Peptides and Chronic Kidney Disease: Can They Restore Kidney Function?

Peptides have become an increasingly common topic of discussion in clinical practice. I am regularly asked whether compounds such as BPC-157, TB-500 or other so-called regenerative peptides might help repair damaged kidneys, improve estimated glomerular filtration rate (eGFR), or even reverse chronic kidney disease (CKD).

There is a legitimate scientific basis for some of this interest. Peptides are short chains of amino acids that can act as biological signalling molecules, and researchers are investigating peptide-based therapies that influence fibrosis, mitochondrial function, inflammation, vascular function and cellular ageing – all processes relevant to the development and progression of CKD. Some of this research is genuinely interesting.

However, there is an important distinction between a peptide showing kidney-protective effects in a laboratory or animal model and having a safe and effective treatment capable of restoring kidney function in people with CKD.

At present, most of the peptides promoted online for ‘kidney repair’ remain firmly within the experimental category. This is particularly important in Australia, where the Therapeutic Goods Administration (TGA) has issued repeated warnings during 2026 regarding unapproved peptide products, including BPC-157, TB-500, CJC-1295, GHK-Cu and retatrutide. These products have not been assessed by the TGA for safety, quality or effectiveness (TGA 2026a; TGA 2026c).

For someone who already has impaired kidney function, the uncertainty surrounding both the therapeutic effects of these compounds and the quality of products available through the online peptide market is particularly relevant.

Peptides Are Not a Single Type of Treatment

The term peptides can be misleading because it is sometimes used as though it describes one therapeutic category.

It does not.

There are already numerous well-established peptide medicines. Insulin is one of the most familiar examples. GLP-1 receptor agonists are another increasingly important group of peptide-based medicines.

These medications have undergone pharmaceutical development, controlled clinical trials, manufacturing quality assurance and regulatory assessment. Importantly, GLP-1 receptor agonists are now supported by substantial evidence showing kidney and cardiovascular benefits in appropriately selected patients.

A 2025 meta-analysis of 11 large randomised controlled trials involving more than 85,000 participants found GLP-1 receptor agonists reduced major kidney outcomes and kidney failure, predominantly in people with type 2 diabetes (Badve et al. 2025). More recent analyses have supported these findings, including a 2026 meta-analysis of more than 90,000 participants that found a 19% reduction in a composite adverse kidney outcome and a slower annual decline in eGFR (Sasaki et al. 2026).

This demonstrates that peptide medicine itself is not the problem.

The problem arises when evidence from approved peptide medicines or experimental peptide research is extrapolated to products such as BPC-157 or TB-500 and used to imply that they can regenerate human kidneys.

They are completely different compounds with completely different levels of evidence.

Why Peptides Are Being Investigated in Kidney Disease

CKD involves considerably more than a reduction in eGFR.

Depending on the underlying disease, progression can involve glomerular injury, tubular damage, endothelial dysfunction, oxidative stress, chronic inflammation, mitochondrial dysfunction and eventually renal fibrosis.

Fibrosis is particularly important because it represents a common final pathway across many different forms of progressive CKD. Excess extracellular matrix gradually replaces functional kidney tissue, contributing to progressive nephron loss and declining kidney function (Abbad et al. 2025).

Researchers are therefore interested in compounds capable of influencing these processes.

Several experimental peptides are particularly interesting from a renal perspective.

Klotho-Derived Peptide 1

One of the more compelling areas of peptide research involves Klotho.

Klotho is a protein expressed predominantly in the kidneys and has important roles in mineral metabolism, ageing, inflammation and cellular signalling. Loss of renal Klotho expression occurs in CKD and has been implicated in the development of fibrosis and premature cellular ageing.

Researchers have consequently developed a small peptide derived from Klotho known as Klotho-derived peptide 1 (KP1).

In experimental models, KP1 has been shown to interfere with transforming growth factor beta (TGF-β) signalling, one of the major pathways involved in renal fibrosis. A 2022 study found KP1 reduced fibroblast activation and kidney fibrosis in mouse models by interacting with the TGF-β receptor (Yuan et al. 2022).

Further research published in 2024 found that KP1 reduced markers of cellular senescence in diseased mouse kidneys while increasing endogenous Klotho expression (Zhang et al. 2024).

This is fascinating research because both fibrosis and cellular senescence are plausible targets for slowing CKD progression.

However, these remain predominantly preclinical findings.

There is currently an enormous difference between demonstrating that a specifically engineered Klotho-derived peptide affects fibrosis in laboratory models and showing that commercially available ‘regenerative peptides’ can restore human kidney function.

Apelin: One of the More Interesting Human Studies

Apelin is an endogenous peptide that interacts with the apelin receptor, which is expressed throughout the cardiovascular system and kidneys.

Unlike many experimental peptides, apelin has now been investigated directly in people with CKD.

Chapman et al. (2024) conducted a randomised, double-blind, placebo-controlled crossover study involving 12 patients with stable CKD stages 1–4 and 12 matched healthy controls. Participants received intravenous apelin-13 or placebo.

Apelin increased renal blood flow by approximately 15%, increased sodium excretion and reduced proteinuria by around 25% in those with CKD. Interestingly, GFR fell by approximately 10% during administration. The researchers interpreted this haemodynamic effect as potentially renoprotective because it occurred alongside a reduction in filtration fraction and proteinuria – somewhat analogous to the initial haemodynamic changes seen with established renoprotective medications.

These findings are certainly worth further investigation.

However, this was a study involving only 12 patients with CKD receiving an acute intravenous infusion. It did not demonstrate regeneration of kidney tissue, sustained improvement in eGFR or prevention of kidney failure.

The authors themselves concluded that the findings justify clinical trials of longer-acting apelin receptor agonists.

That is very different from concluding that apelin is currently a treatment for CKD.

Elamipretide and Mitochondrial Function

Another interesting compound is elamipretide, sometimes known as SS-31.

Elamipretide is a mitochondria-targeted peptide. This is relevant because mitochondrial dysfunction and oxidative stress are increasingly recognised as important contributors to tubular injury and CKD progression.

A small phase 2a trial investigated elamipretide in patients undergoing renal artery stenting for severe atherosclerotic renal artery stenosis.

Six participants received elamipretide and eight received placebo around the revascularisation procedure. Three months later, renal blood flow had increased in the elamipretide group and mean eGFR increased from approximately 40.7 to 46.5 mL/min/1.73 m². The treatment also appeared to attenuate renal hypoxia immediately following the procedure (Saad et al. 2017).

Again, this is interesting.

But the context matters.

This was a very small study involving a specific form of ischaemic kidney disease where blood flow to the kidney was being surgically restored. It does not demonstrate that elamipretide will restore function in diabetic kidney disease, IgA nephropathy, FSGS, polycystic kidney disease or the many other causes of CKD.

It is an example of promising translational research rather than an established regenerative kidney treatment.

What About BPC-157?

BPC-157 is probably the peptide I am asked about most frequently.

It is promoted extensively online for tissue repair, gut healing, inflammation, tendon injuries and increasingly for organ protection.

There is now a reasonable body of animal research demonstrating potentially interesting biological effects.

A 2025 rat study investigating lower-limb ischaemia-reperfusion injury found that BPC-157 reduced subsequent kidney tissue damage, including tubular and glomerular abnormalities (Demirtaş et al. 2025).

More recently, a 2026 study examined severe gentamicin-induced nephrotoxicity in rats. BPC-157 treatment was associated with preservation of serum urea and creatinine, diuresis and renal tubular structure, alongside effects on oxidative stress and nitric oxide signalling (Vukoja et al. 2026).

These results certainly make BPC-157 interesting from a pharmacological research perspective.

They do not demonstrate that BPC-157 reverses human CKD.

Gentamicin toxicity and experimentally induced ischaemia in rats are models of acute kidney injury. They are very different from someone with progressive nephron loss and fibrosis developing over five, ten or twenty years.

This problem becomes even clearer when looking at human evidence.

A 2025 pilot study examining intravenous BPC-157 involved just two healthy adults. No significant abnormalities were identified following the infusions, but two people followed for several days clearly cannot establish long-term safety, appropriate dosing or safety in CKD (Lee and Burgess 2025).

A 2026 review of the development of BPC-157 concluded that despite decades of preclinical research, there remains no approved pharmaceutical formulation, validated dosing regimen or completed phase II clinical trial (Mateescu et al. 2026).

This is a substantial evidence gap.

What About TB-500?

TB-500 presents a slightly different problem.

Much of the research used online to support TB-500 actually concerns thymosin beta-4, a naturally occurring 43-amino-acid peptide involved in cell migration, angiogenesis and tissue repair.

Experimental kidney studies of thymosin beta-4 and its metabolite Ac-SDKP have demonstrated potentially antifibrotic effects.

For example, Zuo et al. (2013) found Ac-SDKP consistently reduced renal fibrosis in experimental models, while the effects of thymosin beta-4 itself were more complex and dependent on the stage and biological context of the injury.

A later review concluded that thymosin beta-4 and Ac-SDKP had demonstrated potentially protective effects across several experimental kidney disease models but emphasised the need for further research before this could be translated into CKD treatment (Vasilopoulou et al. 2018).

Importantly, this research cannot simply be transferred to commercially marketed TB-500.

A 2026 scoping review examining 80 studies involving thymosin beta-4 and TB-500 found the literature remained dominated by preclinical research. Of the 80 included studies, 70 investigated thymosin beta-4 while only one directly investigated TB-500 (McGuire et al. 2026).

This illustrates a recurring problem in the peptide market: biological plausibility is frequently presented as though it were clinical evidence.

Kidney Disease May Also Change How Peptides Behave

There is another reason for caution that is particularly relevant to people with reduced kidney function.

The kidneys participate in the metabolism and elimination of many smaller peptide drugs.

Peptides can undergo glomerular filtration followed by renal metabolism, and declining kidney function can therefore substantially alter their pharmacokinetics (Diao and Meibohm 2013).

A review of 98 peptide and protein drugs found that lower molecular weight compounds could show markedly reduced clearance and prolonged half-life in severe renal impairment or end-stage kidney disease (Czock et al. 2012).

More recent pharmacokinetic research continues to identify renal filtration as an important elimination pathway for many therapeutic peptides (Nordell et al. 2026).

For an approved medicine, these questions are investigated during drug development.

For a peptide purchased from an internet supplier, there may be little or no reliable pharmacokinetic information – and frequently no meaningful research whatsoever examining its use in stage 4 CKD, stage 5 CKD or dialysis.

The Bigger Concern: What Is Actually in the Vial?

For me, one of the strongest arguments against using online peptides in CKD has less to do with whether the theoretical mechanism is interesting and more to do with whether the product can be trusted.

This has become a significant issue in Australia.

In June 2026, the TGA and Australia’s Chief Medical Officer issued a joint warning following hospitalisations associated with unapproved peptide products. Reported complications included liver injury, severe allergic reactions, systemic inflammation and other complications requiring medical attention (TGA 2026a).

Victoria also issued a health alert following six cases of acute liver injury in people using unapproved products labelled retatrutide. Authorities considered contamination a possible contributor and specifically warned of risks including contamination, infection and local tissue injury from injectable products (Victorian Department of Health 2026).

Then, in August 2026, laboratory testing reported by ABC News provided a particularly revealing snapshot of the Australian black-market peptide industry.

A Melbourne laboratory had analysed 18 black-market samples labelled retatrutide during 2026. Only one matched its stated concentration. Around 30% contained more peptide than claimed, approximately 30% contained less, and one vial contained none of the purported peptide at all (ABC News 2026).

This testing only addressed peptide concentration. It does not establish sterility or exclude bacterial contamination, endotoxins, heavy metals or other substances.

The TGA has reported encountering imported peptides supplied as powders or injectables in unmarked vials, with products missing ingredient names, concentrations and dosing instructions. The regulator specifically warns that with these products there may be no reliable way of determining exactly what the vial contains, how much peptide is present or whether the product is sterile (TGA 2026c).

This is a substantially different risk profile from a pharmaceutical medicine manufactured under regulated conditions.

Why This Matters Even More in CKD

The Australian cases reported to date have predominantly involved liver toxicity rather than kidney injury, so it would be inaccurate to claim that black-market peptides are already an established cause of widespread peptide-induced kidney failure.

However, the potential renal consequences are still important.

A contaminated injectable product can cause systemic infection or inflammation. Incorrect concentrations can result in substantial dosing errors. Allergic reactions, vomiting, diarrhoea, reduced oral intake and hypotension can all precipitate acute kidney injury.

Someone with normal kidney function often has considerable renal reserve.

Someone with moderate or advanced CKD does not.

There is also an additional difficulty: if kidney function deteriorates after someone begins taking an unapproved peptide, it may be impossible to determine whether the problem was caused by the peptide itself, an unexpectedly high dose, another substance in the vial, bacterial contamination or an interaction with existing medications.

Are These Peptides Legal in Australia?

This requires some nuance.

Peptides themselves are not illegal. Australia has many approved peptide medicines.

However, products such as BPC-157, TB-500, CJC-1295 and GHK-Cu that are commonly promoted online are examples the TGA currently identifies as unapproved peptide products. This means they are not included on the Australian Register of Therapeutic Goods and have not been assessed by the TGA for safety, effectiveness or manufacturing quality (TGA 2026a).

Unapproved therapeutic goods can sometimes be legally accessed through defined regulatory pathways including the Special Access Scheme, Authorised Prescriber Scheme, clinical trials and, under particular circumstances, the Personal Importation Scheme.

This does not mean that simply purchasing a vial labelled ‘research use only’ from an overseas website makes its importation or use compliant with Australian law. The TGA specifically states that such disclaimers do not change the regulatory status of a product, and prescription or other authorisation requirements may still apply (TGA 2026c).

Regulatory enforcement has also increased. In August 2026, the TGA reported seizing more than $120,000 worth of allegedly illicit peptide and anabolic steroid products in New South Wales, including retatrutide, CJC-1295 and a combination of BPC-157 and TB-500 marketed as the ‘Wolverine Stack’ (TGA 2026b).

Availability on a website therefore tells us very little about either the regulatory status or quality of a product.

My Current Approach to Peptides and CKD

I think peptide research in kidney disease deserves to be taken seriously.

The Klotho system, apelin receptor agonism and mitochondria-targeted peptides are particularly interesting areas of emerging research. It is entirely possible that peptide-based therapies will eventually contribute to the management of particular forms of kidney disease.

But eventually is not the same as currently.

At present, there is no convincing human clinical evidence demonstrating that BPC-157, TB-500 or the typical regenerative peptides purchased from online suppliers can regenerate kidneys or reverse established CKD.

For this reason, I generally recommend that people with CKD avoid experimenting with unapproved peptide products, particularly when purchased online and there is uncertainty regarding their composition, sterility, concentration and manufacturing quality.

My preference is to first address factors for which we have considerably stronger evidence: appropriate medical management of the underlying kidney disease; blood pressure and metabolic risk; individualised protein, sodium, potassium and phosphorus intake where required; appropriate dietary fibre and plant-food intake; exercise and weight management; smoking cessation; avoidance of nephrotoxic exposures; and carefully selected nutritional or herbal interventions that can be safely integrated alongside conventional kidney care.

These approaches may appear considerably less novel than an injectable ‘regenerative’ peptide.

They also have the significant advantage of having a much clearer understanding of their potential benefits, limitations and risks.

Peptide research in CKD is worth watching closely. At this stage, however, the science is considerably more promising than many of the peptide products currently being sold to consumers.

References

Abbad L, Esteve E and Chatziantoniou C (2025) ‘Advances and challenges in kidney fibrosis therapeutics’, Nature Reviews Nephrology, 21:314–329, doi:10.1038/s41581-025-00934-5.

ABC News (28 August 2026) ‘New testing of black market peptides reveals dangerous dosing levels’, ABC News, accessed 31 August 2026, https://www.abc.net.au/news/2026-08-28/black-market-peptides-dangerous-doses/107059092

Badve SV, Bilal A, Lee MMY, Sattar N, Gerstein HC, Ruff CT, McMurray JJV, Rossing P, Bakris G, Mahaffey KW, Mann JFE, Colhoun HM, Tuttle KR, Pratley RE and Perkovic V (2025) ‘Effects of GLP-1 receptor agonists on kidney and cardiovascular disease outcomes: a meta-analysis of randomised controlled trials’, The Lancet Diabetes & Endocrinology, 13(1):15–28, doi:10.1016/S2213-8587(24)00271-7.

Chapman FA, Melville V, Godden E, Morrison B, Bruce L, Maguire JJ, Davenport AP, Newby DE and Dhaun N (2024) ‘Cardiovascular and renal effects of apelin in chronic kidney disease: a randomised, double-blind, placebo-controlled, crossover study’, Nature Communications, 15:8387, doi:10.1038/s41467-024-52447-7.

Czock D, Keller F and Seidling HM (2012) ‘Pharmacokinetic predictions for patients with renal impairment: focus on peptides and protein drugs’, British Journal of Clinical Pharmacology, 74(1):66–74, doi:10.1111/j.1365-2125.2012.04172.x.

Demirtaş H, Özer A, Yıldırım AK, Dursun AD, Sezen ŞC and Arslan M (2025) ‘Protective effects of BPC 157 on liver, kidney, and lung distant organ damage in rats with experimental lower-extremity ischemia-reperfusion injury’, Medicina, 61(2):291, doi:10.3390/medicina61020291.

Diao L and Meibohm B (2013) ‘Pharmacokinetics and pharmacokinetic–pharmacodynamic correlations of therapeutic peptides’, Clinical Pharmacokinetics, 52(10):855–868, doi:10.1007/s40262-013-0079-0.

Lee E and Burgess K (2025) ‘Safety of intravenous infusion of BPC157 in humans: a pilot study’, Alternative Therapies in Health and Medicine, 31(5):20–24, https://pubmed.ncbi.nlm.nih.gov/40131143/

Mateescu DM, Gavrilescu DM, Constantinescu FE, Oancea C, Ilie AC, Folescu R, Popa MD, Iurciuc S, Muresan CO and Enache A (2026) ‘BPC-157 as an investigational peptide therapeutic: biopharmaceutical challenges, formulation strategies, and translational development barriers’, Pharmaceutics, 18(5):625, doi:10.3390/pharmaceutics18050625.

McGuire F, Hughes E, Maak T and Cushman DM (2026) ‘Thymosin Beta-4 and TB-500 in tissue healing, regeneration, and musculoskeletal repair: a scoping review’, Applied Sciences, 16(12):6202, doi:10.3390/app16126202.

Nordell P, Jansson-Löfmark R and Gennemark P (2026) ‘Systemic pharmacokinetic principles of therapeutic peptides’, Clinical Pharmacokinetics, 65(4):571–582, doi:10.1007/s40262-025-01615-z.

Saad A, Herrmann SMS, Eirin A, Ferguson CM, Glockner JF, Bjarnason H, McKusick MA, Misra S, Lerman LO and Textor SC (2017) ‘Phase 2a clinical trial of mitochondrial protection (elamipretide) during stent revascularization in patients with atherosclerotic renal artery stenosis’, Circulation: Cardiovascular Interventions, 10(9), doi:10.1161/CIRCINTERVENTIONS.117.005487.

Sasaki T, Giang SM-L, Wu J, Yokoo T, Gallagher M, Bellomo R and Wang AY (2026) ‘The effect of GLP-1 receptor agonists on renal outcomes: a systematic review and meta-analysis’, Nephrology Dialysis Transplantation, 41(4):681–691, doi:10.1093/ndt/gfaf193.

TGA (Therapeutic Goods Administration) (19 June 2026a) ‘Concerns regarding the public health risks associated with unapproved peptide products’, TGA, Australian Government, accessed 31 August 2026, https://www.tga.gov.au/news/media-releases/concerns-regarding-public-health-risks-associated-unapproved-peptide-products

TGA (Therapeutic Goods Administration) (17 August 2026b) ‘TGA flexes its muscle against illegal peptides and steroids’, TGA, Australian Government, accessed 31 August 2026, https://www.tga.gov.au/news/media-releases/tga-flexes-its-muscle-against-illegal-peptides-and-steroids

TGA (Therapeutic Goods Administration) (7 May 2026c) ‘TGA warning on the risks of importing unapproved peptide products’, TGA, Australian Government, accessed 31 August 2026, https://www.tga.gov.au/safety/safety-monitoring-and-information/safety-alerts/tga-warning-risks-importing-unapproved-peptide-products

Vasilopoulou E, Riley PR and Long DA (2018) ‘Thymosin-β4: a key modifier of renal disease’, Expert Opinion on Biological Therapy, 18(sup1):185–192, doi:10.1080/14712598.2018.1473371.

Victorian Department of Health (19 June 2026) ‘Toxicity linked to unapproved peptide product labelled Retatrutide’, health.vic.gov.au, accessed 31 August 2026, https://www.health.vic.gov.au/health-alerts/toxicity-linked-to-unapproved-peptide-retatrutide

Vukoja I, Vlainic J, Francina M, Barisic I, Zukanovic G, Miskulin I, Kralj L, Popovic Dolic M, Dulcic D, Tubikanec AM, Sikiric S, Krezic I, Kordic M, Beketic Oreskovic L, Oreskovic I, Strbe S, Staresinic B, Pavelic Turudic T, Perovic D, Bilic V, Stancic Rokotov D, Boban Blagaic A, Seiwerth S, Sikiric P and Skrtic A (2026) ‘Stable pentadecapeptide therapy counteracts gentamicin-induced nephrotoxicity via nitric oxide-system modulation: evidence from a triple nitric oxide-agent approach in rats’, Journal of Physiology and Pharmacology, 77(3):377–395, doi:10.26402/jpp.2026.3.08.

Yuan Q, Ren Q, Li L, Tan H, Lu M, Tian Y, Huang L, Zhao B, Fu H, Hou FF, Zhou L and Liu Y (2022) ‘A Klotho-derived peptide protects against kidney fibrosis by targeting TGF-β signaling’, Nature Communications, 13:438, doi:10.1038/s41467-022-28096-z.

Zhang X, Li L, Tan H, Hong X, Yuan Q, Hou FF, Zhou L and Liu Y (2024) ‘Klotho-derived peptide 1 inhibits cellular senescence in the fibrotic kidney by restoring Klotho expression via posttranscriptional regulation’, Theranostics, 14(1):420–435, doi:10.7150/thno.89105.

Zuo Y, Chun B, Potthoff SA, Kazi N, Brolin TJ, Orhan D, Yang HC, Ma LJ, Kon V, Myöhänen T, Rhaleb NE, Carretero OA and Fogo AB (2013) ‘Thymosin β4 and its degradation product, Ac-SDKP, are novel reparative factors in renal fibrosis’, Kidney International, 84(6):1166–1175, doi:10.1038/ki.2013.209.