Reviewed August 2026 by the Corydalis Labs Technical Team. How we research and review.
Why the names mislead
Both names follow the same convention: a number, then "OH," which is chemical shorthand for a hydroxyl group. The number says where on the molecule that group sits. That is all the names have in common — they describe a modification, not a family.
It is the same logic by which 1-butanol and 1-propanol share a naming pattern while being different substances. Reading "13-OH" as a sibling of "7-OH" is like reading "Fifth Avenue" as a sibling of "Fifth Street."
Side by side
| 13-OH | 7-OH | |
|---|---|---|
| Full name | 13-OH Corydalis Yanhusuo | 7-hydroxymitragynine |
| Source plant | Corydalis yanhusuo (poppy family) | Mitragyna speciosa — kratom (coffee family) |
| Parent compound | Tetrahydropalmatine | Mitragynine |
| Alkaloid class | Isoquinoline | Indole |
| Discussed in terms of | Dopaminergic signalling | Opioid receptor activity |
| Federal status, Aug 2026 | Not scheduled | DEA notice of intent, July 2026 |
| State kratom acts | Outside their scope | Within their scope |
| Role in a formula | Synergist at 25–40 mg | Was used as a primary active |
The regulatory difference, and why it is structural
7-OH is a derivative of mitragynine — chemistry regulators had already been examining for years. When action came, it came to the family. Pseudoindoxyl and MGM-15, both also built on mitragynine, were named in the same July 2026 notices.
13-OH is not part of that family. Its parent alkaloid is not scheduled, its source plant has no scheduling history at any level, and the salts-and-isomers principle in the Controlled Substances Act extends control to derivatives only where a parent compound is itself scheduled. There is no existing listing for a rule to attach to.
That is a structural difference rather than a timing difference — which is the distinction worth understanding if you are choosing what to build on next. The regulatory summary sets it out with sources.
What this means practically
13-OH is not a drop-in replacement for 7-OH. We say that plainly because the alternative is selling you a disappointment. They are different compounds doing different jobs — 7-OH was used as a primary active; 13-OH is a synergist that improves a blend.
Brands moving off 7-OH successfully are doing one of two things: adding 13-OH to a mitragynine product to make it genuinely differentiated, or building kratom-free products that were not previously possible. Neither is "7-OH but legal," and any supplier telling you they have that is either misinformed or hoping you are. The reformulation playbook covers both routes.
Common questions
No. Different source plant, different parent compound, different alkaloid family, different regulatory position. The only thing shared is a naming convention that records where a hydroxyl group sits.
The question assumes they are comparable in a way they are not. 13-OH is a synergist used at 25–40 mg to improve a blend; 7-OH was used as a primary active. Asking which is stronger is like asking whether salt is stronger than heat.
You can use the same format, the same line, and often the same packaging — but you should not expect the same formula to behave the same way. Reformulate deliberately rather than swapping one powder for another. The playbook walks through it.
It does not currently share the feature that led to 7-OH being scheduled — being a derivative of chemistry already under regulatory examination. No one can guarantee what any agency will do in future, and we would distrust anyone who claimed otherwise. What we can show you is why the starting position is different. Regulatory summary.