Drug & supplement interaction

Ribose + Tadalafil

Tadalafil brand names: Cialis, Tadliq.

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

We found no known interaction between Ribose and Tadalafil 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 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.

Know someone taking this? Share
Facebook Post Reddit Email
On this page
Interaction report

Ribose and Tadalafil

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 Tadalafil and Ribose 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.

Ribose safety at a glance

Ribose overall Use caution Often well tolerated short-term, but it can lower blood sugar and long-term safety is not well studied.
Pregnancy Avoid There is not enough safety information, so it is best avoided during 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 Tadalafil and Ribose? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Tadalafil

Interactions in our licensed database are recorded against drug classes, not just single drug names. Tadalafil is filed under 5 classifications — including phosphodiesterase-5 inhibitors, vasodilators, cytochrome p450 3a4 (cyp3a4) substrates. Ribose has documented interactions with 2 drug classes — the most serious being antidiabetes drugs (moderate) and insulin (moderate) — and none of Tadalafil’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

Ribose Does Interact With Other Medications

Ribose has 86 moderate known drug interactions in our database — Tadalafil isn’t one of them. If you take anything else, check it against the full list below.

Moderate 86 No known interaction 2,744 (incl. Tadalafil)
Taking anything else?

Check Another of Your Medications Against Ribose

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

What to actually watch for

No Interaction Found — But Data Suggests Ribose and Tadalafil 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 upset Additional detail

    Ribose

    “Orally, ribose can cause diarrhea, gastrointestinal discomfort, and nausea. In one study, lowering the dose of ribose resolved the nausea.”

    Ribose · Natural Medicines adverse-effect record, reported in diarrhea.

    4 sources cited
    1. 5664. Pliml W, von Arnim T, Stalein A, et al. Effects of ribose on excercise-induced ischaemia in stable coronary artery disease. Lancet 1992;340:507-10.
    2. 5676. Gross M, Reiter S, Zollner N. Metabolism of D-ribose administered continuously to healthy persons and to patients with myoadenylate deaminase deficiency. Klin Wochenschr 1989;67:1205-13. PubMed
    3. 15218. Teitelbaum JE, Johnson C, St Cyr J. The use of D-ribose in chronic fatigue syndrome and fibromyalgia: a pilot study. J Altern Complement Med 2006;12:857-62. PubMed
    4. 92891. Thompson J, Neutel J, Homer K, Tempero K, Shah A, Khankari R. Evaluation of D-ribose pharmacokinetics, dose proportionality, food effect, and pharmacodynamics after oral solution administration in healthy male and female subjects. J Clin Pharmacol 2014;54 PubMed

    Tadalafil

    Listed in the ADVERSE REACTIONS section of the FDA label for Tadalafil. Read the label on DailyMed ›

  • Headache reported in 11.1% of FDA reports for Tadalafil Additional detail

    Ribose

    “Orally, ribose can cause headache. It has also been reported to cause a hyperanxious feeling, lightheadedness, increased appetite, and mild anxiety. In one study, lowering the dose of ribose resolved the feeling of anxiety.”

    Ribose · Natural Medicines adverse-effect record, reported in anxiety.

    3 sources cited
    1. 5664. Pliml W, von Arnim T, Stalein A, et al. Effects of ribose on excercise-induced ischaemia in stable coronary artery disease. Lancet 1992;340:507-10.
    2. 92891. Thompson J, Neutel J, Homer K, Tempero K, Shah A, Khankari R. Evaluation of D-ribose pharmacokinetics, dose proportionality, food effect, and pharmacodynamics after oral solution administration in healthy male and female subjects. J Clin Pharmacol 2014;54 PubMed
    3. 15218. Teitelbaum JE, Johnson C, St Cyr J. The use of D-ribose in chronic fatigue syndrome and fibromyalgia: a pilot study. J Altern Complement Med 2006;12:857-62. PubMed

    Tadalafil

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

Reported for Ribose but not commonly for Tadalafil: increased appetite, dizziness, low blood sugar and diarrhea.

Effects for Tadalafil come from the ADVERSE REACTIONS section of its FDA label; effects for Ribose come from the Natural Medicines adverse-effect record, quoted above. Where a percentage is shown, it is the share of 98,103 voluntary FDA FAERS reports for Tadalafil 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.

From our Q&A

Questions About Ribose or Tadalafil

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Ribose or Tadalafil, not necessarily both, but if one is close to what you were about to ask it will usually go further than a database entry can:

Not quite your question? Ask our pharmacists directly — it is free, there is no account required, and answers usually come back within 24 hours.

Everything else you take

See Every Supplement That Interacts With Tadalafil

This page covers Ribose only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Tadalafil page lists 144 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), American Mistletoe (major), Grapefruit (major), Hawthorn (major) and St. John's Wort (major).

By severity: 5 major · 98 moderate · 41 minor.

From our pharmacist’s overview on the Tadalafil page

“Grapefruit juice is the first thing to know about if you take tadalafil (Cialis, Tadliq). It blocks CYP3A4, the enzyme that clears the drug, so blood levels climb and side effects like a steep drop in blood pressure become more likely.”

Reviewed by 2 · Jul 18, 2026

Open the Tadalafil interaction page

One more smart check

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

We hold 543 real supplement products containing Ribose, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Ribose. Even though Ribose itself has no known interaction with Tadalafil, 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 Ribose and Tadalafil 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 Ribose
Top half

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

29 days ago today
Medication Tadalafil
Top 1%

#16 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 Ribose reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 13, 2026. The Ribose and Tadalafil 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 Ribose

What is Ribose?

  • Energy and fatigue
  • Athletic performance and recovery
  • Fibromyalgia symptoms
  • Chronic fatigue
  • Heart-related (cardiac) conditions

Ribose (D-ribose) is a simple sugar your body makes naturally and uses to build energy molecules like ATP. Some people take it for fatigue, fibromyalgia, exercise recovery, or heart conditions, but solid human evidence is limited and mostly small or preliminary. It is generally well tolerated in short-term use, but talk to your pharmacist or doctor before trying it, especially if you have diabetes.

Not applicable (a naturally occurring simple sugar) · Powder, capsules, tablets, drink mixes

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

Ribose: dosing

There is no official standardized dose of ribose, and the amounts used in studies have varied widely depending on the goal. Because of this, it is best to follow the directions on the product label.To lower the chance of stomach upset or low blood sugar, some people take it with food and start with a smaller amount.

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

Read the full Ribose monograph & all interactions
Medication

About Tadalafil

What Is Tadalafil Used For?

Brand names: Cialis, Tadliq

Tadalafil tablets (including Cialis and generic tadalafil) are used to treat erectile dysfunction (ED), the symptoms of benign prostatic hyperplasia (BPH — an enlarged prostate), or both conditions together. When used with the drug finasteride to start BPH treatment, this combination is recommended for up to 26 weeks.

Adcirca, Alyq (tablets), and Tadliq (oral suspension) are indicated specifically for pulmonary arterial hypertension (PAH — high blood pressure in the lungs), to improve the ability to exercise.

Most-Reported Side Effects for Tadalafil

From FAERS, the FDA’s public side-effect reporting system (99,210 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Dyspnea 11,917 reports
Headache 10,982 reports
Diarrhea 8,020 reports
Nausea 6,697 reports
Fatigue 6,080 reports
See full Tadalafil drug information
Keep checking

Other Drugs & Ribose

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

0Major
86Moderate
0Minor
2,743No known interaction
86 Moderate 2,743 No interaction
Moderate

86 interactions

Showing 60 of 86 moderate interactions — see all 86 on the Ribose page.

No interaction 2,743 drugs checked — show the list

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

Showing the 60 most looked-up of 2,743 medications checked with no known interaction — see the full Ribose list.

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

Ribose References

The 8 references that drive our Ribose 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. Segal S, Foley J. The metabolism of D-ribose in man. J Clin Invest 1958;37:719-35. PubMed
  2. Perlmutter NS, Wilson RA, Angello DA, et al. Ribose facilitates thallium-201 redistribution in patients with coronary artery disease. J Nucl Med 1991;32:193-200.
  3. Hegewald MG, Palac RT, Angello DA, et al. Ribose infusion accelerates thallium redistribution with early imaging compared with late 24-hour imaging without ribose. J Am Coll Cardiol 1991;18:1671-81. PubMed
  4. Pliml W, von Arnim T, Stalein A, et al. Effects of ribose on excercise-induced ischaemia in stable coronary artery disease. Lancet 1992;340:507-10.
  5. Burke ER. D-Ribose What You Need To Know. Garden City Park, NY: Avery Publishing Group 1999;1-43.
  6. Gross M, Reiter S, Zollner N. Metabolism of D-ribose administered continuously to healthy persons and to patients with myoadenylate deaminase deficiency. Klin Wochenschr 1989;67:1205-13. PubMed
  7. Teitelbaum JE, Johnson C, St Cyr J. The use of D-ribose in chronic fatigue syndrome and fibromyalgia: a pilot study. J Altern Complement Med 2006;12:857-62. PubMed
  8. Thompson J, Neutel J, Homer K, Tempero K, Shah A, Khankari R. Evaluation of D-ribose pharmacokinetics, dose proportionality, food effect, and pharmacodynamics after oral solution administration in healthy male and female subjects. J Clin Pharmacol 2014;54 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 Ribose and Tadalafil Together: Common Questions

Is it safe to take Ribose with Tadalafil?
We do not list a known interaction between Ribose and Tadalafil. 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 Ribose and Tadalafil 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.
How was the Ribose and Tadalafil combination checked?
Interactions in our licensed database are recorded against drug classes. Tadalafil is filed under 5 classifications, and Ribose has documented interactions with 2 drug classes — none of Tadalafil'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 Ribose interact with any other medications?
Yes. Ribose has 86 documented drug interactions in our database — Tadalafil 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 Tadalafil interact with any supplements?
Yes. Tadalafil has documented interactions with 144 supplements in our database — Ribose is not one of them. The Tadalafil 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

Ribose monograph Uses, safety profile, and every drug interaction in one place Tadalafil drug information The full plain-English guide to this medication Tadalafil supplement interactions Every supplement checked against Tadalafil, 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 8 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Tadalafil and Ribose?

Our pharmacists answer your medication & supplement questions — free.

Ask a pharmacist

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.