TikTok user and health and fitness coach Madison Hoover posted a video documenting her experience with Function of Beauty's haircare products. In the video, she shared that she turned to the custom haircare line to deep condition her newly dyed hair. But after just one week, Hoover claimed that her hair became dry, while her roots remained oily. Many people flocked to her comments section to share similar stories of damaged, tangled hair.

In an April 2021 interview with Vox, Hoover offered more insight on her experience with Function of Beauty. "I was just looking for a good hydrating moisturizing shampoo and conditioner and I had seen influencers promoting Function of Beauty for probably the past four or five years," she explained. "When you first head to the brand's website, it prompts you to take a hair quiz on your hair type, goals, fragrance, and color. The health and fitness coach told Vox that she requested products that "moisturize, give volume, and condition." 

But Hoover said the end results did not deliver as promised. "I went from having gorgeous hair to my scalp being incredibly super oily, but then the rest of my hair falling out and being so dry and brittle. I could not brush it. It was coming out like straw," she revealed. She's not alone. One reddit user noted that though they were initially happy with their hair texture after adding the products to their haircare routine, they also noticed significant hair loss.