Finasteride on Cycle: Why It Often Does Nothing

📅 July 26, 2026 ⏱️ 2 min read ✍️ Team TPS

Finasteride works by blocking the conversion of testosterone to DHT, and on cycle, that creates a genuine conflict.

What it does

Finasteride inhibits 5-alpha-reductase, the enzyme converting testosterone into dihydrotestosterone. DHT is the androgen primarily responsible for pattern hair loss in those genetically susceptible.

Less DHT means slower hair loss. That part is well established and finasteride is a licensed medicine for it.

Why it does not solve hair loss on cycle

Here is the problem. Finasteride blocks conversion of testosterone. It does nothing about compounds that are already DHT derivatives.

Masteron, winstrol, anavar, primobolan and DHB do not require 5-alpha-reductase, they already are what finasteride exists to prevent. Taking it alongside them achieves nothing for hair.

The same applies to trenbolone, which is not reduced by that enzyme either.

Where it does help

On a testosterone-only cycle, where elevated testosterone means elevated DHT, finasteride is doing exactly what it is designed for.

The side effect question

Sexual side effects: reduced libido, erectile difficulty: are the well-known concern, and while the incidence in trials is low, the reports are persistent enough that they deserve to be taken seriously rather than dismissed.

DHT is also involved in libido and wellbeing, so suppressing it on a cycle where you are already managing hormones can compound other problems. If libido drops, it becomes one more variable in a picture that already includes oestrogen and prolactin. See cabergoline and prolactin.

Where it fits

Genetic hair loss, on a testosterone base, in someone who has weighed the side effect question. Not a fix for DHT-derivative compounds, and worth discussing with a doctor given it is a licensed medicine.

Supplied for research purposes only. Not medical advice.