47 citations
,
September 2002 in “Journal of Bone and Mineral Research” A mutation in the vitamin D receptor causes severe resistance to vitamin D, affecting bone health but not hair growth.
20 citations
,
February 1991 in “Archives of dermatology” High doses of tryptophan may cause eosinophilic fasciitis.
16 citations
,
August 2000 in “Il Farmaco” Men have more tryptophan in their hair than women, and it increases with age and is higher in darker and grey or white hair.
33 citations
,
August 1993 in “FEBS Letters” A new enzyme in rats may help regulate hair growth.
21 citations
,
September 1990 in “Journal of The American Academy of Dermatology” Taking L-tryptophan supplements might cause a condition similar to scleroderma in some people, which can get better after stopping the supplement and starting corticosteroid therapy.