Drug & supplement interaction

Soy + 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

Soy has a moderate interaction with Insulin (rDNA). Soy can lower blood glucose and have additive effects with antidiabetes drugs.

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

Soy and Insulin (rDNA)

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

Moderate

ANTIDIABETES DRUGS

Why this applies to Insulin (rDNA)

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

Soy can lower blood glucose and have additive effects with antidiabetes drugs.
Clinical research shows that whole soy diets and soy-based meals reduce fasting glucose levels in diabetic and non-diabetic individuals. Also, individuals following a soy-based meal replacement plan seem to require lower doses of sulfonylureas and metformin to manage blood glucose levels when compared with individuals following a diet plan recommended by the American Diabetes Association.
Severity Moderate Likelihood Possible Evidence A

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 simple version: soy foods can gently nudge your blood sugar downward on their own. Since insulin like Humalog or Humulin already does the heavy lifting of lowering glucose, eating a lot of soy can stack on top of that effect. The research here is solid, mostly showing that regular soy-based eating modestly drops fasting blood sugar.

What this means for you is a slightly higher chance of going too low (hypoglycemia), which can show up as shakiness, sweating, a racing heart, confusion, or feeling lightheaded. This isn't a reason to avoid soy, and ordinary servings in meals are usually easy to account for. Just keep your eating habits fairly steady, check your sugars as directed, and chat with your doctor or pharmacist before starting concentrated soy supplements so your insulin dose stays right.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Li, Z., Hong, K., Saltsman, P., DeShields, S., Bellman, M., Thames, G., Liu, Y., Wang, H. J., Elashoff, R., and Heber, D. Long-term efficacy of soy-based meal replacements vs an individualized diet plan in obese type II DM patients: relative effects on w
  2. Post-Skagegard, M., Vessby, B., and Karlstrom, B. Glucose and insulin responses in healthy women after intake of composite meals containing cod-, milk-, and soy protein. Eur J Clin Nutr 2006;60(8):949-954. PubMed
  3. Azadbakht, L., Kimiagar, M., Mehrabi, Y., Esmaillzadeh, A., Padyab, M., Hu, F. B., and Willett, W. C. Soy inclusion in the diet improves features of the metabolic syndrome: a randomized crossover study in postmenopausal women. Am J Clin Nutr 2007;85(3):7 PubMed
  4. Liu, Z. M., Chen, Y. M., and Ho, S. C. Effects of soy intake on glycemic control: a meta-analysis of randomized controlled trials. Am.J.Clin.Nutr. 2011;93(5):1092-1101. PubMed
  5. Zhang XM, Zhang YB, Chi MH. Soy protein supplementation reduces clinical indices in type 2 diabetes and metabolic syndrome. Yonsei Med J. 2016;57(3):681-9. 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

Soy Also Interacts With Other Medications

Soy has 9 major, 342 moderate, 259 minor known drug interactions in our database — the Insulin (rDNA) one above is one of them. If you take anything else, check it against the full list below.

Major 9 Moderate 342 Minor 259 No known interaction 2,220 (incl. Insulin (rDNA))
Taking anything else?

Check Another of Your Medications Against Soy

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

Everything else you take

See Every Supplement That Interacts With Insulin (rDNA)

This page covers Soy 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 Soy as Part of a Dietary Supplement Product? Check It for Interactions

We hold 821 real supplement products containing Soy, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Soy. Your product may carry other ingredients that interact with Insulin (rDNA) too, on top of Soy — 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 Soy 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 Soy
Top 25%

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

29 days ago today
Medication Insulin (rDNA)
Top half

#1,003 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 Soy

What is Soy?

  • Menopause symptoms (hot flashes)
  • Heart and cholesterol health
  • Bone health
  • Plant-based protein source
  • General nutrition

Soy is a nutritious bean that is a staple food and a popular source of plant protein and isoflavones. Eating soy foods as part of a balanced diet is generally considered safe for most people, and there is moderate evidence it may modestly help cholesterol and some menopause symptoms, though results vary. Talk with your pharmacist or doctor before using concentrated soy isoflavone supplements, especially if you have a history of hormone-sensitive conditions.

Read the full Soy 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 & Soy

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

9Major
342Moderate
259Minor
2,219No known interaction
9 Major 342 Moderate 259 Minor 2,219 No interaction
Major

9 interactions

Moderate

342 interactions

Showing 60 of 342 moderate interactions — see all 342 on the Soy page.

Minor

259 interactions

Showing 60 of 259 minor interactions — see all 259 on the Soy page.

No interaction 2,219 drugs checked — show the list

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

Showing the 60 most looked-up of 2,219 medications checked with no known interaction — see the full Soy list.

See the full Soy 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
Soy 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 Soy and Insulin (rDNA) Together: Common Questions

Can you take Soy 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.
How serious is the Soy 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 Soy?

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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.