OP was referring to PGR’s - ie: “Plant Growth Regulators”. These growth regulators refer to Auxins, Gibberellins, Cytokinins and what they do is to trigger responses from a plant on a cellular level - they can tell a plant to flower, to send out more branching, larger root formation, lateral growth - and much more. Organic sources for example might be Kelp Meal - but what OP is referring to is synthetic sources of PGR’s. I don’t have time to start looking now but it was shown back some years ago that some of the PGR’s marketed to cannabis gardeners were either carcinogenic or caused other issues in people when ingested - or smoked. J
This is what Op was referring to - I believe. PGRs and Medical Marijuana | Hydroponics And here - Plant Growth Regulators Poison Marijuana - Marijuana Growers HQ J
How can you know that...without a lab test and yeah like @jerry111165 says PGRs come in many forms many natural good luck