Drug & supplement interaction

Birch + Lenacapavir

Lenacapavir brand name: Sunlenca.

No Known Interaction
Medically reviewed by · Updated July 2026 · Pair last verified Sep 20, 2026
The bottom line No known interaction

We found no known interaction between Birch and Lenacapavir in our sources. Absence of a documented interaction is not the same as proven safety, and does not guarantee one does not exist. Do not start, stop, or change a medication or supplement based on this page; confirm with your pharmacist or doctor first.

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Interaction report

Birch and Lenacapavir

We checked these two against our interaction database. Here is what we found.

No Known Interaction Found

We did not find a documented interaction between Lenacapavir and Birch in our sources. This does not guarantee that the combination is completely free of risk — there is often limited research on supplements and herbal products, especially around drug interactions.

If you decide to take both, the practical routine is simple: add one new thing at a time and note the date you started it. If the combination is going to disagree with you, it usually shows in the first days to a couple of weeks — and a start date turns “I’ve been feeling off” into something a pharmacist can actually work with. Do not stop a prescribed medicine on your own.

Always talk with your pharmacist or doctor before making changes to your medications or supplements, particularly if you take several medications or have an ongoing health condition.

Birch safety at a glance

Birch overall Use caution Generally well tolerated in food-like amounts, but allergy and quality concerns warrant caution.
Pregnancy Avoid Not enough safety data, so birch supplements are best avoided during pregnancy.
Breastfeeding Avoid Safety has not been established, so it is best avoided while breastfeeding.

Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Still wondering about combining Lenacapavir and Birch? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Lenacapavir

Interactions in our licensed database are recorded against drug classes, not just single drug names. Lenacapavir is filed under 2 classifications — cytochrome p450 3a4 (cyp3a4) substrates, oral drugs. Birch has documented interactions with 1 drug class — the most serious being diuretic drugs (minor) — and none of Lenacapavir’s classifications are among them.

Classification data comes from our licensed Natural Medicines dataset. A medication can belong to classes beyond those recorded there, so this describes how the check was run — it is not a safety guarantee.

Keep it in perspective

Birch Does Interact With Other Medications

Birch has 75 minor known drug interactions in our database — Lenacapavir isn’t one of them. If you take anything else, check it against the full list below.

Minor 75 No known interaction 2,755 (incl. Lenacapavir)
Taking anything else?

Check Another of Your Medications Against Birch

Covers the 2,830 medications we’ve checked against Birch. Pick one to open its full report.

What to actually watch for

What Birch Itself Has Been Linked To

This is not an interaction — nothing below involves Lenacapavir. It is the side-effect record for Birch on its own, from the licensed Natural Medicines monograph. If something new turns up after you add Birch, this list is the first place to look. One entry is worth acting on rather than waiting out — marked below.

  • An allergic reaction Worth acting on Additional detail

    “Birch and birch pollen can cause allergic reactions. Treatment of birch pollen allergy can involve immunotherapy with birch pollen extract given sublingually and by the oral vestibular route.”

    Birch · Natural Medicines adverse-effect record, reported in allergic rhinitis (hay fever).

    1 source cited
    1. 97762. Allam JP, Wuestenberg E, Wolf H, et al. Immunologic response and safety in birch pollen sublingual versus oral vestibule immunotherapy: a pilot study. J Allergy Clin Immunol. 2014;133(6):1757-9.e3. PubMed
  • A skin rash Additional detail

    “Topically, a case of allergic contact dermatitis has been reported for a 51-year-old male who had been applying a cream containing 5% birch bark extract for 4 months prior to the reaction. The constituent betulin was considered to be the most likely cause. Crushed birch leaves and fresh birch sap may also cause allergic contact dermatitis.”

    Birch · Natural Medicines adverse-effect record, reported in dermatitis.

    2 sources cited
    1. 97763. Meyer-Hoffert U, Brasch J. Allergic contact dermatitis caused by betulin-containing triterpene extract from the outer bark of birch (Betula alba). Contact Dermatitis. 2013;68(6):382-3.
    2. 35666. Lahti, A. and Hannuksela, M. Immediate contact allergy to birch leaves and sap. Contact Dermatitis 1980;6(7):464-465. PubMed

Everything above comes from the Natural Medicines adverse-effect record for Birch — expand a row for the licensed statement it rests on. We read the ADVERSE REACTIONS section of Lenacapavir’s FDA label too, and the two lists don’t meaningfully overlap — which is why no Lenacapavir column appears here.

Everything else you take

See Every Supplement That Interacts With Lenacapavir

This page covers Birch only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Lenacapavir page lists 138 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Grapefruit (major), St. John's Wort (major), Acacia Rigidula (moderate) and Adrafinil (moderate).

By severity: 3 major · 94 moderate · 41 minor.

From our pharmacist’s overview on the Lenacapavir page

“Lenacapavir (Sunlenca) treats HIV that has resisted other regimens, so keeping its blood level steady is not optional, and its list of 138 interacting supplements deserves genuine care. Nearly all of them, 121 ingredients, can shift how the body handles lenacapavir through the CYP3A4 enzyme, either pushing its level up along with side…”

Reviewed by 2 · Jul 18, 2026

Open the Lenacapavir interaction page

One more smart check

Taking Birch as Part of a Dietary Supplement Product? Check It for Interactions

We hold 116 real supplement products containing Birch, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Birch. Even though Birch itself has no known interaction with Lenacapavir, another ingredient on your label might. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where Birch and Lenacapavir Sit Against Everything Else

Out of every supplement and medication people look up on HelloPharmacist, here is where these two land this week — and which way each has been moving.

Supplement Birch
Top half

#547 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Lenacapavir
Top half

#1,332 of 2,830 medications looked up here in the last 7 days

29 days ago today

Position among everything looked up on this site, not a measure of how commonly either one is used or how important it is. A supplement can climb this list because of a news story. It counts every request to the page, automated ones included, and nothing here identifies anyone.

Where does our data come from?
  • Source: the Natural Medicines (TRC Healthcare) clinical database — the evidence-graded professional reference for herb & supplement interactions.
  • Citation library: 103,510 references behind our interaction content, 65,311 of them resolved to verified PubMed/DOI sources. See every Birch reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 20, 2026. The Birch and Lenacapavir records this page draws on were last updated July 10, 2026.
  • What “no known interaction” means: no documented interaction in the sources above — not a guarantee of safety. Supplements are studied far less than prescription drugs, so we say exactly what the evidence supports, and nothing more.
Data structure & sourcing designed and verified by .
Supplement

About Birch

What is Birch?

  • Urinary tract and 'flushing' support
  • Joint pain and arthritis
  • Mild fluid retention (diuretic)
  • Skin conditions (topical)
  • General detox or 'cleansing' tonics

Birch is a tree whose leaves, bark, and sap are used in traditional remedies, most often as a mild diuretic or for joint and urinary complaints. Solid human evidence is limited, and birch is a well-known source of pollen and contact allergies, so caution is important. Talk to a pharmacist or doctor before using birch products, especially if you are pregnant, breastfeeding, or have allergies.

Betula pendula · Betulaceae · Leaves, bark, sap, and essential oil (often distilled from bark or twigs) · Tea, capsules, tinctures, birch sap (water), topical essential oil, and birch tar preparations

An interaction check asks whether these two react with each other — it does not ask whether Birch is a good idea for someone in your situation. Here is what our Birch record says about it on its own.

Birch: dosing

There is no well-established standardized dose for birch. Traditional preparations vary widely, and the strength of teas, tinctures, capsules, and birch water differs by product.If you choose to use a birch product, the safest approach is to follow the directions on the product label and not exceed the recommended amount.

From our Birch monograph — the full record covers uses, side effects and every documented interaction.

Read the full Birch monograph & all interactions
Medication

About Lenacapavir Oral

What Is Lenacapavir Oral Used For?

Brand name: Sunlenca

Sunlenca tablets are used in two situations: to treat HIV-1 infection in adults whose virus has become resistant to multiple antiretroviral drugs and whose current regimen is failing — always in combination with other antiretrovirals — and as a short oral loading dose to start the BIXLENVO complete HIV-1 treatment regimen in adults who are already virologically suppressed (virus undetectable) and switching from a stable antiretroviral regimen.

Yeztugo tablets are used as part of HIV-1 pre-exposure prophylaxis (PrEP) — helping HIV-negative people reduce their risk of getting HIV-1. The oral tablet form is used during initiation of Yeztugo, and also as a temporary oral bridge if a scheduled injection must be delayed more than two weeks.

Most-Reported Side Effects for Lenacapavir

From FAERS, the FDA’s public side-effect reporting system (462 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Injection site discharge 141 reports
Injection site pain 137 reports
Injection site nodule 111 reports
Injection site erythema 40 reports
Injection site mass 36 reports
See full Lenacapavir Oral drug information
Keep checking

Other Drugs & Birch

Browse every other medication we’ve checked against Birch — both the ones with a known interaction and the ones without. Select any drug for the full detail.

0Major
0Moderate
75Minor
2,754No known interaction
75 Minor 2,754 No interaction
Minor

75 interactions

Showing 60 of 75 minor interactions — see all 75 on the Birch page.

No interaction 2,754 drugs checked — show the list

We also checked Birch against these medications and found no known interaction in our sources. Open any page to confirm.

Showing the 60 most looked-up of 2,754 medications checked with no known interaction — see the full Birch list.

See the full Birch interactions page
See every supplement checked against Lenacapavir, ranked by severity
Evidence & sources

Birch References

The 4 references that drive our Birch monograph and interaction data, from the evidence-graded Natural Medicines (TRC Healthcare) database. Citations with a link open the study on PubMed or the publisher’s site.

  1. Robbers JE, Tyler VE. Tyler's Herbs of Choice: The Therapeutic Use of Phytomedicinals. New York, NY: The Haworth Herbal Press, 1999.
  2. Lahti, A. and Hannuksela, M. Immediate contact allergy to birch leaves and sap. Contact Dermatitis 1980;6(7):464-465. PubMed
  3. Allam JP, Wuestenberg E, Wolf H, et al. Immunologic response and safety in birch pollen sublingual versus oral vestibule immunotherapy: a pilot study. J Allergy Clin Immunol. 2014;133(6):1757-9.e3. PubMed
  4. Meyer-Hoffert U, Brasch J. Allergic contact dermatitis caused by betulin-containing triterpene extract from the outer bark of birch (Betula alba). Contact Dermatitis. 2013;68(6):382-3.

Medication overviews come from MedlinePlus (NIH); supplement label data from the NIH Dietary Supplement Label Database. Content is written and reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.

Pharmacist Counseling Corner

Taking Birch and Lenacapavir Together: Common Questions

Is it safe to take Birch with Lenacapavir?
We do not list a known interaction between Birch and Lenacapavir. That does not guarantee the combination is risk-free, so confirm with your pharmacist or doctor — especially if you take other medications or have a health condition.
How was the Birch and Lenacapavir combination checked?
Interactions in our licensed database are recorded against drug classes. Lenacapavir is filed under 2 classifications, and Birch has documented interactions with 1 drug class — none of Lenacapavir's classifications are among them. A medication can belong to classes beyond those recorded in our dataset, so this describes how the check was run rather than guaranteeing safety.
Does Birch interact with any other medications?
Yes. Birch has 75 documented drug interactions in our database — Lenacapavir is simply not one of them. If you take anything else, it is worth checking each one; they are all listed on this page.
Does Lenacapavir interact with any supplements?
Yes. Lenacapavir has documented interactions with 138 supplements in our database — Birch is not one of them. The Lenacapavir interaction page linked on this page lists every one, ranked by severity.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

Where next

Keep Exploring

Birch monograph Uses, safety profile, and every drug interaction in one place Lenacapavir Oral drug information The full plain-English guide to this medication Lenacapavir supplement interactions Every supplement checked against Lenacapavir, ranked by severity Supplement interaction checker Check any supplement or product against your medications Browse medications A–Z Every drug we’ve checked against herbs & supplements References The 4 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Lenacapavir and Birch?

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This information is for education only and is not a substitute for professional medical advice. Always check with your pharmacist or doctor before starting, stopping, or combining supplements and medications.