Yes. You get withdrawal if you go above a microdose; even at that level (10mg doses) you get some psychological withdrawal.

That's because it's pharmaceutically akin to an extremely high potency fentanyl derivative as it hits mu opioid as a full agonist, without any delta opioid agonism. As soon as you get to a euphoria-inducing dosage(which is 'only' like 30mg) you get strong b-arrestin dependent internalization of the mu opioid receptor(downregulation) alongside a significant heteromer equillibrium shift away from mu/delta dimer formation, e.g. tianeptine activates both primary mechanisms of opioid tolerance.

This strong tolerance-building effect may play a role in its theraputic action; as the rapid and intense internalization of the mu opioid receptor (and only the mu opioid receptor) normalizes receptor density. Basically in antidepressant use you take tianeptine to get an opioid tolerance without getting opioid effects.

High site occupation time, high intrinsic activity, high potency, high bioavailability, high BBB permiability, and extremely high selectivity towards mu opioid versus delta opioid make tianeptine unique in dependence liability among clinically used opioid ligands.

That said if you want to microdose opioids for mood stabilizing effect it's great, because the tolerance building effect you're after will take effect below a euphoria-inducing dose; which limits your psychological dependence.