Seeing your lab report show:
FSH: <0.05 mIU/mL
can instantly trigger panic.
Many enhanced athletes immediately think:
- “My fertility is gone.”
- “My testicles are permanently shut down.”
- “I’ve damaged my endocrine system.”
But here’s the reality:
👉 If you are on an anabolic steroid cycle, FSH zero is usually suppression — not permanent damage.
The key is understanding physiology before reacting emotionally to lab numbers.
What Is FSH and Why Does It Matter?
FSH (Follicle Stimulating Hormone) is produced by the pituitary gland and plays a critical role in male reproductive health.
In men, FSH:
- Stimulates spermatogenesis (sperm production)
- Supports testicular function
- Works alongside LH in regulating fertility
While LH stimulates testosterone production, FSH primarily drives sperm production inside the testes.
Both hormones are controlled by the Hypothalamic–Pituitary–Gonadal (HPG) axis.
Why Does FSH Drop to Zero on Cycle?
When you introduce external androgens such as:
- Testosterone (Test E, Test P, Sustanon)
- Trenbolone
- Nandrolone
- Oral anabolic steroids
Your brain detects high circulating androgen levels.
In response:
- The hypothalamus reduces GnRH release.
- The pituitary reduces LH and FSH secretion.
- Natural testosterone production shuts down.
- Sperm production declines.
This process is called negative feedback suppression.
The body assumes:
“There is enough testosterone in circulation. No need to produce more.”
As a result, LH and FSH can drop to near zero.
This is expected.
This is suppression.
It is not automatically permanent damage.
Is FSH Zero Dangerous?
It depends entirely on context.
If You Are Currently On Cycle
FSH being extremely low or undetectable is normal physiology.
You are using suppressive compounds.
The axis is intentionally shut down.
Trying to “fix” FSH during active suppression makes no biological sense.
If You Are Off Cycle
Now the situation changes.
FSH may become concerning if:
- You are 8–12 weeks post cycle
- You have completed PCT
- LH begins recovering
- But FSH remains extremely low
- Semen volume is poor
- Testicular size has not returned
That is when structured endocrine recovery becomes necessary.
They see FSH = 0 while still on cycle and immediately:
- Add Clomid
- Add HCG randomly
- Add HMG without understanding indication
- Crash estrogen trying to “restart” the axis
This often creates more hormonal instability.
You cannot restart a suppressed axis while still using suppressive androgens.
That is physiology — not opinion.
HCG vs FSH: Common Confusion
One of the most misunderstood areas in enhanced bodybuilding is the belief that HCG raises FSH.
It does not.
HCG mimics LH, not FSH.
HCG:
- Stimulates Leydig cells
- Helps maintain intratesticular testosterone
- Supports testicular size during cycle
But it does not directly stimulate spermatogenesis.
If fertility support is required post-cycle, HMG (which contains FSH activity) may be considered — but only in structured, medically guided recovery situations.
Blindly adding fertility drugs without indication is poor protocol design.
When FSH Zero Becomes a Red Flag
FSH near zero becomes more concerning in scenarios like:
- Long-term blasting with no recovery phases
- No HCG support during extended cycles
- High prolactin combined with suppressed gonadotropins
- Severe testicular atrophy
- Months off-cycle with no hormonal rebound
In these cases, proper evaluation should include:
- LH
- Total and free testosterone
- Estradiol
- Prolactin
- Semen analysis (if fertility is a goal)
Lab interpretation should never be isolated to one hormone.
Hormones function as a system.
Suppression vs Permanent Damage: Know the Difference
Suppression:
Temporary shutdown due to exogenous hormones.
Damage:
Failure of recovery after adequate time and proper post-cycle protocol.
Most enhanced athletes experience suppression.
True irreversible damage is far less common than online forums suggest — especially when cycles are structured responsibly.
The Smarter Question to Ask
Instead of asking:
“Why is my FSH zero?”
Ask:
- How long have I been suppressed?
- Did I plan recovery before starting the cycle?
- Was HCG used appropriately?
- Is my prolactin controlled?
- Am I monitoring labs correctly?
Enhanced performance requires structured thinking — not emotional reactions.
Final Takeaway
If your FSH is zero on cycle:
Remain calm.
Understand negative feedback.
Plan recovery properly.
Anabolic suppression is predictable physiology — not a mystery.
The real risk is not suppression.
The real risk is poor planning.
Frequently Asked Questions (FAQ)
Is FSH zero normal on a testosterone cycle?
Yes. FSH zero on cycle is typically normal suppression caused by exogenous testosterone or anabolic steroids. When external androgens are introduced, the brain reduces LH and FSH production through negative feedback. This is expected physiology, not automatic damage.
Does HCG increase FSH levels?
No. HCG mimics LH, not FSH. It stimulates testosterone production inside the testes but does not directly stimulate spermatogenesis. If FSH support is required post-cycle, HMG (which contains FSH activity) may be considered under structured recovery protocols.
Can steroids permanently damage fertility?
Most cases involve temporary suppression, not permanent damage. Fertility issues become concerning if FSH and LH fail to recover months after stopping steroids and completing a proper post-cycle therapy (PCT). Structured recovery significantly reduces long-term risks.
How long does FSH take to recover after a cycle?
Recovery varies depending on:
- Length of cycle
- Compounds used
- Whether HCG was used during cycle
- Quality of PCT
- Individual endocrine sensitivity
In many athletes, FSH begins improving within 4–12 weeks post-cycle. Longer or repeated suppression may extend recovery time.
Should I run Clomid during cycle if FSH is zero?
No. Running Clomid while still on suppressive compounds is biologically ineffective. The hypothalamus will remain suppressed as long as exogenous androgens are present. Recovery medications are meant for post-cycle, not during active suppression.
When should I worry about low FSH?
Low FSH becomes concerning if:
- You are fully off cycle
- PCT is complete
- Several weeks have passed
- LH has recovered but FSH remains very low
- Fertility symptoms persist
At that stage, deeper endocrine evaluation may be required.
