As a genealogist,and someone who follows the rules of genealogy, I have to say that, as yet, no one can PROVE descent from Muhammed. I am sure that there are many who have oral genealogies that SAY they are descended from him, but they will not stand up to scrutiny. There are always links that are missing or generations missing. And before you rise to the defence, I must add that I am one of those who has a suspected descent from Muhammed. I have many proven descents from the Kings of Spain, who have a descent from a woman named Zaida baptised Elizabeth who married Alfonso VI of Aragon.( For a long time it was held that she was the daughter of Aben Abeth, King of Seville. But that descent has been put in doubtnow, and, besides, the descent to the modern world does not come through Zaida, but through another wife.
It has been mathematically proven that all Europeans are descended from Emperor Charlemagne, who lived over a century after Muhammed. That doesn't count the many millions of non-Europeans who would also be his descendants. The same mathematical rule would also apply for any of Charlemagne's contemporaries. If we go back to someone who lived over a century before Charlemagne, then how much more would the maths apply? My guess would be that all of Europe, the Middle East and North Africa would descend from Muhammad on at least one line. The problem is that NO ONE can PROVE it without doubt. Remember that Muhammad only had one surviving child, a daughter.