The antibodies bind to, and neutralize, the insulin....the antibodies have a half life of 3-4 weeks...The antibodies delay the action, so even though U-500 is regular insulin it acts like a lente or semilente in resistant patients...When insulin sensitivity returns, it can happen quite suddenly....At these times, large amounts of insulin...previously bound to the antibodies may be released, so avoiding...hypoglycemia is a major concern. The return to normal sensitivity will take at least several weeks due to the half-life of the antibodies, and insulin requirements may fluctuate a great deal during this time. A fast response to U-500 insulin (2-4 hours from injection to measurably lower bg) may indicate the decline of insulin resistance.