What BAC water is, why it is different from saline, and the small mistakes that lead to contaminated vials.
Bacteriostatic water (BAC water) is a quietly important part of every reconstituted peptide vial. Most users buy it, use it, and never think about it. A few minutes of attention here prevents a lot of wasted vials.
BAC water is sterile water for injection with 0.9% benzyl alcohol added as a preservative. The benzyl alcohol prevents bacterial growth inside the vial after the first puncture, which is what gives reconstituted peptides their multi-week useful life.
Regular saline contains no preservative. Once you puncture the stopper, anything that touches that needle path can grow. A vial reconstituted with saline has a useful life measured in hours to a day or two — not weeks.
This is the single most common mistake new self-experimenters make: using sterile water for injection or saline instead of BAC water.
SWFI is unpreserved too. Same problem as saline for multi-dose use. Some protocols (e.g. single-dose preparations done immediately) use SWFI deliberately. For multi-dose reconstitution, BAC water is the correct choice.
Common volumes: 1, 2, or 3 ml per vial. The choice affects:
A practical default for most 5 mg peptide vials is 2 ml of BAC water.
Wait 1–2 minutes. The solution should be clear. Cloudy or particulate solutions indicate a problem — discard.
Refrigerated, upright, in the original box (to protect from light). Log the reconstitution date in Peptide IA so you know when you are approaching the 30-day soft expiry.
That kit, plus a calculator and a tracker, is the whole reconstitution game.
Peptide IA is an educational and self-tracking tool. Nothing in this post is medical advice. Doses mentioned reflect what is commonly reported in research literature — they are not recommendations. Always consult a qualified physician before starting, changing, or stopping any protocol.