When it comes to lash serum, not many can boast a Duchess and a host of celebrities as fans.
But that's precisely the type of cult following RevitaLash Advanced has garnered since its launch in 2006.
It seems the popularity of this lash serum hasn't waned 14 years on as [drumroll please...] sales are up by 40% in the UK alone in 2020 and Amazon now boasts over 2,500 perfect global reviews.
Clearly, despite not currently wearing much make-up, there's something about having lengthier lashes that makes us feel more confident - even without the best mascara.
But back to that special formula. We're talking biotin and green tea extract, which is rich in panthenol (vitamin B) - both key for making hair grow. Peptides and lipids also join the party to help to condition and protect lashes from future breakage.
Other key ingredients include ginseng and Swertia Japonica, which are high in antioxidants and help to thicken hair. It's also vegan, cruelty-free and does not include parabens or phthalates.
RevitaLash Advanced, £89, Cult Beauty
View RevitaLash Advanced at Cult Beauty.
Like all the best eyelash growth serums, RevitaLash Advanced is designed to enhance the appearance of lashes by making them longer, improving their strength at the root and ensuring they are less likely to fall out or break off prematurely.
Once a day, you simply apply a thin line to clean and dry eyelashes above the level of the skin.
It's so effective The Duchess of Sussex told Allure magazine, "I also use RevitaLash on my eyelashes, and I swear they are as long as they could ever be."
High praise indeed, especially from a public figure who has countless beauty unguents at her fingertips.
More recently, model and activist Charli Howard took to her Stories to say the serum "made my lashes so long that I actually had to trim them."
So a well-endorsed product for people looking for how to grow eyelashes indeed.