"Making my morning collagen," Kardashian says in her Instagram Story as she pours hot water from a kettle over a glass of powdered collagen peptides. "It has vitamin C and zinc, so it's immunity-boosting especially, and everyone's getting sick." (Related: Here's What Kourtney Kardashian Eats Before and After Her Workout)

"It has hyaluronic acid so it's really good for your skin. And of course, it has collagen, which is great for skin, hair, nails—so many benefits. I drink this every morning. It also has protein, so it keeps me full until after my workout," she adds

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Found naturally in the body's muscles, skin, and bones, collagen is a protein that keeps skin plump, smooth, and youthful-looking. It makes up about 25 percent of your total body mass, Joel Schlessinger, M.D., a Nebraska-based dermatologist, told Shape previously. And while your body does make new collagen every day, production eventually slows (at a rate of about 1 percent per year beginning at age 20, explained Dr. Schlessinger), and wrinkles start to creep in. (Related: Why It's Never Too Early to Start Protecting the Collagen In Your Skin.)

That's why more people are turning to supplements and skin-care products to try to boost their body's collagen levels. The good news is that some research indicates that collagen supplements do indeed improve skin elasticity. Plus, some experts back up Kardashian's claims that ingesting collagen can support not only skin health, but also your hair, joints, and nails.

While that all sounds promising, don't think you're going to Benjamin Button your way back to the skin of your 20s. Other experts think more research is needed to determine how much collagen supplements actually benefit your health, as many studies so far have been small or sponsored by specific companies.

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The benefits may be questionable, but celebrities like the Kardashian-Jenner gang swear by collagen supplements. Fortunately, investing in a tub of the Vital Proteins peptide powder won't break the bank, and mixing up the beauty elixir is super easy—just add water to the powder and drink up.

The best news? There are a ton of Vital Protein powders similar to Kardashian's favorite on Amazon with Prime shipping, so you can be on your way to healthier skin, hair, and nails by the weekend. (Read more: The Best Collagen Powders for Women, According to a Nutritionist)