My husband used this for four months to see if it increased hair growth. He is in his early 5's with a receding hairline and a bald patch - the two are joining up gradually :)
He took a quarter of a teaspoon only twice a day, instead of three times as recommended, and still got really good results.
After two months, his hair looked a little thicker. By three months his hair was much better - even our friends noticed - with an increase in thickness and reduction of the spread of bald areas. There was even slight regrowth across the bald patch at the back. One of our friends is a hairdresser and she was really impressed.
As with everything, the trick is to keep taking it - which he hasn't. It's a lot cheaper than Regaine, and easy to carry about with you if you're really serious about taking it regularly. A bottle lasts for ages, and I'm testing it out now for skin/hair benefits - report to follow in a few months!