Can I Take St. John's Wort With Leqvio (Inclisiran)? A Women's Health Guide

The Short Answer: The Risk Is Different From What Most People Expect

St. John's Wort does not interact with Leqvio the way it interacts with statins or the pill. The reason matters. Inclisiran is a small-interfering RNA (siRNA) molecule that is taken up directly into hepatocytes, and it is not metabolized by CYP3A4. St. John's Wort is a potent inducer of CYP3A4 and P-glycoprotein, so the classic enzyme-induction problem that slashes levels of statins, hormonal contraceptives, and antiretrovirals does not apply here in the same way.

That should sound reassuring. It is, partly. The real concern for women on Leqvio is not that St. John's Wort will cancel your cholesterol injections. The concern is twofold: first, the interaction has simply not been studied, so "no known pharmacokinetic interaction" is not the same as "proven safe"; second, many women taking Leqvio for cardiovascular risk reduction are also on medications that St. John's Wort will affect, including anticoagulants, antidepressants, and hormonal therapies.

Why Women Are in This Situation in the First Place

St. John's Wort is one of the most commonly used herbal supplements in the United States, and women use it more than men do. A 2017 analysis of NHANES data found that approximately 20 percent of U.S. Adults who use herbal supplements are women managing mood, sleep, or menopause symptoms, and St. John's Wort ranks consistently among the top ten supplements in that group.

The timing matters. Perimenopause, the phase that can begin a decade before the final menstrual period, brings depressed mood, irritability, and disrupted sleep. Women in their 40s and early 50s often reach for St. John's Wort before or instead of prescription antidepressants. Those same years are when LDL cholesterol starts rising as estrogen levels fall, setting up the condition that might eventually lead a cardiologist to prescribe Leqvio.

How ASCVD Risk Climbs in Midlife Women

Premenopausal women have lower rates of atherosclerotic cardiovascular disease than age-matched men, largely because of the favorable lipid effects of endogenous estrogen. After menopause, LDL-C rises by roughly 10 to 14 mg/dL on average, triglycerides increase, and HDL-C falls modestly. Women with familial hypercholesterolemia (FH) face a compounded risk because their baseline LDL is already elevated before this postmenopausal shift.

Inclisiran is approved for adults with heterozygous familial hypercholesterolemia (HeFH) or clinical ASCVD who need additional LDL lowering on top of maximally tolerated statin therapy. The ORION-11 trial showed inclisiran reduced LDL-C by approximately 50 percent from baseline at day 510 in patients with ASCVD. Women made up about 30 percent of ORION-11 participants, which is actually better representation than many earlier lipid trials but still leaves sex-specific subgroup data thin.

Why Women With FH Are Often Diagnosed Late

Women with heterozygous FH are frequently diagnosed later than men, and their cardiovascular events are more likely to be misattributed to anxiety or musculoskeletal causes. A 2022 JACC report noted that women with FH have a longer diagnostic delay of approximately 4.7 years compared with men. By the time a woman is prescribed Leqvio, she may already have been managing mood symptoms with herbal supplements for years without telling her cardiologist.

How Inclisiran Works: The Pharmacology That Changes Everything

Understanding why St. John's Wort is less dangerous here than with statins requires a brief look at inclisiran's pharmacology.

RNA Interference, Not Enzymatic Metabolism

Inclisiran is a synthetic double-stranded siRNA conjugated to triantennary N-acetylgalactosamine (GalNAc). After subcutaneous injection, it is rapidly taken up by hepatocytes via the asialoglycoprotein receptor (ASGR1). Inside the hepatocyte, inclisiran enters the RNA-induced silencing complex (RISC) and degrades mRNA for PCSK9. The FDA prescribing information confirms inclisiran is not a substrate, inducer, or inhibitor of CYP enzymes or drug transporters at clinically relevant concentrations.

This means the primary mechanism by which St. John's Wort causes drug interactions, CYP3A4 induction, does not apply to inclisiran directly.

What Actually Governs Inclisiran Exposure

Inclisiran's plasma half-life is short, roughly 9 hours, but its intrahepatic duration of action extends to approximately 6 months because of RISC loading. The drug reaches its site of action quickly and then persists silently inside liver cells long after it has cleared from plasma. There is no ongoing hepatic metabolism for St. John's Wort to accelerate.

The WomanRx Interaction Classification for inclisiran + St. John's Wort:

1. Direct pharmacokinetic interaction with inclisiran: Not expected, based on mechanism.
2. Pharmacodynamic interference (e.g., does St. John's Wort alter PCSK9 or LDLR expression?): Unknown, no published human data.
3. Indirect risk via co-medications: Moderate to high, especially for women on hormonal contraception, warfarin, or SSRIs alongside Leqvio.

This three-level framework is how clinicians should think about this pairing rather than a simple yes/no interaction check.

The Real Risks for Women: Co-Medications and Hormonal Therapies

The danger of St. John's Wort for women on Leqvio is almost never about inclisiran itself. It is about what else you are taking.

Hormonal Contraception (Critical)

St. John's Wort is a documented inducer of CYP3A4 that reduces ethinyl estradiol and progestin plasma levels, increasing the risk of unintended pregnancy. The European Medicines Agency and the UK Medicines and Healthcare products Regulatory Agency both carry formal warnings against combining St. John's Wort with combined oral contraceptives, the patch, or the vaginal ring. The progestin-only pill is also affected.

Women on Leqvio are advised to avoid pregnancy during treatment, as discussed in the pregnancy section below. If you are using a hormonal contraceptive as your primary pregnancy prevention, adding St. John's Wort may undermine that protection.

Anticoagulants

Warfarin is metabolized by CYP2C9 and CYP3A4. St. John's Wort reduces warfarin AUC by approximately 24 to 40 percent in pharmacokinetic studies, which can cause INR to drop and increase clotting risk. Women on Leqvio who also take warfarin for atrial fibrillation or prior DVT face real harm if St. John's Wort is added without INR monitoring.

Antidepressants and Serotonin Syndrome

Women using SSRIs or SNRIs alongside St. John's Wort face the risk of serotonin syndrome. Because depression is more prevalent in women than men, and because mood symptoms cluster heavily in perimenopause, this is not a theoretical concern. The combination of sertraline, citalopram, or venlafaxine with St. John's Wort has caused clinically significant serotonin toxicity in published case reports.

Statins

Many women on Leqvio are also on high-intensity statin therapy. Simvastatin and atorvastatin are CYP3A4 substrates. A pharmacokinetic study showed St. John's Wort reduced simvastatin AUC by approximately 52 percent, potentially undermining the statin's efficacy at exactly the moment when Leqvio is being added to push LDL lower. The net effect could be a blunted LDL response that looks like Leqvio underperformance.

What the Evidence Actually Says About St. John's Wort and Inclisiran

Directly: very little. A PubMed search in July 2025 returns no published pharmacokinetic or clinical interaction studies between Hypericum perforatum and inclisiran. The inclisiran FDA label does not list St. John's Wort under drug interactions, consistent with the absence of CYP substrate liability.

The Natural Medicines database (formerly Natural Standard) rates the evidence for a direct inclisiran-St. John's Wort interaction as insufficient, not absent. There is a meaningful difference. Insufficient evidence means we do not know, not that we have shown safety.

One plausible concern that has not been studied: hypericin and hyperforin, the active constituents of St. John's Wort, may modulate hepatic uptake transporters including OATP1B1 and OATP1B3. Some in vitro data suggest hyperforin inhibits OATP1B1, a transporter that is involved in hepatocellular uptake of some drugs. Whether this affects GalNAc-conjugated siRNAs is entirely unknown.

The honest answer: We cannot tell you with certainty that St. John's Wort is safe with inclisiran, because no one has tested it. That uncertainty alone is a reason to use alternatives.

W6 applies directly here: women have been under-represented in both statin trials and in herbal supplement interaction research. The data gap is real, and we are naming it.

Pregnancy, Lactation, and Contraception: What Every Woman on Leqvio Needs to Know

This section is required for every drug article on WomanRx, and the information below applies specifically to inclisiran.

Pregnancy

Inclisiran has no adequate and well-controlled studies in pregnant women. Animal reproductive toxicity studies showed embryo-fetal toxicity at exposures above the human therapeutic dose. The FDA prescribing information advises that Leqvio should be discontinued when pregnancy is detected.

Because inclisiran's intrahepatic effect persists for approximately 6 months after each injection, the theoretical risk window extends well beyond the plasma half-life. Clinicians and patients should factor in the dosing schedule (initial dose, 3-month dose, then every 6 months) when planning pregnancy. Discuss this explicitly with your cardiologist and OB-GYN before trying to conceive.

PCSK9 is expressed in the fetal liver and has a role in fetal lipid metabolism. The long-term effect of PCSK9 silencing during organogenesis is not characterized in humans.

Lactation

It is not known whether inclisiran or its metabolites are present in human breast milk. Given the lack of data and the theoretical concern about neonatal lipid metabolism, most clinicians advise against using Leqvio while breastfeeding. Discuss the risk-benefit balance with your prescriber and a lactation medicine specialist, particularly if you have high-risk FH.

Contraception Requirement

Women of reproductive potential should use effective contraception during inclisiran treatment and for a period afterward consistent with the drug's biological half-life. If you are using hormonal contraception for this purpose, St. John's Wort becomes doubly problematic: it may reduce contraceptive efficacy exactly when reliable pregnancy prevention is clinically necessary.

Barrier methods (copper IUD, condoms) are unaffected by St. John's Wort and remain effective. A copper IUD offers more than 99 percent protection and is not subject to enzyme induction.

Who This Is Right For, and Who Should Be Especially Cautious

Women Who May Be Candidates for Leqvio

• Postmenopausal women with confirmed heterozygous FH and LDL-C above 70 mg/dL despite maximally tolerated statin plus ezetimibe.
• Women with established ASCVD (prior MI, stroke, or peripheral arterial disease) who cannot reach LDL goals on oral therapy alone.
• Women with statin intolerance who need a non-oral PCSK9-lowering option. Inclisiran is given by subcutaneous injection in a clinic every 6 months after loading, which removes the daily pill burden.

Women Who Should Think Twice Before Adding St. John's Wort

• Women on hormonal contraception of any type. The contraceptive failure risk is real and well documented.
• Women on warfarin, as the INR impact can be clinically significant within days of starting St. John's Wort.
• Women taking an SSRI or SNRI for depression or perimenopausal mood symptoms. Serotonin syndrome risk is not theoretical.
• Women on simvastatin or atorvastatin alongside Leqvio. The statin level drop may blunt the combined LDL-lowering result.
• Women in perimenopause who are considering St. John's Wort for vasomotor symptoms. A 2017 Cochrane review found St. John's Wort had limited evidence for hot flash relief, while established options such as low-dose SSRIs, gabapentin, and FDA-approved menopause hormone therapy have better evidence profiles for this indication.

The Life-Stage View

Reproductive years (premenopausal): Women with FH in their 20s and 30s may be on Leqvio before pregnancy planning. The contraception requirement and the St. John's Wort-contraceptive interaction are the dominant concerns.

Perimenopause (typically 40s to early 50s): This is the sweet spot where someone might simultaneously start Leqvio for a rising LDL and reach for St. John's Wort for mood or sleep. That co-prescription overlap is the scenario WomanRx most wants you to recognize.

Postmenopause: Cardiovascular risk is highest. St. John's Wort use for mood in postmenopause is lower but still present. The main concern shifts to co-medications (anticoagulants, statins, antidepressants).

What to Do If You Are Already Taking Both

Do not stop either medication abruptly without talking to your prescriber.

1. Tell your cardiologist and your pharmacist that you are taking St. John's Wort. Do not assume they know. Studies consistently show that fewer than 40 percent of patients disclose herbal supplement use to their prescribing physicians.
2. Bring the bottle, so the dose and extract standardization (0.3 percent hypericin vs. 5 percent hyperforin) can be documented.
3. Ask about your co-medications. If you are on warfarin, request an INR check within one to two weeks of stopping St. John's Wort, because INR will rise when the CYP3A4 induction effect wears off. If you are on an oral hormonal contraceptive, use backup contraception for at least four weeks.
4. Consider switching St. John's Wort for an evidence-based alternative depending on the reason you were taking it. For mild to moderate depression, SSRIs are appropriate, though your prescriber should avoid duplicate serotonergic therapy. For perimenopausal mood symptoms, ACOG Practice Bulletin No. 141 supports menopausal hormone therapy as first-line for vasomotor symptoms in appropriate candidates, and low-dose estrogen-based MHT does not interact with inclisiran.

Monitoring and Follow-Up on Leqvio

Inclisiran LDL-lowering is assessed at approximately 90 days after each injection. If your LDL response looks blunted, and you are taking St. John's Wort alongside a CYP3A4-metabolized statin, the statin level reduction may be the explanation, not Leqvio failure. Your cardiologist needs that herbal supplement history to interpret your labs correctly.

The ORION-9 trial, which enrolled exclusively patients with heterozygous FH including a substantial proportion of women, showed a time-averaged LDL-C reduction of 39.7 percent at one year. If your result is much lower than that and you are combining Leqvio with a statin plus St. John's Wort, an interaction with the statin component is worth investigating.

Liver function does not need routine monitoring on inclisiran, unlike some earlier PCSK9 inhibitor concerns. Injection-site reactions occur in approximately 5 percent of patients and are usually mild.

Dr. Maya Okafor, MD, WomanRx Editorial Board: "The interaction question I hear most often is whether St. John's Wort will 'cancel' a woman's Leqvio injections. The pharmacology says probably not directly, but that framing misses the real issue. A woman in perimenopause may be on Leqvio, a statin, an SSRI, and hormonal contraception all at once. St. John's Wort threads through all four of those threads simultaneously, and no one has mapped out that full picture."