Drug & supplement interaction

Oats + Insulin (rDNA)

Insulin (rDNA) brand names: Humalog, Humalog Mix 75/25, Humulin R, Humulin N, Humulin L, and others.

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

Insulin (rDNA) falls into 2 drug categories that Oats can interact with; the most serious is rated moderate. Theoretically, oats may have additive effects with antidiabetic agents and might increase the risk of hypoglycemia.

Read the full interaction report
SeverityModerate
LikelihoodPossible
Interactions2
EvidenceD
What do Severity, Likelihood & Evidence mean?
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Interaction report

Oats and Insulin (rDNA)

These two interact in 2 distinct ways. Each one is explained separately below.

Why Are There 2 Interactions?

Oats interacts with whole categories of medication. Insulin (rDNA) falls into 2 of those categories, so it can interact with Oats in 2 different ways. We’ve listed each one below — your overall risk is driven by the most serious of them (Moderate).

Moderate

ANTIDIABETES DRUGS

1 of 2

Why this applies to Insulin (rDNA)

Insulin (rDNA) falls under ANTIDIABETES DRUGS — the group Oats interacts with.

Theoretically, oats may have additive effects with antidiabetic agents and might increase the risk of hypoglycemia.
Consuming oats can decrease blood glucose in patients with diabetes. In those who require insulin, taking oats 100 grams daily for 2 days reduces the insulin dose required to achieve metabolic control.
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 gist: oats and your insulin both work to lower blood sugar, so eating a lot of oats may add to your insulin's effect. That can be a good thing, but it also means your blood sugar could drop lower than expected. Watch for signs of hypoglycemia, like shakiness, sweating, dizziness, a racing heart, confusion, or feeling unusually hungry.

This is mostly a theoretical concern based on how oats behave, though one small study found people needed less insulin after eating about 100 grams of oats a day. A regular bowl of oatmeal usually isn't a problem. If you start eating oats often or in big amounts, mention it to your pharmacist or doctor so they can help you check your numbers and adjust your dose if needed. Never change your insulin on your own.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Pick ME, Hawrysh ZJ, Gee MI, et al. Oat bran concentrate bread products improve long-term control of diabetes: a pilot study. J Am Diet Assoc 1996;96:1254-61. PubMed
  2. Braaten JT, Scott FW, Wood PJ, et al. High beta-glucan oat bran and oat gum reduce postprandial blood glucose and insulin in subjects with and without type 2 diabetes. Diabet Med 1994;11:312-8.
  3. Chandalia M, Garg A, Lutjohann D, et al. Beneficial effects of high dietary fiber intake in patients with type 2 diabetes mellitus. N Engl J Med 2000;342:1392-8. PubMed
  4. Delgado G, Kleber ME, Krämer BK, et al. Dietary intervention with oatmeal in patients with uncontrolled type 2 diabetes mellitus - A crossover study. Exp Clin Endocrinol Diabetes. 2019;127(9):623-629. PubMed
  5. Hou Q, Li Y, Li L, Cheng G, Sun X, Li S, Tian H. The metabolic effects of oats intake in patients with type 2 diabetes: A systematic review and meta-analysis. Nutrients. 2015;7(12):10369-87. PubMed
Moderate

INSULIN

2 of 2
Concomitant use of oats and insulin might increase the risk of hypoglycemia.
In patients with insulin-dependent type 2 diabetes, taking oats 100 grams daily for 2 days reduces the insulin dose required to achieve metabolic control.
Severity Moderate Likelihood Possible Evidence B

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 practical takeaway if you use insulin (like Humalog or Humulin) and you start eating a good amount of oats regularly. Oats are rich in a soluble fiber called beta-glucan, which slows digestion and smooths out the rise in blood sugar after meals. In one small study, people on insulin needed a lower dose to stay controlled while eating oats. That's a good thing, but it also means your blood sugar can run lower than usual, raising the chance of hypoglycemia (shakiness, sweating, dizziness, confusion).

This isn't a reason to avoid oats. Just check your blood sugar a bit more closely when you change your oat intake, and watch for low readings. If you notice your numbers dropping, talk with your pharmacist or doctor before adjusting any insulin dose.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Delgado G, Kleber ME, Krämer BK, et al. Dietary intervention with oatmeal in patients with uncontrolled type 2 diabetes mellitus - A crossover study. Exp Clin Endocrinol Diabetes. 2019;127(9):623-629. PubMed

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

Oats Also Interacts With Other Medications

Oats has 85 moderate known drug interactions in our database — the Insulin (rDNA) one above is among them. If you take anything else, check it against the full list below.

Moderate 85 No known interaction 2,745 (incl. Insulin (rDNA))
Taking anything else?

Check Another of Your Medications Against Oats

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

Everything else you take

See Every Supplement That Interacts With Insulin (rDNA)

This page covers Oats only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Insulin (rDNA) page lists 242 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Chelation Therapy Products (major), Siberian Cocklebur (major), Acai (moderate), African Wild Potato (moderate) and Agaricus Mushroom (moderate).

By severity: 2 major · 211 moderate · 29 minor.

From our pharmacist’s overview on the Insulin (rDNA) page

“A weed called Siberian cocklebur has caused severe low blood sugar in humans and is the one ingredient to avoid outright while using insulin (rDNA) products like Humalog or Humulin. This list deserves real respect.”

Reviewed by 2 · Jul 18, 2026

Open the Insulin (rDNA) interaction page

One more smart check

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

We hold 2,183 real supplement products containing Oats, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Oats. Your product may carry other ingredients that interact with Insulin (rDNA) too, on top of Oats — 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 Oats and Insulin (rDNA) 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 Oats
Top 10%

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

29 days ago today
Medication Insulin (rDNA)
Top half

#909 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 Oats

What is Oats?

  • Lowering cholesterol
  • Heart and digestive health
  • Soothing itchy or irritated skin
  • Blood sugar support
  • Anxiety and stress (oat straw, traditional)

Oats are a well-studied whole grain whose soluble fiber (beta-glucan) can help lower cholesterol and support heart health when eaten regularly. As a food, oats are safe for most people, and colloidal oatmeal is widely used to soothe skin. Evidence for oat straw supplements (for anxiety, energy, or focus) is much weaker.

Read the full Oats monograph & all interactions
Medication

About Insulin Lispro Injection

What Is Insulin Lispro Injection Used For?

Brand names: Humalog, Humalog Mix 75/25, Humulin R, Humulin N, Humulin L, Humulin 50/50, Humulin 70/30, Humulin U, NovoLog, Velosulin, Novolog Mix 70/30, Actrapid, Humulin S, Insuman Rapid

Insulin lispro injection is used to improve glycemic control (blood sugar management) in people with diabetes mellitus. It is a rapid-acting insulin analog approved for use in both type 1 and type 2 diabetes.

Admelog is specifically indicated to improve glycemic control in patients with diabetes mellitus. Humalog Mix75/25 is indicated to improve glycemic control in adults with diabetes mellitus; it is a fixed-ratio mixture of insulin lispro and insulin lispro protamine, and its fixed proportions do not allow for separate adjustment of basal (background) and prandial (mealtime) doses.

See full Insulin Lispro Injection drug information
Keep checking

Other Drugs & Oats

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

0Major
85Moderate
0Minor
2,744No known interaction
85 Moderate 2,744 No interaction
Moderate

85 interactions

Showing 60 of 85 moderate interactions — see all 85 on the Oats page.

No interaction 2,744 drugs checked — show the list

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

Showing the 60 most looked-up of 2,744 medications checked with no known interaction — see the full Oats list.

See the full Oats interactions page
See every supplement checked against Insulin (rDNA), 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
Oats monograph › Uses, safety, and every drug interaction in one place Insulin (rDNA) supplement interactions › Every supplement checked against Insulin (rDNA), ranked by severity Insulin Lispro 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 Oats and Insulin (rDNA) Together: Common Questions

Can you take Oats with Insulin (rDNA)?
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.
Why are there 2 interactions listed for Oats and Insulin (rDNA)?
Insulin (rDNA) belongs to more than one drug category, and Oats interacts with each of those categories a little differently. We list every one so nothing is missed — your overall risk is driven by the most serious of them.
How serious is the Oats and Insulin (rDNA) 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 Insulin (rDNA) and Oats?

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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.