Most of this applies only to the US, but may apply in other countries. In the late 1980s when Rogaine was first approved, the FDA (Food and Drug Administration) outlawed the advertising of products that grow hair unless they are approved by the FDA. The reason for this was obvious. For hundreds of years, people have been selling treatments with no scientific proof that those products regrow hair. As of this time, Minoxidil/Rogaine is THE only product that the FDA has approved to advertise that it regrows hair. When you see an advertisement for a hair growth products, there are either two possibilities:

1. The product is using fancy wording to make you THINK it regrows hair without ever actually saying it.
2. The product really is saying it regrows hair (illegal in the US!)

In situation 1, companies use phrases like "helps people who are balding" or "helps give your hair a healthy full look". If a product makes the hair you have look thicker, the company can say it "helps people who are balding" without advertising falsely. Does that mean the product will grow hair on your head? Nope. Then again, it does not mean the product doesn't work. It costs millions of dollars to get a product FDA approved, so sometimes companies will sell a drug as a cosmetic product rather than a hairloss drug. The drug may actually work, but the company can not claim it works since it has not been FDA approved for hairloss. Unfortunately, this leaves the consumer in the situation of not knowing which is the product that doesn't work and which does. The only thing you can really do is try to find others who have tried the problem to see if it has worked for them. Some companies offer information to back up their claims. However, even a con company can fake some scientific lingo to convince the average consumer that a product is good. Companies also use photos. Many times photos use varying lighting conditions and hair stylings to make it look like the person has grown more hair when they haven't. Be wary.

In situation 2, companies actually say something like "Our product is 2.5X more powerful than minoxidil at regrowing hair." This would be an illegal statement in the US. These sorts of statements are often made in internet newsgroups or on web pages and never come to the attention of the FDA or proper officials. Often, a company will say they have conducted double-blind scientific studies to back up their claims. Remember that if the company conducted double blind studies for the FDA that were successful, this product would be approved for hairloss treatment by the FDA. Many of these tests are internal and are not really 'blind'. You can come up with just about any result if that is your intention in creating a study. If these studies were so reliable and convincing, why were they never used to get FDA approval? It's possible the study really did show that the product was effective. It is just important to question the source before blindly accepting that what the company is telling you is true. They will ALWAYS try to put their product in the best light. Also, when they mention their studies, they don't cite who conducted them and present the full results. They only tell you what THEY want you to know. Sure their product was 2.5X more effective than minoxidil in their clinical studies. They forgot to mention on their web page it made everybody in the study blind!

Update: The FDA has recently released a statement saying that it's rule applying to hair regrowth claims may not apply to the internet, since internet advertising and web sites may be considered 'conversations.' They are awaiting a court case to set a precedent as to whether they can apply their regrowth advertising rules to the internet. Click here for the full release.