Is applying topical finasteride much safer than taking finasteride orally?

Topical finasteride may be safe but it would not work for treating androgenic alopecia. Your haven't found results on the Internet because it doesn't work.

Finasteride is a the most effective FDA approved medication for hair loss prevention.  DHT blockers including finasteride have been tried topically for years.  However, there is not much scientific evidence that indicate the effecitveness of topical DHT blockers.At this point we only recommned topical minoxidil that works great due to its smaller molecular size therefore minimal systemic effects.

This is a complex question, but I'll share some things we know so far. First off, topical finasteride is not FDA approved for hair loss. Any use is off label. I'm going to limit all discussions here to men as use in women is not FDA  approved. Is topical finasteride safer? Does it get absorbed? Well, it ALL comes down to the dose. Yes, it gets absorbed into the blood and yes it lowers DHT levels. 1% finasteride topical solution is going to have different effects than an 8 % solution.  0.25 % finasteride is going to be different yet! If I were to make up 0.0000000001% finasteride topical solution, it would likely be quite safe with little if an absorption. However, it probably wouldn't do anything for patients with hair loss. So it comes down to dose. One should not talk about topical finasteride unless they are prepared to talk about the doseSo let's talk about what we do know. A study of 0.25 % topical finasteride reduced DHT levels to the same amount as standard 1 mg finasteride. We don't yet have any data to know if this translates into it working just as good, worse or better. What about side effects?We don't know that either. If sexual performance and mood levels are related to DHT then it's pretty likely that lots of men using topical finasteride would be expected to have side effects too. These studies have not been done and we don't know. For hair loss in men, it appears that it comes down to inhibiting DHT. Inhibit it more and you'll get a better outcome for hair loss and you'll get more side effects tooTopical finasteride gets into the blood and inhibits DHT. Side effects are possible. We need to be very careful assuming topical means safer. The scalp is a wonderful way to get drugs into the body. ReferenceA novel finasteride 0.25% topical solution for androgenetic alopecia: pharmacokinetics and effects on plasma androgen levels in healthy male volunteers.Caserini M, et al. Int J Clin Pharmacol Ther. 2014.

Topical finasteride does absorb into the blood stream but at much lower blood levels than the oral pill. The side effects are much more rare with the topical according to a study I just heard at the most recent International Society for Hair Restoration Surgeons

Oral Finasteride is FDA approved as a DHT blocker. However topical Finasteride is not FDA approved so we don’t have the tests or data to know it’s effectiveness.