Most men come into a hair-loss conversation already partway down a Reddit thread. They have heard the names. They want to know which one to take, in what order, and whether to stack them.
The honest answer is that these three medications do not compete. They work on different parts of the same problem, and the men who do best on hair-loss therapy usually use two of them together.
What is androgenetic alopecia?
Androgenetic alopecia is the genetic sensitivity of scalp follicles to dihydrotestosterone (DHT). DHT binds to receptors on follicles at the crown and hairline, miniaturizing them over successive growth cycles until the hair shaft is too fine to cover the scalp.
The pattern is hormonal, but the treatment splits into two strategies. You can lower the DHT signal at the follicle (finasteride and dutasteride). Or you can stimulate the follicle directly (minoxidil). Both work. The mechanisms are independent.
How do finasteride and dutasteride work?
Both are 5-alpha reductase (5AR) inhibitors. 5AR is the enzyme that converts testosterone to DHT. Block the enzyme, lower the DHT, slow or reverse miniaturization.
The difference is which isoforms of 5AR they block:
| Drug | 5AR isoforms blocked | Scalp DHT reduction | Typical dose |
|---|---|---|---|
| Finasteride | Type II only | About 60 to 70% | 1 mg oral daily |
| Dutasteride | Type I and Type II | About 90% | 0.5 mg oral daily |
In a head-to-head trial of 917 men, dutasteride 0.5 mg outperformed finasteride 1 mg on hair-count and global photographic assessment at 24 weeks. The trade is a longer half-life (about 5 weeks for dutasteride versus 6 to 8 hours for finasteride) and a slightly higher rate of sexual side effects in some studies.
Finasteride is the default starting point. Dutasteride is where men move when finasteride alone is not enough, or when the loss pattern is aggressive.
How does minoxidil work?
Minoxidil is not a hormone blocker. It is a vasodilator that was discovered as a hair-growth drug by accident. The current best understanding is that it widens dermal blood vessels around the follicle, opens potassium channels in follicle cells, and shortens the resting (telogen) phase of the hair cycle so more follicles cycle into active growth.
It comes in two forms:
- Topical minoxidil (2% or 5% solution or foam, applied twice daily). FDA approved. Local effect. Side effects are mostly scalp irritation and an early shedding phase.
- Oral minoxidil (1.25 to 5 mg daily). Off-label for hair loss. Systemic effect. Better adherence than topical because it is one pill instead of a twice-daily ritual. Side effects include facial hair growth, mild fluid retention, and rarely lower blood pressure.
The trial data for low-dose oral minoxidil in androgenetic alopecia has grown substantially over the last five years. It is now a reasonable first-line option, particularly for men who will not stick with a twice-daily topical.
How do they stack?
A 5AR inhibitor plus minoxidil is the standard combination. They work on different mechanisms, and the effect is additive rather than redundant.
A typical protocol looks like one of these:
- Finasteride 1 mg daily plus topical minoxidil 5% twice daily.
- Finasteride 1 mg daily plus oral minoxidil 2.5 mg daily.
- Dutasteride 0.5 mg daily plus oral minoxidil 2.5 mg daily (more aggressive loss).
Adding a third pillar (PRP, microneedling, low-level laser) is reasonable but lower yield than getting the first two right. We cover that in PRP, microneedling, and the adjunct stack.
Side effects of each
Finasteride. Sexual side effects (decreased libido, erectile dysfunction, decreased ejaculate volume) occur in roughly 1 to 5% of men in trials. Most resolve on cessation or are transient on continued use. Gynecomastia and mood changes are less common. We cover the full picture in finasteride side effects.
Dutasteride. Similar side-effect profile to finasteride, modestly more frequent in some studies. The longer half-life means side effects, if they occur, take longer to wash out.
Minoxidil. Topical: scalp irritation, early shedding (week 2 to 8, normal and self-limited). Oral: facial hair growth (common in higher doses), fluid retention, occasional postural blood-pressure drop. Cardiac effects are rare at the doses used for hair loss but are why a baseline assessment matters before starting.
How long does it take to work?
The hair cycle is slow. Useful timelines:
- Months 1 to 3. Often a shedding phase, particularly on minoxidil. This is older hairs being pushed out by new growth underneath. Normal.
- Months 3 to 6. Early thickening. Hairs at the periphery of the thinning zone become visibly denser.
- Months 6 to 12. Most of the visible regrowth you will get. Photographs at month 12 versus baseline tell the real story.
- Year 2 and beyond. Maintenance phase. Stopping treatment returns you to your genetic trajectory within 6 to 12 months.
The full week-by-week breakdown is in the hair regrowth timeline.
What the clinician actually checks
Before we prescribe, we do not assume the loss is purely androgenic. About one in five men we evaluate has a secondary contributor: low ferritin, suboptimal thyroid, vitamin D deficiency, or telogen effluvium from a stressor 3 to 4 months prior. Treating those changes the outcome.
Where Vane lands
A 5AR inhibitor is the foundation. Minoxidil is the accelerant. Most men do best on both. The choice between finasteride and dutasteride, oral and topical minoxidil, is a clinical conversation, not a default.
If you are considering starting, the right move is a panel and a photograph, not a prescription off a quiz.
