Drug & supplement interaction

Rice Protein + Phentermine

Phentermine brand names: Adipex-P, Fastin, T Diet, Phentride, Obenix, and others.

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 Rice Protein and Phentermine 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.

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Interaction report

Rice Protein and Phentermine

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 Phentermine and Rice Protein 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.

Rice Protein safety at a glance

Rice Protein overall Generally safe Rice protein is generally considered safe for most healthy adults when used as a food.
Pregnancy Use caution Whole food rice is fine, but concentrated supplements are not well studied in pregnancy, so check with your provider first.
Breastfeeding Use caution Likely fine as a food, but concentrated protein supplements are not well studied while breastfeeding.

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

Still wondering about combining Phentermine and Rice Protein? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Phentermine

Interactions in our licensed database are recorded against drug classes, not just single drug names. Phentermine is filed under 2 classifications — stimulant drugs, oral drugs. Rice Protein has documented interactions with 1 drug class — the most serious being ace inhibitors (aceis) (moderate) — and none of Phentermine’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

Rice Protein Does Interact With Other Medications

Rice Protein has 23 moderate known drug interactions in our database — Phentermine isn’t one of them. If you take anything else, check it against the full list below.

Moderate 23 No known interaction 2,807 (incl. Phentermine)
Taking anything else?

Check Another of Your Medications Against Rice Protein

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

What to actually watch for

No Interaction Found — But Data Suggests Rice Protein and Phentermine May Share a Side Effect

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.

  • Diarrhea Additional detail

    Rice Protein

    “Orally, rice protein has been rarely reported to cause enterocolitis symptoms of vomiting, diarrhea, and dehydration, possibly leading to acidosis and lethargy, in infants and young children. Rarely, enterocolitis symptoms are associated with an allergy to rice protein.”

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

    2 sources cited
    1. 97806. Yasutomi M, Kosaka T, Kawakita A, et al. Rice protein-induced enterocolitis syndrome with transient specific IgE to boiled rice but not to retort-processed rice. Pediatr Int. 2014;56(1):110-2.
    2. 97811. Hojsak I, Kljaic-Turkalj M, Misak Z, Kolacek S. Rice protein-induced enterocolitis syndrome. Clin Nutr. 2006;25(3):533-6. PubMed

    Phentermine

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

Reported for Rice Protein but not commonly for Phentermine: dehydration, vomiting and tiredness.

Effects for Phentermine come from the ADVERSE REACTIONS section of its FDA label; effects for Rice Protein come from the Natural Medicines adverse-effect record, quoted above. 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 Rice Protein or Phentermine

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Rice Protein or Phentermine, 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 Phentermine

This page covers Rice Protein only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Phentermine page lists 61 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Ephedra (major), Peyote (major), Rauvolfia Vomitoria (major) and Sida Cordifolia (major).

By severity: 5 major · 43 moderate · 13 minor.

From our pharmacist’s overview on the Phentermine page

“Ephedra is the pairing I most want anyone taking phentermine (Adipex-P) to know about. Phentermine is itself a stimulant appetite suppressant that raises heart rate and blood pressure, and ephedra piles the same cardiovascular strain on top of it.”

Reviewed by 2 · Jul 18, 2026

Open the Phentermine interaction page

One more smart check

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

We hold 610 real supplement products containing Rice Protein, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Rice Protein. Even though Rice Protein itself has no known interaction with Phentermine, 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 Rice Protein and Phentermine 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 Rice Protein
Top 25%

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

29 days ago today
Medication Phentermine
Top 25%

#450 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 Rice Protein reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 20, 2026. The Rice Protein and Phentermine 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 Rice Protein

What is Rice Protein?

  • Building and maintaining muscle
  • Post-workout recovery
  • Plant-based protein source
  • Meal replacement and shakes
  • Weight management support

Rice protein is a plant-based protein powder made from rice that offers an easy way to add protein to your diet, especially if you avoid dairy or animal products. It is generally considered safe and well tolerated, though on its own it is lower in the amino acid lysine and is often blended with pea protein for a more complete amino acid profile. Talk to your pharmacist or doctor before using it if you have kidney problems or other health conditions.

Oryza sativa · Poaceae · Seed (grain/endosperm and bran) · Powder, protein shakes, capsules, blended plant-protein products

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

Rice Protein: dosing

There is no official standardized dose for rice protein. Serving sizes are usually based on how much protein you want to add to your diet, commonly around 20 to 30 grams of protein per scoop, but this varies by product.Always follow the directions on the product label and consider your total daily protein needs from all foods.

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

Read the full Rice Protein monograph & all interactions
Medication

About Phentermine

What Is Phentermine Used For?

Brand names: Adipex-P, Fastin, T Diet, Phentride, Obenix, Pbc Phentride, Pbw Phentride, Phentrol #3, Ionamin, Phentrol #6, Phentrol #2, Phentrol #5, Phentrol, Obermine, Phentermine, Suprenza

Phentermine is approved as a short-term addition to a weight-loss program — not a standalone treatment. It is used alongside reduced-calorie eating, increased physical activity, and behavior changes to help manage obesity in adults whose body mass index (BMI) is 30 kg/m² or higher, or 27 kg/m² or higher when other risk factors such as controlled high blood pressure, diabetes, or high cholesterol (hyperlipidemia) are also present.

All available phentermine products — including Adipex-P, Lomaira, and various generic capsules and tablets — share this same FDA-approved use. Lomaira tablets are specifically dosed to be taken three times daily before meals, while other formulations are generally taken once daily. Treatment is intended to last only a few weeks.

See full Phentermine drug information
Keep checking

Other Drugs & Rice Protein

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

0Major
23Moderate
0Minor
2,806No known interaction
23 Moderate 2,806 No interaction
Moderate

23 interactions

No interaction 2,806 drugs checked — show the list

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

Showing the 60 most looked-up of 2,806 medications checked with no known interaction — see the full Rice Protein list.

See the full Rice Protein interactions page
See every supplement checked against Phentermine, ranked by severity
Evidence & sources

Rice Protein References

The 6 references that drive our Rice Protein 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. Joy JM, Lowery RP, Wilson JM, et al. The effects of 8 weeks of whey or rice protein supplementation on body composition and exercise performance. Nutr J 2013;12:86. PubMed
  2. Li GH, Qu MR, Wan JZ, You JM. Antihypertensive effect of rice protein hydrolysate with in vitro angiotensin I-converting enzyme inhibitory activity in spontaneously hypertensive rats. Asia Pac J Clin Nutr. 2007;16 Suppl 1:275-80.
  3. Reche M, Pascual C, Fiandor A, et al. The effect of a partially hydrolysed formula based on rice protein in the treatment of infants with cow's milk protein allergy. Pediatr Allergy Immunol. 2010;21(4 Pt 1):577-85. PubMed
  4. Amended final report on the safety assessment of Oryza sativa (rice) bran oil, Oryza sativa (rice) germ oil, rice bran acid, Oryza sativa (rice) bran wax, hydrogenated rice bran wax, Oryza sativa (rice) bran extract, Oryza sativa (rice) extract, Oryza sat
  5. Yasutomi M, Kosaka T, Kawakita A, et al. Rice protein-induced enterocolitis syndrome with transient specific IgE to boiled rice but not to retort-processed rice. Pediatr Int. 2014;56(1):110-2.
  6. Hojsak I, Kljaic-Turkalj M, Misak Z, Kolacek S. Rice protein-induced enterocolitis syndrome. Clin Nutr. 2006;25(3):533-6. 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 Rice Protein and Phentermine Together: Common Questions

Is it safe to take Rice Protein with Phentermine?
We do not list a known interaction between Rice Protein and Phentermine. 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 Rice Protein and Phentermine have any of the same side effects?
Yes — our sources link each of them separately to one 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 Rice Protein and Phentermine combination checked?
Interactions in our licensed database are recorded against drug classes. Phentermine is filed under 2 classifications, and Rice Protein has documented interactions with 1 drug class — none of Phentermine'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 Rice Protein interact with any other medications?
Yes. Rice Protein has 23 documented drug interactions in our database — Phentermine 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 Phentermine interact with any supplements?
Yes. Phentermine has documented interactions with 61 supplements in our database — Rice Protein is not one of them. The Phentermine 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

Rice Protein monograph Uses, safety profile, and every drug interaction in one place Phentermine drug information The full plain-English guide to this medication Phentermine supplement interactions Every supplement checked against Phentermine, 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 6 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Phentermine and Rice Protein?

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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.