Hexarelin Acetate For Lab Research

Hexarelin Acetate Ireland | Buy Research-Grade Growth Hormone Secretagogue | ≥99% Purity

Hexarelin Acetate is a synthetic hexapeptide growth hormone secretagogue and one of the most potent GHS-R1a agonists available to laboratories in Ireland , a six amino acid synthetic peptide that produces among the strongest growth hormone release responses of any compound in the secretagogue class while simultaneously engaging CD36 scavenger receptor biology in cardiac and vascular tissue, making it a uniquely dual-action research tool for studying both GH axis pharmacology at its upper stimulatory limits and the GH-independent cardioprotective and anti-fibrotic mechanisms mediated through CD36 receptor engagement, Researchers and institutions across Ireland can source verified, research-grade Hexarelin Acetate directly from our Irish peptide supply, with domestic-speed dispatch and complete batch documentation.

✅ ≥99% Purity , HPLC & Mass Spectrometry Verified

✅ Batch-Specific Certificate of Analysis (CoA) Included

✅ Sterile Lyophilised Powder | GMP Manufactured

✅ Fast Dispatch to Ireland | Peptides Ireland Stock

What Is Hexarelin Acetate?

Hexarelin Acetate is the acetate salt form of Hexarelin , formally designated His-D-2-MeTrp-Ala-Trp-D-Phe-Lys-NH2 . A synthetic hexapeptide belonging to the growth hormone releasing peptide family, structurally related to GHRP-6 but incorporating a 2-methyltryptophan residue at position two that enhances GHS-R1a binding affinity and produces a more potent GH-releasing response than any other synthetic hexapeptide secretagogue. The acetate salt designation reflects the counterion pairing used in the final pharmaceutical-grade formulation and a standard approach for improving the handling, solubility, and stability characteristics of basic peptides for research use, with the acetate counterion having no biological activity of its own.

Hexarelin was developed as part of the systematic structure-activity relationship programme that produced the GHRP family and the same research programme that ultimately led to the discovery of ghrelin as the endogenous ligand for GHS-R1a. Among the synthetic hexapeptide secretagogues produced through this programme . GHRP-6, GHRP-2, and Hexarelin being the principal members . Hexarelin emerged as the most potent GHS-R1a agonist in the series, with its 2-methyltryptophan modification providing enhanced receptor binding geometry that drives GH release to a greater magnitude than its structural relatives at equivalent molar doses. This potency distinction has made Hexarelin the reference compound for maximum GHS-R1a-driven GH axis stimulation in pre-clinical research designs requiring the strongest possible secretagogue-induced GH response.

What distinguishes Hexarelin from all other synthetic growth hormone secretagogues , and what has made it an object of sustained and growing research interest beyond GH axis pharmacology , is its documented engagement of CD36, a class B scavenger receptor expressed in cardiac muscle, vascular endothelium, macrophages, and adipose tissue that plays central roles in fatty acid uptake, oxidised LDL recognition, and critically, in cardiac biology and protection against pathological cardiac remodelling. Hexarelin’s CD36 binding was identified through research characterising the cardiac effects of Hexarelin that persisted in growth hormone-deficient and GH receptor-knockout animal models , establishing that Hexarelin produces direct cardiac biological effects through a mechanism entirely independent of its GH-releasing activity. This GH-independent CD36-mediated cardioprotective biology has established Hexarelin as a uniquely dual-mechanism research compound , simultaneously the most potent synthetic GHS-R1a agonist for GH axis research and a pharmacological probe for CD36 receptor biology in cardiac and vascular tissue.

What Does Hexarelin Acetate Do in Research?

In controlled laboratory and pre-clinical settings, Hexarelin Acetate is studied across a range of GH axis pharmacology, cardiac biology, CD36 receptor research, and vascular biology applications:

Maximum GHS-R1a Stimulation Research , Hexarelin’s position as the most potent synthetic GHS-R1a agonist makes it the reference compound for studies requiring maximal GH axis stimulation , with research examining peak GH secretory capacity, somatotroph cell maximal response biology, and the upper limits of GHS-R1a-driven GH release. Studies have used Hexarelin to establish GH axis stimulatory ceilings in pre-clinical models and to characterise how the somatotroph cell responds to maximal receptor occupancy , providing fundamental insights into GH secretion biology that lower-potency secretagogues can’t access.

GHS-R1a Receptor Pharmacology Research and Hexarelin’s high GHS-R1a binding affinity has made it a valuable pharmacological tool for characterising GHS-R1a receptor biology . With studies examining receptor binding kinetics, receptor internalisation and desensitisation following maximal stimulation, GHS-R1a expression regulation, and the downstream intracellular signalling cascades linking GHS-R1a activation to somatotroph GH secretion. The compound’s potency makes it useful for receptor saturation studies and for examining GH axis pharmacology at maximal stimulation conditions.

CD36 Receptor Biology and Cardiac Research , The most scientifically distinctive aspect of Hexarelin’s research profile is its CD36 receptor engagement . With studies characterising Hexarelin binding to CD36 in cardiac tissue, vascular endothelium, and macrophages, and documenting the biological consequences of CD36 activation in these tissue contexts. Research has established Hexarelin as the primary pharmacological probe for studying CD36-mediated cardiac biology , enabling investigation of CD36’s roles in cardiac protection, pathological cardiac remodelling, fibrosis regulation, and vascular biology in pre-clinical models.

GH-Independent Cardioprotection Research . Studies examining Hexarelin’s cardiac effects in GH-deficient and GH receptor-knockout models have documented cardioprotective effects that persist in the complete absence of GH signalling , establishing a GH-independent cardioprotective mechanism attributable to direct CD36 engagement in cardiac tissue. Research has characterised Hexarelin-associated improvements in cardiac contractile function, reductions in cardiac fibrosis markers, protection against ischaemia-reperfusion injury, and preservation of myocardial structure in pre-clinical cardiac models . Effects occurring through direct cardiac CD36 receptor activation rather than systemic GH biology.

Cardiac Fibrosis and Remodelling Research , One of the most significant applications of Hexarelin in cardiac biology research is the study of pathological cardiac fibrosis and remodelling and with studies examining Hexarelin’s effects on cardiac fibroblast activity, collagen deposition, and the molecular pathways driving maladaptive cardiac remodelling following injury or chronic pressure overload. CD36’s role in regulating cardiac fibroblast biology and TGF-beta signalling has made Hexarelin a key research tool for studying how CD36 receptor activation influences the fibrotic remodelling response in cardiac tissue.

Vascular Biology and Atherosclerosis Research , CD36 expression in vascular endothelium and macrophages and where it mediates oxidised LDL uptake and foam cell formation . Has made Hexarelin a research tool of interest in vascular biology and atherosclerosis research. Studies have examined how Hexarelin’s CD36 engagement influences macrophage lipid handling, endothelial function, and vascular inflammatory responses, Contributing to understanding of how CD36 receptor pharmacology intersects with the biology of atherosclerotic plaque formation and vascular inflammation.

GHRH Synergy and GH Axis Combination Research , Like all GHS-R1a agonists, Hexarelin produces synergistic GH release when combined with GHRH and with studies characterising how maximum GHS-R1a stimulation by Hexarelin interacts with GHRH receptor activation to produce GH release substantially greater than either compound alone. Hexarelin’s maximal GHS-R1a potency makes this synergistic combination particularly relevant for research designs examining the absolute upper limits of GH axis stimulatory capacity.

GH Axis Desensitisation Research , Hexarelin’s high potency has made it a particularly relevant research tool for studying GHS-R1a desensitisation and GH axis adaptation to repeated strong stimulation and with studies characterising how repeated maximal GHS-R1a activation influences receptor expression, somatostatin tone, and the capacity of the GH axis to sustain responses to ongoing secretagogue stimulation. These desensitisation studies have provided important insights into GH axis regulatory biology and the homeostatic mechanisms that limit sustained GH secretory responses.

Comparative GHS Pharmacology Research . Hexarelin is a standard reference compound in comparative growth hormone secretagogue research , used alongside GHRP-6, GHRP-2, Ipamorelin, and other secretagogues to establish potency rankings, characterise receptor selectivity profiles, and examine how structural differences between synthetic GHS compounds determine their distinct pharmacological properties. Its position as the most potent synthetic hexapeptide GHS makes it an important anchor point for comparative pharmacology studies in the secretagogue research field.

IGF-1 Axis and Downstream GH Biology Research and Studies have characterised the downstream IGF-1 axis consequences of Hexarelin-driven maximal GH release , examining how peak GH elevation driven by the most potent synthetic secretagogue translates to hepatic IGF-1 production, circulating IGF-1 levels, and tissue-level IGF-1 signalling. These downstream biology studies have provided important pre-clinical context for understanding the relationship between maximal GHS-R1a-driven GH secretion and IGF-1 axis activation.

What Do Studies Say About Hexarelin Acetate?

Hexarelin has accumulated a substantial and scientifically significant research literature and uniquely spanning both GH axis pharmacology, where it represents the potency ceiling of the synthetic secretagogue class, and CD36 receptor biology, where it has opened an entirely new and GH-independent research dimension for growth hormone secretagogue compounds.

Maximum GH Release Potency Established , Studies have consistently documented Hexarelin as producing the greatest GH release response of the synthetic hexapeptide secretagogue series , with direct potency comparison research establishing Hexarelin’s superiority over GHRP-6 and GHRP-2 at equivalent molar doses in multiple pre-clinical models. Research has attributed this potency advantage to the 2-methyltryptophan modification at position two of the hexapeptide sequence , with structural biology studies characterising how this modified amino acid enhances GHS-R1a binding geometry and receptor activation efficacy compared to the unmodified tryptophan present in GHRP-6. This established potency superiority has cemented Hexarelin’s position as the reference compound for maximum GHS-R1a-driven GH axis stimulation research.

GH-Independent Cardiac Effects Confirmed in Knockout Models , The most scientifically significant finding in the Hexarelin research literature has been the confirmation of GH-independent cardiac effects in animal models where GH signalling is absent. Studies using hypophysectomised animals , which lack pituitary GH production and and GH receptor knockout models have documented Hexarelin’s capacity to improve cardiac contractile function, reduce cardiac fibrosis, and protect against cardiac injury through mechanisms that can’t be attributed to GH release. These knockout model findings established the existence of a direct cardiac receptor for Hexarelin independent of GHS-R1a and ultimately identified as CD36 and transformed the understanding of growth hormone secretagogue biology beyond the pituitary.

CD36 as Hexarelin’s Cardiac Receptor Identified . Landmark research characterised CD36 as the receptor mediating Hexarelin’s GH-independent cardiac effects , with studies demonstrating Hexarelin binding to recombinant CD36, competitive displacement of Hexarelin binding by CD36 ligands, and the loss of Hexarelin’s cardiac effects in CD36-knockout models. This identification of CD36 as a functional receptor for a synthetic growth hormone secretagogue was an unexpected and highly significant finding , establishing that Hexarelin has a dual receptor biology and that GHS compounds can engage receptor systems entirely outside the classical GHS-R1a/pituitary axis. The CD36-Hexarelin interaction has since become a significant research area in its own right, with implications for cardiac biology, atherosclerosis research, and the broader understanding of scavenger receptor pharmacology.

Cardiac Fibrosis Reduction Documented , Pre-clinical studies have documented Hexarelin-associated reductions in cardiac fibrosis markers and including reduced collagen deposition, attenuated TGF-beta signalling, and preserved myocardial architecture in cardiac injury and pressure overload models. Research has characterised CD36-mediated modulation of cardiac fibroblast biology as a mechanism contributing to these anti-fibrotic effects and establishing Hexarelin as a research tool for studying how CD36 receptor engagement influences the fibrotic remodelling response in cardiac tissue and providing pre-clinical evidence for CD36 as a potential target in cardiac fibrosis biology research.

Ischaemia-Reperfusion Cardioprotection Characterised and Studies have documented Hexarelin’s protective effects in cardiac ischaemia-reperfusion injury models , with research reporting reduced cardiomyocyte death markers, improved post-ischaemic cardiac function recovery, and activation of cardioprotective signalling pathways including PI3K/Akt in Hexarelin-treated pre-clinical cardiac injury models. Importantly, these cardioprotective effects have been documented in both GH-intact and GH-deficient models and confirming the GH-independent nature of Hexarelin’s cardiac protection and attributing it to direct CD36 engagement in cardiac tissue.

GHS-R1a Desensitisation with Repeated Administration Characterised . Research examining repeated Hexarelin administration in pre-clinical models has documented progressive attenuation of GH release responses . With studies characterising GHS-R1a desensitisation, increased somatostatin tone, and reduced somatotroph responsiveness following sustained high-potency secretagogue stimulation. These desensitisation findings are scientifically important for understanding GH axis homeostatic regulation , establishing that the axis actively adapts to sustained maximal stimulation through receptor-level and hypothalamic feedback mechanisms. This desensitisation profile distinguishes Hexarelin from lower-potency secretagogues and has important implications for the design of GH axis research protocols using repeated Hexarelin administration.

Vascular and Atherosclerosis Biology Research Initiated and Studies examining Hexarelin’s effects in vascular biology contexts have documented CD36-mediated effects on macrophage lipid handling and vascular inflammatory parameters . Opening research into how Hexarelin’s CD36 pharmacology intersects with atherosclerotic plaque biology. Research has characterised CD36’s role in macrophage oxidised LDL uptake and foam cell formation as a context in which Hexarelin’s CD36 engagement produces biologically relevant vascular effects and establishing vascular biology as a growing secondary research dimension for Hexarelin alongside its primary GH axis and cardiac research applications.

How does Hexarelin Acetate compare to related compounds?

Feature	Hexarelin Acetate	GHRP-6	GHRP-2	Ipamorelin	CJC-1295 with DAC
Peptide Class	Synthetic hexapeptide GHS	Synthetic hexapeptide GHS	Synthetic hexapeptide GHS	Synthetic pentapeptide GHS	Long-acting GHRH analogue
GHS-R1a Affinity	Highest in hexapeptide series	High	Very high	High . Selective	N/A . GHRH-R target
GH Release Potency	Strongest . Hexapeptide ceiling	Strong	Very strong	Moderate , selective	Sustained elevation
Receptor Selectivity	GHS-R1a + CD36	GHS-R1a + broader profile	GHS-R1a , cleaner	GHS-R1a . Most selective	GHRH receptor
CD36 Engagement	Yes , defining feature	No	No	No	No
GH-Independent Cardiac Biology	Yes . Confirmed in knockout models	Limited	Limited	Not documented	Not documented
Cardiac Fibrosis Research	Directly relevant , CD36 mechanism	Indirect via GH	Not primary focus	Not documented	Not documented
GH Axis Desensitisation	Pronounced , high potency	Moderate	Moderate	Minimal	GHRH receptor dynamics
GHRH Synergy	Yes , strong	Yes and strong	Yes , strong	Yes , moderate	N/A and is GHRH analogue
Half-Life	~15–60 minutes	~15–60 minutes	~15–60 minutes	~2 hours	~6–8 days
Research Profile	Well-documented	Extensively studied	Extensively studied	Well-documented	Well-documented

Product Specifications

Parameter	Detail
Name	Hexarelin Acetate
Full Designation	His-D-2-MeTrp-Ala-Trp-D-Phe-Lys-NH2 acetate salt
Peptide Class	Synthetic Hexapeptide Growth Hormone Secretagogue
Molecular Weight	887.1 Da (free base)
Key Structural Feature	2-methyltryptophan at position 2 . Enhanced GHS-R1a binding
Primary Receptor	GHS-R1a and highest affinity in hexapeptide series
Secondary Receptor	CD36 and GH-independent cardiac and vascular biology
GH Release Potency	Strongest synthetic hexapeptide secretagogue
Key Research Distinction	Only synthetic GHS with confirmed dual GHS-R1a + CD36 receptor biology
Purity	≥99% HPLC & MS Verified
Form	Sterile Lyophilised Powder
Solubility	Sterile water or suitable laboratory buffer
Storage (Powder)	-20°C, protect from light
Storage (Reconstituted)	2–8°C, use within 7 days or aliquot at -80°C
Manufacturing	GMP Manufactured
Intended Use	Research use only

Buy Hexarelin Acetate in Ireland — What’s Included

Every order of Hexarelin Acetate in Ireland includes:

✅ Batch-Specific Certificate of Analysis (CoA)

✅ HPLC Chromatogram

✅ Mass Spectrometry Confirmation

✅ Sterility & Endotoxin Testing Report

✅ Reconstitution Protocol

✅ Technical Research Support

Frequently Asked Questions . Hexarelin Acetate Ireland

Can I Buy Hexarelin Acetate in Ireland?

Yes , we supply research-grade Hexarelin Acetate to researchers and institutions across Ireland with fast dispatch and full batch documentation. This compound is supplied strictly for laboratory research purposes only.

What we know about Hexarelin Acetate in research settings

Hexarelin’s superior GH-releasing potency within the synthetic hexapeptide secretagogue series is directly attributable to its 2-methyltryptophan modification at position two of the peptide sequence. Structural biology research has characterised how this methylated tryptophan residue . Absent in GHRP-6, which uses unmodified tryptophan at the equivalent position, and in GHRP-2, which uses a 2-naphthylalanine residue , produces enhanced geometric complementarity with the GHS-R1a binding pocket, increasing receptor binding affinity and activation efficacy compared to the other synthetic hexapeptides. This single amino acid difference translates to measurably greater GH release at equivalent molar doses in pre-clinical models and establishing Hexarelin as the potency ceiling of the synthetic hexapeptide secretagogue class and making it the reference compound for maximum GHS-R1a-driven GH stimulation research.

What Hexarelin Acetate does in metabolic research

CD36 is a class B scavenger receptor and a multifunctional membrane glycoprotein expressed in cardiac muscle, vascular endothelium, macrophages, platelets, and adipose tissue , with established roles in long-chain fatty acid uptake, oxidised LDL recognition and internalisation, thrombospondin signalling, and critically, in cardiac biology and protection against pathological cardiac remodelling. CD36’s expression in cardiac tissue and its involvement in cardiac fatty acid metabolism and fibrotic remodelling pathways make it a receptor of significant research interest in cardiovascular biology. Hexarelin’s engagement of CD36 and confirmed through binding studies and knockout model experiments and provides a pharmacological tool for studying CD36 receptor biology in cardiac and vascular tissue that’s unique in the growth hormone secretagogue class. No other synthetic GHS compound has confirmed CD36 binding activity . Making Hexarelin irreplaceable as a research tool for studying the intersection of secretagogue pharmacology and CD36-mediated cardiac biology.

What Hexarelin Acetate does in metabolic research

The discovery of Hexarelin’s GH-independent cardiac effects emerged from research designed to characterise Hexarelin’s cardiovascular biology using animal models in which GH signalling could be experimentally eliminated. Studies examining Hexarelin’s cardiac effects in hypophysectomised animals and which lack pituitary GH production and therefore can’t produce GH in response to secretagogue stimulation , observed that Hexarelin continued to produce measurable improvements in cardiac function and reductions in cardiac pathology markers in the complete absence of circulating GH. Further studies in GH receptor knockout models confirmed that these cardiac effects persisted even when GH signalling was genetically ablated , definitively establishing that Hexarelin’s cardiac biology was independent of its GH-releasing mechanism. This unexpected finding prompted the search for a direct cardiac receptor for Hexarelin . Ultimately leading to the identification of CD36 as the mediating receptor , and expanded the scientific understanding of growth hormone secretagogue biology beyond the pituitary GHS-R1a axis.

What we know about Hexarelin Acetate in research settings

Hexarelin and Ipamorelin represent opposite ends of the GH secretagogue spectrum in terms of potency and selectivity . Making them complementary rather than interchangeable research tools. Hexarelin is the most potent synthetic GHS-R1a agonist in the hexapeptide series , producing the strongest GH release with broader receptor engagement including CD36 and some off-target receptor activity that may confound mechanistic interpretation in selectivity-sensitive research designs. Ipamorelin is the most GHS-R1a-selective synthetic secretagogue . Producing moderate GH release with minimal off-target receptor activity and no documented cortisol, prolactin, or appetite effects . Making it the preferred tool when isolated, clean GHS-R1a biology is the research objective. Hexarelin is chosen when maximum GH axis stimulation is required or when studying CD36 biology, while Ipamorelin is chosen when receptor selectivity and clean mechanistic attribution are the priority. Together they bracket the potency-selectivity spectrum of synthetic GHS research tools.

What we know about Hexarelin Acetate in research settings

Hexarelin’s pronounced GH axis desensitisation following repeated administration is scientifically significant for two reasons , it provides important insights into GH axis homeostatic regulation, and it has direct implications for the design of pre-clinical research protocols using Hexarelin. Studies have characterised the mechanisms underlying desensitisation . Including GHS-R1a internalisation and downregulation at the pituitary level, increased hypothalamic somatostatin tone as a feedback response to repeated strong GH stimulation, and reduced somatotroph sensitivity to ongoing secretagogue input. Understanding these desensitisation mechanisms has contributed substantially to knowledge of how the GH axis regulates itself against sustained stimulation , with implications for the broader biology of GH secretion regulation. For research protocol design, Hexarelin’s desensitisation profile means that repeated administration studies must account for progressive attenuation of GH responses , a consideration that distinguishes Hexarelin from lower-potency secretagogues with less pronounced desensitisation characteristics.

What Purity is Recommended for Hexarelin Acetate Research?

≥99% purity is strongly recommended for GHS-R1a receptor pharmacology studies, CD36 binding research, cardiac biology experiments, GH axis stimulation protocols, and pre-clinical in vivo models . Where compound purity directly determines the reliability of GH release measurements, receptor binding data, and cardiac biology outcomes. Given Hexarelin’s potency and its dual receptor biology, impurities could introduce confounding signals in sensitive receptor binding assays and cardiac functional studies. All Hexarelin Acetate Ireland stock is independently verified to ≥99% purity by HPLC and mass spectrometry.

How Do I Reconstitute Hexarelin Acetate for Laboratory Use?

Allow the vial to reach room temperature before opening. Add sterile water or appropriate laboratory buffer slowly down the inside wall of the vial and swirl gently and don’t inject directly onto the lyophilised powder and don’t vortex or shake vigorously. Prepare a concentrated stock solution at your required research concentration. Store reconstituted stock at 2–8°C for short-term use within 7 days, or aliquot into single-use volumes and store at -80°C for longer-term preservation. Avoid repeated freeze-thaw cycles and exposure to elevated temperatures, Handle with standard peptide protocols to maintain GHS-R1a binding activity and CD36 receptor engagement capacity across experimental sessions.

Research Disclaimer

Hexarelin Acetate is supplied exclusively for legitimate scientific research purposes conducted within licensed laboratory environments. This product isn’t intended for human consumption, self-administration, or any therapeutic application. It must be handled by qualified researchers in compliance with applicable Irish and EU regulations and institutional ethics guidelines. By purchasing, you confirm that this compound will be used solely for approved in vitro or pre-clinical research purposes.

What Irish researchers commonly ask about Hexarelin Acetate

Is Hexarelin Acetate legal in Ireland?

Hexarelin Acetate isn’t authorised as a medicine by the HPRA. It’s legal to buy, hold and use as a research chemical for in-vitro laboratory work, and that’s the only use we supply it for. If you want the full regulatory picture, see our Irish researcher’s guide to peptide legality.

What’s in the vial and what does the CoA cover?

Every vial ships with an HPLC purity trace (typically ≥99%), mass-spec identity confirmation, and endotoxin/heavy-metal screening on the batch. The full per-batch Certificate of Analysis is available on request from research@peptideslabuk.com. Our quality system is ISO 9001 certified and third-party testing runs through a UKAS-accredited lab.

How researchers reconstitute Hexarelin Acetate

Standard protocol: let the Hexarelin Acetate vial and your bacteriostatic water come to room temperature, wipe both stoppers with a 70% isopropyl swab, then inject the water slowly down the side wall of the peptide vial. Don’t stream directly onto the powder cake. Swirl gently, don’t shake, and give it five to ten minutes to fully dissolve. Label the vial with compound, concentration and reconstitution date, store at 2–8°C between assays.

How fast does Hexarelin Acetate ship inside Ireland?

Same-day dispatch on orders placed before 2pm on a working day. Delivery is 24–48 hours to any Irish county via An Post Express or DPD. Cold chain is preserved with insulated wrap plus gel pack. No customs step, no border delays . Because it never leaves Ireland.

What’s Hexarelin Acetate often studied with?

In the Irish research space Hexarelin Acetate tends to appear in muscle-cell hypertrophy and satellite-cell activation research. It’s often paired with IGF-1 or CJC-1295 when researchers are studying combined mechanisms rather than the compound alone.

How should Hexarelin Acetate be stored?

Lyophilised Hexarelin Acetate is stable at ≤-20°C long-term. Once reconstituted, keep it refrigerated at 2–8°C and use within the working shelf life described on the CoA. Freeze/thaw cycles degrade peptides, so aliquot the reconstituted solution if you plan to run assays over several weeks.