It will make your skin look dewy and fresh, your bones and nails strong, and your joints pain-free. These are the claims made by the countless manufacturers of collagen supplements that come in the form of powders, pills and creams. For that reason, it’s no surprise that collagen has become a widely sought-after ingredient in the wellness and beauty communities. But collagen’s efficacy is still pretty up in the air. Frustrated? Here’s what we know.

What is collagen?

Collagen is one of the most abundant proteins in the body. In fact, collagen is “the main structural protein that forms the connective tissue throughout our body, from skin to bones, muscles, tendons and ligaments,” said Dr. Shari Marchbein, a board-certified dermatologist based in New York. It’s no wonder that the bottled up version of this protein (usually made of animal collagen) is in high demand.

Collagen makes up a whopping 80 percent of our skin, and works with another protein called elastin that — yes, you guessed it — keeps our skin elastic. But as we age, our bodies naturally start reducing collagen production. The board-certified dermatologist Dr. Whitney Bowe described our body’s collagen as “ropes of protein in the skin.” When we’re young, the rope remains tight, but as we age, the ends begin to fray. Essentially, our bodies are not able to replace the collagen we are losing as quickly as it is breaking down. Starting in our 20s, we begin losing about 1 percent of our collagen each year, said Dr. Bowe. This, unfortunately, means drier skin. Sun exposure, cigarette smoke and pollution can also accelerate collagen breakdown. “The concept of supplementing our collagen, especially as we age and as our body’s natural collagen production declines, is incredibly appealing from a dermatologic standpoint,” she said.

Collagen peptides (also referred to as hydrolyzed collagen) which are in supplements, are different. They’re made of the same amino acids as collagen but are more easily absorbed by our bodies. That’s because they are much shorter chains of amino acids than collagen, making them more easily absorbed into our bloodstream (i.e. more digestible). That said, Dr. Marchbein reminds us that, “how much of the supplement is absorbed and whether those amino acids make it to their target organs to act as the building blocks to make more collagen is still up for debate.” Be sure to look at the label as companies often, or at least should, disclose what their product contains.

Does collagen work?

Some studies show that taking collagen supplements for several months can improve skin elasticity, (i.e., wrinkles and roughness) as well as signs of aging. Others have shown that consuming collagen can increase density in bones weakened with age and can improve joint, back and knee pain. But many of these studies are small and funded by companies that make the product, increasing the opportunity for bias in the results.

It is possible that some of these benefits are attainable, according to a 2019 literature review in the Journal of Drugs in Dermatology. The review found some data from double-blind placebo controlled studies to support that collagen could increase skin elasticity, collagen density and overall hydration.

But a lot more evidence is needed. Dr. Bowe believes that the studies, “though small and preliminary,” show promise. She said she has begun recommending ingestible collagen to her patients and has witnessed noticeable benefits in terms of skin elasticity, firmness and hydration. (She often recommends powder based supplements.)

What’s the best way to absorb collagen?

Absorption can be a tricky game, especially when it comes to a huge molecule like natural collagen. Smaller peptides can more easily pass through our intestinal barrier and into our bloodstream. (In theory, this is what all good supplements should be able to do.) The body can, in theory, utilize absorbed collagen peptides in areas that need repair the most.

Like with any fad, beauty and wellness see an opening and many companies have jumped on the collagen bandwagon fairly quickly. Pills, powders, topical creams and liquids are all out there, promising to beautify your skin and strengthen your bones.

Powders are the most popular because they’re easy to add to smoothies, coffee or even water. In terms of dosage, Dr. Debra Jaliman, another board-certified dermatologist, recommends always following the directions on the bottle because no two supplements are made equally.

As for topical creams, Dr. Bowe explained that because collagen is produced in the deepest layers of the skin, the dermis and the hypodermis (which is lower than the dermis), it is very hard for topical collagen to actually make it there.

(Watch out for products marketed as “plant-based collagen.” They don’t actually contain collagen, and though they say they support collagen production, the science is not there to back it up.)

So, should you try collagen?

Maybe! But get ready for a very committed relationship. If collagen does work, and you’re looking for long-lasting effects, you’ll have to take supplements for the rest of your life. Why? The answer is collagenase. According to Dr. Jaliman, our bodies are constantly producing this enzyme and it eats away at our natural collagen. So if collagen supplements improve your skin, bones and joints, you’ll need to keep taking them.

One of the biggest downsides of consuming collagen, said Dr. Robert Anolik, a clinical assistant professor of dermatology at the N.Y.U. School of Medicine, is that just because you’re taking collagen that doesn’t mean it’s all going directly to your skin.

How do I take collagen?

Collagen supplements — like most supplements — are not closely regulated by the F.D.A. Some supplements carry a USP Verified label, which is better than nothing. But it is very hard to police what ingredients are in a product.

You should also take into consideration the foods you already consume. Dr. Bowe said when it comes to bovine, marine, or porcine collagen in food, the bones and skin are the richest sources, but most people aren’t eating those parts. She recommended bone broth as an easy collagen-rich option. Dr. Jaliman also pointed out that bone broth is rich in amino acids, “so it may help with collagen production” but there is very little research or evidence to support that it has benefits for the skin.

The good news is: if you’re ingesting the recommended dose, there are no documented downsides of taking collagen peptides, aside from the not-so-frugal cost — products range anywhere from $20 to upward of $200 for a limited supply. So, it’s your choice. We just report the facts.