Everything below concerns IGF-1. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Updated 2026-04-26. Numbers and descriptions here follow the published literature rather than marketing material.
Tesamorelin is a synthetic peptide that belongs to the growth hormone-releasing hormone (GHRH) family. Its sequence corresponds to the fully active 44-amino-acid form of human GHRH, with a single structural modification: the addition of a trans-3-hexenoyl group at the N-terminus. That modification is not found in the naturally occurring hormone and was introduced deliberately during development to improve stability against enzymatic degradation. The compound is therefore best described as a stabilized analogue rather than a naturally occurring peptide.
The native hormone is produced in the hypothalamus and acts on the anterior pituitary. Binding of GHRH to its receptor stimulates synthesis and release of growth hormone into circulation. Because the analogue retains the receptor-binding region of the parent sequence, it engages the same receptor and triggers the same downstream signaling. The result is increased growth hormone secretion from pituitary cells, which in turn influences hepatic production of insulin-like growth factor 1. This axis is the basis for the compound's measured biological effects.
Interest in this peptide developed because native GHRH has a short circulating lifetime. The N-terminal modification slows cleavage by dipeptidyl peptidase IV, an enzyme that removes the first two residues of many peptides and terminates their activity. Slower degradation means a longer window of receptor stimulation per administration. This design logic parallels other modified peptide hormones, where a small chemical change at a vulnerable site yields a more durable molecule without altering the core mechanism of action.
Tesamorelin is a synthetic peptide that belongs to the growth hormone-releasing hormone family and contains the same forty-four amino acid sequence as endogenous GHRH, extended at the amino terminus by a trans-3-hexenoyl group. That small fatty acid modification protects the peptide from rapid cleavage by dipeptidyl peptidase-4, the enzyme that shortens the half-life of native GHRH to only a few minutes. Chemically the compound is produced by solid-phase peptide synthesis, purified by chromatography, and supplied as a sterile lyophilized powder for reconstitution.
Regulatory approval in the United States came in 2010, when the Food and Drug Administration cleared the peptide for the reduction of excess abdominal fat in adults with HIV infection and associated lipodystrophy. The decision rested mainly on two randomized phase 3 trials that enrolled roughly eight hundred patients and ran for twenty-six weeks. Participants receiving active drug showed substantially greater declines in visceral adipose tissue than those receiving placebo, while total body weight changed comparatively little. A reformulated presentation was later approved, and the product has remained a niche therapy rather than a general weight-loss agent.
Tesamorelin occupies a narrow position among agents that act on the growth hormone axis. Unlike growth hormone itself, which is given as replacement, it stimulates the pituitary to release the hormone in pulses, so the downstream increase in insulin-like growth factor 1 depends on intact somatotroph function. Other peptides in the same family include shorter GHRH fragments and synthetic secretagogues with different stability profiles. Several points remain unresolved, including whether the reduction in visceral fat translates into fewer cardiovascular events, what happens to metabolic markers after long-term use, and how the drug compares with lifestyle or surgical approaches.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C221H366N72O67S | Reflects a 44-residue peptide with one N-terminal modification |
| Approximate molecular weight | 5136 Da | Sequence length and single acyl group determine the mass |
| Appearance | White to off-white lyophilized powder | Typical form of a purified synthetic peptide |
| Solubility class | Soluble in water and aqueous buffer | Peptide backbone favors aqueous dissolution |
| Common synonyms | GHRH(1-44) analogue; Egrifta | Descriptive name and approved brand name |
Tesamorelin is a synthetic peptide of forty-four amino acids whose sequence reproduces human growth hormone-releasing hormone. Its distinguishing feature sits at the amino terminus, where a trans-3-hexenoyl group replaces the free amine. That acylation slows cleavage by dipeptidyl peptidase IV, an enzyme that otherwise removes the first two residues and inactivates the natural hormone quickly. The modified peptide therefore persists longer in circulation while keeping the same receptor target. It is handled as a lyophilized solid and dissolved shortly before use.
Signaling begins at the GHRH receptor, a class B G protein-coupled receptor displayed on somatotroph cells of the anterior pituitary. Receptor occupancy activates Gs proteins, which raise adenylyl cyclase activity and intracellular cyclic AMP, in turn driving protein kinase A dependent pathways. The downstream output is synthesis and pulsatile secretion of growth hormone into the bloodstream. Hepatic tissue and peripheral sites respond by increasing insulin-like growth factor 1 production. Somatostatin and IGF-1 itself supply negative feedback that caps the size and duration of each secretory burst.
Octopuses appear in mythology as sea monsters such as the kraken of Norway and the Akkorokamui of the Ainu, and possibly the Gorgons of ancient Greece. A battle with an octopus appears in Victor Hugo's book Toilers of the Sea. Octopuses appear in Japanese shunga erotic art. They are eaten and considered a delicacy by humans in many parts of the world, especially the Mediterranean and Asia.
== Role in disease == A genetic protein C deficiency, in its mild form associated with simple heterozygosity, causes a significantly increased risk of venous thrombosis in adults. If a fetus is homozygous or compound heterozygous for the deficiency, there may be a presentation of purpura fulminans, severe disseminated intravascular coagulation and simultaneous venous thromboembolism in the womb; this is very severe and usually fatal. Deletion of the protein C gene in mice causes fetal death around the time of birth. Fetal mice with no protein C develop normally at first, but experience severe bleeding, coagulopathy, deposition of fibrin and necrosis of the liver. The frequency of protein C deficiency among asymptomatic individuals is between 1 in 200 and 1 in 500. In contrast, significant symptoms of the deficiency are detectable in 1 in 20,000 individuals. No racial nor ethnic biases have been detected. At least 177 disease-causing mutations in this gene have been discovered. Activated protein C resistance occurs when APC is unable to perform its functions. This disease has similar symptoms to protein C deficiency. The most common mutation leading to activated protein C resistance among Caucasians is at the cleavage site in Factor V for APC. There, Arg506 is replaced with Gln, producing Factor V Leiden. This mutation is also called a R506Q. The mutation leading to the loss of this cleavage site actually stops APC from effectively inactivating both Factor Va and Factor VIIIa.
== See also == Abzyme: Antibodies can act as enzymes if they are selected against transition state analogues. Abzymes have a low KM, meaning that they readily bind a target molecule, but have low Vmax values, indicating a slow reaction rate. Biomimetics Bioorthogonal chemistry Catalysis Density functional theory Directed evolution Enzyme Molecular machine Molecularly imprinted polymer Nanochemistry Supramolecular chemistry Zeolite
Sources: en.wikipedia.org
=== Range === The conversion efficiency is essentially 100% from minimum detectable levels up to a flow of CO or CO2 at the detector of about 5×10−5g/s. These represent a detection limit of about 200 ppb and a maximum concentration of about 10% in a 0.5mL sample. Both values are dependent upon peak width.
== IGF-binding proteins == IGF-1 and IGF-2 are regulated by a family of proteins known as the IGF-binding proteins. These proteins help to modulate IGF action in complex ways that involve both inhibiting IGF action by preventing binding to the IGF-1 receptor as well as promoting IGF action possibly through aiding in delivery to the receptor and increasing IGF half-life. Currently, there are seven characterized IGF Binding Proteins (IGFBP1 to IGFBP7). There is currently significant data suggesting that IGFBPs play important roles in addition to their ability to regulate IGFs. IGF-1 and IGFBP-3 are GH dependent, whereas IGFBP-1 is insulin regulated. IGFBP-1 production from the liver is significantly elevated during insulinopenia while serum levels of bioactive IGF-1 is increased by insulin.
A potential risk of frequent repeated long-term use of LSD and other serotonergic psychedelics is cardiac fibrosis and valvulopathy due to serotonin 5-HT2B receptor agonism. This may also be the case with microdosing. However, the risks are theoretical, and more research is needed to see if these complications can actually occur with psychedelics. A preliminary animal study found that chronic microdosing of LSD did not result in heart structure changes or valvulopathy in rodents. Research appears to be mixed on whether LSD is a potent serotonin 5-HT2B receptor agonist or not, with some studies finding it to be essentially inactive.
Sources: en.wikipedia.org
== History == In 1935, Hans Adolf Krebs discovered D-amino acid oxidase after an experiment with porcine kidney homogenates and amino acids. Shortly after, Warburg and Christian observed the oxidase had a FAD cofactor making it the second flavoenzyme to be discovered. In the upcoming years other scientists developed and improved the purification procedure for a porcine D-amino acid oxidase. In 1983, inhibitors for the oxidase were discovered. In 2006, the 3D structure of the oxidase was published. Currently, the link between human D-amino acid oxidase (hDAAO) activity and schizophrenia is being researched.
== Epidemiology == Coronary artery disease is the leading cause of death in men and women. This condition is the cause of one third of all deaths, which is especially worse in areas with lower socioeconomic status. Mortality is nearly five times higher in men than women, but mortality difference narrows with age. Black women are more likely than white women to have a heart attack. Black adults have a higher mortality rate than white adults from heart attack. Asian adults have the least incidence of coronary artery disease. Asian Indian men, Filipino men and Filipino women have a higher risk than white people. Young Hispanic women who have a heart attack have a higher mortality rate than young Hispanic men. They have a higher mortality rate than young Black adults and young white adults.
== Alanine world hypothesis == Alanine is one of the twenty canonical α-amino acids used as building blocks (monomers) for the ribosome-mediated biosynthesis of proteins. Alanine is believed to be one of the earliest amino acids to be included in the genetic code standard repertoire. On the basis of this fact the "alanine world" hypothesis was proposed. This hypothesis explains the evolutionary choice of amino acids in the repertoire of the genetic code from a chemical point of view. In this model the selection of monomers (i.e. amino acids) for ribosomal protein synthesis is rather limited to those alanine derivatives that are suitable for building α-helix or β-sheet secondary structural elements. Dominant secondary structures in life as we know it are α-helices and β-sheets and most canonical amino acids can be regarded as chemical derivatives of alanine. Therefore, most canonical amino acids in proteins can be exchanged with alanine by point mutations while the secondary structure remains intact. The fact that alanine mimics the secondary structure preferences of the majority of the encoded amino acids is practically exploited in alanine scanning mutagenesis. In addition, classical X-ray crystallography often employs the polyalanine-backbone model to determine three-dimensional structures of proteins using molecular replacement—a model-based phasing method.
Sources: en.wikipedia.org
It shares the 44-residue sequence of human GHRH but carries an added trans-3-hexenoyl group at its N-terminus. That addition does not occur in the natural hormone and serves mainly to resist enzymatic breakdown. The receptor target and signaling pathway remain the same.
It binds the growth hormone-releasing hormone receptor on anterior pituitary cells. Activation of that receptor promotes synthesis and release of growth hormone. The effect propagates through the growth hormone and insulin-like growth factor 1 axis.
Native GHRH is cleared quickly by peptidases, which limits how long it can stimulate its receptor. The added group hinders one of the primary cleavage enzymes. The practical consequence is a longer period of receptor activity per dose.
It is a laboratory-made peptide of forty-four amino acids whose sequence matches human growth hormone-releasing hormone, with a modified amino terminus. The modification is a short unsaturated fatty acid chain attached to the first residue. This change slows enzymatic breakdown and lengthens the time the peptide stays active in circulation.