Toujeo Works by Slowly Releasing Insulin Into Your Body Over 24 to 36 Hours to Keep Blood Sugar Steady Between Meals and Overnight

If you've been prescribed Toujeo, you might be wondering: how does it actually work? Why does your doctor want you on this specific insulin instead of another one?

This guide explains Toujeo's mechanism of action in plain English — no medical degree required.

What Toujeo Does in Your Body

Toujeo contains Insulin Glargine, which is a lab-made version of the insulin your pancreas naturally produces. In people with diabetes, the pancreas either doesn't make enough insulin (type 1) or the body doesn't use it effectively (type 2). Toujeo steps in to fill that gap.

Here's what happens after you inject Toujeo:

Step 1: It Forms a Tiny Depot Under Your Skin

When you inject Toujeo into the fatty tissue beneath your skin, the insulin glargine forms tiny clumps called microprecipitates. Think of it like a slow-dissolving tablet under your skin — instead of releasing all at once, the insulin dissolves gradually over many hours.

Step 2: Insulin Is Released Slowly Into Your Bloodstream

From that depot, small amounts of insulin are continuously released into your bloodstream. This gives you a steady, background level of insulin — what doctors call basal insulin. It's like a low, constant drip that keeps working around the clock.

Step 3: Insulin Tells Your Cells to Absorb Sugar

Once in your bloodstream, the insulin does two main things:

• Opens the door for glucose: Insulin acts like a key that unlocks your muscle and fat cells, allowing them to absorb glucose (sugar) from your blood for energy.
• Tells your liver to slow down: Your liver constantly releases stored glucose into your blood. Insulin signals it to dial back that release, preventing your blood sugar from climbing too high — especially between meals and overnight.

The U-300 Difference

Here's what makes Toujeo special compared to standard insulin glargine (like Lantus, which is U-100):

Toujeo is three times more concentrated — 300 units per mL instead of 100. This means the same dose of insulin is packed into a smaller volume. That smaller injection creates a more compact depot under the skin, which dissolves even more slowly and evenly.

The result? A flatter, more extended insulin release with fewer peaks and valleys. Imagine the difference between pouring water from a wide bucket (Lantus) versus a narrow bottle (Toujeo) — the narrow bottle lets water out more gradually. That's essentially what Toujeo does with insulin.

How Long Does Toujeo Take to Work?

Toujeo doesn't work instantly. After injection, it takes approximately 6 hours to reach meaningful levels in your bloodstream. This is why Toujeo is not used for covering meals or correcting high blood sugar quickly — that's the job of rapid-acting insulins like Humalog or NovoLog.

Because of this slow onset, it's important to take Toujeo at the same time every day to maintain consistent insulin levels.

How Long Does Toujeo Last?

Toujeo provides insulin coverage for approximately 24 to 36 hours. This is longer than Lantus (which lasts about 24 hours) and contributes to Toujeo's more stable blood sugar control.

The extended duration also means that if you're a few hours late taking your dose, you still have some insulin working in your body. However, you should still aim to take it at the same time daily and follow your doctor's instructions if you miss a dose.

What Makes Toujeo Different from Similar Medications?

Several long-acting insulins are available. Here's how Toujeo compares:

Toujeo vs. Lantus

Both contain Insulin Glargine, but Toujeo (U-300) has a flatter profile and longer duration than Lantus (U-100). Studies suggest Toujeo may cause fewer nighttime hypoglycemia episodes. However, Toujeo may require a slightly higher total daily dose than Lantus for the same blood sugar control.

Toujeo vs. Tresiba

Tresiba (Insulin Degludec) is another ultra-long-acting insulin that lasts up to 42 hours. Both Toujeo and Tresiba offer flat profiles and flexible dosing. Tresiba uses a completely different insulin molecule, while Toujeo uses a concentrated version of glargine. Your doctor may choose one over the other based on insurance coverage, cost, and individual response.

Toujeo vs. Levemir

Levemir (Insulin Detemir) is a long-acting insulin, but it often needs to be taken twice daily for full 24-hour coverage. Toujeo's once-daily dosing and longer duration make it more convenient for many patients.

Toujeo vs. Biosimilars (Basaglar, Semglee)

Basaglar and Semglee are biosimilars of Lantus (U-100 glargine). They are not the same as Toujeo because they use the standard U-100 concentration. They don't have Toujeo's extended, flat absorption profile. If you're considering alternatives to Toujeo, these are options your doctor may discuss.

Final Thoughts

Toujeo works by forming a slow-dissolving depot under your skin that releases insulin steadily over 24 to 36 hours. Its concentrated U-300 formula provides a flatter, more prolonged effect than standard glargine — which can mean smoother blood sugar control and fewer lows, especially at night.

Understanding how your insulin works helps you use it more effectively. If you have questions about your Toujeo regimen, talk to your healthcare provider. And if you need help finding Toujeo at a pharmacy, Medfinder can help you locate it near you.