Testosterone causes acne by ramping up oil production in your skin and changing how skin cells behave inside hair follicles. The process involves several steps, from hormone conversion to bacterial growth, and it explains why breakouts peak during puberty, affect some people more than others, and can appear as a side effect of hormone therapy.
How Testosterone Becomes a Stronger Hormone in Your Skin
Testosterone itself isn’t the main driver of acne at the skin level. Your oil glands contain an enzyme called 5-alpha reductase that converts testosterone into a more powerful hormone called DHT (dihydrotestosterone). DHT binds to hormone receptors in your skin two to five times more strongly than testosterone does, and it’s roughly ten times more potent at activating those receptors. So even a normal amount of testosterone in your blood can produce a significant hormonal signal once your skin converts it to DHT.
Research on oil glands shows that 5-alpha reductase is two to four times more active than the other enzymes competing for testosterone in those glands. The net result is that your oil glands preferentially funnel testosterone toward DHT production, making them essentially small hormone-processing factories. This is why acne concentrates on the face, chest, and back, where oil glands are largest and most dense, rather than spreading evenly across the body.
A telling piece of evidence: males born with a genetic deficiency of 5-alpha reductase develop significantly less acne despite having normal testosterone levels. Without the enzyme to convert testosterone into DHT, the skin simply doesn’t get the stronger hormonal signal.
What DHT Does to Your Oil Glands
Once DHT activates receptors in oil gland cells, those cells produce more sebum, the waxy, oily substance that normally keeps skin moisturized. In moderate amounts, sebum is protective. But when production increases beyond what your pores can handle, the excess oil sits inside the follicle and creates the conditions for a breakout.
The composition of that oil also shifts. Higher androgen activity changes the balance of fatty acids in sebum, and these altered fats are more likely to irritate the lining of the follicle and trigger inflammation. So it’s not just that you produce more oil. The oil itself becomes more problematic.
How Blocked Pores Form
Excess oil is only half the equation. Testosterone and DHT also change the way skin cells mature inside hair follicles, through an indirect route. Androgens stimulate the connective tissue cells beneath your skin to release growth factors, which then alter how the lining cells of the follicle develop. Normally, these lining cells mature and shed in an orderly way, getting carried out of the pore by sebum. Under androgen influence, the cells don’t mature properly. They become stickier and accumulate inside the follicle instead of shedding.
This buildup of dead cells mixes with the excess sebum to form a plug. That plug is a comedone: a whitehead if the pore stays closed, a blackhead if it opens to the surface. Either way, oil and debris are now trapped beneath the skin.
Where Bacteria and Inflammation Fit In
A plugged, oil-filled follicle is an ideal environment for a bacterium called Cutibacterium acnes, which naturally lives on everyone’s skin. This bacterium feeds on sebum components and thrives when oil production increases. As C. acnes multiplies inside the blocked pore, it triggers your immune system to respond with inflammation, turning a simple clogged pore into a red, swollen pimple or, in more severe cases, a deeper cyst.
The inflammatory response can also damage surrounding tissue, which is how acne scars form. So the chain runs directly from testosterone, to DHT, to excess and altered sebum, to clogged pores, to bacterial overgrowth, to the visible inflammation you see on your skin.
Why Some People Are More Affected Than Others
Not everyone with the same testosterone level gets the same acne. Genetics play a major role, particularly in how sensitive your androgen receptors are. A study of Han Chinese men found that those with acne had shorter repeat sequences in a specific region of the androgen receptor gene (an average of about 20.6 repeats versus 22.1 in men without acne). Shorter repeats make the receptor more responsive to DHT, meaning the same hormone level produces a stronger signal in the skin.
Interestingly, this genetic link was significant in men but not in women, suggesting that female acne may involve different or additional mechanisms, such as fluctuations in estrogen and progesterone that change relative androgen activity throughout the menstrual cycle. Your skin’s enzyme activity matters too. People with more 5-alpha reductase in their oil glands will convert more testosterone to DHT locally, even if their blood hormone levels look completely normal on a lab test.
Puberty and Acne Timing
Acne typically appears when testosterone production surges for the first time. For boys, puberty generally begins between ages 9 and 14. For girls, it starts between ages 8 and 13. By the time puberty reaches its later stages, around ages 10 to 15, oilier skin and acne are common features. This timing maps directly to when the gonads begin releasing significant amounts of sex hormones in response to brain signals.
The reason acne often improves in the late teens and early twenties isn’t that testosterone drops. It’s that the skin gradually adapts: oil gland activity stabilizes, and the immune system’s response to C. acnes becomes less aggressive. For some people, though, this adjustment never fully happens, and acne persists into adulthood.
Acne From Testosterone Therapy
If you’re on testosterone replacement therapy, acne is the most common skin side effect, reported in roughly 1% to 10% of patients depending on the formulation. Oral testosterone tends to produce the lowest incidence (around 0.6%), while injectable and topical forms can push rates higher. The mechanism is the same one at work during puberty: more circulating testosterone means more DHT production in the skin, more sebum, and more opportunities for pores to clog.
Acne from testosterone therapy often shows up in the first few months as your body adjusts to higher hormone levels. It tends to concentrate on the back and shoulders, not just the face. For many people it stabilizes over time, but if it doesn’t, adjusting the dosage or switching the delivery method can help reduce the severity without stopping treatment entirely.
The Full Picture
Testosterone causes acne through a cascade, not a single event. Your skin converts testosterone into the more potent DHT, which simultaneously increases oil production, changes the composition of that oil, and disrupts normal cell turnover inside your pores. The resulting plugged, oil-rich follicle feeds bacteria that trigger inflammation. How severely this process affects you depends on your genetics, your skin’s enzyme activity, and how sensitive your androgen receptors are. That’s why two people with identical testosterone levels can have completely different skin.