mechanism is real

Your intestinal lining is a single layer of cells sitting on a connective tissue base. That base is collagen. The cells are held to each other by tight junctions, protein structures that control what passes between them.

That whole structure is built and repaired constantly, faster than almost any tissue in your body. Gut lining cells turn over every few days. That is an enormous protein demand.

Collagen peptides are unusually rich in glycine, and glycine is a building block that shows up throughout that repair process. Collagen also carries glutamine, which is a preferred fuel for intestinal cells specifically.

So the raw material argument makes sense before anyone runs a single study.

what the lab work shows

Chen and colleagues, publishing in Food and Function in 2017, applied collagen peptides to intestinal cell monolayers under inflammatory stress and found the peptides helped preserve tight junction integrity and barrier function.

That is a cell study and I want to label it clearly as one. Cells in a dish are not a person. But it is a direct test of the exact mechanism, and it came out the way the theory predicted.

Animal work has pointed in the same direction, with glycine in particular showing protective effects on the intestinal lining across a number of models.

where the human evidence stands

Honestly, this is the newest corner of collagen research. Skin has 19 randomised controlled trials pooled in a meta analysis. Bone has a twelve month trial. Gut has strong mechanism, good preclinical work, and human trials that are still arriving.

I would rather tell you that than pretend otherwise. What I will say is that the direction of travel is consistent, and that the underlying logic, feeding a fast turning over protein structure the amino acids it is built from, is not exotic.

the thing people miss

Bone broth has been a gut remedy in more or less every food culture on earth for centuries, long before anyone could name a tight junction. That is not evidence, but it is not nothing either.

What bone broth is, chemically, is collagen dissolved in water. Peptides are the same protein, further hydrolysed, at a known dose, without the twelve hours of simmering.

the other reason it comes up

A lot of protein drinks are hard on people's stomachs. Whey is a common offender if you are at all sensitive to dairy, and sugar alcohols in low calorie drinks are a well known cause of bloating.

Collagen peptides are dairy free, and we sweeten with monk fruit rather than sugar alcohols. That is a smaller claim than gut healing, and it is one I can stand behind completely.

the research i leaned on

• Chen Q, Chen O, Martins IM, et al. Collagen peptides ameliorate intestinal epithelial barrier dysfunction in immunostimulatory Caco-2 cell monolayers via enhancing tight junctions. Food and Function. 2017;8(3):1144-1151.
• Wang W, Wu Z, Dai Z, Yang Y, Wang J, Wu G. Glycine metabolism in animals and humans: implications for nutrition and health. Amino Acids. 2013;45(3):463-477.

LÉS is a beverage, not medicine, and nothing here is medical advice.