What is Acetate salt?

The form most synthetic peptides are supplied in. Acetic acid is used during HPLC purification and leaves an acetate counterion bound to the peptide. Acetate salts are water-soluble and suitable for reconstitution with bacteriostatic water.

The building block of peptides and proteins. Each amino acid has a central carbon bonded to an amine group, a carboxyl group, a hydrogen, and a variable side chain. The sequence and composition of amino acids determines a peptide's biological activity.

What is Bacteriostatic water (BW)?

Sterile water containing 0.9% benzyl alcohol. The benzyl alcohol acts as a preservative that inhibits bacterial growth, allowing a reconstituted peptide vial to be stored in the fridge for several weeks after opening. The standard diluent for peptide reconstitution.

What is Certificate of Analysis (COA)?

A document from the testing laboratory that records the results of quality control tests on a specific batch of a product. For peptides, a COA typically includes the HPLC purity percentage, the mass spectrometry identity confirmation, the batch number, and the test date. A legitimate COA comes from an independent third-party lab, not the supplier.

A synthetic analogue of growth hormone-releasing hormone (GHRH). It stimulates the pituitary gland to release growth hormone. Often combined with ipamorelin (a ghrelin mimetic) to produce a synergistic pulse of GH release. Available with or without DAC (Drug Affinity Complex), which dramatically extends its half-life.

The unit used to express molecular weight. One dalton equals approximately the mass of a single hydrogen atom. Small peptides typically range from 500 Da to 5,000 Da. Larger peptides approach the molecular weight of small proteins.

What is Disulfide bond?

A covalent bond formed between the sulfur atoms of two cysteine residues. Disulfide bonds stabilise peptide structure and are important for activity in many peptides. Incorrect disulfide bond formation (disulfide scrambling) during synthesis can reduce purity and potency.

What is GLP-1 receptor agonist?

A class of peptide that activates the glucagon-like peptide-1 receptor. GLP-1 receptor agonists stimulate insulin secretion, suppress glucagon, slow gastric emptying, and reduce appetite. Semaglutide is the most well-known pharmaceutical example. Retatrutide is a triple agonist that also targets GIP and glucagon receptors.

What is GMP (Good Manufacturing Practice)?

A quality system that governs the manufacturing environment, processes, and documentation for pharmaceutical and research-grade compounds. GMP certification indicates that a facility has been audited for contamination controls, equipment calibration, batch traceability, and staff training. Peptide Central sources exclusively from GMP-certified manufacturers.

What is Growth hormone releasing hormone (GHRH)?

A hypothalamic hormone that signals the pituitary to secrete growth hormone. Synthetic GHRH analogues like CJC-1295 replicate this signalling pathway and are used in research on GH secretion and body composition.

A B C DEFG H IJKL MNOPQR S TUVWXYZ

A

Acetate salt: The form most synthetic peptides are supplied in. Acetic acid is used during HPLC purification and leaves an acetate counterion bound to the peptide. Acetate salts are water-soluble and suitable for reconstitution with bacteriostatic water.; See also: TFA salt, Lyophilisation
Amino acid: The building block of peptides and proteins. Each amino acid has a central carbon bonded to an amine group, a carboxyl group, a hydrogen, and a variable side chain. The sequence and composition of amino acids determines a peptide's biological activity.

B

Bacteriostatic water (BW): Sterile water containing 0.9% benzyl alcohol. The benzyl alcohol acts as a preservative that inhibits bacterial growth, allowing a reconstituted peptide vial to be stored in the fridge for several weeks after opening. The standard diluent for peptide reconstitution.; See also: Reconstitution, Sterile water

C

Certificate of Analysis (COA): A document from the testing laboratory that records the results of quality control tests on a specific batch of a product. For peptides, a COA typically includes the HPLC purity percentage, the mass spectrometry identity confirmation, the batch number, and the test date. A legitimate COA comes from an independent third-party lab, not the supplier.; See also: HPLC, Mass spectrometry
CJC-1295: A synthetic analogue of growth hormone-releasing hormone (GHRH). It stimulates the pituitary gland to release growth hormone. Often combined with ipamorelin (a ghrelin mimetic) to produce a synergistic pulse of GH release. Available with or without DAC (Drug Affinity Complex), which dramatically extends its half-life.; See also: Ipamorelin, GHRH, Half-life

D

Dalton (Da): The unit used to express molecular weight. One dalton equals approximately the mass of a single hydrogen atom. Small peptides typically range from 500 Da to 5,000 Da. Larger peptides approach the molecular weight of small proteins.
Disulfide bond: A covalent bond formed between the sulfur atoms of two cysteine residues. Disulfide bonds stabilise peptide structure and are important for activity in many peptides. Incorrect disulfide bond formation (disulfide scrambling) during synthesis can reduce purity and potency.

G

GLP-1 receptor agonist: A class of peptide that activates the glucagon-like peptide-1 receptor. GLP-1 receptor agonists stimulate insulin secretion, suppress glucagon, slow gastric emptying, and reduce appetite. Semaglutide is the most well-known pharmaceutical example. Retatrutide is a triple agonist that also targets GIP and glucagon receptors.; See also: Retatrutide, Semaglutide
GMP (Good Manufacturing Practice): A quality system that governs the manufacturing environment, processes, and documentation for pharmaceutical and research-grade compounds. GMP certification indicates that a facility has been audited for contamination controls, equipment calibration, batch traceability, and staff training. Peptide Central sources exclusively from GMP-certified manufacturers.
Growth hormone releasing hormone (GHRH): A hypothalamic hormone that signals the pituitary to secrete growth hormone. Synthetic GHRH analogues like CJC-1295 replicate this signalling pathway and are used in research on GH secretion and body composition.; See also: CJC-1295

H

Half-life: The time it takes for the concentration of a compound in the body to fall by 50%. Most unmodified peptides have short half-lives (minutes to hours) because enzymes in the blood rapidly cleave the peptide bonds. Chemical modifications such as PEGylation, DAC conjugation, or fatty acid chains can extend half-life from hours to days.; See also: CJC-1295, Semaglutide
HPLC (High-Performance Liquid Chromatography): An analytical technique that separates compounds in a mixture based on how strongly they interact with a stationary phase inside a pressurised column. In peptide analysis, reverse-phase HPLC separates the target peptide from synthesis impurities, truncated sequences, and oxidised variants. The area under the target peak divided by the total peak area gives the purity percentage.; See also: Certificate of Analysis, Mass spectrometry

I

Ipamorelin: A selective growth hormone secretagogue and ghrelin mimetic. It stimulates GH release from the pituitary without significantly raising cortisol or prolactin. Often stacked with CJC-1295 for a synergistic GH pulse. One of the most selective peptides in its class.; See also: CJC-1295, GHRP

L

Lyophilisation (freeze-drying): A preservation process that removes water from a substance by freezing it and then reducing the surrounding pressure so the ice sublimates directly to vapour. The resulting powder is a lyophilate. Most research peptides are supplied as lyophilised powders because this form is stable at room temperature during shipping and has a shelf life of years when stored correctly.; See also: Reconstitution, Bacteriostatic water

M

Mass spectrometry (MS): An analytical technique that measures the mass-to-charge ratio of ions. In peptide quality control, mass spectrometry confirms that the molecular weight of the compound matches the expected weight of the target peptide. A mass spec result that matches the theoretical molecular weight is strong evidence of correct chemical identity.; See also: HPLC, Certificate of Analysis
Melanotan II (MT-II): A synthetic cyclic analogue of alpha-MSH (alpha-melanocyte-stimulating hormone). It acts on melanocortin receptors (MC1R, MC3R, MC4R). MT-II is studied for its role in melanogenesis and tanning, its effects on libido via MC4R, and its potential appetite-suppressing properties.; See also: Melanotan I, Alpha-MSH
Melanotan I (MT-I): A linear synthetic analogue of alpha-MSH. It binds selectively to MC1R with higher receptor selectivity than Melanotan II. Research focuses on its effects on melanogenesis and photoprotection. Unlike MT-II, it has little to no activity at MC4R.; See also: Melanotan II

P

Peptide: A short chain of amino acids linked by peptide bonds (the covalent bond formed between the carboxyl group of one amino acid and the amine group of the next). By convention, chains of 2-50 amino acids are called peptides; longer chains are proteins. The distinction is not strict.
Peptide bond: The covalent bond linking amino acids in a peptide chain. Formed when the carboxyl group of one amino acid reacts with the amine group of the next, releasing water. Peptide bonds are cleaved by proteases and by the acidic environment of the stomach, which is why most peptides are not orally bioavailable and must be administered via injection.

R

Reconstitution: The process of dissolving a lyophilised peptide powder in a liquid diluent (usually bacteriostatic water) to create an injectable solution. The standard approach is to inject the diluent down the side of the vial and allow the powder to dissolve without shaking or vortexing, which can denature the peptide.; See also: Bacteriostatic water, Lyophilisation
Retatrutide: A triple incretin receptor agonist that activates GLP-1, GIP, and glucagon receptors simultaneously. Under investigation for metabolic disease, obesity, and NASH. In early clinical trials it showed the largest weight loss of any agent in its class at the time. Also known as LY3437943.; See also: GLP-1 receptor agonist

S

Semaglutide: A GLP-1 receptor agonist with a fatty acid chain modification that extends its half-life to approximately seven days, allowing once-weekly dosing. The active ingredient in Ozempic and Wegovy. Widely studied for type 2 diabetes management and weight reduction.; See also: GLP-1 receptor agonist, Half-life
Sterile water: Water that has been sterilised to remove microorganisms, but contains no preservative. Suitable as a single-use diluent. Unlike bacteriostatic water, a vial reconstituted with sterile water should be used immediately or within 24 hours, as there is no antimicrobial agent to prevent contamination once the septum is punctured.; See also: Bacteriostatic water, Reconstitution

T

TB-500 (Thymosin Beta-4): A synthetic version of a naturally occurring 43-amino acid peptide produced by the thymus. Studied for its role in actin regulation, angiogenesis, wound healing, and tissue repair. The active fragment of Thymosin Beta-4 responsible for most studied effects is the Ac-SDKP tetrapeptide.; See also: BPC-157
TFA salt: Trifluoroacetate salt. TFA is used as a mobile phase modifier during HPLC purification and can remain as a counterion in the final product if a salt exchange step is omitted. TFA has cytotoxic properties and high TFA content is undesirable in research peptides. Reputable manufacturers perform a salt exchange to supply acetate salts instead.; See also: Acetate salt

V

Vial septum: The rubber stopper that seals a peptide vial. Designed to be punctured repeatedly with a needle without losing its seal. Always clean the septum with an alcohol swab before each puncture to prevent contamination.

Peptide Research Glossary

Plain-language explanations of terms used in peptide research, quality testing, and reconstitution.

A B C DEFG H IJKL MNOPQR S TUVWXYZ

A

Acetate salt: The form most synthetic peptides are supplied in. Acetic acid is used during HPLC purification and leaves an acetate counterion bound to the peptide. Acetate salts are water-soluble and suitable for reconstitution with bacteriostatic water.; See also: TFA salt, Lyophilisation
Amino acid: The building block of peptides and proteins. Each amino acid has a central carbon bonded to an amine group, a carboxyl group, a hydrogen, and a variable side chain. The sequence and composition of amino acids determines a peptide's biological activity.

B

Bacteriostatic water (BW): Sterile water containing 0.9% benzyl alcohol. The benzyl alcohol acts as a preservative that inhibits bacterial growth, allowing a reconstituted peptide vial to be stored in the fridge for several weeks after opening. The standard diluent for peptide reconstitution.; See also: Reconstitution, Sterile water

C

Certificate of Analysis (COA): A document from the testing laboratory that records the results of quality control tests on a specific batch of a product. For peptides, a COA typically includes the HPLC purity percentage, the mass spectrometry identity confirmation, the batch number, and the test date. A legitimate COA comes from an independent third-party lab, not the supplier.; See also: HPLC, Mass spectrometry
CJC-1295: A synthetic analogue of growth hormone-releasing hormone (GHRH). It stimulates the pituitary gland to release growth hormone. Often combined with ipamorelin (a ghrelin mimetic) to produce a synergistic pulse of GH release. Available with or without DAC (Drug Affinity Complex), which dramatically extends its half-life.; See also: Ipamorelin, GHRH, Half-life

D

Dalton (Da): The unit used to express molecular weight. One dalton equals approximately the mass of a single hydrogen atom. Small peptides typically range from 500 Da to 5,000 Da. Larger peptides approach the molecular weight of small proteins.
Disulfide bond: A covalent bond formed between the sulfur atoms of two cysteine residues. Disulfide bonds stabilise peptide structure and are important for activity in many peptides. Incorrect disulfide bond formation (disulfide scrambling) during synthesis can reduce purity and potency.

G

GLP-1 receptor agonist: A class of peptide that activates the glucagon-like peptide-1 receptor. GLP-1 receptor agonists stimulate insulin secretion, suppress glucagon, slow gastric emptying, and reduce appetite. Semaglutide is the most well-known pharmaceutical example. Retatrutide is a triple agonist that also targets GIP and glucagon receptors.; See also: Retatrutide, Semaglutide
GMP (Good Manufacturing Practice): A quality system that governs the manufacturing environment, processes, and documentation for pharmaceutical and research-grade compounds. GMP certification indicates that a facility has been audited for contamination controls, equipment calibration, batch traceability, and staff training. Peptide Central sources exclusively from GMP-certified manufacturers.
Growth hormone releasing hormone (GHRH): A hypothalamic hormone that signals the pituitary to secrete growth hormone. Synthetic GHRH analogues like CJC-1295 replicate this signalling pathway and are used in research on GH secretion and body composition.; See also: CJC-1295

H

Half-life: The time it takes for the concentration of a compound in the body to fall by 50%. Most unmodified peptides have short half-lives (minutes to hours) because enzymes in the blood rapidly cleave the peptide bonds. Chemical modifications such as PEGylation, DAC conjugation, or fatty acid chains can extend half-life from hours to days.; See also: CJC-1295, Semaglutide
HPLC (High-Performance Liquid Chromatography): An analytical technique that separates compounds in a mixture based on how strongly they interact with a stationary phase inside a pressurised column. In peptide analysis, reverse-phase HPLC separates the target peptide from synthesis impurities, truncated sequences, and oxidised variants. The area under the target peak divided by the total peak area gives the purity percentage.; See also: Certificate of Analysis, Mass spectrometry

I

Ipamorelin: A selective growth hormone secretagogue and ghrelin mimetic. It stimulates GH release from the pituitary without significantly raising cortisol or prolactin. Often stacked with CJC-1295 for a synergistic GH pulse. One of the most selective peptides in its class.; See also: CJC-1295, GHRP

L

Lyophilisation (freeze-drying): A preservation process that removes water from a substance by freezing it and then reducing the surrounding pressure so the ice sublimates directly to vapour. The resulting powder is a lyophilate. Most research peptides are supplied as lyophilised powders because this form is stable at room temperature during shipping and has a shelf life of years when stored correctly.; See also: Reconstitution, Bacteriostatic water

M

Mass spectrometry (MS): An analytical technique that measures the mass-to-charge ratio of ions. In peptide quality control, mass spectrometry confirms that the molecular weight of the compound matches the expected weight of the target peptide. A mass spec result that matches the theoretical molecular weight is strong evidence of correct chemical identity.; See also: HPLC, Certificate of Analysis
Melanotan II (MT-II): A synthetic cyclic analogue of alpha-MSH (alpha-melanocyte-stimulating hormone). It acts on melanocortin receptors (MC1R, MC3R, MC4R). MT-II is studied for its role in melanogenesis and tanning, its effects on libido via MC4R, and its potential appetite-suppressing properties.; See also: Melanotan I, Alpha-MSH
Melanotan I (MT-I): A linear synthetic analogue of alpha-MSH. It binds selectively to MC1R with higher receptor selectivity than Melanotan II. Research focuses on its effects on melanogenesis and photoprotection. Unlike MT-II, it has little to no activity at MC4R.; See also: Melanotan II

P

Peptide: A short chain of amino acids linked by peptide bonds (the covalent bond formed between the carboxyl group of one amino acid and the amine group of the next). By convention, chains of 2-50 amino acids are called peptides; longer chains are proteins. The distinction is not strict.
Peptide bond: The covalent bond linking amino acids in a peptide chain. Formed when the carboxyl group of one amino acid reacts with the amine group of the next, releasing water. Peptide bonds are cleaved by proteases and by the acidic environment of the stomach, which is why most peptides are not orally bioavailable and must be administered via injection.

R

Reconstitution: The process of dissolving a lyophilised peptide powder in a liquid diluent (usually bacteriostatic water) to create an injectable solution. The standard approach is to inject the diluent down the side of the vial and allow the powder to dissolve without shaking or vortexing, which can denature the peptide.; See also: Bacteriostatic water, Lyophilisation
Retatrutide: A triple incretin receptor agonist that activates GLP-1, GIP, and glucagon receptors simultaneously. Under investigation for metabolic disease, obesity, and NASH. In early clinical trials it showed the largest weight loss of any agent in its class at the time. Also known as LY3437943.; See also: GLP-1 receptor agonist

S

Semaglutide: A GLP-1 receptor agonist with a fatty acid chain modification that extends its half-life to approximately seven days, allowing once-weekly dosing. The active ingredient in Ozempic and Wegovy. Widely studied for type 2 diabetes management and weight reduction.; See also: GLP-1 receptor agonist, Half-life
Sterile water: Water that has been sterilised to remove microorganisms, but contains no preservative. Suitable as a single-use diluent. Unlike bacteriostatic water, a vial reconstituted with sterile water should be used immediately or within 24 hours, as there is no antimicrobial agent to prevent contamination once the septum is punctured.; See also: Bacteriostatic water, Reconstitution

T

TB-500 (Thymosin Beta-4): A synthetic version of a naturally occurring 43-amino acid peptide produced by the thymus. Studied for its role in actin regulation, angiogenesis, wound healing, and tissue repair. The active fragment of Thymosin Beta-4 responsible for most studied effects is the Ac-SDKP tetrapeptide.; See also: BPC-157
TFA salt: Trifluoroacetate salt. TFA is used as a mobile phase modifier during HPLC purification and can remain as a counterion in the final product if a salt exchange step is omitted. TFA has cytotoxic properties and high TFA content is undesirable in research peptides. Reputable manufacturers perform a salt exchange to supply acetate salts instead.; See also: Acetate salt

V

Vial septum: The rubber stopper that seals a peptide vial. Designed to be punctured repeatedly with a needle without losing its seal. Always clean the septum with an alcohol swab before each puncture to prevent contamination.