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Why platelets matter to dermatologists
Platelets are far more than “blood cells for clotting”. Once activated, they release numerous signalling molecules and participate in processes relevant to haemostasis, inflammation and tissue repair. This is the biological reason platelet-rich preparations such as PRP attract interest in dermatology.
01HaemostasisPlatelets react early to vascular and tissue injury and contribute to the primary haemostatic plug.
02SignallingActivated platelets release contents from α-granules and dense granules as well as other mediators.
03Tissue repairPlatelet-derived signals are associated with cell migration, angiogenesis and wound-healing processes.
What exactly are platelets?
Platelets are small, anucleate cell fragments derived from megakaryocytes in the bone marrow. At rest they circulate in blood. When a vessel is injured, they can rapidly become activated, adhere to damaged structures and aggregate with one another.
For dermatologists, their role in haemostasis is only part of the story. Platelets contain two characteristic types of secretory granules: α-granules and dense (δ) granules. α-Granules contain many proteins involved in processes including haemostasis, angiogenesis, inflammation and wound healing; dense granules store smaller molecules such as ADP, ATP, serotonin and ions.
Interactive: from resting to activated platelet
This is a simplified biological model. Select the steps to see what changes functionally.
Schematic illustration, not to scale.
Resting state
The platelet circulates in blood and stores mediators in different granules.
Which signalling molecules are relevant?
The effects of activated platelets cannot be reduced to one growth factor. PRP and wound-healing research commonly discusses PDGF, TGF-β, VEGF, FGF and EGF. Their biological effects depend on tissue context, concentration, timing and interactions with other cells and mediators.
| Factor | Name | Biological context |
|---|---|---|
| PDGF | Platelet-Derived Growth Factor | Involved in cell migration, fibroblast activity and extracellular-matrix formation. |
| TGF-β | Transforming Growth Factor beta | Regulation of inflammation, matrix formation and tissue remodelling. |
| VEGF | Vascular Endothelial Growth Factor | Involved in angiogenesis and new-vessel formation. |
| FGF | Fibroblast Growth Factors | Involved in cell proliferation, fibroblast activity and angiogenesis. |
| EGF | Epidermal Growth Factor | Involved in epithelial repair and re-epithelialisation. |
Important: The formula “more growth factors = more regeneration” is not supported by evidence. Biological effects result from composition, dose, release kinetics and tissue context rather than a single laboratory value.
From platelets to PRP
Platelet-rich plasma (PRP) is an autologous blood-derived preparation in which platelets are enriched relative to the starting blood. However, the clinical literature has no single universal threshold or composition that defines every PRP product.
Depending on preparation, products differ in platelet and leukocyte content, residual erythrocytes, plasma volume, activation, anticoagulant and centrifugation method. This heterogeneity is a major reason why results from one PRP study cannot automatically be transferred to another system.
Interactive: PRP is not one uniform product
The tube graphic schematically shows separated blood fractions. What matters is not the colour of a layer, but which cellular and plasma components a particular system actually recovers.
Schematic, not to scale; actual layers and cell distribution depend on the sample, rotor and protocol.
Platelets
A PRP process aims for a defined recovery or enrichment of platelets. If concentration matters for research or documentation, it should be measured rather than assumed.
Why is this particularly relevant to dermatology?
Skin healing is a multi-phase process. Haemostasis, inflammation, cell migration, angiogenesis, matrix formation and remodelling must occur in a coordinated sequence. Platelets act early and link coagulation with additional biological signalling pathways.
This biology has led to many dermatological research areas. Evidence strength varies substantially by indication and should not be compressed into the generic statement that “PRP works”.
positive signals, high heterogeneity
Androgenetic alopecia
A 2024 meta-analysis of randomised trials found increased hair density but rated the evidence as low because of high heterogeneity, study quality and publication bias. A broader 2025 meta-analysis reported moderate evidence for hair density and reduced hair loss, while still stressing protocol heterogeneity.
low to very low certainty
Atrophic acne scars
An umbrella review of 15 systematic reviews often found better outcomes when PRP was added to microneedling or laser. However, the certainty of evidence for assessed outcomes was rated low to very low.
no robust standard conclusion
Facial rejuvenation / skin ageing
A 2024 umbrella review considered the evidence insufficient for firm conclusions. A 2025 systematic review reported positive clinical and histological signals but also highlighted differing application techniques, doses and small studies.
data mainly in diabetic foot ulcers
Chronic wounds
A 2025 meta-analysis of 15 randomised trials and 1,010 patients found higher complete healing rates and shorter healing times in diabetic foot ulcers. These findings cannot be generalised to every chronic wound; PRP should be viewed as an adjunct to cause-directed standard care.
The highest platelet count does not automatically win
A high platelet concentration is not automatically equivalent to a better clinical outcome. Characterising a preparation also involves platelet dose, leukocytes and residual erythrocytes, plasma volume, activation and processing.
For professional users, the characteristics of the PRP tubes, their additives, intended purpose and instructions for use therefore matter as well. A study protocol should not be transferred to another system merely because platelet counts appear similar.
Why centrifugation is more than a technical detail
Centrifugation affects how blood components separate. RPM only describes rotational speed. The relative centrifugal force (RCF, × g) also depends on the effective rotor radius. Two centrifuges can therefore produce different forces at the same RPM.
With a PRP centrifuge, rotor, radius, RCF, run time, tube and the manufacturer protocol should be considered together. An isolated RPM value is insufficient for transferring a protocol.
Interactive: why 3,000 RPM does not always mean the same g-force
Change the radius and rotational speed. The calculation only demonstrates the physical relationship between radius, RPM and RCF; it is explicitly not a PRP treatment or centrifugation protocol.
RCF = 1.118 × 10⁻⁵ × r(cm) × RPM²calculated RCF805 × gTechnical demonstration only. Real preparation must follow the specifications and instructions for the specific system.
PRP tubes
Tube types and systems for professional PRP preparation.
View PRP tubes →PRP centrifuge
Centrifuges with different rotors, capacities and technical characteristics.
View PRP centrifuges →So why are platelets interesting to dermatologists?
The interest does not lie in one growth factor or in achieving the highest possible platelet count. Platelets respond to vascular and tissue injury, contribute to haemostasis and release biologically active mediators. They therefore sit at an interface between coagulation, inflammation and tissue repair.
PRP aims to make use of these properties in an autologous blood product. Relevant clinical data now exist for selected dermatological questions, but major methodological heterogeneity in preparations and protocols remains a central problem.
When reading a paper, the important question is therefore not only whether PRP was used, but how the preparation was produced, composed, characterised and applied.
Frequently asked questions
What are platelets?
Platelets are small, anucleate cell fragments derived from megakaryocytes. They are central to haemostasis and contain secretory granules with biologically active molecules.
Why are platelets relevant to skin?
Platelet activation links haemostasis with signalling pathways involved in inflammation, angiogenesis and wound healing.
What is platelet-rich plasma?
PRP is an autologous blood preparation with platelets enriched relative to the starting blood. Composition and concentration vary by preparation method.
Is every PRP preparation the same?
No. Platelets, leukocytes, residual erythrocytes, plasma volume, activation and processing can differ substantially.
Which dermatological areas are being studied?
Frequently studied areas include androgenetic alopecia, acne scars, facial rejuvenation/skin ageing and several wound indications. Evidence strength differs by field.
Does a higher platelet concentration automatically mean a better effect?
No. A universal linear relationship between the highest possible concentration and a better clinical outcome has not been demonstrated.
- PubMed 39617187 – Molecular basis of platelet granule defects
- PubMed 40712724 – Platelet-rich plasma – a comprehensive review of isolation, activation, and application
- PubMed 39013743 – Systematic review and meta-analysis of PRP in androgenetic alopecia
- PubMed 40944844 – Systematic review and meta-analysis of PRP in alopecia
- PubMed 37677095 – Overview of systematic reviews on PRP for acne scars
- PubMed 38557322 – Overview of systematic reviews on PRP for facial rejuvenation
- PubMed 40118148 – Systematic review of PRP in facial rejuvenation
- PubMed 40600985 – Meta-analysis of PRP versus conventional care in diabetic foot ulcers
- PubMed 30730050 – Standardization of relative centrifugal forces in platelet concentrate research
- PubMed 36937123 – PRPCalc2: RCF/RPM and preparation standardization
Professional information notice: This article is intended for scientific and professional information. It is not a treatment recommendation or centrifugation protocol. Statements about clinical evidence refer to the cited publications. Practical use must follow the intended purpose, instructions for use, applicable regulatory requirements and the professional judgement of qualified users.