Topical? Intranasal? SubQ?
So I was curious why some peps/aminos need to be SubQ and can't be intranasal or topical. I read it is due to their molecular weight.
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- If under 500 daltons, it can be absorbed well topically.
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- If under 1000 daltons, it can be absorbed by the nasal mucosa (intranasal bioavailability).
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- If over 1000 daltons, it has to be administered subQ.
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I couldn't find a cheat sheet or chart for most peps so I created this one. I am not a scientist so this is for simple and "recreational" reference only.
Feel free to make suggestions on edits. I know I might be missing a few - I just took a vendor's price list and worked with what they had.
I hope it helps some of you who like me, like to know the reasons for things and don't want to look up a pep at a time online.
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There are exceptions and workarounds to make some molecules penetrate where they normally wouldn't, like adding capreatic acid, but it is not as simple as it sounds.
Molecular weight is not the only thing at play. There are other factors, too, but this is a quick reference for the overall rule regarding why intranasal reta wouldn't work, for example.