Spinach is a leafy green vegetable that is a good source of iron, vitamin A, folate, and vitamin C. Iron “helps carry oxygen to hair follicles,” explains Dr. Berry, who adds that low levels of iron can cause excessive hair shedding. Additionally, folate, a B vitamin, “essential for keratin production and healthy hair growth,” she says.

Even if you're not dealing with hair loss or shedding, rosemary oil products can still deliver some ingredient benefits to your strands: 'Hair oils, including rosemary oil, are also great for those looking for natural approaches to growing smoother, softer, more manageable hair,' says board-certified dermatologist Dr. Brendan Camp, MD.