Collagen supplements that come in powder form can be dissolved in hot or cold liquids. (helovi/iStock)

Any soupmaker worth their salt knows that a good, full-bodied stock is semisolid and jiggly when chilled, and the essential ingredient to make that happen is plenty of bones. It’s why my grandmother, and now I, consider chicken feet the secret ingredient in our soups, and it explains some of the appeal of today’s bone broth craze. Turns out bones — from meat, poultry or fish — provide more than just luxurious texture to soup; they also provide a type of protein that has become a major trend in the supplement market: collagen.

Collagen is the main structural protein of connective tissue in animals, found not only in bone but also skin, cartilage and tendons. When collagen is heated in water, as in soupmaking, it results in gelatin, which explains that desirable jellylike texture after refrigeration. And yes, that is where the powder in those little gelatin packets used for desserts and other dishes comes from. When we eat it, gelatin is digested like any other protein — it is broken down into individual amino acids that our bodies can use to build whatever protein it needs — including our own collagen. As we age, however, our bodies’ collagen production becomes less efficient, and the tissues that depend on it, such as our skin and joints, don’t get repaired the way they used to, which explains, at least in part, why our skin starts to sag and we have more aches and pains as the years tick by.

That’s where the supplements come in. Manufacturers have found a way to apply enzymes to gelatin to create protein chains called collagen hydrolysates. These small collagen chains (peptides) may be absorbed intact by the body to be used directly in the tissues. Predictably, there is a lot of hype and exaggerated claims around these supplements, but there is also a lot of promising, bona fide research pointing to benefits, particularly for more youthful-looking skin and help with joint pain.

Several studies show improved skin elasticity and hydration and reduced formation of deep wrinkles after taking collagen hydrolysate supplements for six weeks or more, with participants older than 30 seeing the biggest improvement. A 2017 study in the Journal of Agriculture and Food Chemistry showed that collagen hydrolysates can be transferred through the bloodstream directly to the skin, which explains the probable pathway for these effects. The supplement may also help improve brittle nails, according to a small study published in 2017 in the Journal of Cosmetic Dermatology in which participants took the supplements for 24 weeks.

Collagen hydrolysates have also been shown to help with joint pain in athletes and those suffering from osteoarthritis, with participants in the greatest pain getting the most relief. A 2018 meta-analysis published in the British Journal of Sports Medicine that examined various supplements used for osteoarthritis identified collagen as one “demonstrating clinically important effects for pain reduction in the medium term.” However, over the long term, the supplements didn’t help any more than a placebo.

Besides the fact that observed benefits have mostly involved short-term studies — there is scant evidence that the effects are anything more than fleeting — there are several other things to consider before you run out and buy collagen supplements. Although the science is building, it is relatively new and there is still a lot to learn, particularly in identifying what types of collagen peptides work with different conditions. Also, although side effects appear minimal, there have been reports of digestive problems when supplements are taken in large amounts.

On top of that, the bulk and cost of the supplements may be prohibitive. Supplements in pill form require swallowing six a day to get a six-gram dose. (The doses used in the studies generally ranged from five to 12 grams a day.) Powders, which can be dissolved in hot or cold liquids, are perhaps less cumbersome but are roughly double the price, running from about $15 to more than $40 for a month’s supply. Also noteworthy: If you are looking for a general protein supplement, collagen alone would not be the best choice because it is not a complete protein — it lacks the essential amino acid tryptophan.

Considering that those who benefited most from collagen supplements in the studies were those who generally ate the least amount of meat (and were possibly, therefore, not getting enough quality protein), it’s worthwhile, whether you decide to try a supplement or not, to turn your attention to optimizing your body’s own collagen-making machinery. That means getting adequate protein overall, from meat, poultry, fish and plant proteins such as beans, nuts, seeds and grains. And you need to get enough vitamin C — found in foods such as citrus fruits, berries, bell peppers and green, leafy vegetables — which is also essential for collagen production.

It’s also worth noting that, although it’s not in hydrolysate form, one cup of chicken stock or bone broth offers about six grams of collagen-rich protein in a tasty and satisfying way.