**Biotin** at 10,000mcg per serving is double the top of the studied supplement range (1,000–5,000mcg), but the clinical reality is that biotin supplementation primarily helps people with an actual deficiency or brittle nail syndrome. If you're not deficient, the research supporting hair and nail benefits is thin — regardless of dose. The D-Biotin form is the standard bioactive version, so no concerns there.

**Zinc** at 10mg falls short of the 15–30mg range used in clinical research for immune and skin support, and it's delivered as zinc citrate — a decent but not top-tier form. **Selenium** is dosed at just 55mcg (the bare RDA), which is roughly half the 100–200mcg range studied for thyroid and antioxidant benefits, and uses sodium selenite — an inorganic form your body retains less efficiently.

The biggest gap: both supporting minerals are underdosed for therapeutic benefit, so you're essentially getting a high-dose biotin supplement with token amounts of zinc and selenium. If immune or thyroid support matters to you, you'd need to supplement those minerals separately.