How Testosterone Cypionate Affects DHT

Dihydrotestosterone is produced from testosterone by 5-alpha reductase, which exists in two main isoforms: type 1, expressed in skin, sebaceous glands and liver, and type 2, expressed in hair follicles, prostate and genital skin. DHT binds the androgen receptor with roughly three to five times the affinity of testosterone and dissociates more slowly, making it a substantially more potent androgen at the receptor.

1. Substrate-driven conversion: More circulating testosterone means more DHT. The conversion is not saturable at the concentrations produced by TRT, so DHT tracks testosterone dose.

2. Route of administration matters, and this is the one real distinction: Transdermal gels are applied to skin, which is rich in type 1 5-alpha reductase, and produce disproportionately high DHT relative to testosterone. Injectable esters bypass that skin conversion step and produce a lower DHT to testosterone ratio. Schulte-Beerbühl and Nieschlag (1980, PMID 7353699) measured DHT alongside testosterone after injection of both testosterone enanthate and testosterone cypionate, and the two esters are treated as equivalent in clinical guidelines.

3. Peak concentration drives peak DHT: A large infrequent injection produces a high testosterone peak and a correspondingly high DHT peak.

4. What DHT actually does: it is responsible for much of the androgenic rather than anabolic effect profile, including sebaceous gland activity and acne, body and facial hair growth, prostate stimulation, and follicular miniaturisation in men carrying the genetic susceptibility to androgenetic alopecia. It also contributes meaningfully to libido, which is why men who suppress it pharmacologically sometimes regret it.

Cypionate versus enanthate: no difference.

Replacement doses (100-200 mg/week, injectable):

• DHT typically rises 1.5 to 2.5 times baseline, roughly in proportion to the rise in total testosterone
• The DHT to testosterone ratio stays broadly stable on injectables

Transdermal comparison:

• Gels commonly produce DHT elevations well beyond what the accompanying testosterone rise would predict, because of skin 5-alpha reductase activity. If DHT-mediated side effects are the concern, injectables are the better route.

Supraphysiological doses (300-600+ mg/week):

• DHT rises proportionally. There is no ceiling within the range used in practice.

With a 5-alpha reductase inhibitor (finasteride, dutasteride):

• Finasteride inhibits type 2 primarily and reduces serum DHT by roughly 70%
• Dutasteride inhibits both isoforms and reduces it by more than 90%
• Both raise circulating testosterone slightly by reducing conversion

Timing: DHT tracks testosterone within days of a dose change.

Sensitivity of the assay: DHT immunoassays are unreliable at low concentrations. If a result is going to drive a treatment decision, an LC-MS/MS method is worth requesting.

Baseline DHT is optional for most men and useful for some:

• Worth measuring if you have a family history of male pattern baldness, existing hair thinning, significant acne, or prostate symptoms.
• Not necessary as routine monitoring in an asymptomatic man.

On protocol:

• Check at 6 to 8 weeks alongside total testosterone if DHT-mediated symptoms appear.
• Interpret DHT as a ratio to total testosterone rather than as an absolute number. A high DHT alongside a high testosterone is proportional; a high DHT alongside a normal testosterone suggests unusually high 5-alpha reductase activity or a transdermal route.

Symptoms to watch:

• Accelerated scalp hair shedding, particularly at the temples and crown
• Acne, especially on the back and shoulders
• Oily skin and scalp
• Increased body hair
• Urinary symptoms, though prostate volume changes on TRT are generally small

Prostate monitoring: PSA at baseline and at 3 to 12 months is standard practice on testosterone therapy regardless of DHT.

If hair loss is the concern:

• The susceptibility is genetic. Testosterone does not cause androgenetic alopecia in men who do not carry it, and it accelerates it in men who do.
• Topical finasteride, and topical minoxidil, reduce systemic exposure compared with oral finasteride while addressing the follicle directly.
• Oral finasteride at 1 mg/day reduces serum DHT by roughly 70% and is effective, but a minority of men report persistent sexual and mood side effects. Discuss this honestly with a prescriber before starting.
• Suppressing DHT systemically removes an androgen that contributes to libido and wellbeing. This is a trade-off, not a free intervention.

If acne is the concern:

• Reducing the peak concentration through more frequent injections often helps.
• Standard dermatological treatment works normally.

Do not switch from cypionate to enanthate to reduce DHT. There is no difference. Switching from a transdermal gel to an injectable ester genuinely does reduce the DHT to testosterone ratio, and that is a real option.

Further reading: TRT, hair loss and DHT