Drug & supplement interaction

Cassava + Testosterone Undecanoate

Testosterone Undecanoate brand names: Andriol, Aveed, Jatenzo, Kyzatrex.

Moderate Interaction
Medically reviewed by · Updated September 2026
The bottom line Moderate

Cassava has a moderate interaction with Testosterone Undecanoate. Evidence from human and animal research suggests that cassava root has marked antithyroid effects, particularly if poorly processed or if consumed as part of a protein-deficient diet.

Read the full interaction report
SeverityModerate
LikelihoodPossible
EvidenceD
What do Severity, Likelihood & Evidence mean?
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Interaction report

Cassava and Testosterone Undecanoate

Here is the interaction we found between these two, with the evidence behind it.

Moderate

THYROID HORMONE

Why this applies to Testosterone Undecanoate

Testosterone Undecanoate falls under THYROID HORMONE — the group Cassava interacts with.

Evidence from human and animal research suggests that cassava root has marked antithyroid effects, particularly if poorly processed or if consumed as part of a protein-deficient diet. Also, clinical research shows that consuming boiled cassava leaves 200 grams twice daily for 9 days significantly reduces levels of the thyroid hormones triiodothyronine and thyroxine. Theoretically, cassava may alter thyroid function, reduce thyroid hormone levels, and interfere with thyroid hormone-replacement therapy.
Severity Moderate Likelihood Possible Evidence D

Interaction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists.

Dr. Brian Staiger, PharmD, BCPS
Dr. Brian Staiger explains PharmD, Clinical Pharmacist

Here's the honest truth on this one: the interaction we have on file is really about cassava and thyroid medication, not testosterone. Cassava, especially when poorly processed or eaten in large amounts, may lower thyroid hormone levels. That matters if you take a thyroid drug like levothyroxine, but testosterone undecanoate works through a completely different pathway.

So for your testosterone replacement, I wouldn't expect cassava to change how well it works or cause new side effects. This concern is theoretical and tied to a different drug class. Still, if you're using concentrated cassava supplements (not just cassava as food), it's worth a quick chat with your pharmacist or doctor, particularly if you also have any thyroid issues.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Akindahunsi AA, Grissom FE, Adewusi SR, et al. Parameters of thyroid function in the endemic goitre of Akungba and Oke-Agbe villages of Akoko area of southwestern Nigeria. Afr J Med Med Sci 1998;27(3-4):239-42.
  2. Osman BA, Ng ML, Bakar AA, Khalid BA. The effect of cassava leave intake on thyroid hormone and urinary iodine. East Afr Med J 1993;70(5):314-5.
  3. Gaitan E, Cooksey RC, Legan J, et al. Antithyroid effects in vivo and in vitro of babassu and mandioca: a staple food in goiter areas of Brazil. Eur J Endocrinol 1994;131(2):138-44. PubMed
  4. Geelhoed GW. Metabolic maladaptation: individual and social consequences of medical intervention in correcting endemic hypothyroidism. Nutrition 1999;15(11-12):908-32. DOI
  5. Biassoni P, Ravera G, Bertocchi J, et al. Influence of dietary habits on thyroid status of a nomadic people, the Bororo shepherds, roaming a central African region affected by severe iodine deficiency. Eur J Endocrinol 1998;138(6):681-5. PubMed
  6. Delange F. The disorders induced by iodine deficiency. Thyroid 1994;4(1):107-28. PubMed
  7. Delange F. [The role of goitrogenic factors distinct from iodine deficiency in the etiology of goiter]. Ann Endocrinol (Paris) 1988;49(4-5):302-5.

What These Ratings Mean

Every interaction above is graded three ways — here’s the key to each label.

Severity how clinically significant the interaction is
Major

Clinically significant. Avoid the combination, or use only under close professional supervision.

Moderate

Usually worth avoiding or managing — may need monitoring, a dose change, or timing apart.

Minor

Generally not serious. Be aware of it and mention it to your pharmacist.

Likelihood how strong the evidence is that the interaction actually happens in people
  • LikelyWell-controlled human studies have demonstrated the likely existence of this interaction.
  • ProbableInteraction has not been documented in well-controlled studies, however, the interaction has been demonstrated in some small human studies or in controlled animal studies in conjunction with multiple case reports.
  • PossibleInteraction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists.
  • UnlikelyInteraction has been demonstrated in animal or in lab research but has been shown not to occur in humans.
Evidence the quality of the studies behind the rating (graded A–D)
  • AHigh-quality meta-analysis (quantitative systematic review).
  • BCase-control study.
  • CConsensus.
  • DAnecdotal evidence.

These ratings are for information only. Never start, stop, or otherwise change your therapy before speaking with your provider.

Keep it in perspective

Cassava Also Interacts With Other Medications

Cassava has 15 moderate known drug interactions in our database — the Testosterone Undecanoate one above is one of them. If you take anything else, check it against the full list below.

Moderate 15 No known interaction 2,815 (incl. Testosterone Undecanoate)
Taking anything else?

Check Another of Your Medications Against Cassava

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

From our Q&A

Questions About Cassava or Testosterone Undecanoate

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

This page covers Cassava only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Testosterone Undecanoate page lists 200 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Beer (major), Grapefruit (major), Siberian Cocklebur (major) and St. John's Wort (major).

By severity: 7 major · 150 moderate · 43 minor.

From our pharmacist’s overview on the Testosterone Undecanoate page

“The supplement list for testosterone undecanoate (Jatenzo, Aveed, Kyzatrex, Andriol) deserves real attention before you combine it with much of anything, and the seven major-rated entries are where I would start. Most of the 200 ingredients on file, 121 of them, can change how the body handles this hormone through the CYP3A4 enzyme; gr…”

Reviewed by 2 · Jul 18, 2026

Open the Testosterone Undecanoate interaction page

One more smart check

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

We hold 35 real supplement products containing Cassava, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Cassava. Your product may carry other ingredients that interact with Testosterone Undecanoate too, on top of Cassava — and those would not show on this page. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where Cassava and Testosterone Undecanoate 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 Cassava
Steady interest

#1,209 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Testosterone Undecanoate
Top 25%

#401 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.

Supplement

About Cassava

What is Cassava?

Cassava
  • Dietary staple/source of carbohydrates
  • Fertility aid (to conceive twins)
  • Digestive support
  • General energy
  • Gluten-free flour alternative

Cassava is a starchy root vegetable that feeds millions of people worldwide, but it must be properly cooked or processed because the raw plant contains compounds that release cyanide. As a supplement, it is marketed for fertility and twin conception, but there is no good scientific evidence to support these claims. Always prepare cassava correctly and talk to your pharmacist or doctor before using cassava products for health reasons.

Read the full Cassava monograph & all interactions
Medication

About Testosterone Injection

What Is Testosterone Injection Used For?

Brand names: Andriol, Aveed, Jatenzo, Kyzatrex

Testosterone injection is primarily used in men whose bodies do not produce enough testosterone on their own — a condition called hypogonadism. This includes primary hypogonadism (a problem with the testicles themselves, such as from injury, infection, or surgery) and hypogonadotropic hypogonadism (caused by problems in the brain's hormone signaling from the hypothalamus or pituitary gland). It is also used to stimulate puberty in carefully selected adolescent males with clearly delayed puberty who have not responded to other support.

Testosterone Enanthate Injection is also approved for use in women with advanced, inoperable metastatic breast cancer (specifically skeletal metastases) who are one to five years past menopause, or in premenopausal women with hormone-responsive breast cancer who have had their ovaries removed. This use should be directed by an oncologist. Aveed (testosterone undecanoate) is specifically approved for male hypogonadism only.

See full Testosterone Injection drug information
Keep checking

Other Drugs & Cassava

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

0Major
15Moderate
0Minor
2,814No known interaction
15 Moderate 2,814 No interaction
Moderate

15 interactions

No interaction 2,814 drugs checked — show the list

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

Showing the 60 most looked-up of 2,814 medications checked with no known interaction — see the full Cassava list.

See the full Cassava interactions page
See every supplement checked against Testosterone Undecanoate, ranked by severity
Sources

Sources & How We Checked

Interaction details are evidence-graded and sourced from the Natural Medicines database. The medication overview comes from MedlinePlus.

Content is written and reviewed by licensed HelloPharmacist pharmacists. See our data sources and editorial standards for how this information is built and checked.

Parts of this content are provided by the Therapeutic Research Center, LLC.

DISCLAIMER: Currently this does not check for drug-drug interactions. This is not an all-inclusive comprehensive list of potential interactions and is for informational purposes only. Not all interactions are known or well-reported in the scientific literature, and new interactions are continually being reported. Input is needed from a qualified healthcare provider including a pharmacist before starting any therapy. Application of clinical judgment is necessary.

© 2021 Therapeutic Research Center, LLC

Keep exploring
Cassava monograph › Uses, safety, and every drug interaction in one place Testosterone Undecanoate supplement interactions › Every supplement checked against Testosterone Undecanoate, ranked by severity Testosterone Injection drug information › The full plain-English guide to this medication Supplement interaction checker › Check any supplement or product against your medications Browse medications A–Z › Every drug we've checked against herbs & supplements Ask a pharmacist › Free, personal answer from our licensed team
Pharmacist Counseling Corner

Taking Cassava and Testosterone Undecanoate Together: Common Questions

Can you take Cassava with Testosterone Undecanoate?
There is a moderate interaction, so it may be acceptable with monitoring or timing changes — but check with your pharmacist first. Read the full details on this page and confirm with your pharmacist before combining them.
How serious is the Cassava and Testosterone Undecanoate interaction?
We rate it Moderate. This combination may require monitoring, a dose adjustment, or separating the times you take each one. Consult your pharmacist before using them together.

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

Still Have a Question About Testosterone Undecanoate and Cassava?

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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.