Jessica Simpson's Snake Semen Concoction Is Likely Bogus, Expert Says

Jessica Simpson may swear by her snake semen drink that she says helps her sing ... but at least one expert tells TMZ the truth is even more of a sticky situation.

Here's the deal ... Jessica recently raved to us about her secret specialty Chinese herb cocktail that she says has legit serpent swimmers in it -- all at the recommendation of her vocal coach.

Zoologist and "Reptile Royalty" star Jay Brewer tells TMZ ... it's highly unlikely Jessica’s concoction has any actual snake sperm in it ... 'cause frankly, it's not that easy to come by (no pun)!

It seems extracting the fluid is super tough ... and even in the largest snakes around the globe, the amount is usually minuscule.

To be clear, Jay ain't calling Jessica a liar … he just suspects she’s been duped -- and the secret ingredient she's actually consuming is snake oil, AKA nothing special.

That said, Jay said anything is possible ... and if JS is really drinking snake semen, the possible benefits would probably be a result of stem cells.

Of course, she isn't the first celeb to turn to animal sperm for personal gain ... Kim Kardashian and Jennifer Aniston both swear by salmon sperm as a route to achieving younger-looking skin.

The whole situation reminds Jay of a tradition done in Southeast Asia where locals put the gall bladder of a snake in their booze and drink it -- to bring them luck.

Whether it be a gall bladder for luck or semen for the vocals ... Jay tells us it’s all BS in his book … and just a mistreatment of animals.