Growing up, Britney Spears influenced my music taste more than any other artist. I’d beg my parents for each one of her new CDs, and when I got them, I’d play them over and over again until the reflective coating was almost completely scratched off. One of my fondest memories is when my parents gifted me her self-titled Britney album for Christmas. I stayed up listening to it with my ear pressed against my pink boombox, so as to not wake my parents who were sleeping down the hall.  I still occasionally listen to my favorite songs (Cinderella, Overprotected, and Lonely among them) but I consider my Britney days to be mostly behind me. Or, at least, I thought I did. As it turns out I’m still being influenced by Britney Spears—except now I’m being influenced to buy beauty products instead of listening to the same song five times in a row. I just found out which shampoo she uses, and it’s under-$20, eco-friendly, and in stock on Amazon. It’s even discounted for Cyber Monday, so I couldn’t help myself but place yet another Prime order. 

Instead of a traditional liquid or gel formula, Spears reportedly uses the plastic-free shampoo bars from Ethique. While we’re not sure exactly which one she uses, there are multiple scents and formulas to choose from—like this minty one that uses peppermint oil, Ghanaian cocoa butter, and organic creamed coconut butter to refresh, moisturize, and cleanse hair without weighing it down. 

These shampoo bars are cruelty-free, plant-based, and made with sustainable and ethically sourced ingredients (there’s no palm oil either). What’s more, each one is packaged in plastic-free, home-compostable cardboard. So yeah, they’re probably some of the most eco-friendly shampoos on the market.

The best part is that using them is easy and they last up to 80 washes. Simply wet your hair and the bar, massage the bar into your roots, and lather. That’s it. From there, just follow up with a conditioner. (I have some recommendations for you but more on that in a minute.)

This one is safe for color-treated hair and uses mango seed butter, peach kernel oil, and rice powder to balance the hair and scalp. It also adds shine and bounce. 

If smoother hair is your goal, this one should help. It’s deeply moisturizing to restore shine. 

Personally, I think Spears would approve of this one. It’s formulated to balance the hair and scalp (in other words, it hits the sweet spot between dry and oily) and is scented with sweet vanilla and zesty grapefruit. I don’t know about you, but to me, that sounds delightful. 

If you have blonde hair like Spears, this one might be for you since it helps keep brassiness at bay. The purple pigment (from naturally occurring sources like beetroot powder) counteracts yellow and orange tones to keep blonde and silver tones bright. 

The brand’s conditioner bars are also plastic-free, but they boast up to 120 uses. This one called The Guardian, uses cocoa butter and coconut oil to condition dry, breakage-prone hair. It has a zesty lime fragrance. 

Curly-haired people, this one’s for you. With shea, jojoba, and cocoa butter, this heavy-duty conditioner moisturizes curls without weighing them down. The best part? There are no sulfates, silicones, drying alcohols, or waxes. 

If you struggle with a sensitive scalp (or nose) this is the one for you. It uses cocoa butter, babassu oil, and THC-free hemp seed oil to condition hair without any potentially irritating fragrances. 

This is the missing puzzle piece to the brand’s Tone It Down Shampoo. Just like the former, it removes brassy tones in the hair. 

If your hair is on the oilier side, this lightweight conditioner is for you. The brand promises it won’t weigh hair down or make it look greasy.