Many men experience hair loss as they become middle age which is normally caused by DHT. There are a lot of DHT blocker shampoos on the market that can help prevent that. Check out some of those products here. Its best to use these types of products two to 3 times a week with normal showers.
Results can normally take 2 to 3 weeks to notice or longer depending on the person or how bad they are thinning. Some people may already have to much thinning to use this type of product. If you are already balding you would want to try a replacement hair type of shampoo not a DHT blocking product.