What the research found

This phase 2 trial tracked people with type 1 diabetes who received either BCG vaccination or placebo, with measurements extending to 8 years. The BCG group showed progressive improvements in HbA1c (a marker of average blood glucose over months), with reductions of around 7% by year 5 and roughly 13% by year 8. The placebo group saw no change in HbA1c over the same period.

Beyond HbA1c, the BCG-treated participants required less insulin to maintain blood glucose control, and continuous glucose monitoring showed they spent substantially more time with blood sugar in the normal range (70–99 mg/dL). Notably, these improvements occurred without any recovery of C-peptide—a marker of pancreatic insulin production—suggesting the benefit came from changes in how the immune system or metabolism processes glucose, not from the pancreas healing.

The mechanism appears to involve "immune training," a concept supported by preclinical work but rarely tested rigorously in humans until now. BCG safety was not flagged as a concern over the follow-up period.

Why it matters for you

If these findings hold up, BCG could represent a fundamentally different approach to type 1 diabetes management—one that doesn't rely on replacing or recovering pancreatic function, but instead recalibrates the immune response that damages it. For MyKine users tracking HbA1c and time-in-range via CGM, a durable reduction in blood glucose variability would likely translate to fewer glycemic excursions, lower average insulin doses, and reduced hypoglycaemic episodes.

This also touches on a broader interest in immune modulation as a metabolic intervention. BCG is an old, inexpensive vaccine with a known safety profile, which means—if validated—it could be a relatively accessible option compared to newer biologics. Users monitoring insulin requirements would want to watch whether such a therapy could meaningfully lower their dose over months or years.

That said, this is still a relatively small, single trial. Reproducibility in independent cohorts and clarification of which people benefit most would both be important before considering it part of a personal protocol.

Caveats

• Phase 2 trial: This is proof-of-concept work, not yet confirmation at the scale and rigor of phase 3 trials
• Single study: No independent replication yet reported
• Long follow-up but modest detail on mechanisms: The mechanism of immune training is inferred but not mechanistically dissected in this summary
• Type 1 diabetes specific: Unclear whether findings would extend to type 2 diabetes or metabolic dysfunction more broadly
• No mention of adverse event rates or dropout reasons: Safety statement is reassuring but limited in detail