Peptides for PCOS (Polycystic Ovary Syndrome)

Peptides may influence PCOS pathophysiology through several mechanisms:

1. Insulin Sensitisation and Metabolic Improvement Insulin resistance is the central metabolic disturbance in PCOS, driving hyperandrogenism and ovulatory dysfunction. GLP-1 receptor agonists (semaglutide, tirzepatide) improve insulin sensitivity primarily through weight loss — reducing visceral adiposity decreases hepatic and peripheral insulin resistance. Clinical trials in PCOS populations have demonstrated significant reductions in fasting insulin, HOMA-IR (a measure of insulin resistance), and HbA1c alongside weight loss. MOTS-c, a mitochondrial-derived peptide, activates the AMPK pathway and has demonstrated direct insulin-sensitising effects in preclinical models, independent of weight loss.

2. Weight Reduction and Adipose Tissue Effects Approximately 50-80% of women with PCOS have overweight or obesity, and even modest weight loss (5-10% of body weight) can significantly improve hormonal profiles, restore ovulation, and reduce symptoms. GLP-1 agonists produce clinically meaningful weight loss through appetite suppression and reduced caloric intake. Tirzepatide's dual GLP-1/GIP agonism may offer enhanced weight loss efficacy. Weight reduction decreases aromatase activity in adipose tissue (reducing peripheral oestrogen production), improves SHBG levels, and reduces bioavailable androgens.

3. Reproductive Hormone Axis Modulation Kisspeptin-10 is a key regulator of the hypothalamic-pituitary-gonadal (HPG) axis, acting as the primary stimulus for GnRH neurone activation. In PCOS, GnRH pulse frequency is increased, favouring luteinising hormone (LH) over follicle-stimulating hormone (FSH) secretion — contributing to anovulation and ovarian androgen overproduction. Research is exploring whether kisspeptin administration can be used diagnostically (assessing HPG axis responsiveness) and potentially therapeutically to normalise GnRH pulsatility. GnRH itself, when administered in pulsatile fashion, has been used to induce ovulation in hypothalamic amenorrhoea and is of theoretical interest in PCOS.

4. Androgen Reduction Hyperandrogenism — manifesting as hirsutism, acne, and androgenetic alopecia — is one of the most distressing aspects of PCOS for affected women. By improving insulin sensitivity and reducing hyperinsulinaemia, GLP-1 agonists may indirectly reduce ovarian androgen production and increase SHBG levels, lowering bioavailable testosterone. Clinical studies of semaglutide in PCOS have reported reductions in total and free testosterone levels. Weight loss itself reduces adrenal androgen contribution and adipose tissue aromatase activity.

5. Ovulatory Function Restoration The ultimate goal for many PCOS patients — particularly those seeking fertility — is restoration of regular ovulatory cycles. Weight loss and insulin sensitisation with GLP-1 agonists have been associated with spontaneous resumption of ovulation in clinical studies. This is thought to occur through improved hormonal balance: reduced insulin levels decrease ovarian androgen production, improving the intra-ovarian environment for follicular development. Metformin achieves a similar effect through insulin sensitisation, and GLP-1 agonists may provide an additional or alternative approach.