Review (2/5): Bad for everyday use, but smells amazing
The first ingredient in this product is Cyclopentasiloxane, which is silicone. While this product has a sweet and subtle scent that is lovely on the hair, habitual silicone use is fundamentally damaging to hair. (Go research Biosilk, a more popular silicone-based hair serum.)
Silicone does create a lovely temporary shine, and it doesn't weigh hair down much. But over time it increases damage, accelerating coarse frizzy hair or split ends. This would make the product addictive: masking the damage CAUSES the damage being covered up.
Who knows, this one may have some effect as claimed in shielding from UV exposure (though I doubt 3-5 drops distributed in a head of damp hair could amount to much sunscreen coverage). And perhaps the Argan oil or other components can balance the effects of the primary silicone ingredient. I wouldn't risk that. I'd use this protector oil for a special occasion for extra pop, shine and an appearance of good grooming, but only with the understanding that occasional use won't cause much harm. It isn't heroin, and using it once won't make you an addict -- just go into it with your eyes open.
Might work for someone who has short, fast-growing hair, where they cut off the hair before damaging effects can become a chronic issue.