OTR-AC
guinea pig
The Dose Guy’s verdictSep 1, 20260 sources
OTR-AC is sold as an acetate ester of ostarine, an upgrade with better absorption and longer action. The evidence for any of that: zero. No published study in any species, no receptor data, no human trial. If you want what ostarine does, take ostarine. OTR-AC is a label, not a compound with receipts.
What it is
Marketed as an acetylated ester of ostarine, designed to improve oral bioavailability and extend duration. The concept is not crazy: ester prodrugs are standard pharmaceutical chemistry, and the idea is that the body cleaves the ester to release ostarine over a longer window. But no published study confirms the chemical identity, characterizes the pharmacology, or demonstrates that esterifying ostarine produces any measurable benefit. RAD-150 runs the same ester-prodrug theory on the testolone scaffold, with equally absent evidence.
What the research shows
There is no research. That is the finding:
Realistic protocols
There is nothing to build a protocol from. No human PK, no animal PK, no studied dose in any species. Forum dosing mirrors ostarine at 10 to 25 mg daily for six to eight weeks, on the assumption that the ester cleaves to release the parent compound. That assumption has never been tested. If you want the ostarine effect, take ostarine, where you know what the capsule contains, backed by a COA, and what the human data shows. If you run OTR-AC anyway, treat the sourcing question as the real risk: you have no way to verify that the product is the claimed compound without analytical testing. Pull bloodwork before and after, and if suppression shows, have a PCT plan ready. Like every SARM, OTR-AC is WADA-prohibited in tested sport.
Side effects
No adverse events have been measured in any setting. The assumptions:
Where to buy
No live listings from tracked vendors right now.
