How long does it take for vitamin B6 to lower prolactin?

October 6, 2025 •

4 min read

Clinical studies have shown significant reductions in serum prolactin levels within four to 16 weeks of vitamin B6 supplementation. The exact timeframe depends on individual factors and the amount used, making the question of how long does it take for vitamin B6 to lower prolactin? a complex one.

Quick Summary

Vitamin B6 reduces prolactin levels by boosting dopamine synthesis, which inhibits prolactin release from the pituitary gland. While can trigger acute effects, sustained reduction typically takes weeks to months of consistent supplementation, varying by individual.

Key Points

Gradual Reduction: Significant prolactin reduction typically occurs over weeks to months, with major drops observed by week 4 and continuing through week 16 of consistent vitamin B6 supplementation.
Dopamine Mechanism: Vitamin B6 (especially the active P5P form) works primarily by boosting dopamine levels, which naturally inhibits prolactin release from the pituitary gland.
Requires Specific Amounts: Amounts of vitamin B6 used for lowering prolactin are much higher than the recommended daily allowance, and therefore carry potential risks.
Consult a Doctor: Due to the risk of nerve damage and other side effects when taken in large amounts, it is critical to use vitamin B6 for this purpose only under a doctor's supervision.
Individual Variation: The exact timeline and efficacy can vary significantly based on the individual's baseline prolactin levels, the underlying cause of hyperprolactinemia, and total amount used.
Side Effects: Potential side effects of large amounts of B6 include sensory neuropathy, nausea, and increased skin sensitivity to sunlight.

The Role of Vitamin B6 in Prolactin Regulation

To understand the timeline for a reduction in prolactin, it is essential to first understand how vitamin B6 influences the body's endocrine system. Prolactin is a hormone primarily produced and secreted by the anterior pituitary gland. Its release is inhibited by dopamine, a key neurotransmitter that travels from the hypothalamus to the pituitary via a specific pathway. Vitamin B6, in its active form known as Pyridoxal 5'-phosphate (P5P), acts as a critical cofactor for the enzyme aromatic L-amino acid decarboxylase (AADC), which is involved in synthesizing dopamine. By facilitating dopamine production, vitamin B6 increases the signal to the pituitary to suppress prolactin secretion, thus lowering its overall levels. Beyond this indirect effect, some research indicates that P5P may also directly inhibit the proliferation and hormone secretion of prolactin-producing pituitary cells.

The Timeline for Prolactin Reduction

Research into vitamin B6's effect on prolactin reveals a varying timeline depending on the amount used and individual physiology. There are both acute and chronic effects to consider:

Acute Effects: In some studies on normal subjects, a significant suppression of prolactin has been observed relatively quickly. For example, a 1982 study found a 52% suppression of prolactin just 90 minutes after administering vitamin B6. However, this rapid reduction is not necessarily sustained and reflects an immediate physiological response rather than a long-term change.
Chronic Effects: For sustained, therapeutic reduction of prolactin in cases of hyperprolactinemia, a longer treatment period is required. Clinical trials have shown significant, lasting drops over several weeks. A 2021 double-blind, randomized controlled study found that patients taking vitamin B6 showed a steep reduction in prolactin levels from baseline to week four, with the reduction continuing to improve through the 16-week study period. Similarly, early reports of women with galactorrhea-amenorrhea syndrome saw the return of ovulatory menses within 37 to 94 days of starting a B6 regimen. This suggests that a sustained approach is needed for clinically meaningful long-term management.

Therapeutic Use and Active Form

The amounts of vitamin B6 used to lower prolactin are significantly higher than the standard dietary reference intake. While the recommended daily allowance for adults is only 1.3 to 1.7 mg, studies have used various amounts. The specific form of B6 used can also matter. The active form, Pyridoxal 5'-phosphate (P5P), is often recommended because it does not require metabolic conversion by the liver, making it more readily available for dopamine synthesis.

Safety Considerations for Vitamin B6

Vitamin B6 supplementation is not without risks, which is why medical supervision is essential. The tolerable upper intake limit (UL) for adults is 100 mg/day. Taking significantly higher amounts for an extended period has been associated with sensory neuropathy, a form of nerve damage that can cause symptoms like numbness, tingling, and a loss of coordination. Other potential side effects include nausea, stomach pain, and photosensitivity. All these symptoms typically resolve upon discontinuing the supplement, but the risk underscores the importance of medical guidance.

Comparison: Vitamin B6 vs. Standard Medication


Feature	Vitamin B6 Supplementation	Standard Dopamine Agonist (e.g., Cabergoline)
Efficacy	Effective in reducing prolactin, particularly in antipsychotic-induced cases.	Highly effective in normalizing prolactin and resolving symptoms.
Timeline	Gradual reduction over weeks to months, with significant drops often visible by week 4 and continuing.	Typically achieves normalization of prolactin levels more quickly than B6.
Mechanism	Enhances endogenous dopamine production; may also have direct effect on pituitary cells.	Direct dopamine agonist action, mimicking dopamine to suppress prolactin.
Side Effects	Potential for sensory neuropathy, nausea, and stomach upset when taken in large amounts.	More frequent side effects may include nausea, dizziness, and headache.
Cost	Generally low cost and widely available over-the-counter.	Requires a prescription and can be more expensive.
Availability	Available as an over-the-counter supplement, though high amounts require caution.	Available by prescription only for medical use.

Factors Influencing the Outcome

The speed and effectiveness with which vitamin B6 can lower prolactin can be influenced by several factors:

Baseline Prolactin Levels: Individuals with higher initial prolactin levels may experience a more pronounced reduction, as seen in some study populations.
Underlying Cause: The cause of hyperprolactinemia matters. For instance, B6 has been shown effective in cases of antipsychotic-induced hyperprolactinemia. For prolactinomas, while B6 can have an effect, medical treatment is generally prioritized.
Individual Metabolism: Genetic variations and individual metabolic rate can affect how efficiently the body utilizes vitamin B6 to produce dopamine, influencing the overall timeline.
Consistent Adherence: As with any supplement, consistent daily intake is crucial for achieving and maintaining therapeutic effects.

Conclusion

High amounts of vitamin B6 can be an effective adjunctive treatment for reducing elevated prolactin levels, exerting its effects primarily by boosting dopamine synthesis. While some acute suppression may occur, significant and sustained reduction typically requires a commitment of several weeks to months. The amounts required are substantially higher than dietary recommendations and carry a risk of adverse effects, notably nerve damage, so supplementation should always be managed under the strict guidance of a healthcare professional. Individual factors, including baseline prolactin and underlying cause, play a key role in determining the speed and success of treatment. For individuals with hyperprolactinemia, understanding this timeframe is crucial for setting realistic expectations for symptom improvement.

Disclaimer: This information is for general knowledge and should not be taken as medical advice. Consult with a healthcare professional before starting any new supplement regimen.

Frequently Asked Questions

While some acute suppression of prolactin has been observed within a few hours of administration, significant and sustained reduction typically requires weeks to months of consistent supplementation. The immediate effect is temporary and not indicative of long-term change.

Studies have used various amounts that are far higher than the standard daily requirements. These amounts must be taken under medical supervision due to potential risks.

Taking amounts above the 100 mg/day tolerable upper limit carries a risk of nerve damage (sensory neuropathy). It is potentially unsafe when taken in very large amounts daily. Medical guidance is necessary.

The active form, Pyridoxal 5'-phosphate (P5P), is often recommended. It is more readily used by the body to produce dopamine and may also have a direct inhibitory effect on prolactin-secreting pituitary cells.

Vitamin B6 acts as a cofactor for the enzyme that synthesizes dopamine. By increasing dopamine production, it signals the pituitary gland to decrease prolactin secretion, as dopamine is the primary prolactin-inhibiting hormone.

While studies show B6 can be effective, its use depends on the underlying cause of hyperprolactinemia. It is not as powerful as prescription dopamine agonists like Cabergoline but can be considered an alternative or adjunct treatment for those who cannot tolerate standard medication, under medical guidance.

Symptoms of hyperprolactinemia include irregular or absent menstrual periods (amenorrhea), milky discharge from the nipples (galactorrhea), infertility, reduced libido, and visual disturbances.