Weight Loss (Unintentional)
Losing weight without trying — particularly losing more than 5% of body weight over 6–12 months — is always medically significant and should be investigated by a doctor. While some causes are benign, unintentional weight loss can be an early sign of an underlying condition including cancer, thyroid disease, diabetes, or malabsorption. Early investigation provides reassurance or allows prompt treatment.
Speak to an English-speaking doctor about unintentional weight loss. No referral needed.
Book NowAppointments available within 24 hours
Already diagnosed and on treatment? Renew your existing prescription online quickly.
Request PrescriptionReviewed by a licensed doctor
On this page
Unintentional weight loss should always be assessed by a doctor. This page provides general information only.
Why unintentional weight loss matters
Unintentional weight loss is defined as losing more than 5% of body weight over a period of 6–12 months without deliberately trying to do so. It is a "red flag" symptom in medicine — not because it always indicates something serious, but because the range of possible causes includes conditions where early diagnosis significantly affects outcome.
In clinical practice, a thorough investigation finds an identifiable cause in around 75% of cases. Of these, around one third are benign (depression, medication side effects, social isolation) and two thirds are organic conditions (cancer, thyroid disease, diabetes, and others). The remaining 25% of cases remain unexplained after investigation — in these, careful follow-up monitoring is recommended.
Possible causes
Non-organic causes
- Depression and anxiety — reduced appetite and food intake
- Social isolation and bereavement — particularly common in older expats
- Medication side effects — many drugs suppress appetite
- Dental problems — difficulty eating leading to reduced intake
Organic causes
- Cancer — any type can cause weight loss; gastrointestinal, lung, lymphoma, and pancreatic cancers particularly
- Hyperthyroidism — accelerated metabolism causes weight loss despite increased appetite
- Diabetes — uncontrolled diabetes causes weight loss through urinary glucose loss
- Malabsorption — coeliac disease, inflammatory bowel disease, and other gut conditions
- Chronic infection — tuberculosis, HIV, and other chronic infections
- Adrenal insufficiency (Addison's disease)
- Heart failure and COPD — increased energy expenditure
When to see a doctor
See a doctor promptly if you have lost more than 5% of your body weight without trying over 6 months. Do not wait to see if it continues — earlier investigation allows earlier diagnosis and treatment. Weight loss accompanied by blood in the stool, persistent cough, night sweats, or fatigue warrants particularly urgent assessment.
Speak to an English-speaking doctor today
No referral, no waiting room. Online consultations available within 24 hours.
What investigation involves
A thorough assessment includes a detailed history, physical examination, and a panel of blood tests covering full blood count, inflammatory markers, thyroid function, glucose, liver and kidney function, and tumour markers where appropriate. Urine analysis, chest X-ray, and further imaging or endoscopy are requested based on findings.
Our doctors arrange this investigation systematically and efficiently, communicate results clearly, and co-ordinate any specialist referrals that are needed.
How eMedClinic can help
Our doctors provide systematic assessment of unintentional weight loss — arranging the appropriate investigations, interpreting results, and providing clear guidance on next steps. For expats who have moved abroad and do not yet have an established GP, we provide continuity of investigation and follow-up that might otherwise fall through the cracks.
Ready to speak to a doctor?
English-speaking specialists online. No referral, no waiting room.