Kratom and prolactin: Can it affect libido?

Kratom is a plant originating from Southeast Asia that has spread worldwide in recent years. It is used for its stimulating, relaxing, and analgesic effects, and it is also associated with questions regarding hormones, sexual health, and libido. One of the most common topics is the effect of kratom on the hormone prolactin. But what do we really know about this based on science? And can kratom affect libido?

What is prolactin and why is it related to libido

Prolactin is a hormone produced by the pituitary gland. It plays a role in the maturation of mammary glands, affects metabolism, and is directly related to sexual function.

High prolactin levels can cause:

• decreased libido
• erectile problems
• reduced testosterone
• fatigue
• menstrual cycle disturbances in women

Thus, if a substance affects prolactin, it may also alter sexual experience.

Does kratom affect prolactin? What do studies say

Important information: To date, there is no clinical study that directly examines kratom and prolactin.

There is therefore no data showing:

• how kratom changes prolactin levels
• whether it causes hyperprolactinemia or a decrease in prolactin
• what direct impact it has on libido via the hormonal axis

This is crucial information. Scientific data are very limited.

What do studies on Kratom say?

While the effect of classical opioids (morphine, methadone) on prolactin and testosterone is indisputable (a condition known as OPIAD – Opioid-Induced Androgen Deficiency), studies directly on kratom are still rare, but do exist.

1. Singh et al. (2018) Study – Surprising Result?

The study published in the Journal of Ethnopharmacology examined testosterone levels in long-term kratom users in Malaysia.

• Findings: The study concluded that regular kratom use did not lead to a drastic reduction in testosterone levels compared to the control group, which is different from strong pharmaceutical opioids.

• Important note: This study does not rule out the effect on prolactin. Users may have normal testosterone but still report sexual dysfunction. This suggests that the prolactin pathway may be the dominant issue rather than the drop in testosterone.

2. Grundmann Survey (2017)

Large survey among users in the USA showed that although kratom is perceived positively for pain relief, side effects including loss of libido are among the most frequently reported negatives (just after nausea and constipation).

The large US survey thus confirmed that reduced libido is a relatively common side effect among kratom users, suggesting a possible hormonal or neurochemical link.

3. Case reports and endocrinology practice

Medical case reports suggest that in heavy kratom users (high daily doses), symptoms typical of hyperprolactinemia appear, including gynecomastia (enlargement of the male breast) and galactorrhea, which is a direct consequence of excess prolactin.

What we know from opioid-like substances research

Kratom acts partially via μ-opioid receptors. In classical opioids, it is well documented:

• that they can increase prolactin
• that they can reduce libido and lower testosterone
• that long-term use can disrupt the endocrine system

This is important because kratom has a similar, though significantly weaker mechanism of action.

It follows that:

User experiences

On discussion forums (Reddit, Bluelight, user reports), people describe:

• in some people increased libido
• in others decreased libido
• sometimes erectile difficulties at high doses
• return to normal after discontinuation

These experiences may point to some hormonal effect but are not scientific proof.

How kratom may indirectly affect libido

Even though there are no direct studies on prolactin, there are several indirect mechanisms:

1) Dopamine

Prolactin is closely linked to dopamine – the more dopamine, the less prolactin. Kratom may affect the dopaminergic system, but the exact impact is still unclear.

2) Effects on stress and fatigue

Reducing stress and pain may improve libido. Conversely, fatigue or sedation at higher doses may reduce libido.

3) Effects on testosterone

Rats at high doses had changes in testosterone, which could secondarily affect libido.

Conclusion

If testosterone often remains normal, but libido decreases and symptoms similar to elevated prolactin appear, it is possible that the prolactin pathway plays a greater role than changes in testosterone. However, this hypothesis has not yet been directly confirmed by any study.

References:

Singh D. et al. (2018). Assessment of gonadotropins and testosterone hormone levels in regular kratom (Mitragyna speciosa Korth.) users. Journal of Ethnopharmacology, 226, 224–230.

Grundmann, O. (2017). Patterns of kratom use and health impact in the US—Results from an online survey. Drug and Alcohol Dependence, 176, 63–70.

Vučković, S., et al. (2004). Opioid-induced hormones changes: Mechanism and clinical significance. Vojnosanitetski pregled, 61(2), 195-203.

Hallinan, R., et al. (2002). Hypogonadism in men receiving methadone and buprenorphine maintenance treatment. International Journal of Andrology, 25(3), 133-139.