Retinol is used for minimizing wrinkles. However, like many topical creams it doesn't defy sag. Facial sagging, in my opinion, can be more aging than creases.
DMAE, short for dimethylaminoethanol, has been cited as an ingredient that will help your jowls defy gravity. It is a naturally occurring substance that facilitates the synthesis of a neurotransmitter called acetylcholine.
It is very hard to find out whether DMAE actually works and, if so how. There is no clear evidence that it halts facial sagging or, if it does, whether it is by stabilizing the membranes, boosting the above mentioned acetylcholine, reducing lipofuscin deposits or none of the above.
As an aside: lipofuscin is a cellular pigment (aging spots on the back of the hands, for instance) consisting of aggregated chunks of molecular waste. It tends to occur in the cells of older people. It is likely that lipofuscin is not simply a byproduct of aging but also contributes to the aging process. Neurons, heart and skin of older people usually contain particularly large amounts of lipofiscin.
Anecdotal evidence about the effects of DMAE suggest it is often noticeable although seldom dramatic. Some people report a cumulative effect with continued use of DMAE.
Evidence beyond the anecdotal is remarkably illusive.
Some tests show that the longevity of animals increased with taking it. Another, on a quail, showed decreased lifespan. A test at the University of Quebec suggests that topical DMEA actually kills cells. This led to a flurry of press reports that DMAE may accelarate aging. However, even the scientist who lead the trial has been relunctant to claim the results were equivocal.
In the meantime DMAE enjoys a consumer market as a supplement. There are all sorts of claims that it increases mental agility and even passion.
Dr Perricone, of the eponymous line of Vitamin C and AHA based anti-aging products, is a proponent of DMAE and, as well as selling a topical DMEA solution and oral supplements, advocates eating fish. However, Nature magazine reported fish yield only a few miligrams of DMAE per pound.
Bottom line: the evidence in favor of DMEA is still so weak that time, money and hope is better directed at other key ingredients such AHAs, retinol and copper peptides.