Yes. MK-677, also called ibutamoren, is prohibited at all times for athletes governed by the World Anti-Doping Agency (WADA), including outside competition. If you compete in NCAA sport, the NCAA also names ibutamoren among banned peptide hormones, growth factors, related substances and mimetics.
MK-677 is a growth hormone secretagogue, meaning it is in the group of substances that signal growth-hormone release. The sport answer is clear: do not treat an online label, a gym recommendation, or a “research” label as clearance to use it.
Short answer: is MK-677 banned?
Under the 2026 WADA Prohibited List, ibutamoren (MK-677) appears in section S2.2.4 as a growth hormone secretagogue. S2 substances are prohibited at all times, both in and out of competition.
That answers the sport-rule question as of October 14, 2026. It is separate from federal law, prescription rules, state sale or delivery rules, and military policy. A sport prohibition does not itself answer those legal questions, and a product’s availability does not make it permitted in tested sport.
What do WADA and the NCAA say?
WADA places MK-677 in its peptide hormones, growth factors, related substances and mimetics category. This is why athletes in WADA-code sport should treat it as off-limits year-round.
The NCAA banned-substances page specifically lists ibutamoren (MK-677) in its peptide-hormones, growth-factors, related-substances and mimetics class. The NCAA says its list is not exhaustive: substances chemically or pharmacologically related to a banned class can also be banned.
| Sport setting | MK-677 status | What to do |
|---|---|---|
| WADA-governed sport | Prohibited at all times under S2.2.4. | Use the WADA list and your governing body’s process. |
| NCAA sport | Named as a banned peptide-hormone-related substance. | Check with your athletics staff before using any substance. |
| Military service | Check the exact ingredient in the DoD database. | Use OPSS rather than a brand-name search. |
Testosterone is also named by the NCAA under anabolic agents. The NCAA likewise lists examples such as nandrolone, oxandrolone, stanozolol and trenbolone, while stressing that examples are not a complete clearance list. Growth hormone (hGH) is named in the peptide-hormones class as well. Your league may have its own rules, so NFL policy is a separate question for the NFL and its current policy documents.
What does this mean for federal, prescription, state, and military rules?
As of October 14, 2026, this page’s WADA source answers the international sport question, and the NCAA source answers the NCAA question. Neither source is a federal statute, a prescription rule, or a state law. Those are separate questions that depend on the exact product, jurisdiction, and rule in force.
The FDA warns that certain bodybuilding products marketed for human use can be unapproved drugs rather than lawful dietary supplements, including products presented with “research” wording. Read the FDA bodybuilding-product warning for the agency’s broader distinction. That warning concerns SARMs and bodybuilding products; it is not a substitute for a product-specific legal opinion about MK-677.
A systematic review of supplement contamination included 44 studies and reported that prohibited substances or unapproved pharmacological agents appeared in about 9–15% of commercially available supplements tested in the included empirical studies. That is one reason a label alone is not a sport-eligibility check.
For service members, the DoD Prohibited Dietary Supplement Ingredients database says to search one exact ingredient at a time, not a brand name. It says service members are prohibited from using substances identified in that database as ingredients in dietary supplements, and that controlled substances and drugs, including unapproved drugs, are prohibited for use in dietary supplements. The database page was last updated September 3, 2026, so check the live entry and your service policy before making a decision.
If you are choosing a regular sports supplement instead, our athlete certification guide explains what NSF Certified for Sport and Informed Sport checks can and cannot tell you about a particular product and lot. For food-first training support, see our endurance supplement guide.
If you already took MK-677, what should you do?
Do not try to guess a testing window or use a workaround. Keep the container, label, purchase record, and any available lot details. Write down the product name and exact ingredient wording so your athletics staff or anti-doping contact can assess the right item.
- For NCAA sport, tell your designated athletics staff and primary athletics health care provider. The NCAA directs student-athletes to check supplements and medications with appropriate athletics staff before use.
- For U.S. anti-doping questions, USADA directs athletes to its Drug Reference Team at DrugReference@USADA.org or 719-785-2000.
- For military questions, use the OPSS exact-ingredient search or its Ask the Expert feature.
- If you feel unwell or have a health concern, contact a clinician promptly and bring the product information.
The practical next step is simple: pause before adding anything else, preserve the label, and ask the organization that governs your sport or service about the exact ingredient. This is general information, not legal advice.
By the Gym Floor Guide Editorial Team