Do hair vitamins work?

If you're keen to grow your hair long and you want it that way as quickly as possible, there are several hair vitamin formulations available over the Internet. These include the two types that I've personally tried: Hairtopia and Hair Formula 37. Both are quite pricey as the shipping from the US to Australia costs a lot, and the vitamins themselves aren't cheap either. But do they work? Here's what my experiences have been.
I took the Hairtopia tablets for three months before I decided that they just didn't work. I was taking six tablets a day, and saw no extra growth from them. They also gave me a hot flush every time I took them, due to the high niacin content. Therefore, I can't recommend Hairtopia to anyone - for me, it was simply a waste of money.

As for Hair Formula 37, well, these vitamins definitely work - my hair's growth rate has almost doubled - but there are side effects involved that aren't mentioned advertisements. I found that the hair on my body, as well as my fingernails and toenails, grew much faster also, meaning that I have to shave my legs every other day. In addition I gained nearly ten kilos in weight, because I found that Step Two of the program - the amino acids component - made me really hungry. Being that I'm (now) only a 65kg woman, that is a lot of weight and I attribute it purely to the HF37 vitamins, as there were no other changes to my lifestyle during the six months I've been taking them.
But the growth! My hair's growth speed has really taken off since the first month of taking HF37. It may have something to do with the extra nutrients in my diet from all that extra food, but it's probably the hair vitamins themselves. The program is a 3-step process, incorporating essential vitamins and minerals, amino acids, and a herbal booster component. You can also buy Grow! Shampoo and Conditioner with the HF37 program, which contains a large amount of niacin to stimulate the scalp, but I doubt that this would cause a considerable difference in growth; it's just pleasant to massage into your scalp. Hair growth is a result of what happens inside the body, and topical treatments, in my opinion, wouldn't affect the hair's growth rate in any measurable way.
The major problem with these vitamins is, of course, the price - one month's supply of the program will cost you nearly AU$200, including shipping. It seems rather extravagant for something that is ultimately superficial, but if you're hair-obsessed like I am, you'll find it to be money well spent. The extra growth I've experienced has really boosted my confidence, as I know I personally look much better with long hair.

So have you tried any hair vitamins? What experiences have you had with them? Let me know by leaving me a comment below.