Oral BPC-157 is bioavailable to a lesser degree than sq but still enough, maybe 80%. But orally, it affects the guts most of all, much less systemic. So, if you target the gut, it is a good option. The drops, if used under the tongue (sublingually) it's a different story, it goes straight to your blood. You need to keep it under the tongue for 10 minutes or so. Also, oral peptides should be taken 2+ hours after them meal and 30+ minutes before the meal.
Another story is TB-500. If we are talking about the full 43-amino TB4, it's not really bioavailable this way. The fragment 17-23 is also considered not much bioavailable orally. Maybe sublingual way is a slightly better option, but I did not hear a good evidence for that either. Some people sell fragment 1-4 as TB-500,this is likely bioavailable, and there are some reports of its effectiveness, but I would stick to a full-sequence variant for the maximum effects.