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How COVID-19 Accelerated Peptide Research

The pandemic didn't just disrupt daily life — it reshaped the trajectory of peptide science. Between early 2020 and 2023, COVID-19 drove a wave of research funding, clinical experimentation, and public interest that pushed peptides from niche academic study into mainstream biomedical conversation.

The pandemic didn't just disrupt daily life — it reshaped the trajectory of peptide science. Between early 2020 and 2023, COVID-19 drove a wave of research funding, clinical experimentation, and public interest that pushed peptides from niche academic study into mainstream biomedical conversation. Thymosin alpha-1 was deployed in Chinese ICUs. BPC-157 interest surged on forums and in clinics. GLP-1 agonists revealed unexpected protective effects against severe infection. And long COVID opened entirely new research questions about how peptides might address chronic post-viral illness.

This article traces how the pandemic reshaped peptide research — what worked, what didn't, and what lasting changes it left behind.

Table of Contents

The Pandemic as a Catalyst for Peptide Interest

Before March 2020, most peptide research existed in specialized academic journals read by biochemists and endocrinologists. The general public had little awareness that peptide therapeutics represented a growing market — one projected to reach nearly $50 billion by 2026.

COVID-19 changed that. The urgency of a novel virus with no approved treatments sent researchers scrambling through existing pharmacopeia looking for anything that might work. Peptides — with their immune-modulating, anti-inflammatory, and tissue-protective properties — became natural candidates.

Several factors converged. First, the pandemic exposed the relationship between metabolic health and infectious disease severity. Patients with obesity, type 2 diabetes, and cardiovascular disease faced dramatically worse outcomes, putting metabolic peptides like GLP-1 agonists under new scrutiny. Second, the immunological chaos of severe COVID — cytokine storms, T-cell exhaustion, lymphocyte depletion — created a need for precision immune modulators. Third, the sheer volume of patients with lingering symptoms after infection opened research questions that didn't exist before 2020.

The result was a three-year period of accelerated peptide research that left permanent marks on the field.

Thymosin Alpha-1: From Hepatitis Drug to COVID Treatment

Thymosin alpha-1 (Ta1) was perhaps the most directly deployed peptide during the pandemic. This 28-amino-acid peptide, secreted by thymic epithelial cells, had been approved in over 35 countries for hepatitis B and C treatment, though it remained investigational in the United States. Its mechanism — promoting T-cell differentiation and modulating immune responses — made it a logical candidate for a disease that attacked the immune system.

The Chinese Clinical Experience

Chinese hospitals began using Ta1 early in the pandemic, and several studies emerged from that experience. A retrospective study of 76 severe COVID-19 cases at two Wuhan hospitals found that Ta1 treatment reduced mortality from 30% to 11.1% (p = 0.044), according to Liu et al. (2020). The proposed mechanism was restoration of lymphocyte counts and reversal of T-cell exhaustion — two hallmarks of severe disease.

But larger studies complicated the picture. A multicenter cohort study across five Hubei hospitals showed that patients receiving Ta1 actually had worse crude outcomes — higher mortality, more intubation, greater ARDS incidence. The researchers flagged an obvious problem: confounding by indication. Sicker patients were more likely to receive the treatment, making it look harmful in unadjusted data. When they controlled for disease severity, earlier Ta1 administration was associated with better outcomes than later use, according to a study published in Frontiers in Immunology.

A separate analysis of 771 critical patients across 19 hospitals initially showed lower 28-day mortality in the Ta1 group (41.3% vs. 60.6%). After propensity score matching to account for baseline differences, the survival advantage disappeared — 51.0% vs. 52.9%, with no statistical significance.

The Meta-Analysis Verdict

A 2022 systematic review and meta-analysis of nine studies covering 5,352 patients concluded that Ta1 therapy had no statistically significant effect on overall mortality (risk ratio 1.03, p = 0.92). However, subgroup analysis identified populations that may benefit: patients over 60, male patients, and those with severe or critical disease showed mortality reductions in the range of 32-34%.

The lesson from the Ta1 story isn't that the peptide failed. It's that deploying a complex immune modulator during a chaotic pandemic, without the scaffolding of proper randomized controlled trials, produced ambiguous results. The data suggested potential benefit in specific subgroups — but the evidence quality, drawn mostly from retrospective Chinese hospital data, left the question unresolved.

BPC-157: The Interest Surge That Outpaced the Science

While Ta1 was being tested in hospitals, BPC-157 experienced a different kind of pandemic-era phenomenon: a massive surge in consumer and clinical interest, driven less by formal research and more by the wellness community's search for recovery tools.

Why BPC-157 Attracted COVID-Era Attention

BPC-157, a 15-amino-acid peptide derived from human gastric juice, had established preclinical credentials in tissue repair, anti-inflammation, and endothelial protection. A 2021 hypothesis paper published in Medical Hypotheses laid out the theoretical case: COVID-19 was increasingly recognized as a vascular disease targeting endothelial cells throughout the body. BPC-157 had demonstrated anti-thrombotic and endothelial-protective effects in animal models. Its interactions with the nitric oxide (eNOS) pathway represented "an attractive therapeutic target that has not yet been pharmacologically employed in COVID-19 patients."

The theory was plausible. The evidence was almost entirely preclinical. And as a 2025 STAT News investigation noted, almost all existing BPC-157 research comes from a single group of researchers in Croatia — a significant limitation that the broader community often overlooks.

The Gap Between Interest and Evidence

A 2025 pilot study by Lee and Burgess gave two healthy adults intravenous BPC-157 infusions up to 20 mg. The treatment was well tolerated with no adverse events. But this is the state of human evidence for one of the most popular peptides in the wellness space — two participants in a safety study.

The pandemic accelerated BPC-157's journey from laboratory curiosity to widely discussed therapeutic option, but that journey outpaced the science. As a 2025 narrative review in PMC concluded, the existing data presents "a decidedly mixed bag" — promising rodent studies but a near-complete absence of rigorous human trials.

GLP-1 Agonists and the Metabolic-Infection Connection

Perhaps the most consequential pandemic-era discovery for peptide research wasn't about a new peptide at all — it was about an old one revealing new tricks. GLP-1 receptor agonists like semaglutide and liraglutide showed unexpected protective effects against severe COVID-19.

Retrospective Evidence of Protection

Early analyses from the pandemic showed that patients with type 2 diabetes who were already taking GLP-1 receptor agonists had a reduced risk of COVID-19 hospitalization and mortality compared to those on other diabetes medications. The mechanism appeared to go beyond glucose control. GLP-1 receptors are expressed on immune cells, and GLP-1 receptor agonist therapy impacts immune function through reductions in blood pressure and systemic inflammation, according to research published by the European Society of Medicine.

An interesting molecular connection emerged: DPP-4 (dipeptidyl peptidase-4), the enzyme that degrades GLP-1 in the body, can also serve as a co-receptor for SARS-CoV-2. This linked the metabolic and viral pathways in ways researchers hadn't previously considered, as described in a 2022 eLife paper on post-acute COVID metabolic complications.

The SELECT Trial's COVID Signal

The landmark SELECT trial — which enrolled 17,604 patients with obesity but without diabetes — provided additional data. Published analysis in the Journal of the American College of Cardiology in 2024 examined semaglutide's effect on mortality and COVID-related deaths. The trial's primary result (a 20% reduction in major cardiovascular events) earned semaglutide FDA approval for cardiovascular risk reduction in March 2024, but the secondary analyses exploring COVID outcomes added evidence to the GLP-1 protection hypothesis.

This research thread directly fed into broader investigations of metabolic health as a predictor of infectious disease outcomes — a research area that barely existed before the pandemic.

Antimicrobial Peptides and the Resistance Crisis

COVID-19 also amplified a quieter but equally important line of peptide research: antimicrobial peptides (AMPs) as alternatives to conventional antibiotics.

During the pandemic, hospitalized patients received widespread antimicrobial drugs — both to treat secondary bacterial infections and, in some cases, empirically. This exposure accelerated antimicrobial resistance, creating what researchers described as a multidrug resistance crisis layered on top of the viral pandemic.

Peptides like LL-37 gained renewed research attention as potential alternatives. Machine learning tools were developed to predict antiviral peptide (AVP) activity against SARS-CoV-2, with multiple computational studies published in 2020 and 2021. Organizations like CARB-X funded new peptide antibiotic development programs targeting gram-negative bacteria.

The pandemic didn't create the antibiotic resistance problem, but it made the need for peptide-based alternatives more urgent and more visible to funding agencies.

How Research Funding Shifted

The pandemic redirected billions in research funding, and while the bulk went to vaccines and small-molecule antivirals, peptide therapeutics benefited from the broader shift toward biological countermeasures.

BARDA (the Biomedical Advanced Research and Development Authority) supported over 130 COVID-19 partnerships during the pandemic, resulting in six approved immunotherapeutics, two antiviral drugs, four vaccines, and 29 diagnostics. Congress allocated $32 billion in emergency pandemic funds. While most of this went to vaccines and established drug classes, the urgency created a spillover effect: academic peptide research programs that could position their work as pandemic-relevant gained access to expedited funding mechanisms.

The AI-driven peptide discovery field received particular acceleration. The need for rapid identification of therapeutic candidates pushed computational approaches forward, with machine learning models trained to identify potential antiviral peptides from massive sequence databases. This infrastructure — originally built for pandemic response — is now being repurposed for broader peptide drug discovery.

One sobering note: by 2025, much of this pandemic research funding was being cut. The NIH began terminating COVID-specific grants, including a $577 million program for antiviral drug discovery that was cancelled in early 2025. The question of whether the peptide research momentum can sustain itself without pandemic-level funding remains open.

Long COVID: A New Frontier for Peptide Exploration

Perhaps the most enduring legacy of the pandemic for peptide research is long COVID — or post-acute sequelae of SARS-CoV-2 infection (PASC). This condition, affecting an estimated 10-30% of COVID survivors, created a massive patient population with chronic symptoms that conventional medicine struggled to address.

The Peptide Rationale for Long COVID

Long COVID involves persistent immune dysregulation, chronic low-grade inflammation, mitochondrial dysfunction, and vascular damage. Each of these pathways has peptide research behind it:

  • Immune dysregulation: Thymosin alpha-1 was studied for immune restoration in PASC patients at the University of Rome Tor Vergata. Ex vivo data showed that Ta1 improved immune response restoration in PASC patients, particularly those who had severe acute illness. Treatment reduced exhausted T-cell populations and improved CD8+ central memory T-cell percentages in patients with psychiatric symptoms.

  • Vascular and tissue damage: BPC-157's endothelial-protective properties and TB-500's tissue repair mechanisms made both candidates for addressing the vascular component of long COVID.

  • Mitochondrial dysfunction: Mitochondrial-derived peptides like MOTS-c and humanin, which influence metabolic function and insulin sensitivity, entered the conversation as potential treatments for the energy production deficits seen in long COVID.

  • Metabolic disruption: GLP-1 agonists were proposed for managing the metabolic complications of long COVID, including new-onset insulin resistance and beta-cell dysfunction. Researchers called for clinical trials evaluating GLP-1 receptor agonists specifically in long COVID populations.

Clinical Reality vs. Theoretical Promise

The honest assessment is that most peptide applications for long COVID remain theoretical or early-stage. Some regenerative medicine clinics have adopted multi-peptide protocols — combining BPC-157, thymosin beta-4, MOTS-c, and others — but these aren't supported by randomized controlled trials in PASC populations. They represent clinical experimentation informed by preclinical data and mechanistic reasoning.

What the pandemic did accomplish was to create the research questions. Before 2020, nobody was studying peptide interventions for post-viral chronic illness at any significant scale. Now, the research infrastructure and patient demand both exist.

The FDA Crackdown and Its Aftermath

The surge in peptide interest during the pandemic collided with regulatory reality in late 2023 when the FDA added more than a dozen peptides — including BPC-157 and thymosin alpha-1 — to its list of substances that should not be compounded. The agency cited "potential significant safety risks," warning that BPC-157 might trigger immune responses and that drugs containing it could harbor impurities.

This created a paradox: public and clinical interest in peptides had never been higher, fueled partly by pandemic-era research and patient demand, while regulatory access was being restricted. Compounding pharmacies, which had been the primary source of peptides like BPC-157 and Ta1, found themselves unable to legally produce them.

The response was politically significant. A November 2025 letter to HHS from Congress urged the agency to reconsider restrictions, arguing that "in the absence of commercial options, patients and their prescribers are turning to licensed compounding pharmacies to access therapies essential to health and quality of life." This political engagement — driven in part by the patient population that discovered peptides during and after the pandemic — represents a lasting change in the regulatory conversation.

For a detailed guide on post-COVID peptide research, see our comprehensive article on peptides for post-COVID recovery.

FAQ

Did COVID-19 directly lead to new peptide drug approvals?

No. The pandemic-era peptide research has not yet produced new FDA approvals. Thymosin alpha-1 remains unapproved in the US, BPC-157 has no approved formulations anywhere, and the GLP-1 agonist approvals during this period (semaglutide for cardiovascular risk, tirzepatide for sleep apnea) were based on pre-pandemic clinical trial programs. What the pandemic did was accelerate research interest and create new clinical questions that may lead to future trials.

Was thymosin alpha-1 effective against COVID-19?

The evidence is mixed. A systematic review of nine studies found no overall mortality benefit, but subgroup analyses suggested possible benefits for patients over 60, male patients, and those with severe disease. The main problem is evidence quality — most studies were retrospective and conducted at Chinese hospitals during the chaotic early pandemic months. More rigorous randomized trials were needed but difficult to conduct during a crisis.

How did BPC-157 interest change during the pandemic?

Consumer and clinical interest in BPC-157 surged during and after the pandemic, driven by its theoretical relevance to COVID's vascular and inflammatory damage. However, this interest was based primarily on preclinical animal data, not human trials. The gap between public demand and scientific evidence remains one of the defining tensions in the peptide field.

Are GLP-1 agonists being studied for long COVID?

Researchers have proposed clinical trials evaluating GLP-1 receptor agonists for long COVID, based on retrospective evidence of protective effects during acute infection and the metabolic disruption common in PASC. As of early 2026, dedicated long COVID GLP-1 trials remain limited, though the biological rationale continues to strengthen.

Did the pandemic permanently change peptide research funding?

It created a temporary surge in funding through pandemic-specific mechanisms at NIH, BARDA, and international agencies. Some of that infrastructure — particularly in AI-driven peptide discovery and computational drug design — has outlasted the pandemic. But dedicated COVID research funding has been cut since 2025, and whether the broader peptide research momentum sustains depends on continued investment from pharmaceutical companies and private funding sources.

The Bottom Line

COVID-19 compressed what might have been a decade of gradual peptide research progress into three frenzied years. Thymosin alpha-1 got its largest-ever clinical exposure, even if the results were inconclusive. BPC-157 jumped from academic obscurity to mainstream awareness, though the science hasn't caught up to the interest. GLP-1 agonists revealed metabolic-immune connections that are reshaping how we think about infection risk. And long COVID created an entirely new category of research questions about peptide applications in chronic post-viral illness.

The pandemic also exposed the field's weaknesses — the reliance on preclinical data, the difficulty of conducting rigorous trials during a crisis, and the gap between what patients want and what regulatory agencies will allow. These tensions haven't been resolved. But the research questions generated by COVID-19 will keep peptide scientists busy for years, and the public awareness created during the pandemic isn't going away.

The lasting effect isn't any single breakthrough. It's that millions of people — patients, clinicians, and researchers — now think about peptides in ways they didn't before March 2020.

References

  1. Liu Y, et al. "Thymosin Alpha 1 Reduces the Mortality of Severe Coronavirus Disease 2019 by Restoration of Lymphocytopenia and Reversion of Exhausted T Cells." Clinical Infectious Diseases. 2020. PubMed

  2. Sun Q, et al. "Efficacy of Thymosin Alpha 1 in the Treatment of COVID-19: A Multicenter Cohort Study." Frontiers in Immunology. 2021. PMC

  3. Pei L, et al. "Thymosin alpha1 use in adult COVID-19 patients: A systematic review and meta-analysis on clinical outcomes." International Immunopharmacology. 2022. PMC

  4. Javorac D, et al. "BPC 157 as Potential Treatment for COVID-19." Medical Hypotheses. 2021. PMC

  5. Kannen V, et al. "Regeneration or Risk? A Narrative Review of BPC-157 for Musculoskeletal Healing." PMC. 2025. PMC

  6. Barrea L, et al. "GLP-1 receptor agonists in the management of COVID-19 and long COVID for patients with underlying metabolic disorders." Medical Research Archives. 2024. European Society of Medicine

  7. Al Mahmeed W, et al. "Post-acute sequelae of COVID-19: A metabolic perspective." eLife. 2022. PMC

  8. Matteucci C, et al. "Thymosin alpha 1 restores the immune homeostasis in lymphocytes during Post-Acute sequelae of SARS-CoV-2 infection." International Immunopharmacology. 2023. PMC

  9. Thakur A, et al. "Multidrug resistance crisis during COVID-19 pandemic: Role of anti-microbial peptides as next-generation therapeutics." Colloids and Surfaces B: Biointerfaces. 2022. PubMed

  10. Freitas N, et al. "Advancing development of medical countermeasures: Incorporating COVID-19 lessons learned." Vaccine. 2022. PMC

  11. Thymosin alpha 1: A comprehensive review of the literature. Journal of Integrative Medicine. 2020. PMC