January 2015 in “Journal of clinical & experimental dermatology research” A protein combining parathyroid hormone and collagen helped hair regrow in mice with a hair loss condition.
Wound healing is complex and requires more research to enhance treatment methods.
September 1999 in “The Journal of The British Menopause Society” The document concludes that skin aging in women can be caused by UV exposure and hormonal changes, and treatments like hormone replacement therapy and various skin therapies can help.
January 1987 in “Side effects of drugs annual” Some cosmetics and dermatological drugs can cause allergic reactions and side effects, like skin irritation and systemic issues.
February 1977 in “Archives of Dermatology” Topical mitotic blocking agents like colchicine can be dangerous and potentially fatal, and hair loss from rapid weight loss is due to low protein, not the speed of weight loss.
April 2018 in “Journal of Investigative Dermatology” Finasteride helps female-pattern hair loss.
April 2018 in “Journal of Investigative Dermatology” 
434 citations
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October 2003 in “PTR. Phytotherapy research/Phytotherapy research” Natural products in cosmetics are beneficial for skin and hair care with low toxicity.
252 citations
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January 2008 in “Trends in Endocrinology and Metabolism” Melatonin in the skin helps protect against damage from stress and UV rays, and could be used to treat certain skin conditions.
157 citations
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April 1994 in “Clinical endocrinology” Androgens can cause hair growth in some areas and hair loss on the scalp.