What hormone levels are associated with polycystic ovary syndrome (PCOS)?
In PCOS, elevated androgens, a higher LH/FSH ratio and greater insulin resistance are the most reliable hormonal features. If you suspect you have PCOS, these are the values your general practitioner or gynaecologist will measure first.
Elevated androgens are the most characteristic hormonal sign of PCOS. Both testosterone and androstenedione are higher in almost all women with PCOS than in healthy women, regardless of whether they are slim or heavier. This is therefore one of the cornerstones on which the diagnosis rests. The ratio between LH (luteinising hormone) and FSH (follicle-stimulating hormone) is also disturbed: LH is too high, FSH relatively too low. This imbalance inhibits the normal maturation of egg cells and ovulation. How clearly this pattern is visible depends on body weight and the point in the cycle. Insulin also plays a central role. Women with PCOS are more insulin-resistant than women without PCOS, even when their weight is comparable. Their bodies produce more insulin to compensate, which over the longer term increases the risk of type 2 diabetes. AMH, a hormone that reflects ovarian activity, is elevated in PCOS due to the large number of small follicles. Researchers are investigating whether AMH could serve as a diagnostic marker in the future, but a universally accepted cut-off value does not yet exist. Notably, in women with PCOS who are overweight, AMH is actually lower than in slim women with PCOS. The same applies to LH and progesterone. Excess weight therefore 'masks' part of the typical hormonal pattern, which can make diagnosis more difficult. Higher androgens, on the other hand, occur more frequently with greater body weight. For growth hormone and ghrelin there are indications of disturbance in PCOS, but this has been described in only a limited number of studies and its significance remains unclear. The same applies to TSH and prolactin: elevated values have been reported in one small study (50 women), but this is not sufficiently substantiated to rely on at present. Finally, it matters which PCOS subtype a person has. Women with both androgen excess and absent ovulation have the most hormonal and metabolic abnormalities. Those who have PCOS without elevated androgens generally have a milder profile.
This answer is based on multiple reviews and a meta-analysis of 23 studies involving more than 4,500 women with PCOS. The findings on androgens, the LH/FSH ratio and insulin resistance are consistent and well documented. AMH is moderately well supported: the meta-analysis supports it, but there is still no consensus on threshold values. The findings on growth hormone and ghrelin come from one narrative review; those on TSH and prolactin from one study of 50 women. These last two represent weak evidence.
How do your hormone levels change throughout your menstrual cycle?
Your hormone levels follow a recognisable pattern throughout the cycle: oestrogen and progesterone rise and fall at set moments, with a sharp LH peak around ovulation. Bear in mind that there are large differences between women, and that the pill largely suppresses this pattern.
What exactly is brain fog and where does it come from?
Brain fog most likely has multiple simultaneous causes, of which a leaking blood-brain barrier in long COVID is the best substantiated. Exactly what goes wrong in the brain differs depending on the underlying condition, so the approach also varies by situation.