I found a Invalid Link Removed (posted on reddit) that did a test on rats. Peptides disolved in water sprayed into the nasal cavities. Compared to injection. Now I know this are rats, but still, it's an indication. Pretty poor bioavailability compared to inject: Ipamorelin: 21%. GHRP-2: 53%. GHRP-6: 30%. More @Wikipedia
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