The specific formulation of rapamycin, such as Pfizer's enteric-coated Rapamune versus non-coated compounded versions, can dramatically alter bioavailability and the effective dose a person receives.

In a 12-week study on older adults, rapamycin appeared to attenuate the muscle function improvements gained from exercise when compared to the placebo group.

An alternative hypothesis suggests a 4-8 week period of strong mTOR inhibition followed by a 'washout' period might be necessary to reduce chronic inflammation and unlock functional benefits.

The commonly cited 62-hour half-life of rapamycin is derived from daily-dosing transplant patients and may not accurately reflect how the drug clears in healthy people taking it once weekly.

The optimal dose and frequency of rapamycin might be different for various organs, meaning a dose that benefits the brain could potentially be suboptimal for muscle.

Based on the study's results, future research should investigate dosing protocols with longer intervals, such as every three or six weeks, to ensure the drug is cleared before exercise.

The popular once-a-week dosing protocol for rapamycin is described as being largely 'cultural' and based on limited data, meaning researchers are still guessing the optimal frequency.