“ A slippery slope ”: a scoping review of the self-injection of unlicensed oils and ﬁllers as body enhancement

Self-injection of a range of oils and ﬁllers for body enhancement dates back to 1899, but due to signiﬁcant associated harms and fatalities this practice has been largely linked to distinct cultural groups in recent times. This scoping review gathers what is currently known on the self injection of body ﬁllers for aesthetic purposes, using Arksey and O’Malley’s (2005) ﬁve stage iterative process scoping review methodology. Thematic manual coding then organised the data into themes through identiﬁed patterns: indicative proﬁling of individuals who self inject body ﬁllers; motivation for use across types of oil injection; sourcing routes and documented harms. It was found that the majority of people who inject body ﬁllers are male and do so to grossly increase muscle size. Injection of oils and other materials in the male genitalia was also described, in addition to female self-injection in the breast, hand and leg areas for augmentation. A range of health consequences were reviewed. Recommendations are made for further research into this unique phenomenon, which although is relatively rare warrant future research attention considering the documented increase in DIY facial ﬁllers and contemporary body image culture.


Background
The injection of unlicensed materials to change the appearance of the body was first documented in 1899 by an Austrian surgeon, Robert Gersuny, who injected vaseline into the scrotum of a patient who had undergone bilateral orchiectomy for genital tuberculosis (Gersuny, 1980). The practice of injecting body filler further popularised over the first twenty years of the twentieth century, expanding from quasi-medical use to purely cosmetic enhancement (in areas such as the breast or the penis) with paraffin building a reputation as a superior material to vaseline (Glicenstein, 2007). Despite emergent warnings about associated health harms, paraffin oil injections continued into the 1950s and 1960s particularly in the Far East (Peters & Fornasier, 2009) and in Italy (Di Benedetto, Pierangeli, Scalise, & Bertani, 2002). However, as reports of sporadic deaths began to emerge, the popularity of oil injection in the mainstream began to decline (Figueiredo, da Silva, De Souza, & De Rose, 2011;Peters & Fornasier, 2009).
Thereafter, self-injection for body enhancement has been largely linked to distinct cultural groups. A range of oils and fillers have been documented as being injected to enhance body parts, including unlicensed materials such as Johnsons brand Baby oil, mechanical transmission oil and vaseline (Figueiredo & Da Silva, 2014). One example is that of "Synthol" or "Syntherol" (typically 85% fat, 7.5% lidocaine and 7.5% alcohol), synonymous with bodybuilding culture since Christopher Clark, a German bodybuilder began to market "Esiclene" (Formebolone) to augment the appearance of muscle, specifically to boost the definition of lagging muscle groups for competitive bodybuilding (Hall, Grogan, & Gough, 2016;Juel, Vestergaard Grejsen, & Pareek, 2017;Schafer, Hvolris, Karlsmark, & Plambech, 2012). Despite being widely described in the literature (Brennan, Kanayama, & Pope, 2013;Brennan, Van Hout, & Wells, 2013;Figueiredo & Da Silva, 2014;Schafer, Guldager, & Jorgensen, 2011) the injection of oils or fillers has a complex relationship with both professional and recreational bodybuilding communities, stigmatised where individuals inject large amounts (Hall et al., 2016) and sometimes even where small amounts are injected. "Synthol" has been documented as being rejected by the majority of bodybuilders, at least publicly, as 'cheating' in striving to quickly attain a physique which typically demands a great deal of training and discipline (Salinas, Floodgate, & Ralphs, 2019). The grossly exaggerated outcomes that are sometimes achieved through oil injection are also often a subject of disdain (Brennan, 2018). Existing survey data indicates that 5% of bodybuilders report ever injecting "Synthol" or other oils (Azevedo & Ferreira, 2009;Ghandourah, Hofer, Kießling, El-Zayat, & Schofer, 2012;Schafer et al., 2012).
Harms documented as being associated with the injection of foreign body materials for aesthetic enhancement include paraffinoma, migration of the material, nodule formation, inflammation, foreign body granuloma, tissue necrosis (Ahmed et al., 2017), severe hypercalcaemia (e.g. Gyldenløve, Rørvig, Skov, & Hansen, 2014), chronic wounds and ulceration (Ikander, Nielsen, & Sørensen, 2015a) and in the case of penile augmentation, deformation, impaired sexual functioning and voiding difficulties (Pehlivanov et al., 2008). Harms can become evident several years after injection (Juel et al., 2017), with no records of these types of unlicensed materials being absorbed into the body or dissolving naturally in any other manner (Cohen, Keoleian, & Krull, 2002;Lee, Choi, Lee, & Lee, 1994;Steffens et al., 2000). The severity of intramuscular injections with paraffin oil has been underscored by Koldkjaer Sølling et al. (2018) highlighting that no curative treatment currently exists.
Currently, body enhancement through DIY cosmetic procedures appear to be increasing (Thomas, Lee, Patton, & Choudhary, 2020;Torre, Murphy, & Ricketts, 2019), supported by online social media discourse (Hopkins, Moreno, & Secrest, 2020;Underwood, 2017), popular use of facial 'filters' and 'selfie' editing apps (Alkarzae, Aldosari, Alalula, Almuhaya, & Alawadh, 2020;Barker, 2020;Butkowski, Dixon, & Weeks, 2019) and celebrity "fandom" (Underwood, 2017). In 2018, a study which conducted content analysis of online discussion forum posts documented for the first time the self-injection of Botox and dermal filler through DIY "kits" purchased online by members of the general population (Brennan, Wells, & Van Hout, 2018). Since then, clinical case reports have emerged where individuals have self-injected similarly, with harms documented (Thomas et al., 2020;Torre et al., 2019). This new evidence may indicate an emergent trend of self-injection of facial materials for cosmetic enhancement. It is of interest where selfinjection of body fillers is situated in this suggested trend of DIY body enhancement, as it has been documented as being subject to scorn within groups of people who use other human enhancement drugs (HED) for aesthetics, such as anabolic androgenic steroids (AAS) (Hall et al., 2016;Salinas et al., 2019) and the literature suggests that acceptable use of body filler may have much narrower margins. While acknowledging that people who inject body fillers are a heterogeneous group, who inject different materials for different reasons, this paper aims to collate and describe what is known on motivators for self-injection of oils, sourcing routes and harms. Why and how do people inject oils for body enhancement despite the associated stigma? What are the implications of injection of body fillers becoming mainstreamed as a contemporary trend, as indicated in the literature on DIY facial fillers? In discussing the findings of this review, the authors aim to further discussion G Model  on a dichotomous practice, on "trend" with contemporary body enhancement culture, yet historically stigmatised within it. This is the first known review of the literature on body enhancement through injection of fillers and oils. Although relatively rare, this review highlights types of injecting which warrant future research attention. This review aims to inform enhanced clinical reporting and seeks to raise awareness of potential harms so that a robust evidence base for effective interventions can be developed.

Methods
Scoping reviews are appropriate where broader research questions exist (Arksey & O'Malley, 2005;Khalil et al., 2016;Levac, Colquhoun, & O'Brien, 2010;Peters et al., 2015). They are used to identify gaps in knowledge, examine the extent (i.e. size), range (i.e. variety), and nature (i.e. characteristics) of the evidence on a certain topic or question (in this case, self-injection of body filler for cosmetic purposes), summarise findings from a wide range of sources and make research and policy recommendations (Arksey & O'Malley, 2005;Brandt, King, & Evans-Brown, 2014;Daudt, van Mossel, & Scott, 2013;Levac et al., 2010;Tricco et al., 2016). The research team for this review adhered to Arksey and O'Malley's (2005) five stage iterative process scoping review methodology. These stages included the following: (1) identifying the essential research question, (2) identifying relevant studies, (3) study selection, (4) charting the data, and (5) collecting, summarising, and reporting the results. The process was underpinned by the research question ("What is known about self-injection of body filler for aesthetic purposes?) and reviewed all available published empirical and grey literature in the English and Danish language on this topic (grey literature appears in searches conducted on many of these databases). The reference list of included studies was also scrutinised for relevant studies. There was no restriction on date of publication or study type. The search was implemented in June 2020. The following databases were accessed: Web of Science; Cochrane Library; MEDLINE; PsycINFO; Social Science Citation Index; PubMed; Science Direct; and Researchgate. Key search terms identified by a transnational research team, who have research expertise in human enhancement drugs, informed the search strategy (see Table 1). Searches were run in English and Danish. The research team proactively sought out a collaboration with an interested Danish academic as we were aware of a number of Danish language papers and were not aware of any other non-English language ones. In addition to this rationale, the only specialist treatment providers we are aware of are in Denmark.
These search terms were searched separately and not combined, in line with the purpose of a scoping review to a broad range of literature and grey literature i.e. what is currently known on the topic. Eligibility criteria focused on the self-injection of body fillers and oils for aesthetic purposes. Inclusion and exclusion criteria were discussed and agreed with all members of the research team (Table 2). The initial search, conducted by author one, identified 423,500 records; and following initial screening, 412,235 were removed for lack of relevance, with the remaining 11,265 screened for inclusion in the study. Finally, duplicates (n = 10, 150) and further records were removed which were not relevant to self-injection (n = 1071), leaving 44 records in total (see Fig. 1). The 44 records were charted and thematically analysed by author one, as per Arksey and O'Malley (2005).
Firstly, a table was created (see Table 3) to chart relevant data (year of publication, author, location, method and aim, key findings) and to analyse the extracted data thematically to identify commonalities, emergent issues, and gaps in the literature. Second, to help evaluate the nature and types of studies within each area the studies were classified into area of oil injection site into five areasi.e. muscle enlargement; penis enlargement; breast enlargement; hand rejuvenation; and others (Table 4). Third, a qualitative content analyses was performed. More specifically the textual dataset was re-read numerous times by author one in order to become familiar with the data and identify and code emerging themes. Thematic manual coding then organised the data and subsequently structured into themes through patterns identified in associated categories (Crossley, 2007). The articles written in Danish language were translated and coded following the same procedure (by author two). Themes were reviewed and cross checked by authors two, three and four. Four themes were identified from the review: (1) indicative profiling of individuals who self-inject body fillers; (2) motivation that varied for use (that varied) across types of oil injection; (3) sourcing routes and (4) documented harms (including treatment applied).    To review the history of site enhancement oil injection in bodybuilding, and to document five clinical cases of granuloma attributed to site enhancement oil injection.

ARTICLE IN PRESS
Case report (n = 5) and desk review.
Five cases of pathological massive muscle granulomas were found in male amateur bodybuilders. A literature review highlighted many consequences of "Synthol" injection including post injection pain and tenderness, irregularity and contour deformities, intravenous injections leading to cardio-respiratory problems and long-term chronic granulomatous disease. Clinical case series report.
Self-injection of foreign materials into the penis Ahmed, U., Freeman, A., Kirkham, A., et al.
To document presentation of a clinical case of medical complications attributed to oil injections in the penis.
Case report. One case (male, 28) of penile oedema resulting in a phimosis due to self-injection of baby oil. One case (male, 61) of large, firm nodular masses in the penis and scrotum due to self-injection of baby oil. One case (male, 35) of indurated nodular masses along the shaft of the penis due to injections of silicone. One case (male, 41) of marked lymphoedema with a number of indurated nodules of varying size due to self-injection of silicone. One case (male, 47) a diffusely oedematous penile shaft with a number of indurated masses due to self-injection of mechanical oil. 11 2017 Lebanon Clinical case report Hypercalcemia and nephrocalcinosis induced bypump and poseïntramuscular injection Chiri, R., Gabriel, K., Chelala, D. et al.
To document presentation of a clinical case of medical complications attributed to intramuscular injections of "Synthol" and paraffin oil.
Case report.
A 30 year old male presented with severe hypercalcemia complicated by recurrent episodes of pancreatitis and nephrolithiasis following intramuscular injection of synthol and paraffin, and caused by formation of a granulomatous reaction to the foreign body in the muscle.  To explore how lay expertise is worked up by Internet forum discussants in order to be able to provide each other with support and advice on their injecting use of "Synthol".

ARTICLE IN PRESS
Content analysis of online forum discussion posts.
Forum discussants offered each other support and advice on how to inject "Synthol" safely and in order to achieve the best results. Individuals sought a natural result, however authors noted that these same results may appear "freakish" to others.

Profile of studies reviewed
Forty four records were included in this this scoping review and are comprised of thirty four clinical case/case series reports, one qualitative online study, one conference presentation, four narrative literature reviews, one retrospective review of clinical case presentations, a report, a clinical study and a letter to the editor (see Table 3). The findings from these will be presented here under headings which directly relate to the research question: What do we know about self-injection of body filler for aesthetic purposes?" These are: indicative profile of people who inject body fillers; motivation for use across types of oil injection; sourcing routes and documented harms.

Theme 1: Indicative profiling of individuals who self-inject body fillers
Details which could be used to inform an indicative profile of individuals who inject were sporadically described in the literature and differed across the site of injection (see Table 3).

Breast enhancement in females
Four clinical case reports described self-injection of oils into the breast area for enlargement purposes (Agac et al., 2017;El Muayed, Costas, & Pick, 2010;Peters & Fornasier, 2009;Sharobaro et al., 2019(which also described muscle enhancement in males above). The age range of these individuals across four studies was between 29 and 58 years old. One case was a transgender female (El Muayed et al., 2010).

Hand rejuvenation in females
Two clinical case reports described self-injection of oils in to the hand for rejuvenation purposes (Ozden, Arinci, Aydin, & Buyukbabani, 2010;Yeo, Park, & Chang, 2013). No age range was given for one study, which reviewed 17 cases (Yeo et al., 2013) and the other study stated that the individual was 58 years old (Ozden et al., 2010).

Other
One study (Lym et al., 2015) which reported on two clinical case presentations, described one case of oil injection into the calves, and a second case of silicone injection into the thighs for augmentation purposes. The individuals were 47 and 59 years old respectively. Schafer et al. (2012) included as part of their review paper a case of turpentine injection in a 22 year old female, described as a psychiatric patient, for unspecified purposes. Di Benedetto et al. (2002) described the practice of paraffin oil injection more generally, without providing specifics of individuals who self-inject. One case of paraffin injection into the knee described a 90 year old man who had injected decades previously to avoid military service (Catalano, Dal Pozzo, & Grifi, 2003).

Breast enhancement in females
Within four clinical case reports (Agac et al., 2017;El Muayed et al., 2010;Peters & Fornasier, 2009;Sharobaro et al., 2019), six individual cases of self-injection of oils into the breast area for enlargement purposes were described. Three cases of self-injection of vaseline were identified (Sharobaro et al., 2019), two case where baby oil was used (Agac et al., 2017;El Muayed et al., 2010) and one case where PAH, an extensively cross-linked polymeric soft tissue filler, was named as the injected substance. One case was a transgender female (El Muayed et al., 2010) whose motivation for breast enlargement was part of the transitioning process.

Hand rejuvenation in females
Two clinical case reports described self-injection of oils into the hand for rejuvenation purposes i.e. to combat the signs of aging (Ozden et al., 2010;Yeo et al., 2013). Within these, eighteen individual cases were identified. A range of oils were used to include: paraffin; silicone; baby oil and an unidentified material. One case reported that she had always been unhappy with the 'wasted' appearance of her hands (Ozden et al., 2010).

Other
One study (Lym et al., 2015), which reported on two clinical case presentations, described one case of oil injection into the calves which the case reported as being "for strengthening purposes". A second case of silicone injection into the thighs was attributed to an attempt at cosmetic augmentation. Schafer et al. (2012) included as part of their review paper a case of turpentine injection in a 22 year old female for unspecified purposes, and reported that this female was a psychiatric patient. One unusual case of paraffin injection into the knee described a 90 year old man who had self-injected decades previously to purposefully injury himself in order to avoid military service (Catalano et al., 2003).

Theme 3: Sourcing routes
Information on sourcing routes of oils and other materials for self-injection was scant in the literature reviewed. One clinical study which analysed performance and image enhancement drugs purchased online in order to verify their contents found that of sixteen products analysed where no active substance was detected, oils for injection labelled and marketed as "synthol" were discovered (Odoardi et al., 2020). Further cases of sourcing oils online were described in Ikander et al. (2015a);Munch and Hvolris (2001) and Abdull-Gaffar (2014). In Agac et al. (2017) a female reported finding the baby oil she had injected in her breasts "at home". Two individuals (Chon et al., 2017;Pasgaard et al., 2016) had transitioned from having paraffin oil injections performed by others (non-medical personnel) to self-injection. Other sourcing routes were described in Abdull-Gaffar (2014) as being through gym trainers; friends and illegal prescriptions, with some oils and materials (i.e. vaseline and plant oils) being freely available in the local market. One case sourced oil for penile injection from a grease gun, which he also used to inject it (Kalsi et al., 2002).

Muscle enhancement in males
A number of harms were documented in males who selfinjected oils for muscle enhancement. These included paraffinomas and paraesthesia (Juel et al., 2017) bilateral upper-arm erythema, pain and swelling, irritation and flushing, ulcerations and chronic wounds (Ikander et al., 2015a(Ikander et al., , 2015bIversen et al., 2009;Banke et al., 2012), large ulcers (Henriksen et al., 2010), plaque-like, multinodular heterogeneous tissue, fibrosis, chronic lymphocytic infiltrate and multinucleated foreign-body giant cell reaction (Prosperi-Porta et al., 2020). Migration of filler, oleogranulomas (cyst of different sizes) (Darsow et al., 2000;Dejanović & Loft, 2017), widespread inflammation and tissue contour definition was also reported (AlShaqsi et al., 2018;Sharobaro et al., 2019). Pain in areas of the body other than the site of injection were also documented. In one case, a male suffered extreme wrist pain and limited wrist mobility after self-injecting in the bicep region (Leary et al., 2017) and in another, a male presented with scrotal pain after injections in the chest, arms and back (Gyldenløve et al., 2014). Accidental intravascular injections were also reported causing acute onset respiratory distress (Hjort et al., 2015;Pasgaard et al., 2016). Chest pain and forms of pneumonia were documented in two studies (Elfituri et al., 2017;Öcal et al., 2019) and acute lung injury (Prosperi-Porta et al., 2020). Severe hypercalcemia was reported in four studies (Gyldenløve et al., 2014;Koldkjaer Sølling et al., 2018;Nerild et al., 2018;Schafer et al., 2011). Many health harms appeared years after self-injection, most notably in the case of a classic sclerosing lipogranuloma-type reaction which occurred twenty years after a self-injection of "Synthol" (Petersen et al., 2015).

Genital enhancement in males
Penile pain, voiding dysfunction and sexual dysfunction were the most common health harms documented in the reviewed literature on self-injection of fillers in the penis (Chon et al., 2017;Cormio et al., 2014;De Siati et al., 2013;Eandi et al., 2007;Kalsi et al., 2002;Rosenburg et al., 2007). Oedema, nodules and granulomas were also reported (Ahmed et al., 2017;Hohaus et al., 2003;Kalsi et al., 2002) as well as irregular penile mass and deformity (Cormio et al., 2014;Eandi et al., 2007). In one case, symptoms did not become problematic until five years after self-injection (De Siati et al., 2013) and in another, a seventy one year old man presented with severe deformity forty years after self-injection (Eandi et al., 2007). One case had respiratory failure and was found to have G Model lipogranulomatous lesions in the lung and scrotum (Bhagat et al., 1995).

Breast enhancement in females
One death due to granulomatous mastitis (paraffinoma)-related hypercalcemia and renal failure was reported in 2010 in a patient (El Muayed et al., 2010). This is consistent with historic accounts of deaths in the 1950s and 60 s associated with breast augmentation through self-injection of oils in a report included in this review (Peters & Fornasier, 2009). Other documented health harms include clerosing adenosis and foreign body granulation tissue, pain, and impaired movement (Agac et al., 2017).

Hand rejuvenation in females
In females who injected oils into their hands, foreign body granulomas, palpable mass and contour deformity are documented (Yeo et al., 2013). Additionally, an acute attack of anaphylactic symptoms with massive swelling at the injection sites, which yielded to hard, inflammatory lumps was documented in one female (Ozden et al., 2010).

Other
Pain and hyper pigmented plaques were found in a female who injected an unidentified oil into her calf muscles and painful nodules discovered in a female who self-injected silicone into her thighs (Lym et al., 2015). In the case of an elderly man who had injected paraffin into his knee decades before, he was unable to walk due to knee pain (Catalano et al., 2003).

Discussion
The aim of the scoping review was to compile what is known on the self-injection of oils and other materials for enhancement of the body, in order to yield a contemporary understanding of indicative groups who self-inject; motivators for self-injection of oils, sourcing routes and harms. Although the sample population reviewed are heterogenous in nature, a common driver for engagement in body enhancement through oil injection is to achieve a subjective body ideal.
In conducting this review, we aimed to further discussion on the practice of self-injection of oil for body enhancement, at a time when DIY cosmetic enhancement appears to be increasingly documented Thomas et al., 2020;Torre et al., 2019). Self-injection of body fillers is of particular interest for several reasons. Firstly, although, it is situated in bodywork culture it has attracted stigmatisation within distinct groups of people who practice bodywork (Hall et al., 2016;Salinas et al., 2019). This may be in part due to its sometimes perceived outlandish outcomes in terms of physical appearance and health, and due to its association with subcultural or marginalised groups e.g. transgender communities (Figueiredo & Da Silva, 2014;Hage et al., 2001;Restrepo et al., 2009;Wilson et al., 2014). Secondly, knowledge and understanding of oil injection as a cosmetic phenomenon remains scant. Finally, there is a need for increased awareness of the implications of injection of body fillers with regard to, potential harms as well as treatment options, their shortcomings and opportunities in relation to health side-effects.
Perhaps unsurprisingly, the reviewed literature found that selfinjection of oils is seen most commonly in males seeking to enhance muscle size. Noteworthy is that in the majority of cases, large volumes of oil are injected to create grossly enlarged muscles. This practice has a longstanding association with fast tracking or 'cheating' to achieve a physique that bodybuilders perceive warrants investing a great deal of time, energy and work (Hall et al., 2016;Salinas et al., 2019). Due to this stigma, many males initially deny that they have self-injected oils when they present for medical attention (Abdull-Gaffar, 2014). This reluctance to admit engagement in self-injection is also seen in males who present with complications due to penile augmentation with oils or fillers (Cohen et al., 2002) and can also delay the individual in making contact with medical services until deformity or dysfunction has reached an untenable level (Ahmed et al., 2017). Though external stigma is evidently absorbed and is consequential for individuals who self-inject body fillers, intrinsic motivation to continue this practice remains. Indeed, many individuals refuse to have the material fully excised when requiring surgery to excise the foreign body material (Ozden et al., 2010). Moreover, studies suggest that many individuals who self inject struggled to engage with healthcare service e.g. nonattendance at blood tests or other checks (Ikander et al., 2015a(Ikander et al., , 2015b online response to Gyldenløve & Hansen, 2015;Munch & Hvolris, 2001).
While the majority of individuals referred to in the reviewed studies appeared to go to what convention considers 'extreme lengths' to achieve their body ideals, internalized body ideals and self-comparison to those ideals contributes to a variety of harmful behaviours. According to Festinger (1954) this can extend to selfinjury. DIY cosmetic surgery has been previously conceptualised as self-harm in the literature (Phillips & Menard, 2006), particularly where the outcomes impede healthy life functioning, for example where males were unable to fully urinate or engage in sex due to penile self-injection (Chon et al., 2017;Cormio et al., 2014;De Siati et al., 2013;Eandi et al., 2007;Kalsi et al., 2002;Rosenburg et al., 2007). There were indications of psychiatric disorder in the studies reviewed (Nerild et al., 2018;Parkhurst et al., 2020;Schafer et al., 2012). Severe body image dissatisfaction is a feature of many formally recognized psychiatric disorders. These are likely to be observed among individuals who engage in body contouring procedures (Sarwer & Polonsky, 2016). Gender dysphoria may lead to injection of body fillers in the transgender community (Hage et al., 2001;Restrepo et al., 2009;Wilson et al., 2014). In this review, we refer to one case of self-injection in a transgender female (El Muayed et al., 2010) which ultimately led to the death of the individual concerned. Lack of access to specialised care (and long waiting lists) were attributed to the practice of "selftransitioning" in the literature (Metastasio, Negri, Martinotti, & Corazza, 2018), where the authors documented transgender individuals sourcing unregulated hormones online. These individuals were also receiving psychiatric care (Metastasio et al., 2018). Transgender individuals who cannot access proper medical care in order to transition may be at risk of self-injection of body fillers and the significantly deleterious harms to health involved in such practices.
Self-injection of body fillers may also be a new type of 'display work' (Mears & Connell, 2016). 'Display work' is a form of bodily capital (Wacquant, 2004), where individuals perform paid or unpaid work on their bodies as investment, such as engagement in fitness regimes, or cosmetic enhancement for sex work. It may also be for the purpose of visual consumption, to please others or to please the self. 'Display workers' expend significant energy on their appearance (Gimlin, 2002) for the reward of exhibitionism and external approval. It also involves regulation of emotionality enmeshed in body image (Entwistle & Wissinger, 2006). 'Display work' may be a performance of gender ideals, eroticism or beauty. The contemporary social media landscape includes unrealistic body types (Hopkins et al., 2020) and includes 'photoshopping' and digital alterations of images to promote 'simulacra' of ideal bodies, which are fluid and dictated by celebrity and popular cultural trends (Alkarzae et al., 2020;Barker, 2020;Butkowski et al., 2019). As such, we are positioned as social media consumers to become 'aesthetic labourers' in projecting the image, personality and energy which is likely to be embraced by an external audience. Vulnerable individuals engaging in 'display work' may be at risk of taking dangerous action to build cultural capital within this sphere, including self-injection of oil or fillers to contour the body.
Of concern is that the documented harms associated with selfinjection of unlicensed oils and fillers are plentiful and the medical responses available to healthcare practitioners are few. In one case we reviewed, where poison control were called for advice on how to treat an individual with chest pain and a form of pneumonia, no recommendations could be made to medical professionals due to lack of data on this particular practice (Elfituri et al., 2017). Presently, the medical response is restricted to the administration of corticosteroids (Juel et al., 2017), antibiotics, compression bandages (Schafer et al., 2011) and the option of surgery to excise the foreign body material, which as already stated, some individuals refuse (Ozden et al., 2010) or are hesitant about (Ikander et al., 2015a(Ikander et al., , 2015b. Long periods of time may pass before an individual presents for medical care. Stigmatisation around use might prevent some individuals from seeking treatment or delay this process. The time delay, however, makes treatment more difficult, and reduces the likelihood of a successful outcome.
Increased public awareness around the potentially devastating effects of self-injection of body fillers is needed, particular in the current climate of body enhancement and indications of increasing DIY procedures. Positive body image campaigns centred on the promotion of health and diversity are warranted. As scant details around motivations for self-injection and sourcing routes were found in this scoping review of extant literature, clinicians should nonetheless be made aware of the importance of building an evidence base on this relatively rare, but potentially increasing and dangerous practice. There is a gap in the literature pertaining to qualitative investigation with individuals who inject oils and body fillers to document their views, experiences and cognitive processes, including those who inject moderately. Future research should focus on the impact of social media discourse on DIY cosmetic procedures and the role of mental and emotional health in decision making processes in the self-injection of unlicensed materials for body enhancement, as well as the development of targeted interventions to reduce harm in individuals who practice DIY body filler injection.

Conclusion
People who inject body fillers are a heterogeneous group, who are motivated to inject for different reasons and who inject a range of oils and materials. This research aimed to collate what is known on profiles of individuals who self-inject; motivators for self-injection of oils; sourcing routes and harms. It was found that the majority of people who inject body fillers are male and do so to grossly increase muscle size. Injection of oils and other materials in the male genitalia was also described, in addition to female self-injection in the breast, hand and leg areas for augmentation. A range of health consequences were reviewed, including one deathof a transgender woman. Recommendations are made for further research into this unique phenomenon, which although is relatively rare, warrants future research attention considering the documented increase in DIY facial fillers and contemporary body image culture, supported by unrealistic social media discourse. Public awareness campaigns centred on the promotion of positive body image, the potentially devastating harms associated with DIY body fillers and enhanced clinical reporting to build an evidence base for effective interventions, training of clinicians and healthcare responses are recommended..

Funding Sources
None

Declaration of Competing Interest
The authors declare no conflict of interest.