Can Optimal Liposomal Glutathione vary in viscosity?

Yes. Variation in viscosity may occur due to a minor water level difference in the finished product.
The fill level sensors in the production tanks have a 3% plus or minus precision. As a result lots can vary by as much as 6%, since some will be 3% over filled and some will be 3% underfilled. The product formulas include a 6% or greater overage of ingredients to ensure that even if the fill level is 3% over due to the sensor precision, the product will still be 3% over specification.
A 6% variability in water level between batches can result in viscosity change that ‘appears’ to be greater, such as 20% to 30% viscosity change. This variation is normal and does not alter the quality of the supplement.