Is the subcutaneous (SQ) route effective for biotin administration?

Subcutaneous Route for Biotin Administration

The subcutaneous (SQ) route is not recommended for biotin administration in clinical practice; oral or intravenous routes should be used instead based on intestinal function and clinical context. 1

Recommended Routes of Administration

Oral Route (First-Line)

• Oral administration is the preferred route for biotin supplementation in patients with normal gastrointestinal function 1
• Standard oral dosing of 30 mcg/day in enteral nutrition (per 1500 kcal) is recommended 1
• For rapid replenishment in deficiency states, oral doses up to 10 mg/day may be used, even in malabsorption or short bowel syndrome 1
• Oral biotin has excellent safety profile with no established upper limit for toxicity 1

Intravenous Route (Alternative)

• IV administration should be used when intestinal function is compromised 1
• In parenteral nutrition, 60 mcg biotin per day should be provided 1
• For deficient PN-dependent patients, IV doses up to 200 mcg/day for 2-3 weeks may be required 1
• No adverse effects have been documented with IV administration of pharmacological doses up to 5 mg/day for prolonged periods 1

Why Subcutaneous Route Is Not Recommended

Lack of Clinical Evidence

• There is no guideline support or established clinical practice for subcutaneous biotin administration 1
• The ESPEN micronutrient guideline specifically states biotin can be administered "either orally, enterally or IV depending on the intestinal function" with no mention of subcutaneous route 1

Safety Concerns from Research

• One toxicology study found evidence of increased resorptions in rats receiving biotin by subcutaneous injection, with concomitant decreases in fetal, uterine, and placental weights 2
• While another mouse study found no differences with subcutaneous injection, the conflicting animal data and lack of human studies make this route inadvisable 2
• Intradermal injection (0.1 ml) in guinea pigs did not produce skin irritation, but this does not establish safety or efficacy for therapeutic subcutaneous dosing 2

Clinical Decision Algorithm

For biotin supplementation, choose route based on:

1. Normal GI function → Use oral route (30-60 mcg/day maintenance; up to 10 mg/day for deficiency) 1

2. Impaired GI function or malabsorption → Use IV route (60 mcg/day in PN; up to 200 mcg/day for severe deficiency) 1

3. Never use subcutaneous route → No clinical evidence, potential safety concerns, and established alternatives available 1, 2

Important Caveats

• Biotin interferes with laboratory assays including thyroid function, troponin, and other critical biomarkers—patients should discontinue biotin before laboratory testing 3
• Despite widespread use, there is no randomized controlled trial evidence supporting biotin for hair, skin, or nail conditions 4, 5, 3
• The subcutaneous route is well-established for other medications (opioids, myeloid growth factors, treprostinil) but has not been validated for biotin 1