Family Fears For Lindsay Lohan

Lindsay Lohan’s skeletal physique is raising fresh health concerns.

The actress, 22, showed off a barely there bod during a Jan. 23 shopping trip in NYC with her sister Ali, 15.

“She’s beyond skinny and needs to gain weight ASAP,” a source close to the Lohan family tells OK!.

“I’m sure her mom is worried that she has gotten dangerously thin.”

Will her hero-worshipping little sister be next?

“Ali is cognizant of her weight,” the source says, “but she’s naturally skinny, so she can eat whatever she wants.”

Last week, OK! was the first to report that Lindsay was shedding the pounds at a frightening rate, and that girlfriend, Samantha Ronson, was trying to keep up.

"Lindsay is bad for Sam's health," a friend of the pair told OK! at the time.

Lohan's rep denied the story -- but then told another publication that the Mean Girls star was, in fact, getting very thin.

"Lindsay is aware that she's lost some weight due to stress," rep told the New York Post's Page Six on Jan 27. But the rep insists that there's no reason to worry about her health.

"We recently did a photo shoot and she ate two full meals."