Skin Growths, Sermorelin, and BPC-157/TB500

A question that surfaces repeatedly in peptide communities: can sermorelin, BPC-157, or TB-500 cause skin growths? A user on r/peptides described developing small, pale, flesh-coloured growths on the upper arms roughly nine months into sermorelin use and about two months after adding BPC-157 and TB-500. A dermatology biopsy returned a finding of acanthosis. This article explains what the published literature says about the connection between growth-hormone-stimulating peptides, IGF-1, and skin changes, so you can have an informed conversation with a dermatologist.

This article does not establish causality in any individual case, and it is not medical advice. If you have developed new or changing skin growths, see a dermatologist.

What sermorelin does to IGF-1 levels

Sermorelin is a synthetic 29-amino-acid analogue of growth hormone-releasing hormone (GHRH). It binds to receptors on the anterior pituitary gland and stimulates pulsatile growth hormone (GH) secretion. Once in circulation, GH travels to the liver and triggers production of insulin-like growth factor-1 (IGF-1). A 2017 retrospective study of 14 men receiving growth hormone secretagogues including sermorelin at 100 mcg three times daily found that baseline IGF-1 of approximately 160 ng/mL rose to approximately 239 ng/mL after a mean 134 days of treatment, representing about a 50% increase^[1]. That degree of IGF-1 elevation is relevant to skin biology, as the literature on acromegaly and GH excess makes clear.

How elevated GH and IGF-1 affect the skin

A 2026 review in Frontiers in Medicine examined skin lesions in patients treated with GH and in those with GH excess. The authors noted that GH receptors are present in the majority of skin cell types, while IGF-1 receptors are expressed predominantly in epidermal keratinocytes. Both hormones drive fibroblast proliferation and collagen synthesis, and both promote accumulation of glycosaminoglycans (hyaluronic acid and chondroitin sulfate) in the dermis, causing skin thickening and water retention^[2]. In acromegaly, the syndrome of uncontrolled GH excess from a pituitary adenoma, the dermatological picture includes skin tags (acrochordons), epidermoid cysts, oily skin, hyperhidrosis, and pseudoacanthosis nigricans^[2].

A 2021 review in Experimental and Therapeutic Medicine on skin anomalies in acromegalic patients described acanthosis nigricans in that population as hyperkeratotic plaques, with or without hyperpigmentation, driven by growth factor overexpression including GH and IGF-1^[3]. The mechanism is that excess insulin or IGF-1 activates IGF-1 receptors on keratinocytes and fibroblasts, accelerating epidermal proliferation. When insulin is elevated alongside IGF-1, insulin can also displace IGF-1 from its binding proteins, further raising the fraction of free IGF-1 available to stimulate skin cells^[4].

What BPC-157 adds to the picture

BPC-157 is a 15-amino-acid synthetic peptide studied extensively in rodent models for tissue repair. A 2018 paper in Biochemia Medica (PMC) reported that BPC-157 dose- and time-dependently increases growth hormone receptor (GHR) expression in tendon fibroblasts, with up to a seven-fold increase by day three of treatment^[5]. The practical implication is that BPC-157 may amplify the effect of whatever GH is circulating, because more receptor surface is available for GH to bind. When that happens alongside sermorelin-driven GH secretion, the combined effect on fibroblasts and keratinocytes is theoretically additive, though no human study has tested this combination directly.

What TB-500 contributes

TB-500 is a synthetic seven-amino-acid fragment of thymosin beta-4, a 43-amino-acid protein involved in actin polymerisation, cell migration, and wound repair. Research confirms that thymosin beta-4 increases keratinocyte migration and fibroblast activity through upregulation of VEGF, matrix metalloproteinases, and laminin^[6]. Its intended application in tissue repair is wound closure; the same keratinocyte-migration activity that closes wounds also promotes epidermal proliferation more broadly. No published study links TB-500 directly to acanthosis or acrochordons, and the compound has no human clinical trial data at therapeutic doses. The mechanistic overlap with growth-factor-driven keratinocyte activity is, however, real.

Skin tags, acrochordons, and the IGF-1 receptor

A case-control study published in PMC in 2020 found that IGF-1 receptor (IGF-1R) and IGF-2R expression was significantly higher in skin-tag tissue from non-diabetic patients compared with controls^[7]. Serum insulin was also higher in the skin-tag group. The authors concluded that insulin metabolism disorders warrant evaluation in anyone presenting with multiple acrochordons. This research was conducted in people not using peptides, but the receptor biology is the same mechanism proposed for GH-secretagogue-associated skin changes.

What we do not know

No published study has specifically examined the skin effects of sermorelin combined with BPC-157 and TB-500 in humans. The mechanistic case rests on: (1) sermorelin raising IGF-1 by documented amounts; (2) elevated IGF-1 activating keratinocyte and fibroblast receptors, a well-characterised pathway; (3) BPC-157 upregulating GH receptors in fibroblasts, amplifying that signal; and (4) TB-500 independently promoting keratinocyte migration. Whether those mechanisms combine to produce acanthosis or acrochordons in any individual depends on factors including baseline IGF-1 sensitivity, metabolic state, dose, and duration, none of which community reports can control for.

The biopsy finding of acanthosis in the community case does not confirm a causal link to peptides. Acanthosis and acrochordons have many causes: insulin resistance, obesity, thyroid disease, certain medications, and rare internal malignancies are all documented. A dermatologist or endocrinologist working up new acanthosis in someone using GH secretagogues would typically check fasting glucose, insulin, HOMA-IR, thyroid function, and IGF-1 levels before attributing the finding to any one agent.

Practical takeaways

First, acanthosis and new skin growths in anyone using GH-stimulating peptides warrant dermatological and endocrinological evaluation, not self-diagnosis from community threads. Second, monitoring IGF-1 levels periodically while on sermorelin is prudent; if levels exceed the upper range of normal for age, that is a signal to discuss with the prescribing clinician. Third, the combination of sermorelin plus growth-factor-active peptides like BPC-157 and TB-500 is not studied in any clinical trial. Fourth, none of BPC-157, TB-500, or sermorelin (outside FDA-supervised paediatric indications) is approved for general use by any regulatory agency we track. Grey-market supply of any of these compounds carries additional quality-control risks.

If you have developed new or changing skin lesions while using any peptide stack, the right next step is a board-certified dermatologist for skin evaluation and your primary care provider or an endocrinologist for hormone panel review. For more on BPC-157's preclinical evidence and regulatory status, see our dedicated page. This article is for educational purposes only. It is not medical advice and does not substitute for professional evaluation.