The claim: stimulates lashes for a 638% increase in lash volume and increased appearance of length, growth and strength.
The experience: For all the highfalutin promises, multiplEYE mascara ain’t all that. (I’m specifically talking about the mascara and not the natural lash enhancer which is a totally different conversation.)
Let’s parse their claim for subtext, shall we?
Whenever you run up against the word “appearance” in a cosmetic or beauty add, use common sense. “Appearance” usually equates to “temporary,” as in no lasting results.
Tarte was careful to craft the statement to read that the product increases the appearance of growth. Surmise from this linguistic trickery that no ingredients contained in this mascara will actually grow lashes à la the prescription lash stimulators. In fact, Tarte disclaims in the small print:
multiplEYE™ clinically proven natural lash enhancing mascara is not intended to treat, prevent, cure, relieve, resolve, stop or reduce hair loss or to promote the growth of hair. Do not get in the eye. Rinse immediately if contact with eye occurs. If irritation or redness occurs, please discontinue use.
Well that explains the burning sensation. 
As for the 638% increase in lash volume – in my experience, bollocks. Don’t expect the rush of a major impact lash with Tarte multiplEYE mascara. All in all, this one is a lashluster disappointment.