By now, you've likely heard of PRP (platelet-rich plasma) injections — after all, they continue to gain popularity thanks to their ability to treat a variety of conditions from sports injuries to hair loss. Heck, they can even rejuvenate your skin to fight signs of aging. But there's a new kid on the block, poised to give PRP a run for its money. PRF (platelet-rich fibrin) injections are all the rage, being touted as PRP's more effective cousin. But is that actually the case? Ahead, experts explain what PRF is, how it differs from PRP, and, most importantly, whether its purported benefits are legit. (Related: What You Need to Know About Regenerative Dermatology)

First, a little biology 101: The four main elements of blood are red blood cells, white blood cells, platelets, and plasma, according to the American Society of Hematology. While red blood cells carry oxygen from the lungs to the rest of the body, white blood cells fight infection, viruses, and bacteria. "Platelets seek out and heal damage, and the plasma is the stuff that it all floats in," Richard Firshein, D.O., previously told Shape. "When you have a wound of any kind, the platelets in your blood rush to the injury and seal it up like a zipper." They also reduce inflammation, which can otherwise contribute to dermatological woes such as acne and aging, and are rich in growth factors, which essentially perform an array of skin-benefiting functions, including boosting the skin's collagen-building process.

Got all that? Good. Now onto the subject at hand: PRF, or platelet-rich fibrin, which is a newer generation platelet-rich preparation that's used for a variety of medical applications to help improve healing, says Y. Claire Chang, M.D., a board-certified cosmetic dermatologist at Union Square Laser Dermatology in New York City. As is the case with PRP, your own blood is drawn from your arm and undergoes a process known as centrifugation Essentially, it's spun around in a high-tech machine to separate out platelets (and other components) suspended in blood plasma. Those other components include a fibrin matrix (fibrin is a protein involved in blood clotting) and white blood cells.

The basic concept is similar and they're used for the same aims, but there are a few key differences between PRF and PRP, including how the two are prepared. For starters, "a lower centrifugation speed is often used when preparing PRF, which is why it contains both white blood cells and a higher amount of platelets than PRP," explains Konstanin Vasyukevich, M.D., a board-certified facial plastic surgeon in New York City. The preparation of PRP also requires the addition of an external anticoagulant (a substance that prevents blood clotting), as well as bovine thrombin (a protein) or calcium chloride to activate it, explains Dr. Chang. To that point, "PRF is considered to be '100 percent natural' since it doesn't contain any additives," adds Azza Halim, M.D., an aesthetic and functional medicine physician in Newport Beach, California.

Both PRP and PRF contain platelets and growth factors; the differences lie in the concentration of the platelets and how quickly those growth factors are released. "PRF contains a 10 times concentration of platelets, whereas PRP contains two to five times," explains Dr. Halim. In other words, PRF has more of the "good" stuff. With PRP, the growth factors are released rapidly after activation (aka when the bovine thrombin or calcium chloride and anticoagulant are added), but with PRF, the fibrin matrix traps the growth factors and slowly releases them over time, says Dr. Chang. Translation: The post-treatment results show up slower, but can last up to a year, according to Dr. Halim. And those growth factors are ultimately what help to stimulate collagen and elastin — the two proteins responsible for strong, healthy, youthful skin, she adds. (Related: Why It's Never Too Early to Start Protecting the Collagen in Your Skin.)

If you've already tried a PRP facial, you can expect a similar experience with PRF. A medical professional draws a vial of blood, puts it through the centrifuge, applies a topical numbing cream, and then reinjects the substance using one long needle or microneedling. The entire process takes 45 minutes to one hour, according to the American Academy of Dermatology. The results last three to six months and cost varies greatly, but typically falls within $500 to $1,000 per treatment, says Dr. Vasyukevich.

PRF can help with fine lines, unwanted textures, skin laxity, and overall skin rejuvenation, says Dr. Halim. It's also been used in combination with fillers to help with facial folds and wrinkles, adds Dr. Chang. However, PRF injections are not a direct replacement for fillers. "PRF is occasionally marketed as a 'natural' filler and a substitute for injectable hyaluronic acid fillers, but there is little evidence to suggest that this is the case," cautions Dr. Vasyukevich.

While PRF may also be used for other things such as acne scars and androgenetic alopecia (a common form of hair loss), more research on its efficacy is still needed, according to Dr. Chang. As of now, however, a handful of studies have analyzed PRF's effects on the skin. One small, uncontrolled study, for example, found that three rounds of PRF injections resulted in "significant rejuvenation" of participants' skin, in terms of surface spots (e.g. hyperpigmentation, freckles, or melasma) and pore visibility. For that matter, PRP doesn't have many human studies backing its benefits for the skin either. It's attracted "high demand for a procedure that has little evidence to back it up," according to the AAD. (Related: 9 Products That Will Get Rid of Acne Scars In Record Time.)

Since a patient's own blood is being used in this treatment, it's very unlikely to cause any type of adverse reaction," says Dr. Vasyukevich. That being said, swelling and bruising from the injecting or microneedling is possible, says Dr. Halim.

While there is some overlap between PRP and PRF injections, they're not entirely synonymous. But that doesn't necessarily mean that one is better than the other. "Some patients come to me saying they've read that PRF is superior to PRP for facial rejuvenation and anti-aging, but more clinical studies are needed before we can make this conclusion," says Dr. Chang. And, at the end of the day, "Anyone who is seeking anti-aging or preventative benefits and who wants to improve the quality of the skin can be a good candidate for either PRF or PRP," adds Dr. Halim. Your best bet? Talk to your doctor about your particular skin concerns and goals so that you can decide if either option is right for you.