Many people assume supplements only come as capsules and powders – but there are other options, too! In our IV therapy Toronto clinic, we commonly prescribe intravenous therapies and intramuscular injections, and these injectable nutrients can be dosed for your needs.
In the integrative functional medicine field, injectable nutrients may be prescribed when oral supplements are not enough to support therapeutic results. IV drip therapies and intramuscular (IM) injections both bypass the digestive system, which ensures that your body fully absorbs high-dose nutrients. Both treatments are effective, but there are differences between them.
In this post from the TFMC (Toronto Functional Medicine Centre), we explain what IV and IM therapies are, and why injectable nutrients might be part of a functional medicine protocol.
When would injectable nutrients be used in functional medicine?
Realistically, you need key amounts of nutrients to function. This is true for supporting your immune health, metabolism, cell health, and hormonal balance. But when deficiencies are formed, these can leave you susceptible to developing health issues, which can range from mild fatigue to a chronic illness. According to a Cureus article, nutrient intake can be simply enhanced with a balanced diet and the oral supplementation route, “However, the bioavailability of nutrients consumed orally…can vary significantly due to numerous factors.” These factors may include:
If these factors affect a person’s oral intake of nutrients, injectable nutrients may be advised.
Also, some people with chronic inflammation, fatigue, stress, and mold exposure symptoms might require higher doses of nutrients, which is something that oral supplements may not necessarily provide. This is due to the fact that some higher-than-normal doses can cause gastrointestinal side effects (i.e. diarrhea, nausea, etc.). Hence, IM vitamin shots and IV therapy treatments can be effective for taking elevated amounts of nutrients, like vitamin C and iron.
What are IV therapy treatments?
IV therapy rapidly dispenses nutrients into the bloodstream through a vein. This guarantees a 100% absorption of nutrients, and these tend to be dosed higher than oral supplements. As nutritional IVs are immediately absorbed and circulated in the body, they could possibly help fast-track therapeutic results.
Scientific research has shown that nutritional IVs can achieve plasma concentrations that are not attainable with oral supplements. “IV vitamin therapy proves highly effective in treating nutrient deficiencies, particularly in populations at increased risk due to malabsorption disorders, post-bariatric surgery, or chronic health conditions,” confirms a Cureus report. Hence, intravenous therapies may be suitable for: managing chronic fatigue, especially when the oral route doesn’t seem to be effective; immune support (i.e. high-dose vitamin C); detoxification help (i.e. glutathione IV drips); and when your gut condition prevents the digestion of nutrients (malabsorption).
What are intramuscular injections?
Intramuscular vitamin shots (or IM vitamin shots) administer nutrients into a muscle, such as the upper arm, hip, or gluteal muscle. It’s a popular modality that takes less than five minutes (not including the initial consultation). Uses of intramuscular vitamin shots include treating deficiencies (i.e. vitamin D, some amino acids, glutathione, B-complex vitamins) and administering lipotropic nutrients for weight loss programs.
The absorption rate is gradual, as IM shots are infused into the bloodstream through your muscle’s blood supply. Absorption after getting an intramuscular injection depends on the substance being administered. Water-soluble nutrients and medications are often absorbed within minutes to hours, while slow-release formulations may release steadily over days, weeks, or months. This slow absorption provides a sustained effect, unlike the rapid peak from IV administration. But keep in mind, your body’s absorption depends on some factors, such as the type of substance being injected; the ease of blood flow to the muscle; the injection site (deltoid, gluteal, thigh); the dose being injected; and whether it’s a water- or oil-based formulation. With that, IM injections still have high bioavailability, potentially in the 90–100% range.
Which one is right for you?
So, should you get intravenous therapy or IM vitamin shots? This really depends on individual elements – and a functional medicine provider can help you make this decision.
IV therapy is opted when rehydration, nutrient support, or high-dose protocols are needed. IM injections can be beneficial for ongoing support and for treating specific nutrient deficits; injections are also ideal for patients who wish to have short appointment times. The differences between the two treatments are summarized below.
Feature - IV Therapy Treatments - Intramuscular Injections
Delivery method - Into a vein - Into a muscle
Absorption speed - Immediate - Gradual
Nutrient dose - Large amounts - Smaller amounts
Treatment duration - 30-120+ minutes - Up to 5 minutes
Rehydration support? - Yes - No
Bioavailability - 100% direct delivery into the bloodstream - 90-100% but absorbed through muscle tissue
Suitable for … - Comprehensive nutrient protocols, hydration, larger doses - Quick nutrient boosts and maintenance support
In the world of functional medicine, IV therapy and intramuscular injections act as complementary tools. For example, a patient may get an IV drip periodically with IM shots administered between treatments. If you’re curious about injectable nutrients for your needs, please call the TFMC to discuss your candidacy.
Suggested reading: Toronto IV Therapy Insight: Regular Functional Medicine Testing Matters – Here’s Why
Experience personalized care in our Toronto IV Lounge
From immune support and weight loss to boosting collagen production and athletic performance, our integrative functional clinicians tailor health strategies for your needs. Our personalized therapies consider your genetic predisposition, lifestyle and environmental components, health history, and more. We can walk you through the steps of your health journey using an array of therapeutic treatments, including Western and naturopathic medicine advice, plant-based medicine (Ayurvedic, Chinese and Amazonian), hormone optimization strategies, weight loss programs, and intravenous therapies.
Our IV Lounge was the first of its kind to open in Toronto, and we continue to customize IV drips with natural ingredients. When injectable nutrients are combined with regular functional medicine visits, a balanced diet and exercise, they can support health improvements. Our IV Lounge is where we administer vitamin injections and IV drip therapies; these require a mandatory consultation and prescription from our IV therapy provider. Our wellness team of naturopathic doctors, registered nurses, and nurse practitioners are available to supervise each session, adhering to safety protocols for your safety and comfort.
Did this article resonate with you? Then let’s help you begin your health journey! Get to the root cause of your wellness issues and access our IV therapy services in Toronto. Click here now or press the button underneath to request your initial consult.
Disclaimer: The information in this article is designed for educational purposes only and is not intended to be a substitute for informed medical advice or care. This information should not be used to diagnose or treat any health problems or illnesses without consulting a doctor. You should always consult with a health care practitioner before relying on any information in this article or on this website. Never delay or disregard seeking professional medical advice from your doctor or other qualified healthcare provider because of information you have read from the Toronto Functional Medicine Centre website or other affiliate media.
References
Alangari A. To IV or Not to IV: The Science Behind Intravenous Vitamin Therapy. Cureus. 2025 Jun 22;17(6):e86527. doi: 10.7759/cureus.86527. PMID: 40548149; PMCID: PMC12182718.
Espinosa-Salas S, Gonzalez-Arias M. Nutrition: Micronutrient Intake, Imbalances, and Interventions. [Updated 2023 Sep 21]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2026 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK597352/
Jackson, Anthony D., and John McLaughlin. “Digestion and Absorption.” Surgery (Oxford), vol. 27, no. 6, 2009, pp. 231-236, https://doi.org/10.1016/j.mpsur.2009.03.003. Accessed 2 Jun. 2026.
Krajmalnik-Brown R, Ilhan ZE, Kang DW, DiBaise JK. Effects of gut microbes on nutrient absorption and energy regulation. Nutr Clin Pract. 2012 Apr;27(2):201-14. doi: 10.1177/0884533611436116. Epub 2012 Feb 24. PMID: 22367888; PMCID: PMC3601187.
Polania Gutierrez JJ, Munakomi S. Intramuscular Injection. [Updated 2023 Aug 13]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2026 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK556121
Stielow, Marlena, et al. “The Bioavailability of Drugs—The Current State of Knowledge.” Molecules, vol. 28, no. 24, 2023, p. 8038, https://doi.org/10.3390/molecules28248038. Accessed 2 Jun. 2026.
Sugandhi, Vrashabh V., et al. “Pharmacokinetics of Vitamin Dosage Forms: A Complete Overview.” Food Science & Nutrition, vol. 12, no. 1, 2023, p. 48, https://doi.org/10.1002/fsn3.3787. Accessed 2 Jun. 2026.
Zuidema, J., et al. “Release and Absorption Rate Aspects of Intramuscularly Injected Pharmaceuticals.” International Journal of Pharmaceutics, vol. 47, no. 1-3, 1988, pp. 1-12, https://doi.org/10.1016/0378-5173(88)90209-8. Accessed 2 Jun. 2026.
Original article "Toronto Functional Medicine Centre – (416) 968-6961" first appeared in the Toronto Functional Medicine Centre website.
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