Drug & supplement interaction

Gossypol + Tasimelteon

Tasimelteon brand names: Hetlioz, Hetlioz Lq.

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 Gossypol and Tasimelteon 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 Tasimelteon 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

Gossypol and Tasimelteon

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 Tasimelteon and Gossypol 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.

Gossypol safety at a glance

Gossypol overall Avoid Gossypol is toxic and is not approved as a safe dietary supplement.
Pregnancy Likely Unsafe When used orally; gossypol seems to have abortifacient and uterine stimulant effects, avoid using. Read the full pregnancy detail
Breastfeeding Possibly Unsafe When used orally; avoid using. 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 Tasimelteon and Gossypol? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Tasimelteon

Interactions in our licensed database are recorded against drug classes, not just single drug names. Tasimelteon is filed under 5 classifications — including cytochrome p450 1a2 (cyp1a2) substrates, cytochrome p450 1a2 (cyp1a2) substrates, cns depressants. Gossypol has documented interactions with 4 drug classes — the most serious being digoxin (lanoxin) (moderate), diuretic drugs (moderate) and stimulant laxatives (moderate) — and none of Tasimelteon’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

Gossypol Does Interact With Other Medications

Gossypol has 104 moderate known drug interactions in our database — Tasimelteon isn’t one of them. If you take anything else, check it against the full list below.

Moderate 104 No known interaction 2,726 (incl. Tasimelteon)
Taking anything else?

Check Another of Your Medications Against Gossypol

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

What to actually watch for

No Interaction Found — But Data Suggests Gossypol and Tasimelteon 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. One of them is worth acting on rather than waiting out — marked below.

  • Liver problems Worth acting on Additional detail

    Gossypol

    “Orally, gossypol seems to be well-tolerated when used at doses below 20 mg daily, short-term. Using gossypol long-term or in doses greater than 20 mg daily may be unsafe.

    Most Common Adverse Effects:

    Orally: Diarrhea, hypokalemia, nausea, and vomiting.

    Serious Adverse Effects (Rare):

    Orally: When used long-term or in high doses, circulatory problems, dermatologic toxicity, heart failure, hepatotoxicity, infertility (…”

    Gossypol · Natural Medicines adverse-effect record, reported in congestive heart failure (chf).

    Tasimelteon

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

Reported for Gossypol but not commonly for Tasimelteon: reduced appetite, a low platelet count, a change in taste and heart failure.

Effects for Tasimelteon come from the ADVERSE REACTIONS section of its FDA label; effects for Gossypol come from the Natural Medicines adverse-effect record, quoted above. Where a percentage is shown, it is the share of 5,765 voluntary FDA FAERS reports for Tasimelteon 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.

Special populations

Gossypol in Pregnancy & Breastfeeding

Pregnancy Likely Unsafe

When used orally; gossypol seems to have abortifacient and uterine stimulant effects, avoid using.

Lactation Possibly Unsafe

When used orally; 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

How to take them

Some Tasimelteon Products Have a Food Rule — Gossypol Should Not Break It

At least one FDA label for a product containing Tasimelteon says to take it on an empty stomach. Most supplements — Gossypol included — are taken with a meal, so the easy mistake is swallowing both together at breakfast. Where that rule applies, keep Tasimelteon on its own and move Gossypol to a meal later in the day.

This may not be true of your version. Food instructions belong to the product, not the ingredient: two Tasimelteon 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.

2 DOSAGE AND ADMINISTRATION Indicated Population Dosage Form Body Weight Recommended Dosage Non-24 ( 2.2 ) Adults Capsules Not applicable 20 mg one hour prior to bedtime Nighttime sleep disturbances in SMS ( 2.3 ) Patients 16 years of age and older Capsules Not applicable 20 mg one hour prior to bedtime Pediatric Patients 3 to 15 years of age Oral Suspension ≤ 28 kg 0.7 mg/kg one hour before bedti

From the Dosage and Administration section of the FDA label we read for Tasimelteon — 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 Tasimelteon

This page covers Gossypol only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Tasimelteon page lists 218 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: 1,4-butanediol (major), Activated Charcoal (major), Beer (major), Gamma-hydroxybutyrate (ghb) (major) and Grapefruit (major).

By severity: 9 major · 166 moderate · 43 minor.

From our pharmacist’s overview on the Tasimelteon page

“Tasimelteon (Hetlioz) resets the body clock in people with non-24-hour sleep-wake disorder, and the sleep aids they often reach for, melatonin and kava among them, sit on an interaction list that deserves real respect. Nine of the 218 ingredients on file rate major, mostly in two directions: sedatives like kava stack drowsiness onto a…”

Reviewed by 2 · Jul 18, 2026

Open the Tasimelteon interaction page

How much people look this up

Where Gossypol and Tasimelteon 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 Gossypol
Steady interest

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

29 days ago today
Medication Tasimelteon
Steady interest

#1,943 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 Gossypol reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 20, 2026. The Gossypol and Tasimelteon records this page draws on were last updated July 11, 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 Gossypol

What is Gossypol?

Gossypol
  • Male contraception (research interest)
  • Reduction of sperm production
  • Endometriosis (historical/research)
  • Antiviral and antiparasitic research
  • Cancer cell research

Gossypol is a toxic yellow pigment from cotton plants that has been studied mainly as an experimental male contraceptive because it can lower sperm production. It is not an approved or safe over-the-counter supplement, and it carries serious risks including possibly permanent infertility, low potassium, and organ toxicity. It should not be used for self-treatment.

Gossypium hirsutum · Malvaceae · Seeds (cottonseed) and seed oil; the pigment gossypol is extracted from these · Purified compound used in research; not commonly sold as a standardized consumer supplement

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

Gossypol: dosing

There is no established safe or standardized dose of gossypol for supplement use. The doses studied in research were used under medical supervision and still carried serious risks.Because gossypol is toxic and not approved as a dietary supplement, we cannot recommend any specific amount. If you encounter a product that lists gossypol, do not use it without first speaking to a pharmacist or doctor, and follow any professional guidance rather than a product label alone.

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

Read the full Gossypol monograph & all interactions
Medication

About Tasimelteon

What Is Tasimelteon Used For?

Brand names: Hetlioz, Hetlioz Lq

Tasimelteon capsules are approved to treat Non-24-Hour Sleep-Wake Disorder (Non-24) in adults. Non-24 is a condition where the body's internal clock does not align with the normal 24-hour day, causing sleep and wake times to shift continuously.

Hetlioz capsules are also approved to treat nighttime sleep disturbances in Smith-Magenis Syndrome (SMS) in patients 16 years of age and older. Hetlioz LQ oral suspension is approved specifically for nighttime sleep disturbances in SMS in pediatric patients ages 3 to 15 years.

Most-Reported Side Effects for Tasimelteon

From FAERS, the FDA’s public side-effect reporting system (5,770 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Insomnia 728 reports
Middle insomnia 414 reports
Somnolence 408 reports
Headache 386 reports
Nightmare 268 reports
See full Tasimelteon drug information
Keep checking

Other Drugs & Gossypol

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

0Major
104Moderate
0Minor
2,725No known interaction
104 Moderate 2,725 No interaction
Moderate

104 interactions

Showing 60 of 104 moderate interactions — see all 104 on the Gossypol page.

No interaction 2,725 drugs checked — show the list

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

Showing the 60 most looked-up of 2,725 medications checked with no known interaction — see the full Gossypol list.

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

Gossypol References

The 53 references that drive our Gossypol 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. The Review of Natural Products by Facts and Comparisons. St. Louis, MO: Wolters Kluwer Co., 1999.
  2. McGuffin M, Hobbs C, Upton R, Goldberg A, eds. American Herbal Products Association's Botanical Safety Handbook. Boca Raton, FL: CRC Press, LLC 1997.
  3. Miller LG. Herbal Medicinals: Selected clinical considerations focusing on known or potential drug-herb interactions. Arch Intern Med 1998;158:2200-11.
  4. Cowart CL, London SN, Vernon MW, Pedigo NG. The effects of cyclic adenosine monophosphate, forskolin, and theophylline on motility parameters in gossypol-treated human sperm. Fertil Steril 1994;61:929-34. PubMed
  5. Coutinho EM. Gossypol: a contraceptive for men. Contraception 2002;65:259-63. PubMed
  6. Guo J, Reidenberg MM. Inhibition of 11beta-hydroxysteroid dehydrogenase by bioflavonoids and their interaction with furosemide and gossypol. J Lab Clin Med 1998;132:32-8.
  7. Coutinho EM, Athayde C, Atta G, et al. Gossypol blood levels and inhibition of spermatogenesis in men taking gossypol as a contraceptive. A multicenter, international, dose-finding study. Contraception 2000;61:61-7. PubMed
  8. Herve JC, Pluciennik F, Bastide B, et al. Contraceptive gossypol blocks cell-to-cell communication in human and rat cells. Eur J Pharmacol 1996;313:243-55. PubMed
  9. Taylor GT, Griffin MG, Bardgett M. Search for a male contraceptive: the effect of gossypol on sexual motivation and epididymal sperm. J Med 1991;22:29-44.
  10. Woolley, R. J. Contraception--a look forward, Part II: Mifepristone and gossypol. J.Am.Board Fam.Pract. 1991;4(2):103-113.
  11. Liu, G. Z., Lyle, K. C., and Cao, J. Clinical trial of gossypol as a male contraceptive drug. Part I. Efficacy study. Fertil.Steril. 1987;48(3):459-461. PubMed
  12. Qian, S. Z. and Wang, Z. G. Gossypol: a potential antifertility agent for males. Annu.Rev.Pharmacol.Toxicol. 1984;24:329-360. PubMed
  13. Qian, S. Z., Jing, G. W., Wu, X. Y., Xu, Y., Li, Y. Q., and Zhou, Z. H. Gossypol related hypokalemia. Clinicopharmacologic studies. Chin Med.J.(Engl.) 1980;93(7):477-482.
  14. Flack, M. R., Pyle, R. G., Mullen, N. M., Lorenzo, B., Wu, Y. W., Knazek, R. A., Nisula, B. C., and Reidenberg, M. M. Oral gossypol in the treatment of metastatic adrenal cancer. J.Clin.Endocrinol.Metab 1993;76(4):1019-1024. PubMed
  15. Bushunow, P., Reidenberg, M. M., Wasenko, J., Winfield, J., Lorenzo, B., Lemke, S., Himpler, B., Corona, R., and Coyle, T. Gossypol treatment of recurrent adult malignant gliomas. J.Neurooncol. 1999;43(1):79-86. 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 Gossypol and Tasimelteon Together: Common Questions

Is it safe to take Gossypol with Tasimelteon?
We do not list a known interaction between Gossypol and Tasimelteon. 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 Gossypol and Tasimelteon 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.
Should I take Gossypol and Tasimelteon at the same time of day?
At least one FDA label for a product containing Tasimelteon says to take it on an empty stomach, and supplements are usually taken with a meal — so taking them together at breakfast is the easy mistake. Where that applies, keep Tasimelteon on its own and move Gossypol to a meal later in the day. Food instructions belong to the product rather than the ingredient, so check the directions on your own box. This is about absorption, not an interaction.
How was the Gossypol and Tasimelteon combination checked?
Interactions in our licensed database are recorded against drug classes. Tasimelteon is filed under 5 classifications, and Gossypol has documented interactions with 4 drug classes — none of Tasimelteon'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 Gossypol interact with any other medications?
Yes. Gossypol has 104 documented drug interactions in our database — Tasimelteon 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 Tasimelteon interact with any supplements?
Yes. Tasimelteon has documented interactions with 218 supplements in our database — Gossypol is not one of them. The Tasimelteon 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

Gossypol monograph Uses, safety profile, and every drug interaction in one place Tasimelteon drug information The full plain-English guide to this medication Tasimelteon supplement interactions Every supplement checked against Tasimelteon, 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 53 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

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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.