London - US President Donald Trump’s golden bouffant is one his defining features.
Now his doctor has revealed how Trump maintains such a full head of hair at 70.
He said the president takes a prostate-related drug that stimulates hair growth. But the medication has side-effects, including impotence and loss of sex drive.
According to Dr Harold Bornstein, Trump takes finasteride which lowers levels of the protein PSA, prostate specific antigen.
Dr Bornstein, his doctor for 36 years, spoke to the New York Times in what appeared to be a breach of patient confidentiality.
He said Trump, who is now attended to by the White House doctor, is "exactly up to date" with his health.
Finasteride stops testosterone from converting into a hormone called DHT which can cause male pattern baldness.
Trump also takes a daily aspirin to reduce heart attack risk, along with antibiotics to control rosacea, a common skin problem, and a statin for elevated blood cholesterol and lipids, Dr Bornstein added.
The doctor entered the spotlight in late 2015 when he released a letter saying Trump would be the "healthiest individual ever elected to the presidency". He later admitted he wrote it in five minutes as Trump waited in a limousine outside his surgery.
Finasteride is sold under the brand names Proscar and Propecia.