The Hidden Third Type: Why Doctors Are Rethinking 'Type 1.5 Diabetes'

Hook

For decades, diabetes was split into two buckets:
Type 1 (“juvenile diabetes”) and Type 2 (“adult diabetes”).
Simple labels — but wrong.

We now know type 1 can strike at any age, and type 2 is more than just “adult onset.”
And sitting awkwardly between them is a condition that affects millions: LADA, or “type 1.5 diabetes.”

Context

Latent Autoimmune Diabetes in Adults (LADA) is real, not a fad label.
It’s autoimmune like type 1 — the immune system destroys the pancreas — but it creeps in slowly, so adults can live for months or years without insulin.
On the surface it looks like type 2. That’s why up to 10% of people told they have type 2 may actually have LADA.

The giveaway is antibodies.
The most important are GAD antibodies — short for Glutamic Acid Decarboxylase antibodies.
They reveal that the immune system is attacking the very enzyme found in insulin-producing cells.

Here’s what else the research shows:

• C-peptide levels start higher but decline gradually, unlike the rapid crash of type 1.
• Sulfonylurea drugs (common in type 2) can actually accelerate pancreatic decline in LADA.
• Insulin therapy doesn’t make the pancreas “lazy” — it reduces stress on surviving beta cells, and may preserve them longer.

These aren’t fringe claims — they’re in Cochrane reviews and an ADA consensus paper published in Diabetes.

Myth-Busting

• “Juvenile diabetes” vs. “adult diabetes” → Outdated. Type 1 can occur at 7 or 70.
• “Type 1.5 is just the honeymoon phase” → Wrong. Honeymoon in type 1 is temporary; LADA is a slower disease course.
• “Insulin will make my pancreas quit” → False. The immune system, not insulin, destroys beta cells. Early insulin may actually help.

Implications

• For patients: If you were labeled “type 2” but don’t fit the profile (lean, younger, quick loss of control, autoimmune history), antibody testing could change everything.
• For clinicians: Stop treating “atypical type 2” like classic type 2. Test, don’t guess.
• For public health: We need to rethink diabetes as a spectrum, not a binary. LADA is proof.

Further Reading

• Latent Autoimmune Diabetes in Adults (Guide)
• ADA Consensus on LADA (2020)

Closing

The labels may be outdated, but the stakes aren’t.
Getting LADA wrong means wasted years, ineffective treatment, and preventable complications.
It’s time we stop pretending diabetes fits neatly into two boxes — because real lives fall through the cracks in between.