Losing Weight On Mounjaro But Feeling Exhausted? Your Iron Levels May Be Worth Checking.
The scales are moving. Your appetite has dropped.
But your energy seems to have disappeared with it.
Fatigue while taking Mounjaro can have many causes.
One worth ruling out is iron deficiency.
At first, everything seems to be going exactly as planned.
You’re eating less. Getting full quicker. Watching the number
on the scales fall.
Then somewhere along the way, you start feeling wiped out.
The stairs feel harder. Training feels flat. Your concentration
disappears by mid-afternoon. You wake up tired despite sleeping.
It is easy to blame everything on Mounjaro or simply assume
fatigue is part of losing weight.
But persistent fatigue deserves a closer look.
Can Mounjaro Affect Your Iron Levels?
Mounjaro contains tirzepatide, a medicine used for type 2
diabetes and weight management in appropriate patients.
Tirzepatide reduces appetite, increases feelings of fullness
and delays gastric emptying.
This can mean some people eat considerably less food than they
did before treatment.
Mounjaro can also cause gastrointestinal side effects such as
nausea, vomiting, diarrhoea, constipation and abdominal symptoms.
The important distinction
Current evidence does not establish that Mounjaro directly
causes iron malabsorption in every patient.
However, reduced food intake, gastrointestinal symptoms and
significant dietary change may make nutritional deficiencies
more relevant during weight loss.
Emerging research into GLP-1 based medicines has also identified
lower ferritin and iron depletion in some patient groups.
That makes persistent fatigue, poor exercise tolerance or other
symptoms worth investigating rather than simply guessing.
Why Could Iron Intake Fall While Taking Mounjaro?
You Are Eating Less
A smaller overall food intake can also mean a smaller intake
of iron, protein and other important nutrients if meals are
not nutritionally balanced.
You Feel Full Quickly
Tirzepatide increases satiety and delays gastric emptying,
which can make larger meals difficult to finish.
GI Side Effects
Nausea, vomiting, diarrhoea and other gastrointestinal
symptoms can make eating a varied diet more difficult.
Signs Your Iron Levels May Be Worth Checking
Iron deficiency can cause symptoms that are easy to dismiss as
dieting, stress, poor sleep or a side effect of weight loss treatment.
- Persistent tiredness
- Low energy
- Feeling weak
- Brain fog or poor concentration
- Headaches
- Breathlessness on exertion
- Reduced exercise tolerance
- Restless legs
- Hair shedding or thinning
- A previous history of low ferritin or iron deficiency
Important:
These symptoms are not specific to iron deficiency.
They can have many possible causes.
Blood testing is the way to establish whether iron deficiency
may actually be part of the problem.
Mounjaro, Hair Loss And Low Iron
Hair shedding is another concern some patients notice during
substantial weight loss.
Hair loss can have many causes, including rapid weight change,
nutritional deficiencies, hormonal factors, stress and medical
conditions.
Iron deficiency is one possible factor worth considering,
particularly where hair shedding appears alongside fatigue,
low energy or a previous history of low ferritin.
Rather than immediately taking supplements, testing can help
establish whether iron deficiency is actually present.
Who May Have A Higher Chance Of Developing Low Iron?
Mounjaro may be only one piece of the picture.
Your underlying risk factors matter too.
Heavy Periods
Regular blood loss can gradually reduce iron stores,
particularly if dietary intake also falls.
Previous Iron Deficiency
People who have previously had low ferritin may be more
likely to experience the problem again.
Restricted Diet
Eating substantially less food or excluding several food
groups may reduce iron intake.
Vegetarian Or Vegan Diet
Careful dietary planning can be particularly important when
calorie intake is falling.
Digestive Conditions
Coeliac disease, inflammatory bowel disease and other
gastrointestinal conditions can affect iron status.
Previous Bariatric Surgery
Some types of weight loss surgery can increase the risk of
long-term nutritional deficiencies including iron deficiency.
Start With Blood Testing
Feeling tired does not automatically mean you need iron.
And taking Mounjaro does not automatically mean your iron levels
are low.
The sensible first step is checking.
Our private iron assessment can include:
- Ferritin
- Full Blood Count
- Serum iron
- Transferrin
- Total Iron Binding Capacity
- Transferrin saturation
Your results can then be interpreted alongside your symptoms,
diet, medical history and current medicines.
What If My Iron Is Low?
Confirm The Deficiency
Blood testing establishes whether your iron stores are
actually depleted.
Understand Why
Low iron can result from blood loss, reduced intake,
gastrointestinal conditions, malabsorption or several
other causes.
Consider Oral Iron
Iron tablets are appropriate for many people and may be
considered depending on your results and circumstances.
Assess Response And Tolerance
Some patients experience stomach upset, constipation,
nausea or inadequate improvement despite oral iron.
Consider IV Iron Where Appropriate
If iron deficiency is confirmed and oral iron is ineffective,
poorly tolerated or clinically unsuitable, IV iron may be
considered following clinical assessment.
Follow Up
Repeat blood testing and appropriate follow-up help assess
your response to treatment.
Does Taking Mounjaro Mean I Need An Iron Infusion?
No.
Mounjaro use alone is not an indication for IV iron.
An iron infusion should only be considered when blood testing and
clinical assessment show that iron replacement is required and
IV treatment is appropriate.
If your iron levels are normal, another cause for your symptoms
should be considered.
Already Tried Iron Tablets?
Some patients already know they are iron deficient.
They have taken tablets for weeks or months, only to find the
stomach pain, nausea or constipation makes them difficult to tolerate.
Others tolerate oral iron but their blood results fail to improve
sufficiently.
Where iron deficiency has been confirmed and oral iron has been
ineffective, poorly tolerated or is clinically unsuitable, our
clinicians can assess whether IV iron may be appropriate.
Complete Iron Assessment & Treatment Pathway
Holden’s Chemist Express currently offers a complete private
iron pathway including blood testing, clinical review,
independent prescriber assessment and a 500mg IV iron infusion
where clinically appropriate.
Current package price: £649
Private Iron Testing And IV Iron In Doncaster & Newark
Holden’s Chemist Express offers private iron deficiency assessment,
ferritin testing and IV iron treatment where clinically appropriate
from our clinics in Scawsby, Doncaster and Newark.
Scawsby, Doncaster
Holden’s Chemist Scawsby
4 Barnsley Road
Scawsby
Doncaster
DN5 8QE
Tel:
01302 785465
Newark
Holden’s Chemist Newark
77b Eton Avenue
Newark-on-Trent
Nottinghamshire
NG24 4JH
Tel:
01636 701274
Already Using Mounjaro Through Our Weight Loss Clinic?
If you are receiving weight management support through Holden’s
Chemist Express and develop persistent fatigue, hair shedding,
poor exercise tolerance or other symptoms that concern you,
speak to our clinical team.
Depending on your circumstances, blood testing may help identify
whether iron deficiency or another nutritional issue should be
investigated.
Frequently Asked Questions
Does Mounjaro cause iron deficiency?
Current evidence does not prove that Mounjaro directly causes
iron deficiency in every patient. However, reduced appetite,
lower food intake, gastrointestinal side effects and substantial
dietary change may affect nutritional intake. Emerging research
into GLP-1 based medicines has also identified iron depletion
in some patient populations.
Does Mounjaro stop iron tablets being absorbed?
Tirzepatide delays gastric emptying and can affect the rate at
which some oral medicines are absorbed. There is not currently
enough evidence to state that Mounjaro reliably prevents oral
iron absorption. If oral iron is not improving your blood results,
your response should be assessed clinically.
Can Mounjaro make you tired?
Tiredness is reported as a possible side effect of tirzepatide.
However, persistent or significant fatigue can have many other
causes, including iron deficiency, so symptoms may warrant
further assessment.
Should I have a ferritin test while taking Mounjaro?
Routine testing needs depend on your individual circumstances.
If you develop persistent fatigue, reduced exercise tolerance,
hair shedding or have risk factors for iron deficiency, a
healthcare professional may recommend appropriate blood tests.
Can I have an iron infusion while taking Mounjaro?
Suitability depends on your blood results, medical history,
medicines and clinical assessment. Taking Mounjaro alone does
not mean that IV iron is required.
What if my iron tablets are upsetting my stomach?
Oral iron can cause gastrointestinal side effects in some people.
If iron deficiency has been confirmed and tablets are difficult
to tolerate, speak to a healthcare professional about appropriate
alternatives.
Do I need a GP referral for your iron service?
You do not need a GP referral to start the private assessment
process with Holden’s Chemist Express. Further investigation or
communication with your GP may be recommended depending on your
blood results and medical history.
More About Iron Deficiency
Private Iron Blood Test
Check ferritin and iron status before deciding on treatment.
Iron Infusion Treatment
Learn when IV iron may be considered and how assessment works.
Iron Infusion Process
See the pathway from blood testing to clinical review,
treatment and follow-up.
Losing Weight But Losing Your Energy Too?
Find out what your iron levels actually look like before
blaming everything on Mounjaro.
Start with a blood test. If iron deficiency is confirmed,
we can explain the appropriate next step.
Medical information on this page is provided for general
information and does not replace individual medical assessment.
Do not stop or alter prescribed tirzepatide or iron treatment
without speaking to an appropriate healthcare professional.
Persistent or worsening symptoms should be medically assessed.
Clinical information sources:
NHS information on tirzepatide (Mounjaro).
Electronic Medicines Compendium, Mounjaro Summary of Product Characteristics.
Published medical literature examining nutritional and micronutrient
status during GLP-1 based treatment.