There is no such thing as flea shampoo for humans. So, call off the search.
If you feel you have to put some special shampoo in your hair, go out and buy some lice removal shampoo. But, even this is not really necessary in my estimation.
Do not use a flea shampoo for your dog or cat on your person. Although some people have endorsed the practice it seems rather silly to me. Fleas do not find the area of the human head to be a particularly suitable place for living and thriving. Fleas feed on humans because they are in the vicinity and happen to be crimes of opportunity for opportunistic critters seeking to eat fresh blood.
Additionally, treatment of this area with flea medication requires great care and one risks injuring their eyes and sever discomfort.
Here is a warning:
Even though it is a natural product pyrethrin and pyrethroids can be toxic if overused or ingested. These types of products should be used with great care. Avoid getting them in your eyes, nose or throat. Pyrethrins can cause shaking, vomiting and seizures. If you are using a pyrethrin product and suffer or witness these symptoms in others please see a doctor immediately.
There is a 99.99% chance that any fleas you find on your body or in your hair are merely jumping onto you to feed and they will jump off and move on to other meal sources. Energy spent searching for secret flea shampoos for humans or homemade recipes and formulas should be spent on finding the source of the flea infestation and attacking it with all your vigor.
With that said, there are numerous advocates and peddlers of homemade and herbal concoctions that are supposedly all-natural. That ain’t my bag, but if it strikes your fancy you may want to give it a go. And there are many different flea treatments for humans that have their followers and detractors.