Testosterone converts to DHT through an enzyme called 5-alpha reductase, and blocking that enzyme is the most direct way to reduce DHT levels. You can do this with prescription medications, topical treatments, or certain natural compounds, each with different levels of effectiveness. The right approach depends on why you want to lower DHT and how much reduction you actually need.
How Your Body Makes DHT
Inside your cells, an enzyme called 5-alpha reductase takes testosterone and converts it into dihydrotestosterone (DHT), a more potent form of the hormone. DHT binds to the same receptors as testosterone but does so more strongly, which is why it drives specific effects like prostate growth and hair follicle miniaturization in people genetically prone to pattern hair loss.
There are three versions of this enzyme spread throughout the body. One type is concentrated in the prostate, another is found in skin and hair follicles, and a third is present almost everywhere, including the kidneys, liver, and skeletal muscle. This wide distribution is why completely eliminating DHT conversion isn’t realistic or desirable. DHT plays roles in wound healing, neurological function, and sexual health. The goal for most people is targeted reduction, not elimination.
Prescription DHT Blockers
Oral medications are the most powerful option. Finasteride, the drug most commonly prescribed for male pattern hair loss, blocks one version of the 5-alpha reductase enzyme and reduces blood DHT levels by roughly 70%. For hair loss, it’s taken at 1 mg daily. Dutasteride blocks two versions of the enzyme and is significantly more aggressive, suppressing DHT by about 93 to 95%. Dutasteride is FDA-approved for enlarged prostate and prescribed off-label for hair loss in some cases.
In a head-to-head comparison of 917 men with hair loss, dutasteride at 0.5 mg daily produced greater increases in hair count and hair thickness than finasteride at 12 and 24 weeks. That extra potency comes with a trade-off: because dutasteride suppresses more DHT across more tissue types, it stays in the body much longer and carries a broader hormonal impact.
Sexual side effects are the main concern with both drugs. Clinical data puts the rate of sexual side effects with finasteride between about 2% and 4%, with erectile difficulty being the most common, followed by changes in ejaculation and reduced libido. In long-term studies, the incidence of each side effect dropped to 0.3% or less by the fifth year of treatment, and side effects resolved in most men who continued therapy. Reports of persistent sexual side effects after stopping the drug exist but appear to be rare, and the actual incidence remains unknown.
Topical Finasteride
If you want to lower DHT at the scalp without as much systemic exposure, topical finasteride is an increasingly popular option. Applied directly to the scalp, it reduced scalp DHT by 50 to 70% in clinical studies while still producing meaningful hair regrowth. One study found that topical finasteride actually reduced plasma DHT by 68 to 75%, comparable to the 62 to 72% reduction from oral tablets, though researchers noted less overall drug absorption with the topical form. The most common side effects were skin irritation and itching at the application site, with no patients in those studies reporting sexual dysfunction.
Natural 5-Alpha Reductase Inhibitors
Several plant-based compounds inhibit the same enzyme that prescription drugs target, though with less potency and less consistent results.
- Saw palmetto is the most studied natural option. In lab settings, saw palmetto extract inhibited the type II 5-alpha reductase enzyme by 76% at certain concentrations. Clinical results in humans, however, have been mixed. Some trials using 320 mg daily showed benefit for prostate symptoms, while others, including a well-designed study of 225 men and an escalating-dose trial of 369 patients going up to 960 mg daily, found no significant difference from placebo. The inconsistency likely comes from differences in how the extracts are prepared, since the active compounds vary between products.
- Pumpkin seed oil is rich in phytosterols and essential fatty acids. Animal studies suggest it may inhibit 5-alpha reductase, and a randomized, placebo-controlled trial in men with hair loss showed increased hair count after supplementation. The exact mechanism isn’t fully confirmed in humans.
- Green tea polyphenols have demonstrated 5-alpha reductase inhibition in laboratory studies. The active compounds in green tea appear to reduce the enzyme’s activity, though human clinical data specifically measuring DHT reduction is limited.
Natural options are best understood as mild modulators, not replacements for prescription treatment. If you’re dealing with significant hair loss or a diagnosed prostate condition, these supplements alone are unlikely to produce the 70 to 95% DHT reduction that medications deliver.
How Exercise Affects DHT
Physical activity does influence DHT levels, but not in the direction most people hope. A randomized trial found that exercise significantly increased DHT levels. Acute bouts of both resistance training and aerobic exercise can temporarily raise testosterone and its derivatives, including DHT, though the magnitude varies by exercise type, intensity, and age. This doesn’t mean you should avoid exercise to control DHT. The elevations are transient, and the overall health benefits far outweigh any short-term hormonal fluctuation. It does mean, however, that exercise is not a tool for lowering DHT.
Newer Approaches That Skip the Enzyme Entirely
A different strategy bypasses 5-alpha reductase altogether and instead targets the androgen receptor, the protein that DHT activates inside your cells. Even if DHT is present, blocking or destroying its receptor prevents it from triggering hair loss or prostate growth.
Pyrilutamide is a topical androgen receptor blocker currently in phase II clinical trials. Applied to the scalp, it blocks DHT from binding to receptors in hair follicles. Early results showed significant increases in hair count in men and improvements in both hair thickness and count in women, with only mild local irritation and no serious side effects. Another compound called GT20029 takes a more aggressive approach: rather than just blocking the receptor, it tags it for destruction by the cell’s own recycling machinery. This compound is also in phase II trials for male pattern hair loss.
These therapies are not yet available outside of clinical trials, but they represent a fundamentally different way to address DHT’s effects without altering your hormone levels at all.
Choosing the Right Strategy
Your best approach depends on why you’re trying to reduce DHT and how aggressively you need to do it. For male pattern hair loss that’s still in early stages, topical finasteride offers localized DHT reduction with a lower side-effect profile. For more advanced hair loss or prostate concerns, oral finasteride provides reliable 70% DHT suppression. Dutasteride’s 93% suppression is reserved for cases where finasteride hasn’t been sufficient, given its broader hormonal impact.
Natural supplements like saw palmetto or pumpkin seed oil can be reasonable additions to a broader strategy, particularly if you’re looking for mild support or aren’t ready for prescription options. Stacking a natural inhibitor on top of a prescription one doesn’t have strong clinical evidence behind it, though some people do combine them.
One important consideration: suppressing too much DHT isn’t without consequences. Your body maintains a specific ratio of testosterone to DHT for a reason. In healthy men, that ratio typically falls between about 8:1 and 16:1. Pushing DHT levels extremely low can affect sexual function, mood, and neurological health. The goal is reducing DHT enough to address your specific problem, not driving it as close to zero as possible.