the bone study nobody in this category talks about

Every collagen product on the shelf is sold on skin. Glow, radiance, a woman touching her own cheek in soft focus. I understand why. Skin is what people buy.

But the study that made me sit up was not about skin at all. It ran for a full year and it was about bone, and I have never once seen it on a label.

what they did

König and colleagues, published in Nutrients in 2018. A randomised, placebo controlled, double blind trial in 131 postmenopausal women with reduced bone mineral density.

Five grams of specific collagen peptides daily, or placebo, for twelve months.

The collagen group showed a significant increase in bone mineral density in the spine and the femoral neck compared with placebo. Bone markers moved in the right direction too, with a rise in a marker of bone formation and a fall in a marker of bone breakdown.

why twelve months matters

Most nutrition trials run eight or twelve weeks because that is what is affordable. A twelve month randomised controlled trial is expensive and slow, and it is also the only way to measure something as slow as bone.

So this is one of the longest and most rigorous pieces of evidence in the entire collagen literature, and it sits almost unused by the industry because bone density does not photograph well.

bone is not just a mineral

I always pictured bone as chalk. It is not.

Bone is roughly a third organic matrix by weight, and about 90 percent of that matrix is type I collagen. The mineral crystallises onto a collagen scaffold. The scaffold is what gives bone the ability to bend slightly instead of shattering.

Which means the same protein that structures your skin is also structuring your skeleton, and it is the same type I. That connection is why the bone finding did not surprise me once I stopped thinking of collagen as a beauty ingredient.

the part that is specifically about us

Women lose bone density fastest in the years around and after menopause, for the same hormonal reason skin collagen drops off in the same window, documented by Brincat and colleagues back in 1985.

Two structural systems, made largely of the same protein, declining together, on a timetable nobody warned me about in my twenties.

I am not going to tell you a drink is a treatment for anything, and it is not. But the fact that a year long controlled trial found something measurable in bone, at five grams a day, is a serious piece of evidence and it deserves more attention than it gets.

There are 20 grams of collagen protein in our can. Some of that goes to your skin. Some of it is going somewhere you will never see, and that has become the part I think about most.

the research i leaned on

• König D, Oesser S, Scharla S, Zdzieblik D, Gollhofer A. Specific collagen peptides improve bone mineral density and bone markers in postmenopausal women, a randomized controlled study. Nutrients. 2018;10(1):97.
• Brincat M, Moniz CF, Studd JW, et al. Long-term effects of the menopause and sex hormones on skin thickness. British Journal of Obstetrics and Gynaecology. 1985;92(3):256-259.

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