What is the difference between PRP and PRF and which is better when used in the under eye area?

PRP uses FDA 510k approved tubes. PRF does not. PRF has a higher number of red and white cells leading to inflammation. PRP can be delivered via a Cannula while with PRF it is difficult. PRF is stated to be used as a filler, however it dissipates quickly. In short, PRF is heavily promoted on social media, however no good clinical trials or published studies substantiate the claims of PRF superiority. I prefer Progen PRP for undereye treatment. Remember, both of these products can improve undereye fine lines and discoloration. They will not treat a hollow contour.
Jeff Rapaport, MD, FAAD
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PRF (Platelet-Rich Fibrin) and PRP (Platelet-Rich Plasma) are both derived from your blood and used for skin rejuvenation. PRF releases growth factors more slowly over time and does not contain anticoagulants, while PRP works more immediately due to its composition.I personally prefer to use PRF .Unlike fillers, PRP/PRF rarely carries a risk of blindness since they are not volumizing agents and don’t compress blood vessels. However, proper technique and injection depth are essential to avoid complications. Always choose an experienced professional for these treatments.

The undereye area is one of the first to show signs of aging, due to the very thin skin in this area, only 0.3mm thick. This area may show dark circles, volume loss, crepey skin, or some combination of the above. Both PRP (platelet-rich plasma) and PRF (platelet-rich fibrin) have been shown to be helpful for treating the undereye area, improving dark circles, skin laxity, wrinkle scores and photoaging. This was highlighted by a recent systematic review and meta-analysis by Evans et al. (2021, Archives of Dermatological Research), which reviewed a total of 19 studies.
The difference between PRP and PRF is in the preparation technique. PRF is just PRP that has formed a fibrin clot (hence the name). Both start with a blood sample, but with PRP, an anticoagulant is mixed with the blood to keep it from clotting. PRF does not use any anticoagulant, so while it starts as PRP, after several minutes, it starts to form a fibrin clot, PRF. Some believe that creating PRF may be more natural (no anticoagulant), and that the fibrin mesh allows the platelets to stay in the same area for a longer time, allowing more growth factors to be released. There are studies that show that PRF can work well for the under eye area (see below).
Sometimes, PRF is created from PRP that has already been mixed with anticoagulant, by adding a small amount of calcium solution to cause the platelets to activate. This needs to be done just prior to use, and some PRP kits even include this calcium (e.g. Selphyl). But really any PRP can be turned into PRF with the addition of a just a few drops of calcium. Gel can also be made from PPP through a heating process but the results are not as long-lasting as dermal filler.
It's difficult to say whether PRP or PRF is better for the undereye area, or any area for that matter. This is because there are many different types of PRP kits on the market, and they often perform inconsistently from what the manufacturers claim. At our clinic, we use both PRF and PRP and they both work well, as long as the concentration, purity and dose is high enough. This is also why we test all PRP and PRF prior to use, as every sample can be different.
For good results, concentration is very important, as this will directly affect the number of growth factors available. Both PRP or PRF could be low concentration, depending on the preparation method, and thus less effective. If the concentration is lower than baseline, the sample might be PPP, or platelet poor plasma. The only way to be sure is to test the sample. The review mentioned above by Evans concluded that PPP does not work as well as PRP or PRF. In general, single spin systems produce the lowest concentration PRP. Double spin systems produce the highest concentration, but are at risk for lower levels of purity, with higher numbers of red blood cells and white blood cells in the PRP.
There are good PRF kits which have been shown effective for the under eye area. One clinical study from Germany (Aust et al, 2018) treated 20 patients with PRF made from an Arthrex ACP kit, (FDA 510K number BK190406). Interestingly, the authors called it PRP even though technically, it was PRF. The reason is without anticoagulant, the PRP will form PRF gel within a short time. But before the sample gelled, the PRF was injected with a 27g cannula. Overall, they reported a high level of patient satisfaction, with increased skin firmness and elasticity. Arthrex ACP has been reported to obtain PRP with a good increase in concentration of approximately 2.5x the normal platelet concentration and practically free from red blood cells and white blood cells (Loibl et al, 2016).
In conclusion PRP or PRF will work for the undereye area, although PRF is more gel-like and may release growth factors over a longer period of time. There are good, FDA 510K approved kits available for both, but the only way to know platelet concentration is to test before using the PRP or PRF. For best results, multiple treatments may be required.