Beyoncé Shows Real Locks in Cécred Hair Tutorial, Shuts Down Haters

Beyoncé's shutting down the haters and showing she's more than just wigs and extensions ... by embracing her luscious, natural locks while promoting her new natural hair care line.

The singer dropped her in-depth hair-washing routine on IG Sunday ... embracing her naturally thick, glossy tresses as they were washed, conditioned, blow-dried, and styled using products from her own brand, Cécred.

While her stylists worked their magic, Beyoncé narrated, "Now that Cécred is known for the quality in what it does for your hair, I think it's about time I show y'all what it does for my hair."

Beyoncé also appeared to address the backlash she's been getting since announcing the beauty venture back in February. Some fans complained Bey lacks credibility in the hair biz because they hadn't seen enough of her real hair ... as opposed to hair extensions she wears for productions.

She's clearly heard the criticism, because during the tutorial ... Beyoncé called out the misconception that people who wear wigs and extensions don't have long and healthy hair underneath, labeling it "some bulls**t cause it ain't nobody's business!"

Beyoncé's dad, Mathew Knowles, already stepped up to back his daughter ... telling TMZ she definitely knows a thing or 2 about keeping hair happy and healthy, considering he and Tina Knowles ran a successful salon in Houston for nearly 2 decades.