Navalny, the leading opponent of Russian President Vladimir Putin, fell ill on a domestic flight in Siberia last month and was airlifted to Berlin while still in a coma.
“Let me tell you how my recovery is going. It is already a clear path although a long one,” Navalny wrote.
In the Instagram post he said he had difficulties using his phone, pouring water or climbing stairs because his hands failed him and his legs trembled.
Germany says laboratory tests in three countries have determined that Navalny was poisoned with a Novichok nerve agent. Western governments have demanded an explanation from Russia.
The Kremlin denied Russia was responsible for Navalny’s illness and said that there was not enough evidence of his poisoning.
Russian authorities have refused to open a formal probe into Navalny’s case and instead have launched a preliminary procedure, which should conclude if an investigation is needed.
Russian prosecutors also ordered an inspection of the hotel in Siberian city Tomsk where Navalny stayed before collapsing on a plane and where his team said traces of Novichok were discovered on a water bottle.
The inspection found several minor health and sanitation violations in the hotel’s restaurant, for which its staff would be fined 62,000 roubles ($820), according to a report on the Prosecutor’s General Office website, published on Saturday.
Among the listed violations were celery used by the restaurant without documentation on its quality, absence of trash bin covers and drying dishes on unsuitable shelves.
The head of Germany’s foreign affairs committee, Norbert Roettgen, told the Frankfurter Allgemeine Sonntagszeitung weekly newspaper that there should be an international investigation into the circumstances in which Navalny fell ill.
“This can be done within the framework of the UN or the Council of Europe,” he said.
Navalny said in his post that after weeks in a medically induced coma and with assisted breathing, his current health problems seemed minor.
“I’ll tell you why. Only recently I couldn’t recognize people and didn’t know how to talk,” he wrote.
Earlier this week he posted his first picture from hospital, surrounded by his family. His spokeswoman said he planned to return to Russia as soon as he recovers.