Does St John's Wort (Hypericum perforatum) affect height or libido similarly to Selective Serotonin Reuptake Inhibitors (SSRIs)?

St. John's Wort Does Not Impact Height and Has Fewer Sexual Side Effects Than SSRIs

St. John's wort does not affect height in any documented way, and it demonstrates significantly better tolerability than SSRIs with lower rates of treatment discontinuation due to adverse events, suggesting fewer sexual side effects including libido problems. 1, 2

Impact on Height

• There is no evidence in the medical literature that St. John's wort affects height or growth in any population 3, 1, 2, 4
• This question likely stems from confusion with SSRIs, which also do not directly impact height in adults or adolescents under typical clinical use

Impact on Libido and Sexual Function

Superior Tolerability Profile Compared to SSRIs

• St. John's wort has significantly lower discontinuation rates due to adverse events (4%) compared to SSRIs (7%), indicating better overall tolerability including sexual side effects 2
• Overall treatment discontinuation rates are markedly lower with St. John's wort (12%) versus SSRIs (16%), suggesting patients experience fewer bothersome side effects 2
• Moderate-quality evidence confirms St. John's wort is better tolerated than second-generation antidepressants across multiple studies 1, 2, 4

Documented Adverse Effects

• The documented adverse effects of St. John's wort include mild gastrointestinal symptoms, skin reactions, fatigue or sedation, dizziness or confusion, headache, and dry mouth—notably absent from this list are sexual dysfunction or libido changes 4
• Unlike SSRIs, which commonly cause sexual dysfunction in 30-70% of patients, St. John's wort does not appear to have significant sexual side effects based on clinical trial data 1, 2

Hormonal Effects

• A pilot study examining androgen concentrations found that St. John's wort did not significantly alter testosterone, DHT, DHEAS, or SHBG levels in healthy men and women after 14 days of treatment 5
• There was a slight decrease in 5α-reduced androgens (androsterone sulfate and epiandrosterone sulfate), but this did not translate into clinically significant effects on sexual function or libido 5

Clinical Efficacy Context

• St. John's wort demonstrates equivalent response rates (54% vs. 52%) and remission rates (36% vs. 30%) compared to SSRIs for mild-to-moderate depression 2
• The standard dosing is 300 mg three times daily (900 mg/day total) of standardized extract containing 0.3% hypericin 2

Critical Safety Considerations

Absolute Contraindications

• St. John's wort is absolutely contraindicated with MAOIs or SSRIs due to serotonin syndrome risk 1, 4
• Patients must wait at least 24-48 hours after discontinuing St. John's wort before starting SSRIs, as serotonin syndrome can emerge during this transition period 1

Major Drug Interactions

• St. John's wort is a potent inducer of CYP3A4 and P-glycoprotein, significantly reducing plasma concentrations of numerous medications 1, 6
• Oral contraceptives: Reduces effectiveness, causing breakthrough bleeding and unintended pregnancies 1, 7, 6
• Immunosuppressants (cyclosporine, tacrolimus): May cause organ rejection 1, 6
• Anticoagulants (warfarin): Increases thrombotic risk 1, 6
• HIV medications: Significantly decreases protease inhibitor levels 1, 6

Regulatory Issues

• St. John's wort is not FDA-regulated in the United States, with no standardization of content or potency 1, 2, 4
• Quality-controlled European preparations are preferred when considering this treatment 2

Clinical Bottom Line

For patients with mild-to-moderate depression who cannot tolerate SSRI sexual side effects, St. John's wort offers comparable antidepressant efficacy with superior tolerability, but only if they are not taking contraindicated medications and can access quality-controlled preparations. 1, 2 The herb does not affect height and appears to have minimal impact on libido compared to the well-documented sexual dysfunction associated with SSRIs.