Gamma-aminobutyric acid (usually abbreviated to GABA) is increasingly being used with or without Arguireline (the brand name for acetyl=hexapeptide 3). They both pretty much do the same thing, which is not much. Ostensibly, GABA and Arguireline inhibit movement of the facial muscles and, for this reason, are marketed as a Botox in a jar. In fact, they are fairly weak and what effect they do have is short lived.
Even Dr Beilis, the pharmacist in charge of product development at Freeze 24/7, admitted to the New York Times that GABA really does little more than coagulate when it dries and then grip the skin in place. This is because GABA does not work alone to inhibit the nerves. It requires many other substances that are not present in the skin care products that use GABA as a key ingredient.
I can't find out why GABA seems to be taking over from acetyl-hexapeptide. I suspect it is because there are claims that GABA stimulates the anterior pituitary, leading to higher levels of Human Growth Hormone. This is why GABA is taken as a supplement by body builders. I have a feeling that Human Growth Hormone will be one of the next cosmetic miracles waiting to happen and that products with GABA will make full use of the link. It should be noted that the link is tentative and based on studies that haven't been replicated. Furthermore, it is hard to imagine how a cream is going to make its way from your crows' feet to the anterior pituitary.
I really don't think that a product with GABA or acetyl-hexapeptide is worth a cent of my money. But I have noticed that it is getting harder to avoid. It is even being used by Tracie Martyn in her Enzyme Exfollient (something I have been using for years) and Menscience Anti-Aging Formula (which double dips with GABA and acetyl hexpeptide).
GABA, less surprisingly, is the key ingredient in Dr Brandt's Double Dose in a Box, pH Advantage Peptides Rydex-2, LiftFusion Eye Lift and Face Lift, and all the Freeze 24/7 products, including Icecream, seem to be switching from AH3 to GABA, promoting (as can be seen on the jar pictured above) as an advanced technology.