Microneedling for Medical and Aesthetic Purposes: Current Indications and New Advances

In recent years, microneedling has become a valuable tool in dermatology, offering a non-surgical option for individuals seeking skin rejuvenation and improvement to address various aesthetic or medical concerns [1-4]. The procedure relies on controlled physical trauma, where needles penetrate into the skin generating micro-channels, creating minimal epidermal damage, and stimulating dermis regeneration. This process triggers the release of growth factors and the recruitment of platelets and neutrophils to induce the natural wound-healing cascade leading to non-fibrotic skin remodeling [5,6]. 

The applications of microneedling have expanded beyond aesthetic indications such as acne scars, surgical scars, stretch marks, and fine line and wrinkles into treating various dermatological conditions [2,7]. Clinical trials have demonstrated its effectiveness in treating pigmentation disorders [2]. Additionally, microneedling has gained attention as a potential treatment for hair pathology by stimulating stem cells in the dermal papilla, increasing blood flow to hair follicles, and recruiting growth factors and signaling pathways involved in hair growth [8]. 

With proven high efficacy outcomes, a favorable safety profile, and minimal post-treatment recovery time, microneedling has granted clinicians a result-oriented gold standard in aesthetics before opting for more invasive procedures. High patient satisfaction rates in clinical studies have raised awareness amongst new patients intending to pursue an aesthetic procedure. With the rise in demand for non-surgical or minimally invasive procedures, microneedling has become integral to treating facial and neck rhytides and acne scarring correction [9]. This literature review aims to explore the latest advancements and current applications of microneedling, specifically for practitioners seeking to integrate this procedure into their practice. The review will focus on identifying innovations and developments that have emerged since the previous review.

The studies included in this review were collected through comprehensive searches conducted on databases such as PubMed, MEDLINE, and google scholar, as well as electronic journals specializing in dermatology. The search terms utilized for this review encompassed “microneedling,” “collagen induction,” “reviews,” and (remove and)“trials” and “case reports.”

Microneedling has been studied to investigate its mechanism of action. This controlled injury initiates the natural wound-healing cascade in the deeper layer of the dermis, involving inflammation, proliferation, and remodeling [3,4,10]. It is understood that microneedling atrophic acne scars disrupts the collagen bundles in the top layer of the skin while simultaneously triggering the production of new collagen, elastin, and skin remodeling [2,7,11]. In wrinkled skin, microneedling promotes skin remodeling and the formation of a robust extracellular matrix [2,12]. Pinpoint bleeding during microneedling leads to forming a fibronectin matrix, which serves as a scaffold for the deposition of non-fibrotic tissue during the skin remodeling process. 

The micro-injury caused by microneedling triggers release of growth factors such as platelet-derived growth factor, fibroblast growth factor, and transforming growth factor. These growth factors stimulate the proliferation and migration of fibroblasts, leading to neovascularization and neocollagenesis [2,5,6]. Studies have shown that undergoing multiple microneedling sessions increases collagen deposition during the skin remodeling process, resulting in a normal and organized lattice structure [2,10,13,14]. 

Additionally, analysis has revealed the downregulation of pro-inflammatory cytokines [3]. This indicates that microneedling treatment suppresses the production of these inflammatory molecules, which are typically associated with inflammation and tissue damage. A key feature of non-fibrotic skin remodeling initiated by microneedling could be attributed to the downregulation of pro-inflammatory cytokines. This downregulation can help create a more favorable environment for collagen synthesis and remodeling, leading to improved skin texture and appearance. 

An alternative theory for the mechanism of action proposes that the wounds created by microneedling are exceptionally small and cannot be classified as true wounds, thereby not activating the usual repair mechanisms. Instead, this theory suggests that the presence of the needles near cell membranes induces a change in the membrane's electrical potential [15]. Thus, triggering  the release of growth factors into the extracellular matrix, promoting the migration of fibroblasts and the induction of collagen production. 

Multiple microneedling devices are on the market, with the first automated microneedling pen cleared by the US FDA in 2018 (SkinPen Precision medical device, Crown Aesthetics, Dallas, Texas). Automated pens have gained popularity as an alternative to standard roller drum devices. They utilize single-use, sterile disposable cartridges, eliminating the risk of contamination that arises from multiple uses of rolling devices. Additionally, electric pens create significantly more microchannels due to their efficient and precise operation. To ensure the best possible clinical results for patients, it is crucial to adjust the needle depths based on the precise location, skin thickness, and the condition being treated. Not all automated pens are equal in their performance. A previous study discovered that when a device was configured with a needle length of 3mm, its actual penetration into the skin reached only a depth of 1.5 to 2mm [2].

Microneedling effectively treats various skin concerns, including facial wrinkles, scars and stretch marks, pigmentation disorders, and androgenetic alopecia. Multiple studies have demonstrated the efficacy of microneedling for improving the appearance of wrinkles, with significant improvements observed in wrinkle assessments and global aesthetic improvement [3,4,10]. To achieve optimal results, patients are advised to undergo a series of 3 to 6 microneedling sessions, spaced biweekly or monthly [2-4,11]. For scars and stretch marks, microneedling has been shown to improve their appearance and texture significantly. Patients with facial and non-facial scars of different origins (acne, trauma, surgery) experienced substantial improvement, with over 80% of patients showing a 50-75% improvement and 65% demonstrating over 75% improvement [16]. Stretch marks also showed reduction after multiple microneedling sessions, with some patients experiencing a 51% to 100% reduction in appearance after three treatments [11,17]. In treating pigmentation disorders such as melasma and periorbital hyperpigmentation, microneedling has shown promise. Combining microneedling with topical agents has resulted in better treatment responses than skin-lightening agents alone. Significant improvement has been observed in patient assessments, and the treatment is generally well-tolerated with transient side effects [7,18]. Minimal damage to the epidermis limits the risks of post inflammatory hyperpigmentation compared to other aesthetic procedures. In addition, implementing adequate pre microneedling use of sunscreen at least a few weeks prior to treatment is highly recommended when managing pigment disorders. 

Vitiligo is a complex skin condition that causes the loss of pigmentation, resulting in the appearance of depigmented macules on the skin. Finding an effective vitiligo treatment has proven challenging, primarily due to the incomplete understanding of its exact cause. However, it is widely believed to be an autoimmune disorder. It's important to note that the effectiveness of treatment can vary from person to person, and the choice of treatment often depends on the extent of vitiligo, the person’s preference, and the potential side effects of the treatment. Combination therapies with topical agents and UV light therapy have shown significant repigmentation of vitiligo lesions, while adding microneedling to another combination therapy did not yield improved outcomes [18-20]. 

Microneedling has been found to promote hair growth by increasing certain proteins and improving blood flow to the hair follicles. When combined with topical solutions like minoxidil, growth factors, or platelet-rich plasma, microneedling has shown significant hair regrowth in individuals with alopecia [15]. 

Microneedling also enhances transdermal drug delivery by creating pores in the skin. This has been observed in studies where topical agents, such as lidocaine-prilocaine anesthetics, were more effectively absorbed after microneedling [11,18]. When comparing the effectiveness of a single bleomycin injection against microneedling and bleomycin combination for treating warts, it was observed that the combination approach resulted in a higher clearance rate of 83.3% in contrast to the injection. Suggesting that microneedling could have played a significant role in enhancing the absorption of bleomycin [21]. Although studies have shown the efficacy of microneedling in treating the above conditions, further research is necessary to optimize microneedling protocols. This includes investigating the optimal size of the microneedles and determining the ideal frequency and interval between treatments. Conducting more well-controlled randomized trials with larger sample sizes is crucial to establish stronger evidence and draw more reliable conclusions. These studies will contribute to refining microneedling techniques and providing clearer guidelines for its use in clinical practice. The latest comprehensive review on microneedling for treating the mentioned indications was published in 2017 [11], and Table 1 provides a summary of publications covering these indications from 2018 to 2023.

Table 1: A summary of publications from 2018 to 2023, encompassing study aims, outcomes, and reported adverse events for the indicated conditions. Abbreviation key- MN: Microneedling MPA: Male Pattern Alopecia, AGA: Androgenetic alopecia, AA: Alopecia Areata, PRP: Platelet-Rich Plasma, TA: tranexamic acid, MASI: Melasma area and severity index scores, PDT: Photodynamic therapy, NB-UVB: Narrowband UVB, CP: Chemical peel, HA: hyaluronic acid, NAFL: Nonablative fractional laser, TCA: Trichloroacetic acid, and GBGs: Goodman and Baron grading.

There is a growing trend among clinicians to expand the utilization of microneedling beyond its current indications. This shift is accompanied by a reevaluation of previously held misconceptions regarding the appropriate timing and application of microneedling. Notably, microneedling extends beyond dermatology and finds relevance in other fields, such as dentistry. This broader perspective highlights the versatility of microneedling and its potential benefits across various medical disciplines. As a result, the understanding and application of microneedling are undergoing significant changes, driven by the progressive insights of healthcare professionals. A significant advancement in microneedling is the discovery of its effectiveness as a therapeutic approach for treating inflammatory acneic lesions. 

Acne vulgaris, a common skin disorder, affects the pilosebaceous unit and is experienced by nearly everyone at some point in their lives. Traditional treatment modalities for acne, such as antibiotics and sebum reduction methods, may have drawbacks and long-term adverse effects. There is a demand for new and efficient treatment alternatives that prioritize safety and effectiveness. While microneedling is contraindicated for active acne lesions due to concerns of exacerbating the condition and spreading bacteria, no published scientific literature supports this claim. A recent publication by Alqam, et al. challenged the prevailing perception by microneedling subjects with active acneic lesions [22]. The study demonstrated that microneedling, when performed on acne lesions does not cause post-treatment complications or worsen acne. Instead, it can significantly reduce inflammatory and non-inflammatory acne lesion counts. The authors proposed that microneedling could potentially target a different underlying cause of acne by addressing the issue of hyperkeratinization and blockage of sebaceous glands. Their study presented objective evidence that challenges the current contraindication of microneedling for acne treatment, indicating that microneedling could be a valuable and potentially safer alternative to conventional treatments. Their authors called for a reassessment of the current standard of care for acne vulgaris and highlighted the potential benefits of incorporating microneedling into treatment approaches. 

The development of spider veins (telangiectasia) is attributed to intra-arteriolar vasodilation, although the specific cause can vary. They are a common benign vascular anomaly characterized by the presence of one or multiple lesions. However, when facial spider veins appear, they can have a negative impact on the patient’s quality of life. A recent case study explores the use of microneedling as an effective approach for treating facial spider veins, achieving a clearance rate of over 50% after the initial treatment [23]. Microneedling outcomes appear to have the same level of efficacy as sclerotherapy and laser treatment, making it a compelling alternative. Notably, microneedling has demonstrated a remarkable safety profile, as no complications have been observed during the treatment, unlike other methods that carry potential risks and complications.  The neovascularization that occurs during skin remodeling could also contribute to improving skin appearance. 

Surgical scars can negatively impact a person's appearance, psychological well-being, and social interactions. Currently, it is advised to wait for a minimum of one year before considering any treatment to reduce the visibility of scars. In a recent study by Claytor, et al. researchers investigated whether initiating microneedling treatment at an earlier stage, before the scar matures, could improve clinical aesthetic outcomes for subjects [24]. The study included participants who had undergone surgery, and the treatments were initiated at different time points ranging from 6 to 16 weeks postoperatively. The results showed statistically significant improvements in scar appearance throughout the study. When comparing the data based on the timing of treatment initiation, it was observed that patients who received treatment at 6 to 7 weeks after the surgery showed significantly superior results compared to those who received treatment at 13 to 16 weeks postoperatively. The traditional approach to scar management has focused on conservative care during the inflammation and proliferation phases, with treatment options during the maturation phase. However, this investigator proposed a hypothesis that conservative care during the early maturation phase may miss an important time period for scar modulation. This suggests that delaying intervention may result in missing an optimal window of opportunity for effective scar management. 

Gingival hyperpigmentation, characterized by a deep discoloration of the gums, can be influenced by various factors. These factors can be either exogenous or endogenous, including drug usage, genetic predisposition, hormonal imbalances, and smoking. Different techniques have been employed to treat gingival hyperpigmentation, such as scalpel scraping, electrosurgery, and lasers. These methods typically involve the removal of the pigmented epithelium to facilitate the regeneration of new gingival tissue without melanin. However, these techniques may have drawbacks, including higher costs, increased complications, prolonged healing time, and the requirement for a periodontal dressing. Laser and electrosurgery are effective but tend to be more expensive and complex. New research aimed to find an alternative treatment approach that addresses these limitations by offering lower costs, fewer complications, faster healing, and eliminating the need for periodontal dressing [25]. Their study enrolled 16 participants seeking treatment for their gingival hyperpigmentation and aimed to evaluate the effectiveness of combining microneedling and topical Ascorbic Acid (AA). Microneedling was utilized to create microchannels in the gingival tissue, enabling the topical application of AA to effectively inhibit melanin production. The results demonstrated that seven out of the 16 patients achieved complete depigmentation, while the remaining participants experienced reduced pigmentation. The healing process was relatively fast, taking only 7-10 days, quicker than other depigmentation methods. The investigator extended the application of microneedling from dermatology and found that combining microneedling with topical AA is a novel and non-invasive dental procedure that effectively treats gingival hyperpigmentation.

Our review highlights the rapid growth and expanding scope of microneedling beyond traditional dermatological applications, exploring its potential use in other therapeutic areas. In recent years, microneedling has emerged as a valuable tool in dermatology, providing a non-surgical option for addressing various aesthetic and medical concerns. Its applications have expanded beyond aesthetic indications to encompass the treatment of dermatological conditions such as pigmentation disorders and hair pathology, demonstrating high efficacy outcomes, a favorable safety profile, and minimal post-treatment recovery time. 

The mechanisms of microneedling involve collagen induction, non-fibrotic skin remodeling, and the release of growth factors that promote fibroblast proliferation, neovascularization, and cellular turnover. It has shown effectiveness in improving various skin concerns, including wrinkles, scars, stretch marks, and pigmentation disorders. Microneedling combined with topical agents has yielded better treatment responses in pigmentation disorders than agents alone. Additionally, it has shown promise in hair growth stimulation and enhancing transdermal drug delivery. 

The utilization of microneedling has expanded beyond dermatology, as demonstrated by its exploration in other medical disciplines. Recent studies challenge the conventional contraindication of microneedling for active acne lesions, suggesting that it may be a safe and effective alternative treatment option. Additionally, microneedling has shown promise in treating facial spider veins, offering comparable efficacy to sclerotherapy and laser treatments while maintaining a remarkable safety profile. Early intervention with microneedling in the early maturation phase of surgical scars presents a novel approach to scar management, potentially improving aesthetic outcomes. Furthermore, microneedling combined with topical ascorbic acid has emerged as an innovative and non-invasive dental technique for effectively treating gingival hyperpigmentation. 

Although our review underscores the promising potential of microneedling, it also serves as a purposeful cross examination of where we are with microneedling and to curiously question its innovative, prospective future.  Microneedling has evolved into a versatile procedure with expanding applications in dermatology and other medical fields. Its ability to address various aesthetic and medical concerns, coupled with its high efficacy, safety, and minimal downtime, positions it as a valuable treatment option. However, further research is necessary to optimize protocols, establish guidelines, and explore new avenues for its use. The latest advancements discussed in this review pave the way for practitioners seeking to integrate microneedling into their practice and highlight the need for ongoing exploration and innovation in this field.

We would like to thank Thomas Hitchcock, PhD, for reviewing, editing, and comments, which greatly enhanced the quality of the manuscript.

Does not apply/Not needed.

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