The short answer: nearly every peptide in this space is prohibited
Growth hormone and effectively everything used to raise it are prohibited in sport. Somatropin itself, the GHRH analogues including sermorelin, tesamorelin and CJC-1295, the secretagogues including ipamorelin, hexarelin and the growth hormone releasing peptides, IGF-1 and its analogues including IGF-1 LR3, and thymosin beta-4 with the derivatives sold as TB-500 all fall inside section S2 of the World Anti-Doping Agency Prohibited List.
What athletes miss is when the prohibition bites. S2 sits in the group prohibited at all times, in and out of competition. An out-of-competition sample taken in the off-season, months from any event, establishes a violation. The categories that apply only during competition hold stimulants, narcotics, cannabinoids and glucocorticoids, and no peptide hormone or growth factor is among them.
A peptide that is not named is not thereby permitted. Section S0 covers any pharmacological substance that no government health regulator anywhere has approved for human therapeutic use, and it also applies at all times. Between S0 and the deliberately open drafting of the substance classes, coverage across this compound space is close to total.
How the Prohibited List is organised, and how something gets on it
The Prohibited List is an annexe to the World Anti-Doping Code, published by WADA, revised each year and in force from 1 January. It is not a catalogue of brand names but a taxonomy of pharmacological classes, each illustrated with examples that are explicitly non-exhaustive.
There are three tiers. Prohibited at all times covers non-approved substances, anabolic agents, peptide hormones and growth factors, beta-2 agonists, hormone and metabolic modulators, and diuretics and masking agents, together with the prohibited methods: blood manipulation, chemical and physical manipulation, and gene and cell doping. Prohibited in competition adds stimulants, narcotics, cannabinoids and glucocorticoids on top of all of that. A third tier applies in particular sports only, which is where beta-blockers sit.
Article 4.3 of the Code governs inclusion. A substance is added if it meets any two of three criteria: potential to enhance sport performance, an actual or potential health risk, and violation of the spirit of sport. Two of three is a lower bar than most people assume, and a compound with no demonstrated benefit can qualify on risk and spirit of sport alone. WADA separately publishes a Monitoring Program of substances tracked but not prohibited; appearing there is notice, not clearance.
Why peptide hormones and growth factors sit in the all-times half
The reasoning is pharmacological rather than administrative. Growth hormone and IGF-1 do not act in minutes. Their effects on protein synthesis, connective tissue turnover and body composition accumulate over weeks and persist after the drug has cleared. A substance whose benefit outlasts its presence in blood has to be prohibited during the period when it is useful, which is training, not race day.
S2 has internal structure. One subsection covers erythropoietins and other agents affecting erythropoiesis. A second covers peptide hormones and their releasing factors: chorionic gonadotrophin and luteinising hormone in males only, the corticotrophins, and growth hormone with its fragments and all its releasing factors, meaning the GHRH analogues, the growth hormone releasing peptides and the non-peptide secretagogues. A third covers growth factors, including IGF-1 and its analogues, the mechano growth factors and thymosin beta-4 with its derivatives.
One boundary case shows how the tiers interact. Corticotrophins and their releasing factors are in S2 and prohibited at all times, while the glucocorticoids they cause the adrenal to release are in the in-competition section and restricted by route. Two drugs on one axis, two rules, because the peptide upstream is used differently from the steroid downstream. Somatropin used in December by an athlete who competes in June is a violation in December.
S0, and why not being named is not permission
Section S0 is the provision most often overlooked by people scanning the list for a specific name. It prohibits, at all times, any pharmacological substance not addressed by another section that has no current approval by any governmental regulatory health authority for human therapeutic use, naming drugs in development, withdrawn drugs, designer drugs and veterinary-only substances.
That single clause captures almost the entire research peptide market, because a compound sold under a research use only label has by definition no human therapeutic approval anywhere. BPC-157 is a clear case: whatever one makes of its preclinical data, no regulator has approved it for human use, so it is prohibited at all times under S0 whether or not it is ever named in a substance class.
The named classes are drafted the same way. Each S2 subsection is introduced as including but not limited to, and the definitions extend to substances of similar chemical structure or similar biological effect. An analogue of a named secretagogue is prohibited because it is an analogue. The real question is never whether a name appears in the document; it is whether the compound falls inside a described class or fails the S0 approval test.
The list is republished every year, and checking it is the athlete's job
We are not reproducing the current Prohibited List here, and no article should. It is reissued annually, substances are added and occasionally removed, entries move between categories, and route or threshold conditions change. The glucocorticoid rules were rewritten around route of administration in a recent revision, and the Monitoring Program turns over faster still. Any snapshot in a blog post starts going stale on 1 January.
An athlete bound by anti-doping rules must check the version in force on the date of use, from WADA directly or from their national anti-doping organisation, along with the summary of modifications published with each edition. Several national organisations jointly run a searchable tool for licensed medications sold in specific countries, which settles brand-name questions but does not cover unapproved research chemicals, since those have no medicinal product record to look up.
This matters more than it sounds. Under strict liability the athlete carries the consequence of a mistake, so the burden of verification falls on the athlete personally, not on a coach, a clinic, a supplier or a writer. Treat this article as a description of how the system is built, and the current list as the only authority on what is on it today.
Strict liability, and why not knowing is not a defence
Article 2.1 of the Code makes the presence of a prohibited substance, or its metabolites or markers, in an athlete's sample a violation. Article 2.1.1 puts the principle directly: it is each athlete's personal duty to ensure no prohibited substance enters their body, and intent, fault, negligence or knowing use need not be demonstrated. That is what makes the system workable, because proving intent in a doping case is usually impossible.
Fault does not disappear; it moves to the sanctioning stage. Findings of no fault or no significant fault, and the specific contaminated-product provisions, can substantially reduce a period of ineligibility. But the violation is established, results from the relevant period are disqualified, and the case sits on the record. Reduced is not excused.
Presence is only one of the violations the Code defines. Use or attempted use, possession, trafficking, administration, tampering, complicity and prohibited association are separate ones. Possession of somatropin out of competition without a valid exemption is a violation on its own, with no sample and no laboratory involved. Athletes in a registered testing pool also file whereabouts, and three missed tests or filing failures within twelve months is itself a violation.
Contamination is real rather than a stock excuse, which is why the Code addresses it. An international survey of non-hormonal nutritional supplements published in the mid-2000s found undeclared anabolic androgenic steroids in roughly one in seven of the six hundred and thirty-four products analysed across thirteen countries. Products sold as research peptides face no comparable scrutiny, and none of that changes who answers for the sample.
Therapeutic use exemptions and the four criteria
A therapeutic use exemption lets an athlete with a genuine medical condition use a prohibited substance without committing a violation. It is governed by the International Standard for Therapeutic Use Exemptions and assessed by a panel of physicians. It is an application, not a note from a prescriber.
Four criteria must all be satisfied. The substance must be needed to treat a diagnosed medical condition supported by relevant clinical evidence. Its use must be highly unlikely to enhance performance beyond a return to the athlete's normal state of health. There must be no reasonable permitted therapeutic alternative. And the need must not follow from prior use of a prohibited substance without an exemption.
Applied to growth hormone those criteria are demanding. The first requires documented deficiency: provocative stimulation testing, supporting endocrine results and specialist records rather than one low reading. The second confines the exemption to physiological replacement. Age-related decline in growth hormone secretion, slow recovery from training and body-composition goals are none of them a diagnosed deficiency, and the third criterion rarely survives contact with them. Exemptions for growth hormone are granted, but to people with pituitary disease.
Process matters as well. Applications go to the international federation or the national anti-doping organisation depending on competitive level, and generally must be made before use. Retroactive exemptions are permitted only in narrow circumstances such as emergency treatment, and athletes below a defined level in many jurisdictions may apply retroactively if tested. An exemption from one body may need recognition by another.
How growth hormone is actually tested for
Two validated methods are in routine anti-doping use, on completely different principles. The isoform differential immunoassay exploits the fact that the pituitary secretes a mixture of growth hormone isoforms while recombinant products contain only the 22 kilodalton form. Injected recombinant hormone suppresses endogenous secretion, the ratio between the recombinant form and the rest shifts, and the assay measures that ratio rather than a concentration.
Its window is short, on the order of a day after the last administration, which is why a second method was developed. The biomarker approach from the GH-2000 research project measures IGF-1 and the N-terminal propeptide of type III procollagen and combines them into a score. Because those markers reflect growth hormone action on liver and connective tissue rather than the hormone itself, the window extends to something nearer a couple of weeks.
Both are decision rules built on population reference distributions, with thresholds set so a clean athlete essentially never exceeds them. That is correct, and it has a mathematical consequence: making false positives vanishingly rare necessarily makes false negatives common. Detection across the rest of the class is harder again. Laboratories have published targeted mass spectrometry methods for the releasing peptides, GHRH analogues, modified IGF-1 variants and thymosin beta-4 derivatives, but each has to be validated and actually included in the panel run on a sample.
Why a negative test proves less than athletes assume
The first reason is coverage: a sample is screened for what that day's panel targets, and peptide and growth factor analyses are more involved and more expensive than routine screens. The second is frequency, since most competitors are tested a handful of times a year and out-of-competition testing depends on being in a testing pool at all. The third is threshold design: a negative growth hormone result says only that the sample did not clear a deliberately high bar.
The fourth reason is time. Under the Code samples may be stored and reanalysed within a ten-year limitation period, and reanalysis programmes have repeatedly produced sanctions years after the event as methods improved. A negative result is provisional in a way athletes rarely price in.
The fifth is that a positive test is not required at all. In January 2016 the Court of Arbitration for Sport upheld violations against thirty-four current and former Australian Football League players for use of thymosin beta-4, decided on invoices, records, correspondence and testimony rather than any analytical finding. None of the reasoning above is a map of what escapes detection; it is an argument that the absence of a finding is not evidence of anything.
The compounds people actually ask about
Somatropin is approved in many countries for defined indications including growth hormone deficiency, several paediatric growth disorders and HIV-associated wasting, and is prescription-only wherever it is approved. None of that affects its status in sport: it is in S2, prohibited at all times, and lawful use needs an exemption a healthy athlete will not be granted. Approval status and prohibited status answer different questions.
Ipamorelin and CJC-1295 are unapproved for human therapeutic use in the United States and fall within the secretagogue and GHRH analogue descriptions in S2. IGF-1 LR3 is an IGF-1 analogue covered by the growth factor subsection, and being unapproved is reachable under S0 as well. TB-500 is covered through its parent molecule and likewise has no approval anywhere.
It is worth separating two questions that get conflated constantly. Whether a compound works and whether it is prohibited are independent. TB-500 has no controlled human trial demonstrating a healing benefit, and it is still an anti-doping rule violation. The two-of-three criteria are satisfied by potential performance enhancement and health risk in a compound with no approval and no human safety record; no proof of efficacy is needed.