Drug & supplement interaction

S-23 + Abemaciclib

Abemaciclib brand name: Verzenio.

No Known Interaction
Medically reviewed by · Updated June 2026 · Pair last verified Sep 13, 2026
The bottom line No known interaction

We found no known interaction between S-23 and Abemaciclib 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

S-23 and Abemaciclib

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 Abemaciclib and S-23 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.

Worth understanding: our licensed dataset holds no drug-interaction record for S-23 at all — not against Abemaciclib, and not against any other medication we track. This verdict therefore rests on the absence of any recorded data, not on research that looked at this combination and found nothing. We cannot rule an interaction out.

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.

S-23 safety at a glance

S-23 overall Avoid S-23 is an unapproved experimental drug with no human safety data and known hormonal risks.
Pregnancy Possibly Unsafe When used orally or parenterally. The U.S. Food and Drug Administration and other regulatory agencies warn that dietary supplements containing selective androge... Read the full pregnancy detail
Breastfeeding Possibly Unsafe When used orally or parenterally. The U.S. Food and Drug Administration and other regulatory agencies warn that dietary supplements containing selective androge... Read the full breastfeeding detail

Pregnancy & breastfeeding ratings are from Natural Medicines (Therapeutic Research Center) — the full detail is in the Special populations card below. Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Still wondering about combining Abemaciclib and S-23? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
What to actually watch for

What Abemaciclib’s Own FDA Label Lists

This is not an interaction — none of it involves S-23. These are the most notable effects listed in the ADVERSE REACTIONS section of Abemaciclib’s own FDA label, for the medication by itself. Knowing the drug’s own list makes it easier to work out the likely cause if something new turns up while you take both. 10 of them are worth acting on rather than waiting out — marked below.

  • A stroke or mini-stroke Worth acting on
  • A heart attack Worth acting on
  • Blood clots Worth acting on
  • Heart failure Worth acting on
  • A low platelet count Worth acting on
  • Anemia Worth acting on
  • A low white blood cell count Worth acting on
  • Liver problems Worth acting on
  • Bleeding or bruising Worth acting on
  • A higher chance of infection Worth acting on

Showing the 10 most notable of 21 label-listed effects — ranked by how unusual each one is across medicines generally, with serious effects weighted up.

From the ADVERSE REACTIONS section of the FDA label for Abemaciclib. Read the label on DailyMed › S-23’s licensed record lists no adverse effects our clinical vocabulary could match, so there is no S-23 side to compare — that is a limit of the record, not a statement that S-23 has no side effects.

Special populations

S-23 in Pregnancy & Breastfeeding

Pregnancy And Lactation Possibly Unsafe

When used orally or parenterally. The U.S. Food and Drug Administration and other regulatory agencies warn that dietary supplements containing selective androgen receptor modulators (SARMs) are dangerous. Avoid using.

DISCLAIMER: This tool is intended for informational purposes only, and should not be interpreted as specific medical advice. Patients should consult with a qualified healthcare provider before making decisions about therapies and/or health conditions.© 2026 Therapeutic Research Center

Overlapping uses

What Abemaciclib Is Prescribed For, and What S-23 Has Been Studied For

These two come up together because they touch the same health topic — not because they do the same job. Abemaciclib is a prescription medicine with approved uses on its FDA label. S-23 is a supplement: what follows is what researchers have looked at it for, and how strong that evidence is.

Abemaciclib is prescribed for: Verzenio (abemaciclib) is used to treat HR-positive, HER2-negative breast cancer in adults. For early breast cancer at high risk of recurrence, Verzenio is taken alongside endocrine therapy (tamoxifen or an aromatase inhibitor) after surgery to help prevent the cancer from coming back. For advanced or metastatic breast cancer (cancer that has spread), Verzenio can be used in combination with an aromatase inhibitor as a first hormonal treatment, in combination with fulvestrant after the cancer has progressed on endocrine therapy, or alone after prior endocrine therapy and chemotherapy have stopped working.

S-23 has been studied for:

  • Breast cancer studied, not established S-23 has been studied for this. Natural Medicines rates the evidence: Insufficient Reliable Evidence To Rate Read what the research shows

    S-23 for breast cancer

    Although there is interest in using oral S-23 for breast cancer, there is insufficient reliable information about the clinical effects of S-23 for this condition.

Effectiveness ratings and the research summaries above are the verbatim record from the Natural Medicines database, which grades evidence from “Effective” down to “Insufficient Reliable Evidence To Rate”. A rating below the top of that scale means researchers have looked at it — not that it works, and never that it can stand in for a prescribed medicine. Do not stop or replace Abemaciclib on your own; if you are taking S-23 for the same health topic, tell your prescriber, especially if the medicine is being adjusted to a target.

Everything else you take

See Every Supplement That Interacts With Abemaciclib

This page covers S-23 only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Abemaciclib 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 Abemaciclib page

“A daily pill for a common form of advanced breast cancer, abemaciclib (Verzenio) only helps when its blood level stays steady, so this list of 138 supplements deserves genuine care. Nearly all of them act on CYP3A4, the liver enzyme that clears abemaciclib, meaning a supplement can push its level up and intensify side effects, or drag…”

Reviewed by 2 · Jul 18, 2026

Open the Abemaciclib interaction page

One more smart check

Taking S-23 as Part of a Dietary Supplement Product? Check It for Interactions

We hold 5 real supplement products containing S-23, each one broken down to its full ingredient list — and combination products often carry several ingredients besides S-23. Even though S-23 itself has no known interaction with Abemaciclib, 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 S-23 and Abemaciclib 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 S-23
Steady interest

#1,106 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Abemaciclib
Top 5%

#35 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 S-23 reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 13, 2026. The S-23 and Abemaciclib records this page draws on were last updated June 22, 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 S-23

What is S-23?

  • Muscle building
  • Fat loss
  • Athletic performance enhancement
  • Body recomposition
  • Investigational male contraceptive (research only)

S-23 is an experimental, non-prescription synthetic drug called a selective androgen receptor modulator (SARM), not a dietary supplement, herb, or natural product. It has never been approved for human use, has not been proven safe in people, and is banned in sports; we do not recommend using it.

Not applicable; S-23 is a synthetic chemical compound · Liquid solutions, capsules, and powders sold as 'research chemicals'

An interaction check asks whether these two react with each other — it does not ask whether S-23 is a good idea for someone in your situation. Here is what our S-23 record says about it on its own.

S-23: dosing

There is no established or safe dose of S-23 for humans. It has never gone through the clinical testing that would set a safe and effective dose, so any amounts shared online are unverified and potentially dangerous.We do not provide dosing guidance for S-23 because doing so could imply it is safe to use, which it is not.

From our S-23 monograph — the full record covers uses, side effects and every documented interaction.

Read the full S-23 monograph & all interactions
Medication

About Abemaciclib

What Is Abemaciclib Used For?

Brand name: Verzenio

Verzenio (abemaciclib) is used to treat HR-positive, HER2-negative breast cancer in adults. For early breast cancer at high risk of recurrence, Verzenio is taken alongside endocrine therapy (tamoxifen or an aromatase inhibitor) after surgery to help prevent the cancer from coming back.

For advanced or metastatic breast cancer (cancer that has spread), Verzenio can be used in combination with an aromatase inhibitor as a first hormonal treatment, in combination with fulvestrant after the cancer has progressed on endocrine therapy, or alone after prior endocrine therapy and chemotherapy have stopped working.

See full Abemaciclib drug information
Keep checking

Other Drugs & S-23

Browse every other medication we’ve checked against S-23 — both the ones with a known interaction and the ones without. Select any drug for the full detail.

0Major
0Moderate
0Minor
2,829No known interaction
2,829 No interaction
No interaction 2,829 drugs checked — show the list

We also checked S-23 against these medications and found no known interaction in our sources. Open any page to confirm.

Showing the 60 most looked-up of 2,829 medications checked with no known interaction — see the full S-23 list.

See the full S-23 interactions page
See every supplement checked against Abemaciclib, ranked by severity
Evidence & sources

S-23 References

The 1 references that drive our S-23 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. Joseph JF, Parr MK. Synthetic androgens as designer supplements. Curr Neuropharmacol. 2015;13(1):89-100. PubMed

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 S-23 and Abemaciclib Together: Common Questions

Is it safe to take S-23 with Abemaciclib?
We do not list a known interaction between S-23 and Abemaciclib. 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.
Are S-23 and Abemaciclib used for the same thing?
They overlap in purpose, which usually means the real question is whether you need both rather than whether they are safe together. This page lists the shared uses and how strong the evidence is for S-23 in each. That is a conversation for your prescriber, especially if Abemaciclib is being adjusted to a target.
Does Abemaciclib interact with any supplements?
Yes. Abemaciclib has documented interactions with 138 supplements in our database — S-23 is not one of them. The Abemaciclib 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

S-23 monograph Uses, safety profile, and every drug interaction in one place Abemaciclib drug information The full plain-English guide to this medication Abemaciclib supplement interactions Every supplement checked against Abemaciclib, 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 1 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Abemaciclib and S-23?

Our pharmacists answer your medication & supplement questions — free.

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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.