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Someone on a public forum asked a simple, practical question: when mixing peptides like selank or semax into a nasal spray, should they dissolve them in sterile saline (salt water) or in a solution that contains benzalkonium chloride (BAC), a preservative? They wanted experiences or advice from others who’ve done this. There was no formal study attached — just a request for input. Selank and semax are short chains of amino acids called peptides. They’re sometimes used as nasal sprays by people hoping for effects like improved focus, reduced anxiety, or cognitive benefits. These peptides aren’t pills — they’re sensitive molecules that can break down if not stored or prepared properly. People preparing them at home often need to mix a dry powder into a liquid before putting it into a spray bottle. The question on the forum is about the liquid used for reconstitution. Sterile saline is basically sterile salt water; it’s gentle, commonly used for nasal rinses, and doesn’t contain extra chemicals. BAC is an antimicrobial preservative used in some nasal sprays and eye drops to keep bacteria from growing in the bottle. The trade-off is that BAC can irritate the lining of the nose for some people, especially with repeated use, while sterile saline is less likely to cause irritation but offers no built-in protection against contamination once the spray is opened or used repeatedly. There’s no formal clinical evidence presented in that forum thread to declare a winner. In sterile, controlled pharmaceutical manufacturing, preservative-containing solutions are sometimes used to allow multi-dose bottles; but in medical practice, many clinicians prefer preservative-free saline for repeated nasal use to avoid irritation. For home mixing, the bigger risks are contamination and dosing errors rather than the choice of BAC versus saline alone. If a preparation isn’t kept sterile, bacteria or mold can grow regardless of the starting liquid, especially without proper preservatives and handling. So who should care? Anyone considering making or using homemade nasal peptide sprays should think about safety first. People with sensitive nasal tissue, frequent nosebleeds, or certain allergies may react to BAC and would likely prefer sterile saline. Anyone worried about contamination or planning to keep a multi-dose bottle for extended time should be cautious: commercially made products follow strict sterile procedures that are hard to replicate at home. Bottom line: the forum question reflects a real practical concern, but it doesn’t resolve the safety trade-offs. Sterile saline is gentler but offers no preservative, while BAC can prevent microbial growth but may irritate some users. If you’re considering doing this yourself, talk to a medical professional or pharmacist and avoid homemade compounding whenever possible.
Source: r/Peptides