PRP vs PRF: Platelet-Rich Plasma vs Fibrin for Hair Loss and Under-Eyes

Autologous blood concentrates have become foundational therapies across aesthetic dermatology, plastic surgery, and hair restoration. However, commercial marketing frequently blurs the distinction between first-generation Platelet-Rich Plasma (PRP) and second-generation Platelet-Rich Fibrin (PRF), presenting them as interchangeable "blood treatments."

They are not interchangeable. PRP and PRF differ fundamentally across four scientific dimensions:

1. Tube Additives & Anticoagulants: PRP requires chemical anticoagulants—such as Acid Citrate Dextrose (ACD-A) or sodium citrate—to stop the blood from clotting during processing. PRF uses 100% additive-free glass or specialized silicone-coated tubes, allowing natural physiological thrombin to polymerize fibrin.
2. Centrifugation Physics (The Low-Speed Centrifugation Concept / LSCC): PRP relies on high relative centrifugal force (RCF > 1,000g), which packs white blood cells and stem cells to the bottom of the tube and discards them. PRF utilizes low RCF (200g to 400g), capturing up to 10-fold higher concentrations of viable leukocytes, monocytes, and CD34+ mesenchymal stem cells within the harvested layer.
3. Growth Factor Release Kinetics: In PRP, the absence of a fibrin scaffold causes a rapid "growth factor burst," releasing over 90% of concentrated cytokines (PDGF, VEGF, TGF-β1) within 60 minutes of injection. In PRF, cytokines are trapped within a 3D uncrosslinked fibrin meshwork, releasing bioactive growth factors steadily over 10 to 14 days as the scaffold slowly degrades.
4. Orbital Safety: For the delicate under-eye tear trough, PRF (and heated albumin PRF EZ Gel) forms an autologous structural matrix with zero risk of hyaluronic-acid-associated Tyndall effect, delayed malar edema, or vascular occlusion.

The master comparison matrix below summarizes the essential biological, clinical, and regulatory differences.

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What is the biological difference between PRP and PRF?

To understand why PRF was developed, one must examine the physiological role of blood components in natural wound healing. When a cutaneous injury occurs in the human body, platelets do not remain in a liquid suspension; they aggregate within a polymerized fibrin clot. This fibrin mesh acts as an extracellular matrix (ECM) that anchors platelets, white blood cells, and circulating stem cells at the wound site, releasing regenerative cytokines as surrounding tissues repair.

BLOOD COMPONENT ARCHITECTURE & CONCENTRATE FORMATION

  WHOLE BLOOD DRAW (100%)
  ├── Red Blood Cells (Erythrocytes) ~45% (Discarded at tube bottom)
  └── Plasma + Buffy Coat ~55%
       ├── Centrifuged at High RCF (>1000g) + Anticoagulant ──> [ PRP ]
       │    └─ Pure liquid plasma; isolated platelets; no fibrin mesh; 1-hr cytokine burst
       │
       └── Centrifuged at Low RCF (200-400g) Additive-Free ───> [ PRF ]
            └─ 3D Fibrin matrix; platelets + leukocytes + CD34+ cells; 14-day sustained release

• PRP Mechanics: Developed in the 1990s (initially for maxillofacial and orthopedic surgery), PRP separates platelets by spinning whole blood at high speeds. Because blood naturally clots upon contact with glass or plastic, chemical anticoagulants are introduced to keep the platelets liquid. While this yields a high concentration of platelets (often 3x to 7x baseline), it destroys the natural clotting cascade and strips away vital structural proteins.
• PRF Mechanics: Developed in 2001 by Dr. Joseph Choukroun in France, PRF eliminates anticoagulants entirely. By utilizing low centrifugation speeds, the clotting cascade initiates during the spin. Fibrinogen is gradually cleaved by endogenous thrombin into fibrin monomers, which polymerize into an elastic, 3-dimensional, uncrosslinked fibrin network. This living matrix houses living cells and growth factors in their natural biological state.

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Tube additives and centrifugation: why PRF skips chemical anticoagulants

The elimination of chemical additives in PRF is not merely a "clean beauty" marketing concept—it is a critical physiological differentiator.

The Problem with Chemical Anticoagulants in PRP

Standard PRP preparation tubes contain Acid Citrate Dextrose Solution A (ACD-A) or 3.2% Sodium Citrate. Citrate prevents coagulation by binding and chelating ionized calcium (Ca²⁺) in the blood, an essential cofactor in the clotting cascade.

This creates two distinct clinical drawbacks:

1. Tissue Acidification & Pain: ACD-A drops the pH of the plasma to approximately 6.5 to 6.8. When injected into sensitive facial tissue or the scalp, this acidic solution causes significant burning and localized stinging.
2. Inhibition of Clotting Biology: Because calcium is bound, platelets cannot form a natural fibrin matrix upon injection. To overcome this, some PRP protocols add exogenous calcium chloride (CaCl₂) or bovine thrombin immediately prior to injection. However, this produces an artificial, brittle clot with rapid syneresis (shrinkage), failing to replicate physiological matrix stability.

The Low-Speed Centrifugation Concept (LSCC)

In 2018, Choukroun and Ghanaati published the Low-Speed Centrifugation Concept (LSCC) (European Journal of Trauma and Emergency Surgery, 2018). Their research demonstrated that centrifugation physics dictates cellular survival:

RCF (g-force) = 1.118 × 10⁻⁵ × r × (RPM)²

• When blood is spun at high RCF (>1,000g, standard PRP protocols), the high gravitational force crushes heavy white blood cells and pushes them to the bottom of the tube along with red blood cells, discarding them.
• When blood is spun at low RCF (200g to 400g for 5 to 8 minutes, PRF protocols), the lighter cellular fractions remain suspended in the upper layer.

Histological and flow-cytometry assays show that LSCC-prepared PRF contains up to 10 times more leukocytes (specifically pro-healing M2 macrophages and monocytes) and CD34+ stem cells than high-speed PRP. These leukocytes continue to actively synthesize and secrete cytokines in vivo for days following injection.

CENTRIFUGATION TUBE CROSS-SECTION: PRP VS PRF LAYERS

   HIGH-SPEED PRP TUBE (with Anticoagulant)        LOW-SPEED PRF TUBE (Additive-Free)
   ┌─────────────────────────────────────┐         ┌─────────────────────────────────────┐
   │ Top: Platelet-Poor Plasma (PPP)     │         │ Top: Liquid i-PRF / Fibrin Layer    │
   │ (Discarded or used for volume)      │         │ (Platelets + Leukocytes + Fibrin)   │
   ├─────────────────────────────────────┤         ├─────────────────────────────────────┤
   │ Middle: Concentrated Platelet Pellet│         │ Middle: Buffy Coat (Rich in CD34+)  │
   ├─────────────────────────────────────┤         ├─────────────────────────────────────┤
   │ Gel Separator Barrier               │         │ Bottom: Red Blood Cell Fraction     │
   ├─────────────────────────────────────┤         │ (Trapped RBC pellet)                │
   │ Bottom: RBCs & Trapped WBCs (Waste) │         │                                     │
   └─────────────────────────────────────┘         └─────────────────────────────────────┘

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Growth factor release kinetics: 60-minute burst vs 14-day sustained release

The most consequential clinical difference between PRP and PRF lies in their growth factor elution curves over time.

In a landmark comparative study by Miron et al. (Clinical Oral Investigations, 2017), ELISA assays measured the total release of key growth factors—including Platelet-Derived Growth Factor (PDGF-AA and PDGF-BB), Vascular Endothelial Growth Factor (VEGF), Transforming Growth Factor-Beta 1 (TGF-β1), and Epidermal Growth Factor (EGF)—over a 10-day incubation period.

ELISA GROWTH FACTOR ACCUMULATION OVER TIME (MIRON ET AL. 2017)

  Cumulative
  Growth Factor
  Concentration
       ▲
       │                                     ═════════════════ PRF (10-14 Day Sustained)
       │                                  ═══
       │                              ═══
       │                          ═══
       │                      ═══
       │                  ═══
       │  ─────────────────────────────── PRP (60-min burst; plateaus at Day 1)
       │
       └──────────────────────────────────────────────────────────► Time (Days)
          0 hr   1 hr    24 hr   Day 3   Day 5   Day 7   Day 10

Key Kinetic Findings

1. The PRP Burst: In PRP samples, over 90% of total growth factor content was released within the first 60 minutes. By hour 24, platelet degranulation was complete, and growth factor release ceased entirely. Any unbound growth factors not immediately utilized by local cell-surface receptors were rapidly degraded by tissue proteases.
2. The PRF Sustained Release: In PRF samples, growth factor release was continuous and linear across the entire 10-to-14-day monitoring window:
   • At Day 10, PRF had released significantly higher cumulative totals of PDGF-BB, TGF-β1, and VEGF compared to PRP.
   • The slow release is driven by physiological plasmin degradation: as tissue plasmin slowly dissolves the 3D fibrin polymer mesh, encapsulated platelets and active leukocytes continuously synthesize and shed new growth factors into the surrounding microenvironment.

For tissue regeneration—where fibroblast proliferation, angiogenesis, and collagen deposition require weeks of sustained stimulation—the 14-day elution profile of PRF provides superior biological signaling compared to a 1-hour burst.

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PRF vs PRP for under-eye hollowing and dark circles: why PRF wins the orbital area

The infraorbital tear trough is one of the most anatomically unforgiving areas in aesthetic medicine. The skin over the orbicularis oculi muscle is the thinnest on the human body (0.3 to 0.5 mm), and lymphatic drainage in the lower eyelid is delicate.

Injecting synthetic hyaluronic acid (HA) tear-trough fillers carries substantial risks:

• The Tyndall Effect: Superficial placement of clear HA gel scatters blue light, creating a permanent bluish-gray bruise-like discoloration.
• Chronic Malar Edema: HA is hydrophilic, binding up to 1,000 times its weight in water. In the periorbital zone, this frequently obstructs fragile lymphatics, leading to recurrent under-eye bags that persist for months.
• Vascular Danger: The angular and infraorbital arteries present rare but catastrophic risks of skin necrosis or retinal artery occlusion.

UNDER-EYE INTERVENTION COMPARISON

  Modality           Biological Mechanism        Tyndall Risk    Edema Risk    Vascular Occlusion Risk
  ────────────────────────────────────────────────────────────────────────────────────────────────────
  HA Dermal Filler   Synthetic hydrophilic gel   High (if placed Moderate to   Present (blindness /
                     (Restylane / Belotero)      superficial)    Severe        tissue necrosis)
  ────────────────────────────────────────────────────────────────────────────────────────────────────
  PRP (1st Gen)      Liquid autologous plasma    None            Low (transient None (no synthetic
                     (rapid 1-hour absorption)                   edema 24 hr)  embolism risk)
  ────────────────────────────────────────────────────────────────────────────────────────────────────
  PRF / PRF EZ Gel   Autologous 3D fibrin matrix None            Low / None    None (autologous
  (2nd Gen)          + 14-day neocollagenesis                    (non-hydrophilic) tissue compatibility)
  ────────────────────────────────────────────────────────────────────────────────────────────────────

Why PRF Excels in the Periorbital Space

1. Non-Hydrophilic Tissue Remodeling: Unlike HA, PRF does not absorb water from surrounding tissues. It provides smooth, natural structural support without causing morning puffiness or fluid retention.
2. Skin Thickening & Neovascularization: Sustained VEGF and PDGF release stimulates dermal collagen synthesis and microvascular perfusion. By thickening the dermis by 20% to 30% over a 3-session series, PRF camouflages underlying dark orbicularis muscle fibers and superficial venous pooling (the primary cause of genetic dark circles under eyes).
3. Cannula Safety: Liquid PRF or PRF EZ Gel is placed smoothly along the pre-periosteal plane using a 22G or 25G blunt micro-cannula through a single lateral cheek entry point, minimizing bruising and eliminating sharp needle trauma.

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PRF vs PRP for hair loss (androgenetic alopecia): what clinical trials show

Both PRP and PRF are widely prescribed as autologous adjuncts for male and female pattern hair loss (androgenetic alopecia). Their primary mechanism is the stimulation of dermal papilla cells, prolongation of the anagen (growth) phase, and activation of quiescent follicular stem cells in the bulge area.

HAIR RESTORATION CLINICAL DECISION FLOW

                     PATIENT WITH ANDROGENETIC ALOPECIA
                                     │
         ┌───────────────────────────┴───────────────────────────┐
         ▼                                                       ▼
   BROAD, EXTENSIVE SCALP COVERAGE                 FOCAL, CONCENTRATED THINNING
   (Norwood 4–6 / Ludwig 2–3)                     (Early Vertex, Hairline, Temples)
         │                                                       │
         ▼                                                       ▼
   PRP Advantage:                                  PRF Advantage:
   Higher liquid plasma yield per draw             Denser leukocyte & stem cell payload;
   (8–12 mL liquid covers entire scalp)            sustained VEGF angiogenesis for 14 days
         │                                                       │
         └───────────────────────────┬───────────────────────────┘
                                     │
                                     ▼
                   MANDATORY FOUNDATIONAL MEDICAL THERAPY
             (Oral/Topical Finasteride, Dutasteride, Minoxidil)

Comparative Clinical Trial Evidence

In clinical trials evaluating autologous concentrates in alopecia (e.g., ClinicalTrials.gov NCT04909775; Miron et al., Dermatol Surg 2020):

• Hair Count and Density: Both PRP and PRF demonstrate statistically significant increases in hair count (typically 15 to 30 additional hairs per cm²) and follicular shaft diameter at 3 to 6 months.
• Angiogenic Superiority of PRF: PRF's continuous VEGF secretion over 14 days promotes significantly greater perifollicular capillary vascularization compared to the short burst of PRP.
• The Yield / Volume Tradeoff: PRP yields a higher total volume of liquid per draw (typically 8 to 12 mL of PRP from a 30 mL blood draw), allowing broad coverage across the entire crown, mid-scalp, and hairline. PRF yields a smaller volume of highly concentrated liquid (typically 3 to 5 mL from a 40 mL draw), requiring precise micro-injections into focal areas of thinning (hairline, temples, or crown vertex).
• The Critical Medical Boundary: Autologous blood concentrates are biological stimulants, not DHT blockers. Neither PRP nor PRF halts the genetic enzymatic conversion of testosterone to dihydrotestosterone by 5-alpha reductase. For durable long-term hair preservation, autologous injections must be combined with FDA-approved medical therapy—see medical treatments for androgenetic alopecia.

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What is PRF EZ Gel (Alb-PRF) and how does it act as an autologous volumizer?

A major technological limitation of standard liquid PRF (i-PRF) has been its rapid physical resorption; while cellular signaling lasts for weeks, the initial fluid volume disperses within several days.

To create a natural, long-lasting autologous dermal filler without synthetic cross-linking agents (such as 1,4-butanediol diglycidyl ether, BDDE), researchers developed Albumin Gel (Alb-PRF), commercially known as PRF EZ Gel.

THE PRF EZ GEL (ALB-PRF) PRODUCTION CASCADE

  Whole Blood Draw (Additive-Free Tubes)
  ┌─────────────────────────────────────────────────────────────┐
  │ Step 1: Low-Speed Centrifugation (LSCC, 200–400g)           │
  └──────────────────────────────┬──────────────────────────────┘
                                 │
         ┌───────────────────────┴───────────────────────┐
         ▼                                               ▼
  Upper Platelet-Poor Plasma (PPP)               Buffy Coat & Liquid i-PRF
  ┌─────────────────────────────────────────┐   ┌─────────────────────────────┐
  │ Heated to 75°C for 10 Minutes           │   │ Kept at Room Temperature    │
  │ • Denatures serum albumin               │   │ • Preserves live platelets, │
  │ • Forms dense, viscous protein gel      │   │   leukocytes, and stem cells│
  └────────────────────┬────────────────────┘   └──────────────┬──────────────┘
                       │                                       │
                       ▼                                       ▼
  Cooled to 25°C ────> └───────────────┬───────────────────────┘
                                       │
                                       ▼
  Reconstituted via Luer-Lock Syringe Mixing
  ┌─────────────────────────────────────────────────────────────┐
  │ Result: Autologous Biovolumizer (Alb-PRF / EZ Gel)          │
  │ • Physical volume retention: 3 to 6 months                  │
  │ • Living growth factor release: continuous over 14 days     │
  │ • 100% natural, fully biocompatible, zero BDDE crosslinker  │
  └─────────────────────────────────────────────────────────────┘

The Albumin Denaturation Mechanism

1. Fraction Separation: After centrifugation, the upper Platelet-Poor Plasma (PPP) layer (which is rich in serum albumin proteins) is separated from the lower liquid i-PRF layer (which contains platelets, leukocytes, and cytokines).
2. Thermal Gelation (75°C): The PPP is placed in a specialized heating block at 75°C for 10 minutes. This thermal exposure denatures the tertiary structure of serum albumin, causing the unfolded protein chains to cross-link into a thick, opaque, viscous protein gel.
3. Cooling & Reconstitution: The heated albumin gel is cooled back to room temperature (25°C). It is then mixed via a female-to-female Luer-lock connector with the unheated, viable liquid i-PRF layer.
4. Clinical Longevity: The resulting Alb-PRF gel combines the structural stability of heat-denatured albumin with the regenerative growth factors of living PRF. When injected into the tear troughs, nasolabial folds, or cheeks, PRF EZ Gel maintains physical volume for 3 to 6 months before undergoing natural enzymatic breakdown by endogenous proteases.

For broader clinical evidence on autologous biomaterials, see regenerative aesthetics clinical trial evidence.

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FDA Regulatory Status: 510(k) Centrifuge Kits vs Autologous Medical Procedures

There is widespread confusion regarding whether PRP and PRF are "FDA-approved."

In the United States, the biological concentrate itself (the patient's own blood) is an autologous human cellular product that is not classified as a drug or biological license application (BLA) when prepared and reinjected in the same surgical procedure under the "same surgical procedure exception" (21 CFR 1271.15(b)).

However, the devices and tube systems used to harvest and process the blood are strictly regulated by the US FDA:

• Device Classification: Blood centrifuge processing systems and collection tubes are regulated as Class II medical devices cleared under 21 CFR 864.9245 (Automated or Manual Blood Cell Separator for Autologous Use).
• Product Codes:
  • BKQ: Automated blood cell separators cleared for the rapid preparation of autologous platelet-rich plasma from whole blood.
  • OEQ: Centrifuge systems cleared for the preparation of autologous platelet-rich fibrin.
• Notable 510(k) Clearances:
  • EZPRF System: FDA 510(k) BK190333 (Decision Date: 2019, Product Code BKQ).
  • Selphyl System: FDA 510(k) BK090033 (Decision Date: 2009, Product Code BKQ).
  • Eclipse PRP System: FDA 510(k) BK140136 (Decision Date: 2014, Product Code BKQ).

The injection of PRP or PRF into the scalp, tear troughs, or facial dermis is considered an autologous medical procedure governed under the state-regulated practice of medicine.

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Cost Comparison: Is PRF Worth the Price Premium Over PRP?

PRF processing equipment, specialized low-speed horizontal centrifuges, and additive-free glass tubes carry higher manufacturing and disposables costs than generic PRP test tubes. Consequently, clinics typically price PRF at a 20% to 40% premium over PRP.

TREATMENT COST & PROTOCOL PLANNING

  Procedure Format             Cost per Session       Recommended Initial Protocol
  ─────────────────────────────────────────────────────────────────────────────────────────────
  Standard PRP (Face or Hair)  $600 – $1,200          3 Sessions (spaced 4–6 weeks apart)
  ─────────────────────────────────────────────────────────────────────────────────────────────
  Injectable PRF (i-PRF)       $800 – $1,800          3 Sessions (spaced 6–8 weeks apart)
  ─────────────────────────────────────────────────────────────────────────────────────────────
  PRF EZ Gel (Alb-PRF)         $1,200 – $2,200        2–3 Sessions (spaced 8 weeks apart)
  ─────────────────────────────────────────────────────────────────────────────────────────────
  Annual Maintenance           $600 – $1,500          1 Session every 6 to 12 months
  ─────────────────────────────────────────────────────────────────────────────────────────────

Decision Framework: When to Choose PRF vs PRP

• Choose PRF if:
  • You are treating the under-eye tear troughs or periorbital area (where PRF's non-hydrophilic matrix, absence of Tyndall risk, and sustained 14-day growth factor release drastically outperform PRP).
  • You are combining the concentrate with acne scar subcision as an autologous physical spacer.
  • You want an entirely natural, additive-free treatment with zero chemical anticoagulants or synthetic crosslinkers.
  • You are seeking natural autologous volume via PRF EZ Gel.
• Choose PRP if:
  • You require broad-surface scalp coverage across the entire head for diffuse androgenetic alopecia, where a single blood draw must yield 10+ mL of liquid concentrate.
  • You are undergoing superficial microneedling (e.g., a "vampire facial" for global textural glow), where rapid surface platelet contact is sufficient.

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Frequently asked questions

Which lasts longer, PRF or PRP?

PRF lasts significantly longer at the cellular signaling level. In-vitro kinetic studies show that PRP releases over 90% of its growth factors within the first 60 minutes, whereas PRF's 3D fibrin matrix delivers continuous growth factor secretion over 10 to 14 days. In terms of volumetric hold, PRF EZ Gel provides visible structural support for 3 to 6 months, whereas liquid PRP disperses within 24 to 48 hours.

How much do PRF injections cost?

Injectable PRF (i-PRF) typically costs $800 to $1,800 per session. PRF EZ Gel (heated albumin autologous volumizer) ranges from $1,200 to $2,200 per session. A standard initial treatment protocol consists of 3 sessions spaced 6 to 8 weeks apart, followed by maintenance sessions every 6 to 12 months.

Is PRF really better than PRP for hair loss?

PRF provides a denser concentration of white blood cells, monocytes, CD34+ stem cells, and sustained VEGF output over 14 days, resulting in superior angiogenic signaling around miniaturized hair follicles. However, PRP yields a higher total liquid volume from a single draw, making it easier to cover large scalp areas. Both modalities require concurrent medical therapy (finasteride, minoxidil) to block DHT for permanent hair preservation.

Can PRF replace under-eye filler?

For patients with mild-to-moderate hollows, thin crepey skin, or dark circles caused by vascular pooling, PRF (or PRF EZ Gel) is widely preferred over synthetic hyaluronic acid fillers because it carries zero risk of the blue Tyndall effect, zero risk of chronic lymphatic puffiness, and zero risk of vascular blindness. However, for patients with severe skeletal volume loss, autologous fat grafting or deep periosteal filler may still be required.

Is PRF FDA-approved?

In the United States, blood collection tubes and centrifuge processing units for PRP and PRF are Class II medical devices cleared via FDA 510(k) under 21 CFR 864.9245 (Product Codes BKQ and OEQ; e.g., EZPRF BK190333, Selphyl BK090033). The biological concentrate itself is an autologous medical procedure governed under the practice of medicine.

How many PRF sessions are needed?

Most clinical indications—including under-eye rejuvenation, facial biostimulation, and hair restoration—require an initial series of 3 sessions spaced 6 to 8 weeks apart. Results develop progressively over 3 to 6 months as new collagen, elastin, and capillaries mature. Maintenance treatments are recommended once every 6 to 12 months.

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Sources

1. Kobayashi E, et al. Comparative release of growth factors from PRP, PRF, and advanced-PRF. Clin Oral Investig. 2016;20(9):2353-2360. Available at: https://pubmed.ncbi.nlm.nih.gov/26809431/
2. Wang X, Yang Y, Zhang Y, Miron RJ. Fluid platelet-rich fibrin stimulates greater dermal skin fibroblast cell migration, proliferation, and collagen synthesis when compared to platelet-rich plasma. J Cosmet Dermatol. 2019;18(6):2004-2010. Available at: https://pubmed.ncbi.nlm.nih.gov/31002446/
3. Choukroun J, Ghanaati S. Reduction of relative centrifugation force within injectable platelet-rich-fibrin (PRF) concentrates advances patients' own inflammatory cells, platelets and growth factors: the first introduction to the low speed centrifugation concept. Eur J Trauma Emerg Surg. 2018;44(1):87-95. Available at: https://pubmed.ncbi.nlm.nih.gov/28283682/
4. Shah N, et al. Fluid Platelet-Rich Fibrin (PRF) Versus Platelet-Rich Plasma (PRP) in the Treatment of Atrophic Acne Scars: A Comparative Study. Cureus. 2023;15(5):e38714. Available at: https://pmc.ncbi.nlm.nih.gov/articles/PMC10205840/
5. FDA CDRH 510(k) Database: BK190333 — EZPRF Centrifuge and Processing Tube Kit (Decision Date: 2019, Product Code: BKQ, 21 CFR 864.9245). Available at: https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfpmn/pmn.cfm?ID=BK190333
6. ClinicalTrials.gov: Comparative Study of PRF vs PRP in Androgenetic Alopecia (NCT04909775). Available at: https://clinicaltrials.gov/study/NCT04909775
7. Miron RJ, et al. Injectable platelet rich fibrin (i-PRF): opportunities in regenerative dentistry? Clin Oral Investig. 2017;21(8):2619-2627. Available at: https://pubmed.ncbi.nlm.nih.gov/28484831/