Shaving your head might seem easier, but not everyone is ready for that look. If you’re losing more hair in the shower than you’re comfortable with, you’ve probably heard about finasteride. It’s been called a game-changer for male pattern baldness, but here’s what most guys don’t realize: not all finasteride works the same. There’s a whole conversation going on right now about whether popping a pill really does a better job than using a topical formula. And when it comes to doses, it’s not just about the milligrams—it’s about how much your body actually absorbs and how effectively it can crush that pesky DHT.
The Science Behind Finasteride Absorption
Here’s the deal—whether you swallow it or put it on your scalp, finasteride’s real job is to drop your dihydrotestosterone (DHT) levels. This hormone is public enemy number one for hair follicles. But your body handles each version differently. Pop a standard 1mg pill, and around 65-80% of it actually makes it into your bloodstream. That’s because oral pills get processed and absorbed through your gut, zipping right into systemic circulation.
But squirt a bit of topical finasteride onto your scalp, and it mostly stays near the roots, with a much smaller amount creeping into your blood. This means you get a concentrated effect where you want it (your hair) without flooding the rest of your body. One 2022 pharmacokinetic study out of Madrid measured blood DHT suppression after guys used topical 0.25% finasteride once daily: it cut scalp DHT by about 75%, but only dropped blood DHT by 25%. Compare that to the pill, which slashes both hair and blood DHT by nearly 70%.
Most manufacturers play it safe and use higher concentrations in topical forms to compensate for this localized effect. Absorption is also affected by your scalp’s “barrier” function – think thick skin, oily residue, or how much hair you’ve got left up top. Got dry skin or are already pretty bald? You may actually absorb more topically, but not nearly the same as through swallowing a pill.
How DHT Suppression Stacks Up: Oral vs Topical
It’s all about beating DHT. With daily 1mg oral finasteride, clinical trials say serum DHT drops by up to 70%, which is usually enough to either stop hair loss or trigger regrowth if you catch it early. That’s pretty straightforward. Topical? It’s more of a mixed bag, since formulas and dosing vary. Most topical studies use 0.25% daily (which is about 2.5mg per gram), but some go as low as 0.1% or as high as 1%.
Here’s what matters—topical finasteride generally lowers scalp DHT almost as much as the pill, but keeps your blood DHT closer to normal. For dudes worried about side effects like low libido or mood swings, that’s a selling point. But get this: some topical formulas barely budge blood DHT at all, while others come close to matching the oral pill. Brands play with ethanol, propylene glycol, and other stuff to boost absorption, but there’s no FDA standard, so you’re relying on what your pharmacy mixes up.
Still, side-by-side, the math looks something like this:
| Form | Dosage | Avg. Scalp DHT Suppression | Avg. Serum DHT Suppression |
|---|---|---|---|
| Oral | 1mg/day | ~70-75% | ~70% |
| Topical | 0.25% solution, 1ml/day | ~60-80% | ~25-50% |
Now, don’t get distracted by the numbers alone—the type of balding you’ve got, how fast it’s progressing, and your age seriously impact results. And if you want to look into other non-pill options, check this detailed resource for a finasteride equivalent for hair loss that breaks down alternatives in real-world terms.
Real-World Dosing: How to Measure Apples-to-Apples
Don’t fall into the trap of thinking “stronger must be better.” Just because topical versions use bigger concentrations (like 0.25% versus 1mg) doesn’t mean you’re absorbing more. Studies show only a fraction of topical finasteride crosses into systemic circulation. In one multicenter trial, after applying a standard 1mL squirt of 0.25% topical finasteride, men only absorbed enough to match about 0.2mg-0.3mg of the oral pill. So if you’re switching from oral to topical, or vice versa, you can’t do a straight mg-to-mg swap.
- If you’re using the generic oral tablet (1mg daily), that’s been the gold standard in most trials since 1997.
- Topical, meanwhile, works best at 0.25% in a standard 1mL dropper applied once a day. Anything much lower (like 0.025%) hasn’t performed well in peer-reviewed tests.
- Don’t overdo it hoping for bonus regrowth. Greasy hair, itchy scalp, and, yes, more absorbed systemically—especially with broken skin—can all happen if you’re heavy-handed with drops or foam.
It takes at least 3-6 months to see noticeable results regardless of the route. Dudes giving up after a month or two often regret quitting right before things kick off. That goes double if you’re combining with minoxidil, where the delayed reward is standard.
Side Effects and Safety: What’s Actually Different?
You’ve probably seen horror stories online about lost libido or even depression with the oral pill. Statistically, side effects actually affect a small percent of men—around 2-5% in big post-marketing studies. Most of these disappear after stopping the drug. But here’s the honest part: topical finasteride does appear to drop those risk numbers even lower.
Out of dozens of skin-based studies, very few bothered reporting issues beyond mild itching, redness, or occasional extra hair growth on the face or neck (that’s just from runoff—wipe your hands after applying). Blood DHT is less suppressed with topical, so the risk of sexual or mental side effects is probably much lower, but no study has had a long enough follow-up to say risk is zero.
If you’re nervous about side effects but desperate to stop your Widows Peak from turning into the Grand Canyon, topical is worth a shot. Still, talk to your doctor if you already have low testosterone or a history of mental health struggles—sometimes, even a little DHT drop can affect more than just your scalp.
For those prone to allergies or eczema, watch for propylene glycol and other skin irritants in the liquid. Sometimes switching to a foam or alcohol-free formula solves the problem.
Practical Tips and Common Questions About Finasteride Use
A few things guys never ask but always wonder about once they start:
- Will it mess with your blood test results? Oral finasteride can lower PSA (prostate-specific antigen) levels—handy to tell your doctor if you get screened for prostate cancer. Topical has much less effect, but mention it anyway.
- How bad is post-finasteride syndrome? It’s real, but thankfully rare; less common with topicals, but no one has ruled it out completely.
- Need to apply topical every day, exactly? Best to stay daily, but a missed day here and there isn’t disastrous because the drug hangs around in hair follicles for days.
- Combined with minoxidil: Double the effort, but not necessarily double the result. Still, combo therapy is king in aggressive hair loss cases.
- Is topical safe for beards? Not really studied in patchy beard fixers—use at your own risk.
- What about cost? Topicals are often pricier if compounded in a pharmacy, but costs are dropping with off-the-shelf formulations.
- Storage? Store both forms out of direct sunlight, and don’t leave the topical in a hot car or on a sunny window ledge. Stability matters for potency.
For the record, one real-world tip: take a picture once a month under the same bathroom lighting. You’ll go nuts trying to notice change otherwise—it’s slow progress but steady for most people.
Worried about which approach is best for you? There’s no universal answer. What matters most is finasteride dosing tailored to your hair loss stage, your risk tolerance, and whether side effects scare you more than thinning hair. Check with a knowledgeable doctor, and don’t be fooled by miracle claims in sketchy online ads. And, yeah, keep that hat handy for bad hair days—but with the right approach, you might not need it as often as you think.
Written by Guy Boertje
View all posts by: Guy Boertje