Sport's rulebook catches up with peptides: what the 2027 WADA list changes

Every autumn the World Anti-Doping Agency (WADA) publishes the list of substances banned in sport for the coming year. The 2027 edition takes effect on 1 January 2027 ², and for anyone who follows peptide science it holds one notable change: peptides as a group are now spelled out under the list's catch-all class for unapproved drugs ¹. Alongside that, WADA left the GLP-1 medicines semaglutide and tirzepatide unbanned but under study ².

This is a policy story rather than a biology story. Nothing here tells us whether any peptide works or is safe in people. What it shows is how regulators are responding to peptides, and how the lab science of detecting them is developing.

What actually changed

The list has a class called S0, "non-approved substances." It covers drugs with no current approval for human therapy, such as compounds still in development, discontinued drugs, designer drugs and veterinary-only products, and it applies at all times, in and out of competition ¹⁵.

According to the US Anti-Doping Agency's (USADA) athlete advisory, the 2027 list now names "peptides" in general as prohibited within S0 ¹. France's anti-doping agency, AFLD, describes a related addition: a warning that the peptides named on the list are examples only, and that a peptide not named may still be banned and still carry health risks ³.

This builds on earlier steps. In 2022 WADA named a substance as an example in S0 for the first time: BPC-157, which it described as an experimental peptide sold as a supplement ⁴. Many better-known peptides already sit in class S2, peptide hormones and growth factors. On the current list those named examples include the growth hormone fragments AOD-9604 and hGH 176-191, growth hormone-releasing peptides, and thymosin beta-4 derivatives such as TB-500 ⁵. USADA's summary of where common peptides fall for 2027 lists the same S2 placements, with ipamorelin under S2 and ibutamoren (MK-677) under S1 ¹.

Other additions touch metabolism research. The experimental compounds SLU-PP-332 and SLU-PP-915 were added as examples in S4, hormone and metabolic modulators ¹.

GLP-1 drugs: watched, not banned

For the approved GLP-1 receptor agonists semaglutide and tirzepatide, WADA said their status stays unchanged for 2027 while more data come in ². They remain in the Monitoring Program, which tracks substances that are not prohibited so WADA can gather evidence on use ¹².

WADA's Senior Director of Science and Medicine, Olivier Rabin, said its expert advisory group weighed the drugs' status carefully but did not yet have enough evidence to conclude with confidence that they meet the criteria for the list ². One sport-related study is already running and WADA has started a second, with the aim of making a firm decision later ².

Why detection science matters

A ban is only as useful as the test behind it, and peptides can be hard to catch, partly because they break down into fragments that a test must also find ⁶.

The analytical work here is quietly impressive. In a 2023 study, researchers mapped how BPC-157 is broken down using human liver and skin enzyme preparations in the lab ⁶. Using a version of the peptide tagged with heavy isotopes, they picked out nine breakdown products, including one from a pathway not described before ⁶. They then built a urine test for BPC-157 and five of its fragments with detection limits around 0.01 to 0.11 nanograms per millilitre ⁶. This was cell-free lab work, not a study in people, so the real-world detection window is still to be measured.

An annual review of doping-analysis research summarised this BPC-157 assay and said its sensitivity should be adequate for routine doping controls ⁷. The same review notes a wider move toward small capillary blood samples, including dried blood spots, for some tests ⁷.

The safety thread

The list is about fair play, but health runs through it. The 2023 BPC-157 paper notes that proper clinical trials in humans have not yet been done ⁶. USADA warns athletes that peptides sold under other names may not appear on the list or on lookup tools yet can still be banned and harmful ¹. A US Department of Defense supplement-safety program adds that for peptides sold online as "research" products, neither purity nor potency can be assured ⁸.

The optimistic reading is that peptides now matter enough that sport's rulebook has to plan for them. And the tools to detect peptides and their breakdown products keep getting sharper ⁶⁷.

What to watch

• The GLP-1 studies: WADA expects its two athlete studies to provide the data needed for a firm decision on semaglutide and tirzepatide ².
• Human detection data: whether lab-built peptide tests, like the BPC-157 urine assay, hold up in samples from people ⁶⁷.
• The full 2027 text: the list enters into force on 1 January 2027, and WADA's published explanatory notes set out the added S0 examples and clarifications ².

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