warum nehme ich nicht ab test — what are common causes?

The question 'why am I not losing weight' has many possible causes, and a single test rarely provides a complete answer. Based on the provided context, relevant factors include: 1. **Cortisol & Stress**: Low cortisol can cause weight gain and fatigue. A morning cortisol test gives a snapshot but is not diagnostic alone. Evidence is practice-based, not from large trials. Caveat: a single test does not reflect HPA axis function. (Source: mybody-x.com/blogs/cortisolmangel-gewichtszunahme) 2. **Gut microbiome**: Gut health influences stress and cortisol via the gut-brain axis. A microbiome test can show bacterial balance but not cortisol directly. Evidence is mechanistic, not clinically validated. (Source: mybody-x.com/blogs/darm-mikrobiom-test) 3. **Genetics**: DNA tests (e.g., ACTN3, VDR) provide hints about muscle fiber type or vitamin D metabolism, but effect sizes are small and not deterministic. (Source: rs1815739, rs1544410 from 1000 Genomes) 4. **Thyroid, insulin resistance, leptin**: These classic hormonal axes are not directly addressed in the given context but are common causes of weight loss resistance. A comprehensive blood test (TSH, fT3, fT4, fasting insulin, HOMA-IR, leptin) ordered by a doctor is more useful than a single home test. 5. **Test quality**: Finger-prick tests (e.g., for vitamin D, B12) are convenient but less accurate than venous draws. They serve as screening, not diagnosis. (Source: mybody-x.com/bluttest-zuhause) **Conclusion**: The most common causes of stalled weight loss are multifactorial: calorie balance, hormonal status (cortisol, thyroid, insulin), sleep, stress, microbiome, and genetics. There is no single 'weight loss test'. A medical workup with targeted lab tests based on symptoms is recommended. Evidence is mixed: for cortisol and microbiome mostly mechanistic/practice-based, for genetics partly GWAS but with small effects.