Biotin (Vitamin B7) Injection

Biotin, also known as vitamin B7 or vitamin H, is a water-soluble B-complex vitamin essential for the metabolism of carbohydrates, fats, and proteins.^[1] It acts as a coenzyme in various enzymatic reactions and is often promoted for supporting healthy hair, skin, and nails, although scientific evidence for these cosmetic benefits in individuals without biotin deficiency remains limited.^[2][3]

Biotin deficiency is quite rare in healthy populations, as the vitamin is available in many foods and also produced by gut bacteria. When biotin deficiency does occur (for example, due to genetic enzyme disorders or prolonged consumption of raw egg whites), it can lead to symptoms such as thinning hair (alopecia), a scaly red rash around the eyes, nose, and mouth, and neurologic issues like fatigue, depression, or numbness.^[3]

Biotin (Vitamin B7) Injection is a compounded sterile solution intended to treat or prevent biotin deficiency in patients who cannot maintain adequate levels through diet or oral supplementation. This formulation is available by prescription only and is prepared in a concentration of 10 mg/mL, typically dispensed in multi-dose vials.

Being a 503A compounded medication, biotin injection is not an FDA-approved manufactured drug product but is custom-made by compounding pharmacies for individual patient needs. It may be prescribed in cases of confirmed biotin deficiency or certain medical conditions, and while it is sometimes used in hopes of improving hair or nail growth, its efficacy in otherwise healthy individuals remains unproven.^[2][3]

Biotin’s mechanism of action in the body stems from its role as an essential cofactor for several carboxylase enzymes involved in key metabolic pathways.^[4][5] In human cells, biotin is covalently attached to five specific carboxylase enzymes that catalyze critical steps in the metabolism of fatty acids, glucose, and amino acids.^[4]

For example, biotin-dependent enzymes facilitate the conversion of pyruvate to oxaloacetate (an important step in gluconeogenesis), the synthesis of malonyl-CoA from acetyl-CoA (the first step in fatty acid biosynthesis), and the catabolism of certain amino acids into Krebs cycle intermediates.^[5] Through these biochemical actions, biotin helps the body generate energy and synthesize necessary fatty acids and glucose.

In addition to its metabolic functions, biotin may also influence gene regulation: it can attach to specific lysine residues on histone proteins (a process known as histone biotinylation), thereby potentially affecting chromatin structure and gene expression.^[5] This dual role – serving as a coenzyme for carboxylases and modulating gene activity – underlies biotin’s importance in cellular function.

Biotin is a water-soluble vitamin, so it is not stored in large amounts; any excess is rapidly excreted in the urine. This property contributes to its wide safety margin, as the body efficiently eliminates surplus biotin and thus prevents accumulation or toxicity.^[5]

Biotin (vitamin B7) is generally regarded as a very safe nutrient with no well-defined contraindications for its use.^[6][7] There are no known disease states or conditions in which biotin supplementation is explicitly contraindicated, since biotin is a natural vitamin required for normal metabolism.^[6]

The only notable exception is that biotin should not be used in anyone with a known hypersensitivity or allergy to biotin or any ingredients in the injection formulation (such as the diluent or preservatives), though such cases are exceedingly rare.^[6] In practice, biotin injections are well tolerated by most individuals.

Even high doses of biotin have not demonstrated toxic effects, so there is no strict upper limit for safety established in humans.^[7] Nevertheless, it is prudent for healthcare providers to evaluate each patient’s context. For example, if a patient has had previous allergic reactions to vitamin supplements or injection components, biotin injections would be avoided in that patient.

Overall, aside from potential hypersensitivity, there are no absolute contraindications to biotin therapy on record.^[6][7]

Although biotin itself does not have direct pharmacological interactions with most medications, it can be affected by certain drugs and can affect laboratory test results. Long-term use of some anticonvulsant medications has been associated with lower biotin levels in the body, presumably by increasing biotin metabolism or reducing its absorption.^[8]

For instance, patients on anti-seizure drugs like carbamazepine, phenytoin, primidone, or phenobarbital have shown reduced biotin status in clinical observations, suggesting these medications may accelerate biotin catabolism or clearance. Chronic antibiotic therapy may also contribute to biotin deficiency by altering gut flora that synthesize biotin.^[8]

Another important interaction is between biotin and certain laboratory assays: high doses of biotin can interfere with diagnostic tests that use biotin–streptavidin technology (such as some immunoassays). This interference can cause falsely elevated or falsely decreased results in tests for hormones (for example, thyroid hormones) and cardiac biomarkers (such as troponin).^[8][9]

The FDA has issued warnings that patients taking large amounts of biotin (often found in hair/nail supplements in doses of 5–20 mg or higher) have had misleading lab results, including one reported case in which a troponin assay gave a falsely low reading and led to a missed diagnosis of a heart attack.^[9] Therefore, clinicians should be aware of a patient’s biotin supplementation when interpreting lab results. It is advisable to discontinue high-dose biotin supplementation for a few days before having certain lab tests drawn, if possible, to minimize the risk of interference.

Finally, biotin can interact with certain dietary elements: raw egg whites contain a protein called avidin that binds biotin strongly and prevents its absorption – overconsumption of raw egg whites over time can induce biotin deficiency (a phenomenon historically noted as “egg white injury”)⁸. Cooking denatures avidin, so this is not a concern with cooked eggs.

In summary, while biotin does not interact significantly with other drugs in a classical pharmacologic sense, several factors (anticonvulsant drugs, antibiotics, and high-dose supplement use) can influence biotin levels or assay readings and should be managed accordingly.^[8][9]

Biotin is generally very well tolerated, and adverse effects are uncommon even at high doses. No severe toxicity has been observed from biotin supplementation in humans. In fact, the Food and Nutrition Board did not establish an upper tolerable intake level for biotin because no adverse effects were noted at even very large intakes.^[10]

Clinical studies have reported no harmful effects with chronic daily doses as high as 200 mg (many times the nutritional requirement), indicating a wide safety margin for this vitamin. Most people can take biotin without any side effects. In rare cases, mild gastrointestinal upset has been reported – for example, some individuals taking high doses may experience nausea, cramping, or diarrhea, but these symptoms are infrequent and usually transient.^[10]

There have been no documented reports of serious organ toxicity or systemic reactions caused by excess biotin. A single unusual case report did describe a life-threatening eosinophilic pneumopericardium effusion (a type of fluid accumulation around the lungs and heart with high eosinophil counts) in an elderly woman who had been concurrently taking high-dose pantothenic acid (vitamin B5 at 300 mg/day) and biotin (10 mg/day) for two months. This appears to be an idiosyncratic reaction, and the effusion resolved after the vitamins were discontinued.^[11]

Such extreme reactions are exceedingly rare, and biotin alone has not been clearly implicated in other serious adverse events. Allergic reactions to pure biotin are also very rare, but as with any compound, a hypersensitive individual could theoretically develop itching, rash, or other allergy symptoms – if any signs of an allergic reaction occur, the supplementation should be stopped and medical attention sought.

Overall, for the vast majority of patients, biotin supplementation (whether oral or via injection) is free of significant side effects.^[10] Patients should always inform their healthcare provider of all supplements they are taking, but biotin’s side effect profile is minimal and it is considered a very low-risk therapy in appropriate doses.

Biotin is an essential nutrient during pregnancy, as it plays roles in fetal development (including fatty acid synthesis and energy metabolism), but it should be used cautiously and only in recommended amounts during pregnancy.^[12][13] Pregnancy can increase the body’s demand for biotin – research has shown that a substantial proportion of pregnant women develop marginal biotin deficiency by late pregnancy, even while consuming normal diets.^[12]

Despite this increased requirement, routine high-dose biotin supplementation during pregnancy is not recommended unless there is a documented deficiency. Biotin is considered likely not dangerous in the doses typically found in prenatal vitamins (the recommended adequate intake for pregnant women is 30 µg per day).^[13] These standard prenatal doses help ensure that both the mother and developing fetus have enough biotin for normal metabolic needs.

However, taking biotin in amounts exceeding the dietary or prenatal vitamin level has not been proven safe or beneficial in pregnancy and should be avoided. Animal studies have suggested that biotin deficiency can be teratogenic (causing birth defects) in some species, raising concerns that even marginal biotin deficiency might be undesirable in pregnancy.^[12]

Fortunately, no congenital abnormalities in humans have been directly linked to biotin deficiency, and ensuring an adequate intake (through diet or a prenatal vitamin) appears to maintain normal pregnancy outcomes. The key point is that pregnant (and breastfeeding) individuals should meet the daily biotin requirement through a balanced diet or prenatal supplement but should not take additional high-dose biotin supplements unless specifically instructed by their healthcare provider.^[13]

If a true biotin deficiency is diagnosed during pregnancy – which is rare – it can be treated under medical supervision. Otherwise, the focus should be on a healthy prenatal diet.

In summary, biotin is important for a healthy pregnancy, but more is not necessarily better: stick to the recommended intake and consult an obstetrician before using any biotin-containing injections or high-dose supplements during pregnancy.^[12][13]

Proper storage of biotin (vitamin B7) injection is important to maintain its stability. The medication should be stored at controlled room temperature, generally around 20–25 °C (68–77 °F), and protected from excessive heat, moisture, and light.^[6][7] Always keep the vials in their original packaging or a well-closed container to avoid exposure to light which could degrade the vitamin.

Do not freeze biotin injection and avoid storing it in very hot places (such as in direct sunlight or a car glovebox on a hot day) as extreme temperatures can reduce potency.^[6] Like all medications, this injection should be kept out of reach of children to prevent accidental ingestion or injury.^[7] If children or pets were to get hold of the vial or syringe, it could pose a risk, so store it securely.

Observe the beyond-use date (expiration date) provided by the compounding pharmacy – any unused portion of the biotin injection should be discarded once it is past that date or if instructed by the pharmacy that it must be used within a certain time after opening. Do not use the solution if you notice particulate matter, discoloration, or any signs of contamination; in such cases, safely dispose of it and obtain a new vial.

For disposal of unused or expired biotin injection, follow proper medical waste protocols. It is recommended to use a medication take-back program if available, or otherwise to dispose of the vial in accordance with FDA guidelines (for example, by mixing the liquid with an unpalatable substance like coffee grounds and placing it in a sealed bag in the trash, if local regulations allow) rather than flushing it down the sink or toilet.^[7]

By storing the biotin injection correctly and disposing of it safely, patients and caregivers can ensure the medication remains stable and avoid any preventable hazards.

1. National Library of Medicine. (n.d.). Biotin: MedlinePlus Supplements. Retrieved May 27, 2025, from https://medlineplus.gov/druginfo/natural/313.html
2. Bistas, K. G., & Tadi, P. (2023). Biotin. In StatPearls [Internet]. StatPearls Publishing.
3. Office of Dietary Supplements. (2018). Biotin: Fact Sheet for Health Professionals. National Institutes of Health. Retrieved May 27, 2025, from https://ods.od.nih.gov/factsheets/Biotin-HealthProfessional/
4. Linus Pauling Institute. (2022). Biotin. Micronutrient Information Center, Oregon State University. Retrieved May 27, 2025, from https://lpi.oregonstate.edu/mic/vitamins/biotin
5. Institute of Medicine. (1998). Biotin. In Dietary Reference Intakes: Thiamin, Riboflavin, Niacin, Vitamin B6, Vitamin B12, Pantothenic Acid, Biotin, and Choline (pp. 374–389). Washington, DC: National Academy Press.
6. RxList. (2021). Biotin: Side Effects, Uses, Dosage, Interactions, Warnings. Retrieved May 27, 2025, from https://www.rxlist.com/biotin/generic-drug.htm
7. Drugs..com. (2025). Biotin (Vitamin B7) – Professional Natural Products Monograph. Retrieved May 27, 2025, from https://www.drugs.com/npp/biotin.html
8. U.S. Food and Drug Administration. (2019, November 5). FDA in Brief: FDA reminds patients, health care professionals and laboratory personnel about the potential for biotin interference with certain test results. [Press release]. Retrieved May 27, 2025, from https://www.fda.gov/news-events/fda-brief/fda-brief-fda-reminds-patients-health-care-professionals-and-laboratory-personnel-about-potential
9. Mock, D. M., & Dyken, M. E. (2001). Safety assessment of biotin. International Journal of Toxicology, 20(Suppl 4), 1–12.
10. Debourdeau, P. M., Djezzar, S., Estival, J. L., Zammit, C. M., Richard, R. C., & Castot, A. C. (2001). Life-threatening eosinophilic pleuropericardial effusion related to vitamins B5 and H. The Annals of Pharmacotherapy, 35(4), 424–426.
11. Drugs..com. (2025). Biotin – Pregnancy/Lactation. In Drugs.com Natural Products Database. Retrieved May 27, 2025, from https://www.drugs.com/npp/biotin.html
12. National Library of Medicine. (n.d.). Biotin – Pregnancy & Breastfeeding. MedlinePlus Supplements. Retrieved May 27, 2025, from https://medlineplus.gov/druginfo/natural/313.html
13. Bistas, K. G., & Tadi, P. (2023). Biotin – Dosage & Administration. In StatPearls [Internet]. StatPearls Publishing.
14. Drugs..com. (2025). Biotin – Dosing Information. In Drugs.com Natural Products Database. Retrieved May 27, 2025, from https://www.drugs.com/npp/biotin.html
15. National Institutes of Health. (2022). Biotin: Fact Sheet for Consumers. Office of Dietary Supplements. Retrieved May 27, 2025, from https://ods.od.nih.gov/factsheets/Biotin-Consumer/