There is no research in animals, cells, or anything to suggest excess glutathione is a problem in the brain, nor that it is even possible that liposomal glutathione raises levels in the brain. It is simply a theory that Dr Standfield is guessing could happen (and a jealous competitor amplifies)
The fact that as we age, glutathione levels do not fall in the brain, but do fall in other tissues shows that it is important enough to preferentially maintain glutathione levels in the brain, and there are systems in place that make it happen.
Dr. Standfield is a smart guy and does a good job explaining research in layman's terms. But he is a medical doctor, not a researcher, and has been reading research on the side for 2 years. His ideas on NMN, NR, Resveratrol and more have changed dramatically over the last 2 years. I think that his conjecture on what could possibly happen here should not be taken as something that actually does occur, when there is zero evidence.
Dr. Rhonda Patrick is a very knowledgeable longevity researcher for many years, and has been taking Pure Encapsulations Liposomal Glutathione for a long time now. Bulletproof also makes a Liposomal Glutathione. They do not share Dr. Standfields concern.