This lightweight serum functions as a deep moisturizer and heat protectant for all hair types. With a cocktail of nourishing oils, like jojoba, moringa, and argan, it coats the strands with moisture and leaves it feeling silky soft. And with the amount of antioxidants in this oil blend, shoppers swear it leaves their hair fuller and thicker, too. 

Hair Serum, Nuele ($34)

For extremely dry strands, this creamy leave-in is a must-have. Castor oil is the star ingredient, and it's a classic beauty staple for imparting moisture. It's rich in fatty acids (especially ricinoleic acid1), vitamin E, minerals, and other antioxidants, which often translates to happily moisturized, shiny, strong hair.  

Goddess Strength Leave-In Cream, Carol's Daughter ($11.99)

There's nothing you can't do with this potent oil blend: Slather it on as an overnight hair mask; mix with your favorite conditioner for a DIY deep treatment; mix with leave-in; use as a heat protectant, a hot oil treatment, or for a stimulating scalp massage. Plus, with safflower oil and rosehip seed oil (which are considered "dry" oils), it'll sink into the strands without any oily residue. 

Nourish Skin & Hair Serum, Beneath Your Mask ($60)

This oil-cream contains everything we love about a moisturizing leave-in: shea butter to soften, hydrolyzed almond protein to repair damage, olive-leaf extract for antioxidants, and 16 essential oils for a fresh, airy scent. Truly, what's not to love? 

Milk Anti-Frizz Leave-In Nourishing Treatment, Reverie ($42)

Another creamy number, this leave-in is beloved for parched, textured hair. For good reason, of course: There's coconut oil, sweet almond oil, and shea butter (read: all the ingredients thirsty hair craves), as well as nettle extract for antioxidants and shine. 

Baomint Leave-In Conditioning Styler, adwoa beauty ($24)

Looking for a lightweight hair moisturizer that won't weigh down curls? Let us introduce you to this milky hydrator: The castor-oil-and-glycerin-rich formula leaves hair silky without any flakes or a crunchy feel. "This is the holy grail for me," one review reads, and a string of other devotees sing its praises. 

Baby ButterMilk Daily Natural Hair Moisturizer, Miss Jessie's ($14)

The main player here is avocado oil, a hair care wonder that can actually penetrate the hair shaft rather than sitting atop it and creating buildup. It also features rice amino acids, as well as hydrolyzed quinoa—the two grains are chock-full of antioxidants and earn a worthy space in your hair care lineup.

Curl Charisma Rice Amino + Avocado Leave-In Defining Cream, Briogeo ($22)

With botanical extracts and hydrolyzed rice protein, this leave-in yields soft, frizz-free curls with just the right amount of bounce. Not to mention, it's housed in a bottle made from 25% recycled content and is 100% recyclable when you're through. 

Leave-In Conditioner, Odele ($11.99)

This elixir of a leave-in moisturizes and protects the hair with glycerin, panthenol, and cartucciaru melon extract—an extremely hydrating compound that's rich in vitamins A, C, and potassium. 

MOMO Hair Potion, Davines ($26)

For extremely thirsty hair, this leave-in is downright transformative. Shea butter and castor oil are the main players, which coat the strands with intense moisture, along with rice protein and hydrolyzed keratin to strengthen strands. As Roberts told us about deep conditioners, "Healthy hair is a balance between moisture and protein, so we need to use both, depending on the individual needs of our hair." 

Jamaican Black Castor Oil Strengthen & Restore Leave-In Conditioner, SheaMoisture ($13.99)

Like all Olaplex products, this moisture mask contains the brand's patented bond-building technology to strengthen and repair fragile strands. Along with the highly concentrated infusion, it features avocado oil, hemp seed oil, and sunflower seed oil to impart a healthy shine. 

No. 8 Bond Intense Moisture Mask, Olaplex ($28)

Spray this leave-in treatment whenever your strands are in dire need of uplifting. Aloe, glycerin, and honey fill the hair shaft with hydration, and it features an invigorating herbal scent. 

Sweet Spirit Leave-In Conditioner, Innersense ($26)

This potent hair and body serum features just three powerful ingredients: sunflower, jasmine, and amla oils. The latter is a staple in Ayurvedic medicine: It's part of triphala, an herbal concoction native to India that can have a protective effect on the epidermis and promote collagen production2. As such, "amla is known as the secret ingredient to conditioning hair," as the brand notes. 

Mighty Majesty Fortifying Hair Serum, Ranavat ($70)