Industry had been hoping that the governor would veto the bill after he stopped a similar law entering into force last year.
But his press secretary Margita Thompson said this new bill is more specific than that which he vetoed for vagueness last year.
Bill SB-37, introduced by Senator Jackie Speier in December last year as an amendment to the California Education Code, will require high school athletes to pledge not to use ephedrine alkaloids, dehydroepiandrosterone (DHEA) or synephrine (also known as bitter orange or citrus aurantium), and prohibits their marketing at school-related events.
But trade association, the Council for Responsible Nutrition, and other supplement groups have heavily criticised the bill for referring only to 'dietary supplements' and not including performance enhancing substances.
This creates the impression that dietary supplements are a problem, and that all or many dietary supplements are unsafe and prohibited by the USADA, it previously warned.
The CRN has also questioned the scope of the bill, pointing out that ephedrine alkaloids are already banned both in California and by the FDA, and that the sale of DHEA (dehydroepiandrosterone) to minors is also restricted in the state.
Synephrine, meanwhile, is not restricted by the US Anti-Doping Agency but is merely on its monitoring list, along with caffeine.
"It is a bill that does nothing," said Judy Blatman, senior vice president of communications at CRN.
"We are very disappointed that the governor bowed to political pressure rather than looking at the merits of the bill," she told NutraIngredients-USA.com
Schwarzenegger said little about the new bill during a signing ceremony on Friday and took no questions about it.
Many of these wanted to know if he had signed Speier's bill into law because of pressure to deny his ties with the supplements industry, which caused media outrage this summer.
A federal securities filing disclosed he would earn at least $1 million a year for five years as a consultant to a publisher of fitness magazines for which much of the advertising comes from nutritional supplement companies.
"We still maintain that it inappropriately singles out the dietary supplements industry while ignoring the real problem. Unfortunately it sends a negative message to Californians," added Blatman.
"It's still a waste of tax-payers money," she said.