Persistent tiredness deserves a diagnosis before it gets a treatment. The common causes in women are specific, testable and treatable — and most of them are missed for months because fatigue feels too vague to investigate.
Iron deficiency. This is the one most often skipped. Ferritin can be low enough to cause profound fatigue long before haemoglobin falls, so a normal full blood count does not rule it out. In women with heavy periods it is common enough to check first.
Thyroid underactivity. Easily tested, easily treated, and it also explains weight gain, cold intolerance and low mood that often get attributed to something else.
Vitamin B12 and vitamin D. B12 deficiency is more likely with a plant-based diet, after bariatric surgery, or on long-term metformin.
Sleep apnoea. Under-recognised in women, who more often present with fatigue and low mood than with loud snoring.
Depression, which very frequently presents as physical exhaustion rather than sadness. In perimenopause, night sweats fragmenting sleep produce exactly the daytime fatigue and mental fog that wellness infusions are marketed for — and treating the sleep disruption addresses the cause rather than the sensation.
A blood panel and a proper history cost a fraction of a course of infusions and give you an answer. If they come back clear and you still want to try an elective drip, that is an informed choice. Doing it the other way round is how treatable conditions get missed.