One of the most common questions we hear is:

“I’m taking SiderAL® iron. My hemoglobin has improved — but my ferritin is still low. Why?”

This pattern is actually very common in iron deficiency and iron deficiency anemia, and in most cases, it reflects normal physiology rather than treatment failure.

Hemoglobin vs. Ferritin: What’s the Difference?

Hemoglobin is the iron-containing protein inside red blood cells that carries oxygen. When hemoglobin rises, it means your body is successfully using iron to make new red blood cells.

Ferritin, on the other hand, reflects your iron stores — your body’s reserve supply of iron. Think of hemoglobin as your “daily operating system” and ferritin as your “backup battery.”

They measure different things — and they do not always rise at the same time.

Why Hemoglobin Improves First

When you begin effective iron therapy — including Sucrosomial® iron technology used in SiderAL® — your body prioritizes what it needs most urgently: oxygen delivery.

If you are iron deficient, your body directs newly absorbed iron to the bone marrow to produce hemoglobin. Restoring oxygen-carrying capacity is the immediate priority.

Only after hemoglobin normalizes does the body begin rebuilding iron stores. That is when ferritin starts to rise more meaningfully.

This is why it is common to see:

• Hemoglobin improve within weeks
• Ferritin rise more gradually over months

Other Factors That Can Affect Ferritin

Ferritin levels can also be influenced by:

• Ongoing blood loss (heavy menstrual bleeding, GI losses)
• Inflammation or chronic illness
• Inadequate duration of therapy
• Suboptimal dosing or absorption

Iron repletion is a process, not a single lab result.

The Bottom Line

If your hemoglobin is rising on SiderAL®, that’s a strong sign your body is responding. Ferritin often lags behind — and that’s normal.

For full iron repletion, treatment typically continues 3–6 months after hemoglobin normalizes to rebuild iron stores properly.

Have questions about your iron levels?
Speak with your healthcare professional — and explore more evidence-based insights on iron deficiency at SideralIron.ca.