Several traditional treatments for GBS onset are IVIG & plasmapheresis. Both are designed to influence your immune system to stop attacking / damaging the myelin sheath in your peripheral nervous system. I was prescribed a 5-day IVIG treatment while an in-patient, which involved a daily bag of medication administered by IV. Research has shown neither to be more effective, but I believe the IVIG solution is the dominant choice. Once the ascending nature of paralysis has been stopped, healing usually proceeds very slowly. I've explored, but am unaware of any other non-medically prescribed treatments / nutrition or supplements / or exercise regimens that truly accelerate recovery from GBS. I've read that some vibration therapy can be beneficial to nerve recovery, & some NASA studies indicate certain wavelengths of light can stimulate nerve healing. As I did, you may be able to access the light therapy on outpatient PT. I occasionally use a large back massager to massage (vibrate) the bottom of my feet, in case it may be beneficial, but I can't say with certainty that it's a healing aid.