Pinning

Overview

“Pinning” refers to self-administered injections performed outside traditional medical settings, including direct injection near an area of aesthetic concern or subcutaneous/intramuscular injections for systemic absorption, often using compounds obtained through gray market international suppliers or social media marketplaces. (1)

Many of the agents used are marketed as naturally-derived products, peptides, or regenerative compounds. (1, 2) Products are commonly compounded, unlabeled, repackaged, or sold for “research purposes only.” (2)

Pinning is frequently marketed for skin rejuvenation, anti-aging, fat loss, tanning, muscle growth, or “facial optimization.”

Commonly Reported Agents

Peptides

Peptides are typically discussed as subcutaneous or intramuscular injections at distal sites for intended systemic absorption. (2) Commonly promoted peptides include copper peptides (GHK-Cu), Matrixyl, Argireline, and Snap-8, marketed for collagen stimulation, skin tightening, wrinkle reduction, active acne, acne scars, hair growth, and as “natural Botox.” (2)

Melanotan I and II are promoted for tanning, appetite suppression, and sexual enhancement. (3, 4) These unregulated synthetic α-melanocyte-stimulating hormone (α-MSH) analogues are particularly relevant for dermatologists due to their direct effects on melanocyte melanocortin receptors. (3, 4) Melanotan increases cAMP signaling, tyrosinase activity, and melanogenesis, and α-MSH–mediated proliferative and immunomodulatory effects may further stimulate melanocytic precursor cells and reduce immune surveillance of atypical melanocytes. (3, 4) These mechanisms may contribute to darkening of existing nevi or emergence of new atypical nevi in predisposed individuals, with associated melanoma-related concerns discussed further in the dermatologic complications section. (3, 4)

“Recovery peptides” such as Body Protection Compound-157 (BPC-157), Thymosin Beta-4 (TB-500), Thymosin Alpha-1, and Leucine Leucin-37 (LL-37) are promoted for wound healing, tissue repair, reduced inflammation, antimicrobial effects, active acne, acne scars, tendon recovery, and accelerated training recovery, frequently in multi-peptide “stacks.” (5)

Growth Hormone-Releasing Factor (CJC-1295), Ipamorelin, Growth Hormone-Releasing Peptide-6 (GHRP-6), Long R3 Insulin-like Growth Factor-1 (IGF-1 LR3), Anti-Obesity Drug 9604 (AOD-9604), Glucagon-like peptide-1 (GLP-1), and Ibutamoren (MK-677) are promoted for fat loss, muscle fullness, appetite manipulation, sleep, growth hormone signaling, and “anti-aging.” (2, 5)

Reported concerns include pigmentary changes, (3) water retention, appetite changes, (3, 6) endocrine disruption (insulin resistance, hyperglycemia, and hypothalamic-pituitary-adrenal axis dysregulation with growth hormone secretagogues, (7, 8) contamination, and injection-related complications (erythema, swelling, pain, pruritus, granulomas), (9, 10) while long-term safety data for many compounds remain limited.

Fat-dissolving agents

Products such as Aqualyx, Kybella (deoxycholic acid), Lipolab, Lemon Bottle, and similar injectable “fat dissolvers” are increasingly promoted online for direct local injection into subcutaneous facial or submental fat compartments for jawline contouring, buccal fat reduction, nasal tip refinement, cheek hollowing, and submental fat reduction. (11)

Online forums share detailed self-injection protocols, including injection mapping, needle depth, facial anatomy guidance, intraoral buccal fat injections, and adjunctive practices such as prophylactic amoxicillin. (12)

These agents are traditionally administered by trained medical professionals; however, growing at-home self-injection practices raise concerns for complications including infection, vascular injury, tissue necrosis, scarring, and contour irregularities. (13)

Hormonal and performance-enhancing agents

Forums promote manipulation of testosterone, estradiol, sex hormone-binding globulin (SHBG), prolactin, cortisol, and dehydroepiandrosterone (DHEA) levels to improve facial leanness, jawline definition, libido, mood, and perceived attractiveness, with injectable agents generally administered subcutaneously or intramuscularly at distal sites for systemic effects. (14)

Online recommendations include reducing body fat to 12% and extensive hormone laboratory panels. Frequently discussed agents include GLP-1–type peptides, testosterone-related compounds, DHEA, growth hormone, melanotan, aromatase inhibitors, ashwagandha, vitamin E, ginger extract, and zinc. (14)

Salmon sperm–derived products (PDRN)

PDRN has recently surged in popularity across social media, where it is commonly promoted for localized intradermal or subcutaneous injection into treatment areas for skin regeneration, anti-aging, wound healing, and collagen support. (15)

Potential dermatologic complications

Foreign-body granulomas and inflammatory nodules

Persistent papules, nodules, induration, and granulomatous reactions may occur after injection of poorly characterized or contaminated products, potentially driven by the injected material itself, excipient vehicles such as microspheres, bacterial biofilm formation, or product impurities. (10, 16-18) Gray-market injectable peptides have demonstrated purity as low as 5-75%, toxic elemental contaminants including inorganic arsenic and lead, and frequent mislabeling that may amplify local inflammation. (10, 16-18)

Hypersensitivity reactions

Delayed inflammatory reactions, swelling, erythema, urticaria-like eruptions, and tenderness may occur. (16, 19)

Infection

Nonsterile injection technique, contaminated vials, reuse of needles, and improper storage may increase risk of bacterial infection and abscess formation. (5, 20)

Acneiform eruptions

Hormonal agents and peptide regimens may contribute to acne flares or worsening inflammatory acne. (21)

Ischemia and necrosis/polyneuropathy

Self-injection of non-standardized compounds into high-risk facial regions may result in arterial occlusion, ischemia, cutaneous necrosis, and motor or sensory neuropathy if injected into or adjacent to major neurovascular structures. (13) Risk is heightened by inaccurate injection depth, poor anatomical training, and unregulated formulations. (13)

Pigmentary and melanocytic changes

Reported complications of unregulated melanotan use include eruptive nevi, rapid darkening or enlargement of existing moles, atypical melanocytic lesions, transverse melanonychia, palm freckling, dysplastic nevi, pigmented Spitz nevus formation, and melanoma development. (3) Multiple case reports describe sudden onset of numerous new nevi and concerning dermoscopic or histopathologic changes following melanotan I or II exposure, with several progressing to melanoma or severe dysplasia. (3)

Limitations and unknowns

For many compounds, human dermatologic safety data remain sparse. Product purity, concentration, sterility, and ingredient consistency are frequently unknown.

Important history questions

• Have you “pinned” or injected any peptides or “healing” compounds?

• Have you “pinned” or injected salmon sperm products or PDRN?

• Have you “pinned” or injected any fat-dissolving products?

• Were any products purchased online or internationally?

• Did you mix or reconstitute products yourself?

• Who performed the injections?

• Do you know the exact ingredients or source?

Patients may refer to products using social media or brand terminology rather than pharmacologic names.

Counseling considerations

Dermatologists can counsel patients regarding:

• Risks of gray market injectables and unknown sterility.

• Potential for granulomatous inflammation and persistent nodules.

• Risk of infection and scarring.

• Lack of long-term safety data.

• Need for medical evaluation if swelling, nodules, pain, drainage, or progressive inflammation occur.