Looking for advice - B12 treatment, low iron despite supplementation, worsening symptoms

Hi everyone,

I’m looking for some advice and would really appreciate your thoughts.

TL;DR: After 2 years of EOD B12 injections, I’m getting worse again with fatigue, brain fog and neurological symptoms. Iron markers remain low despite supplementation. Could low iron be preventing B12 from working optimally? Looking for insight into my bloodwork.

I’ve been treating a vitamin B12 deficiency for over 2 years and have been self-injecting hydroxocobalamin every other day (EOD) with guidance from my doctor. Two years ago I was extremely ill, and the B12 injections made a huge difference and helped me get my life back.

Unfortunately, over the last few months I’ve started feeling worse again.

My current symptoms include:

* Increased fatigue
* More anxiety/panic
* Brain fog
* Muscle and nerve symptoms
* Feeling like my body just isn’t functioning properly, almost as if I could “crash” at any moment

In addition, since having a two-week period of fever in early May, I’ve been experiencing almost daily ocular migraines, and no cause has been found so far.

I’m currently dealing with what seems to be a flu or COVID infection. I’ve been feeling genuinely unwell with headache, nausea, muscle aches (especially in my arms), fatigue and an overall flu-like feeling. My CRP is elevated (35 mg/L), which likely reflects the current infection. However, even before getting sick, I had already noticed a gradual worsening of my symptoms.

Because of low iron markers, I started taking Solgar Gentle Iron (iron bisglycinate), 40 mg every other day, on May 8th. My iron values have improved only slightly.

Current blood results:

* Hemoglobin (Hb): 7.2 mmol/L (ref 7.5-10.0)
* RBC: 4.12
* Hematocrit: 0.35 (ref 0.35-0.45)
* MCV: 84 fL (ref 80-100)
* Ferritin: 233 µg/L (ref 30-175)
* Serum iron: 6.8 µmol/L (ref 10-30)
* Transferrin: 1.4 g/L (ref 2.0-3.6)
* Total iron binding capacity (TIBC): 36 µmol/L (ref 45-78)
* Transferrin saturation: 18.8% (ref 20-45%)
* CRP: 35 mg/L (ref <5)
* WBC: 5.09
* Platelets: 224
* Sodium: 139 mmol/L
* Potassium: 4.0 mmol/L
* TSH: 1.66 mIU/L
* Vitamin D (25-OH): 97 nmol/L
* Folate: 12.0
* HbA1c: 33 mmol/mol
* Non-fasting glucose: 5.3 mmol/L

Iron results before starting iron supplementation (May 8th):

* Hemoglobin: 7.3 mmol/L
* MCV: 89 fL
* Ferritin: 268 µg/L
* Serum iron: 5.4 µmol/L
* Transferrin: 1.4 g/L
* TIBC: 36 µmol/L
* Transferrin saturation: 14.8%

So after several weeks of iron bisglycinate, my serum iron has increased from 5.4 to 6.8 µmol/L, and my transferrin saturation from 14.8% to 18.8%, but both are still below the reference range.

My questions are:

1. Looking at these results, is there anything that stands out that I could optimize?
2. Could low iron availability be preventing my B12 treatment from working properly, even though I’ve been injecting every other day for over two years?
3. Has anyone experienced worsening neurological symptoms despite ongoing B12 injections, only to find that iron was the missing piece?

I’d really appreciate hearing from anyone with similar experiences or knowledge. My GP is actively trying to help, but has also said that this is outside their area of expertise and they’re currently unsure what the next step should be. That’s why I’m reaching out to this community for additional insight.

Thank you!