Yes, ingredients can work in synergy. From the Oxford English Dictionary:
synergy
- Joint action, cooperation
There follows Theological Examples, then a definition and examples for Physiology, then examples from Pharmacology, which I give below, omitting only the first example
1945 Sci. News-Let. Jan. 14/3 Synergy..acquires tremendous
importance in applied chemistry. It means tripling the effectiveness
of an insecticide or doubling the yield of a reaction.
1978 Jrnl. Infectious Dis. 137 123/1 Testing for synergy with
combinations of any number of agents..might lead to the discovery of
antibiotic combinations considerably more potent than those now in
use.
2008 Proc. National Acad. Sci. U.S.A. 105 13977/1 Very little is
known about how the evolution of resistance is affected by the nature
of the interactions—synergy or antagonism—between drugs
Finally, definition #4:
- Any interaction or cooperation which is mutually reinforcing; a dynamic, productive, or profitable affinity, association, or link.
I omit three examples that illustrate the synergy between people or institutions and give the fourth example, below, about synergy between products:
2006 Wall St. Jrnl. 27 Nov. r4/1 A software and hardware
‘ecosystem’ that tries to mimic the successful synergy between iTunes
software and iPod gadgets
Whether you believe the claims of the beauty product is another issue, but two chemicals can work in synergy.