What is the difference between A5 and A15?Updated 17 hours ago

Which One Is Right for Me?

The HairIQ™ assessment is built to answer this: it routes between strengths based on your stage of loss, treatment history, and clinical fit. That said, here is the general guidance our physicians use:

A5: Everyday Regrowth · 5% minoxidil

• Best for early to moderate thinning
• A simple entry point into topical treatment
• Good for prevention or maintaining results
• Uses the FDA-approved 5% strength

A15: Extra Strength Regrowth · 15% minoxidil (Best Seller)

• Best for moderate to advanced thinning
• 3× the concentration of standard 5% formulas
• Designed for people who need more than baseline support, or who didn't see results from a 5% formula
• Still applied the same way as A5

Why Concentration Matters, and Why 15% Is Hard to Make

Minoxidil is dose-dependent: within safe limits, more active reaching the follicle means more benefit. Most formulas stop at 5%, and many that try to go higher stop at 6–7%, because getting more minoxidil to actually dissolve and stay stable in a topical solution is genuinely difficult. A15 delivers 150 mg/mL of minoxidil versus 50 mg/mL in a standard 5% formula. The breakthrough isn't just the number on the label: it's keeping that much active soluble and stable so the scalp can absorb more of it from the same amount of solution. (Your scalp can only absorb so much liquid, so concentration is what lets you deliver more in each application.)

Why Some People Don't Respond to Standard Minoxidil

Minoxidil is a prodrug: it only works after your body converts it into its active form, minoxidil sulfate, using an enzyme called sulfotransferase. An estimated 40–50% of people are "non-responders" because they don't produce enough of this enzyme, so standard minoxidil never fully activates on their scalp. Our formulas use tretinoin, which supports that conversion and improves how well the actives penetrate the skin, and the minoxidil itself is micronized for better delivery: two reasons A15 can work for people a 5% formula didn't.

Both A5 and A15 also include the ARB™ complex (which blocks DHT at the follicle) and a supporting blend of caffeine, niacinamide, adenosine, and biotin. ARB™ addresses the root cause, the DHT signal restricting blood flow at the follicle, while minoxidil supports circulation, so they reinforce each other rather than working alone.

If You Used Our Older Topicals

Our topical formulas have been upgraded. The prescription lineup still includes our proprietary ARB™ technology, but it has been meaningfully improved:

• We now use tretinoin in place of retinol
• Micronized minoxidil, along with additional formulation improvements designed to support follicle health and ingredient delivery
• For the first time, you may have the option to add topical finasteride or topical dutasteride directly into your formula

The strengths you know are still here: 5% and 15% extra-strength. Being prescription-compounded is what unlocks the additions the old over-the-counter bottles legally could not carry.

What if I Need a DHT Blocker Too?

A5 and A15 do not contain finasteride or dutasteride. If your physician recommends adding a topical DHT blocker, the variants are:

• A5F or A15F: adds finasteride
• A5D or A15D: adds dutasteride (more potent DHT suppression)

See our guide on the difference between finasteride and dutasteride for more detail.