Your hesitation is reasonable. I wouldn’t recommend starting this regimen based on a coach’s advice. Ostarine, also called MK-2866 or enobosarm, is an experimental selective androgen receptor modulator (SARM), not an approved muscle-building supplement. There is no established safe bodybuilding dose.
SARMs have been associated with liver injury, sexual dysfunction and fertility problems, and the FDA warns of potential heart attack and stroke risks. Long-term safety remains uncertain. Splitting the capsules between morning and evening doesn’t establish that the proposed amount is safe. FDA
Before using it, speak with a qualified clinician about the product and your health history. Blood tests can help assess your current health, but normal results cannot guarantee safe use.
Four years of training also doesn’t necessarily mean you’ve reached your natural limit. Reviewing your training progression, calorie intake, protein, sleep and recovery is a more appropriate next step—especially when you’re uncomfortable with the risks.
Further reading: FDA guidance on SARMs and their risks.