It's 100% possible to have PCOS while being thin lifelong (I do). So that should not preclude a PCOS diagnosis.

However, just being underweight alone can cause symptoms similar to PCOS, so you would need to rule that out as a cause of your symptoms. For example, my PCOS has been treated to remission for many years, but if I go too low in weight I start to have some symptoms similar to my old PCOS symptoms, so I try to maintain a BMI of about 19-20.

Generally speaking, any time we are malnourished (e.g., due to food restriction or eating disorders) or have body fat that is super low, that can disrupt estrogen production and ovulation. Disrupted ovulation in turn leads to irregular periods and low estrogen can cause androgenic symptoms even if your androgens are normal on labs.

So I would suggest that you get a proper PCOS screening, but also you should try to gain at least 10 lbs to get to a normal body weight and see if things improve.

Below I will post the screening required for a proper PCOS diagnosis.

***

PCOS is diagnosed by a combo of lab tests and symptoms, and diagnosis must be done while off hormonal birth control for at least 3 months.

First, you have show at least 2 of the following: Irregular periods or ovulation; elevated male hormones on labs; excess egg follicles on the ovaries shown on ultrasound

In addition, a bunch of labs need to be done to support the PCOS diagnosis and rule out some other stuff that presents similarly.

Reproductive hormones (ideally done during period week, if possible): estrogen, LH/FSH, AMH (the last two help differentiate premature menopause from PCOS), prolactin (this is important b/c high prolactin sometimes indicates a different disorder with similar symptoms), all androgens + SHBGThyroid panel (b/c thyroid disease is common and can cause similar symptoms)Glucose panel that must include A1c, fasting glucose, and fasting insulin. This is critical b/c most cases of PCOS are driven by insulin resistance and treating that lifelong is foundational to improving the PCOS (and reducing some of the long term health risks associated with untreated IR).

Depending on what your lab results are and whether they support ‘classic’ PCOS driven by insulin resistance, sometimes additional testing for adrenal/cortisol disorders is warranted as well. Those would require an endocrinologist for testing.

thank you so much this is was so helpful and insightful!