Interactions on record — worth a quick check against your medications. Based on 1 of 2 ingredients. Check your meds →
Dietary supplement

Extra Strength IGF-1 Extreme Ingredients & Drug Interactions

by NOW Sports

Extra Strength IGF-1 Extreme label
See full label image
Liquid Category: Other Combinations
Most serious interaction: Minor
Clinical methodology reviewed by · Updated Sep 16, 2026 · Label data from the NIH DSLD
What is this page for?

First and foremost: checking Extra Strength IGF-1 Extreme against your medications. The heart of this page is the interaction checker and the full interaction report — how this product’s ingredients may interact with prescription and over-the-counter medicines you may be taking.

Around that, we add a pharmacist’s high-level view of the product as a whole — what’s inside, the evidence for its stated use, how transparent the label is, and what safety data exists — so you can see the full picture in one place. It’s educational information from our licensed clinical databases and the clinical staff at HelloPharmacist — not medical advice — and we don’t sell or endorse products. Our editorial policy

The interaction bottom line Most serious interaction: Minor

Extra Strength IGF-1 Extreme is a dietary supplement by NOW Sports with 2 active ingredients. Its ingredients are commonly taken for treating or preventing b12 deficiency, pernicious anemia, low energy and fatigue.Based on those ingredients, 20 medications have a known interaction with it, the most serious rated minor. The ingredients most likely to interact are Vitamin B12. Use the checker below to test your specific medication, or read the full HelloPharmacist Interaction Report.

Jump to a section

Check Your Meds Against Extra Strength IGF-1 Extreme by NOW Sports

Ask about any prescription or over-the-counter medication and we check it for interactions with Extra Strength IGF-1 Extreme by NOW Sports — and tell you which ingredient is responsible.

Pharmacist-reviewed data Checks every ingredient Answer in seconds
Prefer a human? Send your question to our licensed pharmacists — free, answered by email within 24 hours.

HelloPharmacist Scorecard of Extra Strength IGF-1 Extreme by NOW Sports

Our pharmacy team’s full take, with four database checks built into the cards below — a summary of what is known, not a grade of the product itself.

From our pharmacy team — supplement deep dive

Generated from HelloPharmacist’s pharmacist-curated databases and editorial rules · Last generated Jul 30, 2026

What’s inside

Full disclosure
Ingredient Transparency · database check
Full

Every active ingredient lists its own amount on the label.

Why this rating?
  • The label discloses an exact amount for 2 of its 2 active ingredients.
  • No proprietary blends here — you can verify the dose of every single component.

This liquid supplement contains 2 active ingredients: vitamin B12 and IGF-1. Vitamin B12 is an essential nutrient your body needs for nerve function, red blood cell formation, and DNA synthesis — it's especially important if you don't get enough from food or if your body has trouble absorbing it.

IGF-1 (insulin-like growth factor 1) is a naturally occurring compound involved in growth and metabolism. The remaining ingredients are inactive — vegetable glycerin, water, xylitol, natural fruit flavors, stevia leaf extract, phospholipids, citric acid, and potassium sorbate — which serve as sweeteners, preservatives, and flavorings.

Does it work?

Strong evidence
Evidence for Intended Use · database check
By FDA rules, dietary supplements can’t claim to treat, cure, or prevent disease — so labels speak in careful marketing language. We discern each product’s intended use from its name, label claims, and label statements, then grade the clinical evidence for that use. How these ratings are computed

This product doesn't appear to be marketed for a specific use, so we graded Vitamin B12's overall clinical evidence instead.

Strong

Strong clinical evidence supports Vitamin B12 for:

Why this rating?
  • We looked at the product name, claims, and label statements and couldn't find a stated purpose to grade.
  • Since the label doesn't commit to one use, we graded the ingredient's overall clinical evidence instead.
  • On file: Imerslund-Grasbeck disease — rated "Effective" (Natural Medicines).
  • On file: Vitamin B12 deficiency — rated "Effective" (Natural Medicines).
  • On file: Cyanide poisoning — rated "Likely Effective" (Natural Medicines).
  • On file: Hyperhomocysteinemia — rated "Possibly Effective" (Natural Medicines).
  • On file: Postherpetic neuralgia — rated "Possibly Effective" (Natural Medicines).

Vitamin B12 in this product is rated Effective for treating vitamin B12 deficiency and Imerslund-Grasbeck disease (a rare genetic disorder affecting B12 absorption). It's also rated Likely Effective for cyanide poisoning and Possibly Effective for canker sores and postherpetic neuralgia (nerve pain after shingles).

We don't hold effectiveness data for IGF-1 in this product, so we can't speak to what the research shows about its benefits.

The evidence, ingredient by ingredient Vitamin B12

How safe is it?

Well-documented data
Safety Information · database check
Well characterized

Adverse-effect, pregnancy, and general safety data are on file for most of these ingredients.

Why this rating?
  • We hold adverse-effect (side-effect) data for 1 of the 1 matched ingredient.
  • Pregnancy & breastfeeding safety ratings cover 1 of 1.
  • General safety write-ups exist for 1 of 1.
  • Remember: this measures how much safety information exists. Thin data is not the same as being safe.

Vitamin B12 is generally well-tolerated and has no established upper limit because your body excretes excess amounts in urine. It's considered Likely Safe during pregnancy and lactation at recommended amounts — in fact, it's needed during both periods, so follow your provider's guidance on dosing.

Rare serious adverse effects from B12 supplementation include severe low potassium (hypokalemia), particularly when correcting certain types of anemia. Allergic reactions such as rash, itching, or hives are also rare but possible; they may be linked to the cobalt in the B12 molecule, especially in people with cobalt sensitivity.

Side effects, ingredient by ingredient Vitamin B12

Meds to double-check

Minor interactions only
Known Interaction Concern · database check
Minor only

Only Minor-severity interactions are documented for these ingredients.

Why this rating?
  • 1 of the 1 matched ingredient can interact with medications — Vitamin B12.
  • The most serious interaction on file is rated Minor.
  • For scale: 20 individual medications appear in the full list. A big number alone doesn't make a product dangerous — what matters is whether YOUR medication is on it, so run yours through the interaction checker on this page.

If you take metformin (Glucophage) for diabetes, be aware it can lower B12 levels — discuss with your doctor or pharmacist whether you need monitoring. We could not check IGF-1 against medications, so no other interactions are documented for the ingredients we were able to review.

Check your own medication Run your meds through the checker above

The bottom line

Scorecard at a glanceFully disclosed formula with strong clinical evidence behind its ingredients' uses. Only minor medication interactions are documented, and safety information is well characterized.

This product makes sense if you have vitamin B12 deficiency or can't absorb B12 well from food, especially in liquid form for easier dosing. If you take metformin for diabetes, check with your doctor or pharmacist before starting — they can monitor your B12 levels if needed.

Because we can't check IGF-1 against medications, and because the product's full interaction profile depends on your exact prescriptions, run your complete medication list through the checker on this page.

Educational only — not medical advice; always confirm with your pharmacist. Our editorial policy · How we use AI

Assessment coverage: 1 of 2 active ingredients matched to our full ingredient reviews (monographs). Based on the product label dated Sep 24, 2019.

This Scorecard evaluates available label information, ingredient evidence, and known medication-safety considerations. It does not independently verify product identity, purity, potency, contamination, or manufacturing quality. How these ratings are computed

At a glance

General information

Key facts about Extra Strength IGF-1 Extreme, straight from the product label.

Brand NOW Sports
Barcode (UPC) 733739031914
Net contents 2 fl. Oz.; 59 mL
Market status On market
Date entered into DSLD Sep 24, 2019
DSLD ID 205906
Product type Other Combinations
Supplement form Liquid
Dietary claims / uses Nutrient, All Other
Intended target group(s) Adult Male (18-50 Years), Gluten Free, Dairy Free
From the label
Everything in this section is reproduced from the manufacturer’s own product label — it’s the label speaking, not HelloPharmacist. We show it so you can see exactly what the maker states; we don’t verify or endorse those statements.

Supplement Facts

The label details for Extra Strength IGF-1 Extreme by NOW Sports, sourced from the NIH Dietary Supplement Label Database.

Supplement Facts

Daily Value (DV) Target Group(s):
Adults and children 4 or more years of age
Minimum serving Sizes:
0.75 mL
Maximum serving Sizes:
0.75 mL
Servings per container
79
UPC/BARCODE
733739031914
IngredientAmount% DV
Vitamin B121 mg41667%
IGF-155 ng--

Other ingredients: Vegetable Glycerin, de-ionized Water, Xylitol, natural Fruit flavors, organic Stevia leaf extract, Phospholipids, Citric Acid, Potassium Sorbate

Tap any ingredient to jump to its full detail below.

Label statements
These statements are the manufacturer’s wording, reproduced from the product label — the label is saying it, not HelloPharmacist. We don’t verify or endorse them.
Suggested/Recommended/Usage/Directions

Suggested Usage: Shake well before use. Spray 1 time under tongue, hold momentarily, and then swallow. Consume 1 to 2 times daily as needed.

Formulation

Not manufactured with wheat, gluten, milk, egg, fish or shellfish ingredients.

Precautions

Not manufactured with wheat, gluten, milk, egg, fish or shellfish ingredients. Produced in a GMP facility that processes other ingredients containing these allergens.

Caution: For adults only.

Do not use if pregnant or nursing. Consult physician if taking medication or have a medical condition.

Keep out of reach of children.

Contains Xylitol, which is harmful to pets. If you are a competitive athlete who is regularly tested, please check with your sanctioning body for the status of IGF-1.

Formula

Contains Xylitol, which is harmful to pets.

Deer antler velvet extract

Men's Health

With vitamin B12

Storage

Store in a cool, dry place after opening.

General Statements

Advanced absorption

Liposomal spray

“ng” is the abbreviation for nanograms (1 billionth of a gram). Natural color variation may occur in this product.

FDA Statement of Identity

A Dietary Supplement

Is this label outdated? Report a formula or label change and our pharmacy team will review it.

See for yourself

Extra Strength IGF-1 Extreme by NOW Sports label

The label scan from the NIH Dietary Supplement Label Database. Tap to enlarge.

Extra Strength IGF-1 Extreme label

Label images are published by the NIH Dietary Supplement Label Database for the version of this product on file. Always read your actual product label.

View the full label (PDF)
What’s inside

The Ingredients in Extra Strength IGF-1 Extreme by NOW Sports

These are the 2 active ingredients this product is made of. Select any to open its full monograph.

Serving size0.75 mL Dosage formLiquid Servings per container79 Amounts shown are per serving.

Most supplement products combine several ingredients, and a medication can interact with the product through any one of them. Each ingredient below shows whether it has known drug interactions.

Vitamin B12

Interacts with
20 drugs
1 mg per serving Form: Cyanocobalamin

Vitamin B12 (cobalamin) is an essential nutrient your body needs to make red blood cells, keep nerves healthy, and support DNA. Supplements are very h...

Vitamin B12 monograph & interactions

IGF-1

55 ng per serving Form: Deer Antler Velvet extract

Other (inactive) ingredients: Vegetable Glycerin, De-ionized Water, Xylitol, Natural Fruit flavors, Organic Stevia leaf extract, Phospholipids, Citric Acid, Potassium Sorbate. These complete the product’s ingredient list but are not active constituents.

Interaction report

Extra Strength IGF-1 Extreme by NOW Sports Drug Interactions

Want to check YOUR meds against Extra Strength IGF-1 Extreme?

Ask about interactions with your drugs in plain English — “Can I take it with lisinopril?” — and we find you the answer in seconds, ingredient by ingredient.

 Go to the checker
20Drugs
20 Minor

Ingredients driving the most interactions

Vitamin B12 20

Individual Drug Interactions

The ingredients in Extra Strength IGF-1 Extreme interact with 20 drugs. Click any drug to see the details.

1 of the 2 ingredients in Extra Strength IGF-1 Extreme interact with drugs. Each result below shows which ingredient is responsible. Vitamin B12

Each ingredient & the kinds of drugs it affects

For each ingredient in Extra Strength IGF-1 Extreme with known interactions, here are the types of medications it can affect. Open any type for the detail — or search your exact drug in the checker above.

Vitamin B121 drug type · 20 drugs

Metformin (Glucophage)

Metformin, a common medication used to manage type 2 diabetes, has been associated with lower vitamin B12 levels in some individuals. Prolonged use of metformin can interfere with the absorption of B12 in the digestive system, potentially leading to a deficiency in this essential vitamin.

Likelihood Possible Evidence A
Vitamin B12 full monograph & interactions
The maker

Brand information

Manufacturer and brand details for Extra Strength IGF-1 Extreme, from the product label.

NOW Sports

See all NOW Sports products
Name
NOW Foods
Street Address
395 S. Glen Ellyn Rd.
City
Bloomingdale
State
IL
ZipCode
60108
Web Address
nowsportsproducts.com
Pharmacist Counseling Corner

Extra Strength IGF-1 Extreme by NOW Sports: Common Questions

Does Extra Strength IGF-1 Extreme by NOW Sports interact with any medications?
Yes. Based on its ingredients, Extra Strength IGF-1 Extreme has a known interaction with 20 medications. Use the checker to see how it interacts with a specific drug.
How can one product interact with so many drugs?
Extra Strength IGF-1 Extreme contains 2 active ingredients, and an interaction can come from any of them. We check every ingredient, combine the results into one list per medication, and show which ingredient and mechanism is responsible.
Where does this information come from?
The product label data comes from the NIH Dietary Supplement Label Database (DSLD); the interaction data is built on the Natural Medicines database and reviewed by HelloPharmacist pharmacists.
Is vitamin B12 safe if I'm pregnant or breastfeeding?
Yes — B12 is rated Likely Safe during pregnancy and lactation at recommended amounts. In fact, it's important during both periods. Follow your provider's advice on the right dose for you.
What does vitamin B12 actually do in my body?
B12 supports nerve function, helps form red blood cells, and is needed for DNA synthesis. You need it for energy, mood, and overall cell health. If you're deficient, supplementing is rated Effective at correcting that.
I take metformin for diabetes — is this product okay for me?
Metformin can lower your B12 levels over time because it interferes with absorption. Since this is a B12 supplement, it could help — but talk to your doctor or pharmacist first so they can advise you on whether you need it and monitor your levels.
What are the side effects of B12?
B12 is generally very well-tolerated. Serious side effects are rare. The most common issue with injections is mild reaction at the injection site. Allergic reactions like rash or itching are uncommon but possible, especially in people sensitive to cobalt.
Does this product contain fillers?
The active ingredients are vitamin B12 and IGF-1. The liquid also contains vegetable glycerin, water, xylitol, fruit flavors, stevia, phospholipids, citric acid, and potassium sorbate — these are inactive ingredients that help preserve and flavor the product.

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

Not sure if Extra Strength IGF-1 Extreme is safe with your meds?

Our pharmacists answer your medication & supplement questions — free.

Ask a pharmacist

Label information is sourced from the NIH Dietary Supplement Label Database and reflects the product version on file; always read your actual product label. This page is for education only and is not a substitute for professional medical advice. Confirm with your pharmacist or doctor before combining supplements and medications.

Extra Strength IGF-1 Extreme label
Go deeper

The Full Monographs Behind Extra Strength IGF-1 Extreme’s Ingredients

Every ingredient we hold a full HelloPharmacist monograph for — uses, evidence, safety, and the complete interaction list.

Herb & supplement monograph

Vitamin B12

Interacts with 20 drugs

Vitamin B12 (cobalamin) is an essential nutrient your body needs to make red blood cells, keep nerves healthy, and support DNA. Supplements are very helpful for people who are deficient — su...

Read the full Vitamin B12 monograph →
Sources

Sources & How We Checked

Extra Strength IGF-1 Extreme's label data comes from the NIH Dietary Supplement Label Database; the ingredient interaction data is from the Natural Medicines database, reviewed by our pharmacists.

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

The 30 references behind this product’s interaction data

Every citation that drives the interaction findings for this product’s ingredients, from the evidence-graded Natural Medicines (TRC Healthcare) database. Open an ingredient to browse its citations — links open the study on PubMed or the publisher’s site.

Vitamin B12 30 references
  1. Food and Nutrition Board, Institute of Medicine. Dietary Reference Intakes for Thiamin, Riboflavin, Niacin, Vitamin B6, Folate, Vitamin B12, Pantothenic Acid, Biotin, and Choline (2000). Washington, DC: National Academy Press, 2000. Available at: http://b
  2. Hartman TJ, Woodson K, Stolzenberg-Solomon R, et al. Association of the B-vitamins pyridoxal 5'-phosphate (B6), B12, and folate with lung cancer risk in older men. Am J Epidemiol 2001;153:688-94.. DOI
  3. Jansen T, Romiti R, Kreuter A, Altmeyer P. Rosacea fulminans triggered by high-dose vitamins B6 and B12. J Eur Acad Dermatol Venereol 2001;15:484-5..
  4. Lange H, Suryapranata H, De Luca G, et al. Folate therapy and in-stent restenosis after coronary stenting. N Engl J Med 2004;350:2673-81. PubMed
  5. Collin, S. M., Metcalfe, C., Refsum, H., Lewis, S. J., Zuccolo, L., Smith, G. D., Chen, L., Harris, R., Davis, M., Marsden, G., Johnston, C., Lane, J. A., Ebbing, M., Bonaa, K. H., Nygard, O., Ueland, P. M., Grau, M. V., Baron, J. A., Donovan, J. L., Nea
  6. Geissbuhler, P., Mermillod, B., and Rapin, C. H. Elevated serum vitamin B12 levels associated with CRP as a predictive factor of mortality in palliative care cancer patients: a prospective study over five years. J.Pain Symptom.Manage. 2000;20(2):93-103. PubMed
  7. Salles, N., Herrmann, F., Sakbani, K., Rapin, C. H., and Sieber, C. High vitamin B12 level: a strong predictor of mortality in elderly inpatients. J Am Geriatr.Soc 2005;53(5):917-918.
  8. Looker, H. C., Fagot-Campagna, A., Gunter, E. W., Pfeiffer, C. M., Sievers, M. L., Bennett, P. H., Nelson, R. G., Hanson, R. L., and Knowler, W. C. Homocysteine and vitamin B(12) concentrations and mortality rates in type 2 diabetes. Diabetes Metab Res R
  9. Uhl, W., Nolting, A., Golor, G., Rost, K. L., and Kovar, A. Safety of hydroxocobalamin in healthy volunteers in a randomized, placebo-controlled study. Clin Toxicol (Phila) 2006;44 Suppl 1:17-28. PubMed
  10. Borron, S. W., Baud, F. J., Barriot, P., Imbert, M., and Bismuth, C. Prospective study of hydroxocobalamin for acute cyanide poisoning in smoke inhalation. Ann Emerg.Med 2007;49(6):794-801, 801. PubMed
  11. Borron, S. W., Baud, F. J., Megarbane, B., and Bismuth, C. Hydroxocobalamin for severe acute cyanide poisoning by ingestion or inhalation. Am J Emerg.Med 2007;25(5):551-558. PubMed
  12. Lewis, J. G. Gout, Steatorrhoea, and Megaloblastic Anaemia. Ann Rheum.Dis 1962;21(3):284-286. PubMed
  13. Tal, S., Shavit, Y., Stern, F., and Malnick, S. Association between vitamin B12 levels and mortality in hospitalized older adults. J Am Geriatr.Soc 2010;58(3):523-526. PubMed
  14. Baztan, J. J., Gavidia, J. J., Gomez-Pavon, J., Esteve, A., and Ruiperez, I. High vitamin B12 levels and in-hospital mortality. J Am Geriatr.Soc 2010;58(11):2237-2238. PubMed
  15. Omboni, E., Checchini, M., and Longoni, F. [Hypopotassemia and megaloblastic anemia. Presentation of a case]. Minerva Med 8-31-1987;78(16):1255-1257.
  16. Aalfs As, Scholvinck LH, Horvath B. Acneiform eruption in a 5-year old due to vitamin B12 supplementation. Eur J Dermatol 2013;23(5):726-7. PubMed
  17. Balta I, Ozuguz P. Vitamin B12-induced acneiform eruption. Cutan Ocul Toxicol 2014;33(2):94-5. PubMed
  18. Carman KB, Belgemen T, Yis U. Involuntary movements misdiagnosed as seizure during vitamin B12 treatment. Pediatr Emerg Care 2013;29(11):1223-4. PubMed
  19. Djuric V, Bogic M, Popadic AP, et al. Anaphylactic reaction to hydroxycobalamin with tolerance to cyanocobalamin. Ann Allergy Asthma Immunol 2012;108(3):207-8. PubMed
  20. Kartel O, Gulec M, Demirel F, et al. Vitamin B12 allergy and successful desensitization with cyanocobalamin: A case report. Allergol Immunopath (Madr) 2012;40(5):324-5.
  21. Patiroglu T, Unal E, Yildirim S. Infantile tremor syndrome associated with cobalamin therapy: A case report. Clin Neurol Neurosurg 2013;115(9):1903-5. PubMed
  22. Schulte S, Barkema LW, Kardaun SH. Long-lasting atypical acneiform eruption with prominent comedones induced by hydroxocobalamin (vitamin B12). J Dtsch Dermatol Ges 2014;12(6):502-3.
  23. Zanus C, Alberini E, Costa P, et al. Involuntary movements after correction of vitamin B12 deficiency: A video-case report. Epileptic Disord 2012;14(2):174-80. PubMed
  24. Fanidi A, Carreras-Torres R, Larose TL, et al. Is high vitamin B12 status a cause of lung cancer? Int J Cancer. 2019 Sep 15;145(6):1499-1503. PubMed
  25. Fujita Y, Mizukami T, Maya Y, et al. Vitamin B12 allergy manifesting as lymphomatoid contact dermatitis. Eur J Dermatol. 2020;30(3):304-305. PubMed
  26. Dépret F, Hoffmann C, Daoud L, et al. Association between hydroxocobalamin administration and acute kidney injury after smoke inhalation: a multicenter retrospective study. Crit Care. 2019;23(1):421. PubMed
  27. Khairan P, Sobue T, Eshak ES, et al. Association of dietary intakes of vitamin B12, vitamin B6, folate, and methionine with the risk of esophageal cancer: the Japan Public Health Center-based (JPHC) prospective study. BMC Cancer 2021;21(1):982. PubMed
  28. Evans J, Pandya A, Ding Y, Qunibi WY. Hydroxocobalamin-Induced Oxalate Nephropathy in a Patient With Smoke Inhalation. Kidney Int Rep 2021;6(8):2228-2231. PubMed
  29. Lacombe V, Chabrun F, Lacout C, et al. Persistent elevation of plasma vitamin B12 is strongly associated with solid cancer. Sci Rep 2021;11(1):13361. PubMed
  30. Pegalajar-García MD, Cebolla-Verdugo M, Prados-Carmona Á, Llamas-Segura C, Navarro-Triviño FJ. Systemic allergic dermatitis to cobalt present in cyanocobalamin supplementation. Contact Dermatitis 2023;89(3):203-205. PubMed

See these in context on the Vitamin B12 monograph →

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
Supplement interaction checker › Check any supplement or product against your medications Drug–drug interactions › Check two or more of your medications against each other Browse medications A–Z › Every drug we've checked against herbs & supplements NDC & pricing lookup › Find a drug’s NDCs, packaging and costs Ask a pharmacist › Free, personal answer from our licensed team