I would give it a try, but from what I have read, the peptide chains are very fragile; even rough handling can cause some degradation, so Transcutol may not be the best solution.
Here is a take from one Ai site:
Query: “Would adding Transcutol diethylene glycol monoethyl ether) to the BPC-157 peptide in an attempt to apply BPC-157 externally to the heel to alleviate the effects of Plantar Fasciitis have any effect, or would the Transcutol break up the peptide molecular structure?”
Answer: "Adding Transcutol (diethylene glycol monoethyl ether) to the BPC-157 peptide for external application to the heel in an attempt to alleviate plantar fasciitis may have potential therapeutic effects, but there are important considerations regarding the stability and efficacy of the peptide.
Transcutol is known to enhance the skin penetration and permeation of various drugs by interacting with the stratum corneum lipids, increasing their disorder and fluidity, which facilitates the delivery of small molecules and some larger molecules through the skin.[1-2] However, the effect of Transcutol on the stability and molecular structure of peptides like BPC-157 is less clear.
BPC-157 has shown promising results in wound healing and tissue repair when applied topically in various formulations, including creams.[3-4] However, the stability of BPC-157 in the presence of Transcutol has not been specifically studied. Given that Transcutol can alter the lipid structure of the skin, it is possible that it could also affect the stability of the peptide.
Therefore, while Transcutol may enhance the penetration of BPC-157 through the skin, there is a risk that Transcutol could disrupt the peptide’s molecular structure, potentially reducing its therapeutic efficacy. Further research is needed to confirm the stability and effectiveness of BPC-157 when combined with Transcutol for topical application. It is advisable to consult with a healthcare provider or a specialist in pharmaceutical formulations before attempting such a combination."
One study used BPC-157 in a cream to treat burns on mice.
(50 microg of BPC 157 dissolved in 2 ml of distilled water was mixed with 50 g of commercial neutral cream (also used as local vehicle-control)), while silver sulfadiazine 1% cream was a standard agent acting locally.}
https://sci-hub.se/10.1016/s0305-4179(01)00055-9