Drug & supplement interaction

Pygeum + Glycerol Phenylbutyrate

Glycerol Phenylbutyrate brand name: Ravicti.

No Known Interaction
The bottom line No known interaction

We found no known interaction between Pygeum and Glycerol Phenylbutyrate 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. Additionally, although there is no interaction, the label for Glycerol Phenylbutyrate states a food rule worth keeping to, and the two are separately associated with some of the same side effects, which would make a new symptom harder to attribute to one or the other.

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Interaction report

Pygeum and Glycerol Phenylbutyrate

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 Glycerol Phenylbutyrate and Pygeum 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 Pygeum at all — not against Glycerol Phenylbutyrate, 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.

Pygeum safety at a glance

Pygeum overall Use caution Generally well tolerated short-term, but quality and long-term safety data are limited.
Pregnancy Avoid Pygeum is used for men's prostate health and has no established safe use in pregnancy.
Breastfeeding Avoid There is not enough safety information, 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 Glycerol Phenylbutyrate and Pygeum? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
What to actually watch for

No Interaction Found — But Data Suggests Pygeum and Glycerol Phenylbutyrate May Share Several of the Same Side Effects

This is not an interaction. Neither one changes how your body handles the other, and nothing here says they react together. What our sources do show is that each has separately been linked to the effects below — so taking both can make those effects more likely to turn up, and harder to pin on one or the other if they do.

  • Stomach pain / Nausea reported in 5.4% of FDA reports for Glycerol Phenylbutyrate Additional detail

    Pygeum

    “Orally, pygeum has been associated with nausea and abdominal pain in some clinical research. However, the rate of these events were similar to placebo.”

    Pygeum · Natural Medicines adverse-effect record, reported in nausea and vomiting.

    3 sources cited
    1. 10425. Ishani A, MacDonald R, Nelson D, et al. Pygeum africanum for the treatment of patients with benign prostatic hyperplasia: a systematic review and quantitative meta-analysis. Am J Med 2000;109:654-64.. PubMed
    2. 10426. Wilt T, Ishani A, Mac Donald R, et al. Pygeum africanum for benign prostatic hyperplasia. Cochrane Database Syst Rev 2002;CD001044.. PubMed
    3. 70238. Andro M and Riffaud J. Pygeum africanum extract for the treatment of patients with benign prostatic hyperplasia: a review of 25 years of published experience. Curr Ther Res 1995;56(8):796-817. DOI

    Glycerol Phenylbutyrate

    Listed in the ADVERSE REACTIONS section of the FDA label for Glycerol Phenylbutyrate, and in voluntary FDA adverse-event reports. Read the label on DailyMed ›

Effects for Glycerol Phenylbutyrate come from the ADVERSE REACTIONS section of its FDA label; effects for Pygeum come from the Natural Medicines adverse-effect record, quoted above. Where a percentage is shown, it is the share of 1,358 voluntary FDA FAERS reports for Glycerol Phenylbutyrate that mention that effect — a reporting proportion, not an incidence rate and not evidence the drug caused it. Wording is matched across sources by our own clinical vocabulary, so treat this as a prompt to pay attention, not a diagnosis.

How to take them

Some Glycerol Phenylbutyrate Products Have a Food Rule — Pygeum Should Not Break It

At least one FDA label for a product containing Glycerol Phenylbutyrate says to take it with food. If you take Pygeum on an empty stomach out of habit, keep them separate — and take Glycerol Phenylbutyrate with a meal where the label says to.

This may not be true of your version. Food instructions belong to the product, not the ingredient: two Glycerol Phenylbutyrate products can carry different directions, and extended-release forms often differ from immediate-release ones. The label we read is quoted below — check the directions on your own box or bottle, or ask your pharmacist, for how to take the exact product you were given.

Instruct patients to take glycerol phenylbutyrate oral liquid with food or formula and to administer directly into the mouth via oral syringe.

From the Dosage and Administration section of the FDA label we read for Glycerol Phenylbutyrate — where that label names a specific product, the instruction is that product's. Read the label on DailyMed ›

A food rule is not an interaction — it is about how much of the medicine you absorb. The directions that came with your own product, and your pharmacist, outrank anything on this page.

Everything else you take

See Every Supplement That Interacts With Glycerol Phenylbutyrate

This page covers Pygeum only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Glycerol Phenylbutyrate page lists 17 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Coffee Charcoal (moderate), European Mandrake (moderate), Glucomannan (moderate) and Guar Gum (moderate).

By severity: 1 major · 7 moderate · 9 minor.

From our pharmacist’s overview on the Glycerol Phenylbutyrate page

“Ravicti (glycerol phenylbutyrate) pulls ammonia out of the blood in people with urea cycle disorders, so a dose that never gets absorbed is not a small problem, it can let ammonia climb toward dangerous levels. That is why this list deserves real attention even though it is short.”

Reviewed by 2 · Jul 18, 2026

Open the Glycerol Phenylbutyrate interaction page

One more smart check

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

We hold 905 real supplement products containing Pygeum, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Pygeum. Even though Pygeum itself has no known interaction with Glycerol Phenylbutyrate, 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 Pygeum and Glycerol Phenylbutyrate 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 Pygeum
Top 25%

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

29 days ago today
Medication Glycerol Phenylbutyrate
Top 25%

#309 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 Pygeum reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 27, 2026. The Pygeum and Glycerol Phenylbutyrate 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 Pygeum

What is Pygeum?

  • Benign prostatic hyperplasia (BPH) symptoms
  • Urinary symptoms in men
  • Prostate health
  • Inflammation

Pygeum is an extract from the bark of the African cherry tree that is most often used to ease urinary symptoms linked to an enlarged prostate. Some studies suggest modest benefit for these symptoms, but the research is limited and not high quality. Talk with your doctor or pharmacist before using it, especially since urinary symptoms can have serious causes.

Prunus africana · Rosaceae · Bark · Capsules, tablets, liquid extracts

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

Pygeum: dosing

There is no single official or standardized dose of pygeum. Do not assume that taking more will work better, and let your healthcare provider know you are using it so they can monitor your symptoms.

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

Read the full Pygeum monograph & all interactions
Medication

About Glycerol Phenylbutyrate

What Is Glycerol Phenylbutyrate Used For?

Brand name: Ravicti

Glycerol phenylbutyrate oral liquid — available as the brand Ravicti and as a generic — is used for the long-term (chronic) management of urea cycle disorders (UCDs). UCDs are rare inherited conditions where the body cannot properly convert ammonia into urea, causing toxic ammonia levels to build up in the blood and brain.

It is used in patients whose ammonia cannot be controlled by a low-protein diet and/or amino acid supplements alone. It must always be used alongside dietary protein restriction and, in some cases, additional dietary supplements such as essential amino acids, arginine, or citrulline. It is not for treating a sudden, severe spike in ammonia (acute hyperammonemia), and its safety and effectiveness for N-acetylglutamate synthase (NAGS) deficiency have not been established.

Most-Reported Side Effects for Glycerol Phenylbutyrate

From FAERS, the FDA’s public side-effect reporting system (1,358 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Ammonia increased 197 reports
Vomiting 165 reports
Hyperammonaemia 158 reports
Decreased appetite 104 reports
Nausea 74 reports
See full Glycerol Phenylbutyrate drug information
Keep checking

Other Drugs & Pygeum

Browse every other medication we’ve checked against Pygeum — 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
No interaction 2,829 drugs checked — show the list
Evidence & sources

Pygeum References

The 3 references that drive our Pygeum 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. Ishani A, MacDonald R, Nelson D, et al. Pygeum africanum for the treatment of patients with benign prostatic hyperplasia: a systematic review and quantitative meta-analysis. Am J Med 2000;109:654-64.. PubMed
  2. Wilt T, Ishani A, Mac Donald R, et al. Pygeum africanum for benign prostatic hyperplasia. Cochrane Database Syst Rev 2002;CD001044.. PubMed
  3. Andro M and Riffaud J. Pygeum africanum extract for the treatment of patients with benign prostatic hyperplasia: a review of 25 years of published experience. Curr Ther Res 1995;56(8):796-817. DOI

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 Pygeum and Glycerol Phenylbutyrate Together: Common Questions

Is it safe to take Pygeum with Glycerol Phenylbutyrate?
We do not list a known interaction between Pygeum and Glycerol Phenylbutyrate. 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.
Do Pygeum and Glycerol Phenylbutyrate have any of the same side effects?
Yes — our sources link each of them separately to 2 of the same effects. That is not an interaction: neither changes how your body handles the other. It does mean that if one of those effects turns up, it can be harder to tell which one is behind it. They are listed on this page with the source behind each.
Should I take Pygeum and Glycerol Phenylbutyrate at the same time of day?
At least one FDA label for a product containing Glycerol Phenylbutyrate says to take it with food. If you take Pygeum on an empty stomach out of habit, keep them separate and take Glycerol Phenylbutyrate with a meal where the label says to. Food instructions belong to the product rather than the ingredient — two Glycerol Phenylbutyrate products can differ — so check the directions on your own box. This is about absorption, not an interaction.
Does Glycerol Phenylbutyrate interact with any supplements?
Yes. Glycerol Phenylbutyrate has documented interactions with 17 supplements in our database — Pygeum is not one of them. The Glycerol Phenylbutyrate interaction page linked on this page lists every one, ranked by severity.

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

Still Have a Question About Glycerol Phenylbutyrate and Pygeum?

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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.