Does keto cause hair loss?

By Dr. Stephen Phinney and the Virta Team‍

Hair loss is not commonly seen with a well-formulated ketogenic diet. There are many causes of hair loss. One treatable cause is deficiency in the mineral zinc, which is also associated with very dry skin and reduced sense of taste and smell. Zinc repletion is a bit tricky, and is discussed in chapter 9 of our book ‘The Art and Science of Low Carbohydrate Performance’.

Our hair (for those of us who still have some) typically grows for about 12-15 months, then stops for 3 months, falls out, and the same hair follicle starts growing a new hair 3 months later. This 24-month growth, shedding, and regrowth cycle occurs at random for each of the 200,000 hairs in our scalp. But in the event of a major stress such as physical or psychological trauma, surgery, childbirth, or major weight loss, a synchronized hair loss called a telogen effluvium can occur. This hair loss typically occurs 2-4 months after the stress and is temporary, as new hairs start to regrow 2-3 months later.

So whatever the cause, a telogen effluvium rarely causes shedding of more than half of one’s hair, and in almost every case it’s resolved within a year. So don’t go out and buy an expensive wig or toupee. More importantly, since a telogen effluvium is not commonly seen with a well-formulated ketogenic diet, one may choose to avoid extremes of calorie restriction like very low calorie diets or prolonged fasting.