Histogen is a wilder bet than ARI. The new hair gains may be better & sooner but the whole thing could topple more easily. They have only done very preliminary testing on humans. Our faith in their program comes mainly from those preliminary results being very good and our general understanding of the methodology not suggesting any obvious danger. It’s not an unfounded set of expectations, but the expectations are founded more on educated guesses than results.
ARI is a big lumbering operation that does not change direction easily. The good news is their deal is most likely to be very safe. They will probably not fall victim to any stupid stuff like a last-minute patent lawsuit, distribution problems, etc. There is probably nothing major & unforseen that could happen at any stage between their research and your scalp that ARI will simply overlook.
(I know that probably does not sound like much of a selling point. But IMHO it really is. So many of the other HM operations have always been one scrap of bad news away from lost funding and failure. ARI is just too big for that. If this operation fails it will not be due to something trivial or avoidable.)
The big question is whether ARI’s stuff can grow commercially & cosmetically viable amounts of hair. If it can, then they will probably come through for us within 4-6 years.