Most research-peptide shops in Ukraine carry the same dozen popular items. Longeva deliberately does something different: alongside the staples, we keep genuinely rare, frontier compounds in stock, the kind that, for most of the market, exist only as lines in journal papers rather than as something you can actually order. Each of these arrives from a vetted supplier and passes lab checks for purity and identity, because with niche molecules it is provenance and analytics that matter, not the label. Below are five such compounds, each with a real scientific explainer: what it is, how it works, what the research shows, and why you almost never see it anywhere.
On framing. Everything described here is strictly research-use-only (RUO) material. We summarize what preclinical and early studies in cells and animals have shown; we give no medical advice, protocols, or human dosing. If you need a compound matched to a specific research protocol, start with our catalog.
| Compound | Class | Research focus |
|---|---|---|
| SLU-PP-332 | Synthetic pan-ERR agonist (small molecule) | Mitochondrial biogenesis, endurance, "exercise mimetic" |
| FOXO4-DRI | Senolytic peptide (D-retro-inverso) | Selective clearance of senescent cells via the FOXO4-p53 axis |
| Humanin | Mitochondrial-derived peptide (MDP) | Cytoprotection, anti-apoptosis, mitochondrial signaling |
| P021 (P21) | CNTF-derived neurotrophic peptidergic mimetic | Neurogenesis, BDNF, synaptic plasticity |
| B7-33 | Single-chain RXFP1 agonist (relaxin analogue) | Anti-fibrosis, vasoprotection, biased signaling |
SLU-PP-332, a synthetic ERR agonist, the "exercise mimetic"
What it is
SLU-PP-332 is not a peptide in the classic sense but a synthetic small molecule, a pan-agonist of the estrogen-related receptors ERRα, ERRβ, and ERRγ, developed in Thomas Burris's lab (hence "SLU," for Saint Louis University). In research shorthand it is known as an "exercise mimetic": a compound that pharmacologically reproduces part of the adaptation that aerobic training produces. SLU-PP-332 in our catalog is exactly the kind of item you will struggle to find anywhere in Ukraine.
Mechanism
ERRs are orphan nuclear receptors, the key transcriptional partners of the coactivator PGC-1α, the hub through which a cell governs mitochondrial biogenesis and oxidative metabolism. By activating ERRα, SLU-PP-332 switches on a transcriptional program in skeletal muscle that is normally triggered by acute aerobic exercise, without the exercise itself [1]. The effect is ERRα-dependent: when the receptor is knocked out, the endurance gain disappears [1].
What the research shows
In the foundational paper by Billon and colleagues (ACS Chemical Biology, 2023), dosing mice with SLU-PP-332 increased the fraction of oxidative type IIa muscle fibers, induced an ERRα-dependent "acute aerobic exercise" gene program (targets include Ddit4 and Slc25a25), and extended treadmill running distance and time versus controls [1]. In a later paper from the same group (Journal of Pharmacology and Experimental Therapeutics, 2024), in obesity models the compound reduced fat mass, improved glucose tolerance, and increased fatty-acid oxidation, easing features of metabolic syndrome [2].
Why it is rare
The "exercise mimetic" class is one of the youngest in metabolic pharmacology, and fully characterized, journal-vetted ERR agonists number in the single digits. All the available efficacy is preclinical, in rodents; there is no human data [1][2]. That is precisely why SLU-PP-332 stays a research tool rather than a commodity, and rarely turns up on shelves.
FOXO4-DRI, a senolytic peptide that breaks the FOXO4-p53 complex
What it is
FOXO4-DRI is an engineered senolytic peptide: a D-retro-inverso version of a fragment of the transcription factor FOXO4 (D-amino acids in reverse order, which makes the molecule protease-resistant). Its job is to selectively clear senescent, "zombie", cells that accumulate with age. See the FOXO4-DRI listing in the catalog.
Mechanism
In senescent cells, FOXO4 binds and holds p53 in the nucleus, preventing it from triggering apoptosis, so the damaged cell stays alive. FOXO4-DRI competitively disrupts the FOXO4-p53 interaction; the released p53 leaves the nucleus and is directed to the mitochondria, firing the intrinsic (mitochondrial) apoptosis pathway specifically in senescent cells. Normal cells do not depend on the FOXO4-p53 axis for survival, so they are largely spared [3].
What the research shows
In the foundational paper by Baar and colleagues (Cell, 2017), FOXO4-DRI selectively drove senescent cells into apoptosis and, across several mouse models, naturally aged, fast-aging, and doxorubicin-treated, improved health markers such as physical activity, fur density, and kidney function, while counteracting chemotherapy toxicity [3]. The work became one of the pillars of the senolytics concept: targeted removal of senescent cells as a healthy-longevity strategy [4].
Why it is rare
FOXO4-DRI is one of the first rationally designed senolytic peptides and is still more an object of academic work than a routine reagent. Synthesizing a D-retro-inverso sequence is harder than a standard peptide, and the senolytics category itself remains frontier science [4]. Finding it in stock is therefore uncommon.
Humanin, a mitochondrial-derived peptide with cytoprotective action
What it is
Humanin is a short 24-amino-acid peptide encoded within the mitochondrial 16S rRNA gene (MT-RNR2). It was discovered in 2001 by Hashimoto and Nishimoto while analyzing a cDNA library from a brain region of an Alzheimer's patient that had remained relatively spared [5]. It is the first described member of an entire class, mitochondrial-derived peptides (MDPs). Our Humanin is exactly this kind of niche item.
Mechanism
Humanin is a cytoprotective signaling molecule. Its classic action is anti-apoptotic: Humanin interferes with activation of the pro-apoptotic protein Bax and its translocation to the mitochondria, blocking the intrinsic death pathway [6]. It also binds insulin-like growth factor-binding protein 3 (IGFBP-3), tuning the balance between survival and apoptosis [7]. Humanin's action is mediated by specific receptors, and together these elements make it a retrograde "mitochondria-to-cell" signal [8].
What the research shows
In the discovery paper, Humanin almost completely suppressed neuronal death induced by a wide range of familial Alzheimer's disease genes and by amyloid-β [5]. Follow-up work resolved the mechanism of this protection through Bax [6] and the IGFBP-3 axis [7], and reviews placed Humanin in a broader context: it turned out to be a "harbinger" of the MDP family (later joined by, among others, MOTS-c), and circulating Humanin declines with age [8].
Why it is rare
Humanin is a first-of-its-kind mitochondrial signaling peptide, the founder of an entirely new class of molecules [8]. It is more a subject of fundamental aging and neuroprotection research than a fast-moving product, so it is seldom in stock.
P021 (P21), a CNTF-derived neurotrophic peptidergic mimetic
What it is
P021 is a neurotrophic/neurogenic peptidergic compound derived from the most active region of ciliary neurotrophic factor (CNTF), identified by epitope mapping. An adamantylated glycine group is attached to the short peptide core to improve blood-brain-barrier penetration and protect the molecule from exopeptidases. It was developed in the Iqbal and Kazim lab. In the catalog it is P021 (P21).
Mechanism
P021 reproduces the neurotrophic activity of CNTF but bypasses the adverse LIF/CNTFRα signaling responsible for the native factor's side effects. The compound increases expression of the neurotrophic factor BDNF (by raising its transcription), stimulates neurogenesis in the dentate gyrus of the hippocampus, and supports synaptic plasticity [9][10]. A key advantage among peptides is that it is orally available and blood-brain-barrier-permeable [10].
What the research shows
In the paper by Kazim and colleagues (Neurobiology of Disease, 2014), chronic oral P021 in the triple-transgenic Alzheimer's model (3xTg-AD) had a disease-modifying effect: it reduced tau hyperphosphorylation, enhanced neurogenesis, and improved cognition [9]. A review from the same group framed small neurotrophic mimetics as a distinct therapeutic modality [10], and in the Ts65Dn Down-syndrome model, early neurotrophic pharmacotherapy with P021 eased developmental delay and memory deficits [11].
Why it is rare
An orally active, blood-brain-barrier-penetrant neurotrophic peptidergic mimetic is a genuine rarity: most peptides neither cross that barrier nor work orally [10]. P021 remains a specialized neuroscience research tool and is almost never openly available.
B7-33, a single-chain agonist of the relaxin receptor RXFP1
What it is
B7-33 is a synthetic single-chain peptide derived from the B-chain of human relaxin-2 (H2 relaxin). Native relaxin is a two-chain insulin-superfamily hormone; B7-33 is a minimized single-chain analogue created by the Hossain and Bathgate group at the Florey Institute [12]. See B7-33 in the catalog.
Mechanism
B7-33 is a functionally selective (biased) agonist of RXFP1: it preferentially activates the pERK1/2 pathway with minimal cAMP stimulation. Acting through RXFP1-angiotensin II type-2 receptor (AT2R) heterodimers, it raises the activity of the collagen-degrading enzyme matrix metalloproteinase MMP-2, the molecular basis of its anti-fibrotic action, which reproduces the effect of native relaxin [12].
What the research shows
In the foundational paper by Hossain and colleagues (Chemical Science, 2016), B7-33 prevented or reduced organ fibrosis and dysfunction across three preclinical rodent models of heart or lung disease, with potency comparable to native H2 relaxin [12]. Later, Marshall, Leo and colleagues showed that B7-33 replicates the vasoprotective functions of serelaxin: in rodent mesenteric arteries it produced the same acute vascular effects and prevented endothelial dysfunction induced by placental trophoblast-conditioned media, making it a candidate in the context of preeclampsia as well [13].
Why it is rare
B7-33 solves relaxin's central problem as a molecule, the costly, complex manufacture of a two-chain hormone, with a single chain, and with biased signaling on top [12]. It is a young, frontier compound for cardiovascular and anti-fibrotic research, and the market almost never carries it.
Why research peptides are worth buying from a lab-tested source
For rare compounds, where exactly you bought it matters more than for staples. Small-batch peptides are more often the target of substitution, contamination, and misidentification, simply because the buyer has nothing to compare against. Longeva closes that at the process level: a vetted supply chain, lab checks for purity and identity on every batch, and transparent accompanying data. For a researcher, that means what is in the vial is what is on the label, the precondition without which any result is meaningless. See the full range, including these five, in the catalog.
Disclaimer (RUO)
This material was prepared from peer-reviewed scientific sources and is provided for reference and informational purposes only. It is not medical advice or a recommendation for use. All compounds described above are supplied strictly for laboratory research; they are not intended for human consumption, nor for diagnostic or therapeutic use. All effects cited above were observed under controlled preclinical conditions (cells, animals) and cannot be construed as instructions for use in humans.
The full list of sources with links, is in our scientific monographs: SLU-PP-332, FOXO4-DRI, Humanin, P021, B7-33.
