There are two reasons why an male pattern baldness sufferer should use Nizoral.
First, Keto IS a mild anti-androgen, and it IS scientifically backed.
Second, the malaseezia yeast that occurs naturally on all human scalps creates an ambient irritation in the scalp (even for non-dandruff sufferers) and this irritation is similar in nature to and can actually attack the scalp in a synergistic way with the irritation caused by DHT in the follicle.
You don't have to take Keto or Nizoral for the second point, any anti-dandruff shampoo would do, and in fact it is good to rotate them as malaseezia can become resistant to a particular anti-fungal if you use it alone for long periods of time.