A potent effect in cultured cells is not the same as a demonstrated increase in human muscle size or strength. The distinction is especially important when a workout sensation is presented as confirmation that a growth factor is building new tissue.
The early LR3 analogue paper compared biological activity in cell models, including rat myoblasts. It investigated protein synthesis, DNA synthesis and related responses. Those experiments helped characterize the analogue, but they were not trials of human hypertrophy.
A pump, a molecular signal and a lasting outcome differ
A short-lived sensation during exercise cannot establish a durable structural change. A laboratory signal is also not a complete account of how an organism adapts. Even if both are real, the evidence must connect them to the claimed outcome rather than assume the connection.
A convincing human muscle claim would need appropriate measurements over time, a comparison group and an assessment of function and unwanted effects. The relevant starting conditions and other interventions would also need to be described.
This is why anecdotal rankings of LR3, DES IGF or other growth-factor products are unreliable. A participant may change training, nutrition and several substances simultaneously while crediting one product for the result.
The cell study does not establish that a catalog vial has comparable identity or potency. Nor does a reported laboratory purity result turn a cell-model finding into clinical evidence.
For a reader worried about loss of muscle or physical function, the appropriate question is what medical or training-related factors need assessment, not which analogue produces the most dramatic immediate feeling.
The paper supports an experimental biological activity claim. It does not establish a bodybuilding treatment, a safe exposure pattern or a personal probability of gaining muscle. Preserving that boundary allows interesting cellular science to remain informative without turning it into a promise the experiment did not test.