Is it safe to vape while undergoing hormone therapy?

Vaping and Hormone Therapy Safety

Vaping while on hormone therapy is strongly discouraged due to the compounding thrombotic risks—hormone therapy already increases venous thromboembolism (VTE) risk 2-3 fold, and nicotine exposure from vaping likely adds additional cardiovascular and thrombotic burden similar to traditional smoking. 1

Critical Risk Considerations

Baseline Thrombotic Risk from Hormone Therapy

All forms of estrogen-containing hormone therapy carry inherent VTE risk:

• Transgender women on gender-affirming hormone therapy (GAHT) face increased VTE risk due to prothrombotic effects of estrogen, with ethinyl estradiol conferring particularly high risk 1
• Postmenopausal women on hormone therapy experience nearly 3-fold increased VTE rates, with highest risk in the first 90 days of treatment 1
• Combined estrogen-progestin therapy increases risk of deep venous thrombosis (12 more cases per 10,000 woman-years) and pulmonary embolism (9 more per 10,000 woman-years) 1
• Estrogen-only therapy increases DVT risk (7 more per 10,000 woman-years) 1

Nicotine's Compounding Effects

Smoking significantly interferes with hormone therapy through multiple mechanisms:

• Smoking causes dose-dependent elevated hepatic clearance of oral estrogens, reducing therapeutic efficacy while potentially generating toxic and mutagenic estrogen metabolites 2
• Nicotine exposure increases cardiovascular risk factors, which compound the 2-4 fold increased cardiovascular mortality already seen in transgender women on GAHT 1
• The combination of smoking and hormone therapy creates synergistic negative health consequences 3

While vaping research specific to hormone therapy is limited, the nicotine exposure and potential prothrombotic effects make it inadvisable.

Practical Clinical Approach

If Patient Continues Vaping Despite Counseling

Route of administration becomes critical:

• Strongly prefer transdermal estrogen delivery (patches, gels) over oral formulations in anyone with nicotine exposure 2
• Transdermal routes bypass hepatic first-pass metabolism, avoiding formation of unphysiological metabolites and maintaining lower, more stable estrogen levels 2
• This applies to both menopausal hormone therapy and gender-affirming hormone therapy

Avoid ethinyl estradiol entirely in patients who vape, as it carries higher VTE risk than other estrogen formulations 1

VTE Prophylaxis Considerations

During high-risk periods:

• Consider discontinuing hormone therapy during hospitalization or immobilization, or ensure appropriate VTE prophylaxis measures 1
• Risk of VTE increases 5-fold in the first 90 days after myocardial infarction in patients on hormone therapy 1

Monitoring Strategy

Enhanced surveillance is warranted:

• Regular assessment for signs/symptoms of VTE (leg swelling, chest pain, shortness of breath)
• Monitor cardiovascular risk factors more closely (blood pressure, lipid profiles) 1
• In transgender men on testosterone, monitor for erythrocytosis which further increases thrombotic risk 1

Common Pitfalls to Avoid

Do not simply increase oral estrogen doses in patients who vape to compensate for reduced efficacy—this increases production of toxic metabolites and cancer risk 2

Do not assume vaping is "safer" than smoking regarding hormone therapy interactions—nicotine exposure remains the primary concern for cardiovascular and thrombotic complications

Do not continue oral contraceptives in older patients who vape—these are contraindicated in elderly smokers, though this specific contraindication doesn't extend to menopausal HRT 2

Bottom Line Recommendation

The safest approach is complete nicotine cessation before initiating or continuing hormone therapy. If the patient cannot or will not stop vaping, transdermal estrogen at the lowest effective dose should be used, with heightened monitoring for thrombotic complications and strong counseling about the compounded risks. 2, 1