Luteinising Hormone (LH) is a key player in the endocrine system – particularly when it comes to testosterone production, fertility, and the hormonal feedback loop that governs reproductive health in both men and women. Produced by the anterior pituitary gland, LH stimulates the Leydig cells in the testes to produce testosterone. Without LH, natural testosterone synthesis grinds to a halt.
For women, LH plays a central role in the menstrual cycle, triggering ovulation and supporting the production of progesterone.
How LH Works in the Body
In men, LH acts like the “on switch” for testosterone. Here’s how the loop works:
GnRH stimulates the pituitary to release LH and FSH.
LH stimulates Leydig cells in the testes to produce testosterone.
Testosterone feeds back to the hypothalamus and pituitary to regulate LH production.
If testosterone levels drop (e.g. due to castration, suppression, or chemical intervention), the body usually increases LH secretion to compensate.
LH Suppression and SARMs: What’s the Connection?
SARMs (Selective Androgen Receptor Modulators) are often touted as a “safer” alternative to anabolic steroids. They work by binding to androgen receptors in muscle and bone tissue – promoting growth while theoretically sparing other organs. However, SARMs still activate negative feedback loops in the endocrine system.
“When SARMs are used at research-level dosages, they can suppress LH levels by tricking the body into thinking testosterone is already sufficient.” – Endocrinology of the aging prostate, 2021
The body senses elevated androgen activity and reduces LH and FSH output.
As a result, endogenous testosterone drops – sometimes dramatically.
This is why post-cycle therapy (PCT) is often recommended after SARM studies.
Low LH = Low Testosterone = Risk of Hypogonadism
A sustained drop in LH can lead to hypogonadotropic hypogonadism, where the testicles no longer receive enough stimulation to produce testosterone. Symptoms may include:
Low libido
Erectile dysfunction
Mood swings and fatigue
Loss of muscle mass
Infertility (due to reduced spermatogenesis)
Testicular Atrophy
While SARMs are selective, they are not invisible to the endocrine system.
“Even supposedly non-suppressive SARMs like Ostarine have been observed to reduce LH and FSH levels in clinical models.” – Journal of Clinical Endocrinology & Metabolism, 2020
Can LH Be Restored After SARMs?
Yes – but it depends on the individual, the SARM used, dosage, and duration. In most cases, LH rebounds naturally over several weeks once the SARM is discontinued. However, in more pronounced suppression cases, a PCT protocol using Clomiphene or Enclomiphene may be advised to stimulate LH production.
Clomiphene works by blocking estrogen receptors in the hypothalamus, triggering increased GnRH and LH.
Enclomiphene, the active isomer, is even more targeted and is used in clinical settings for male infertility, but has concerns about the effect of Enclomiphene on the Libido
Key Takeaways
LH (Luteinising Hormone) is essential for natural testosterone production.
Different SARM types can suppress LH, even though they are selective.
Prolonged LH suppression may result in low testosterone and fertility issues.
Post-cycle recovery – with or without PCT – may help reboot LH levels.
Victoria Atkinson is a freelance science journalist based in York. Victoria specialises in chemistry and its interface with the natural and human-made worlds, and has written for Chemical and Engineering News, Live Science, Physics World and Technology Networks. Victoria was formerly a science content developer at the University of Oxford and a member of the Chemistry World editorial team, and was nominated for the Association of British Science Writers Newcomer of the Year award in 2023.
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TL;DR Yes, authorised clinical studies and preclinical trials suggest that SARMs can reduce testicular size, primarily through suppression of luteinizing hormone (LH) and testosterone production. This testicular shrinkage is generally temporary and reversible in post-trial recovery periods, but highlights the need for careful hormonal monitoring in clinical settings. Key Takeaways SARMs: Targeted Action, Systemic Impact …
Meet MK-677, also known as Ibutamoren. It’s not a SARM. Let’s get that out of the way early. It merely loiters in the same online forums, gets mistaken for one due to guilt by association, and is occasionally found wearing a hoodie that says “anabolic.” But scientifically? It’s a growth hormone secretagogue. A fancy term …
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What Is LH (Luteinising Hormone) and how it relates to SARMs
By Victoria Atkinson, DPhil
Published · Updated · 3 min read
Luteinising Hormone (LH) is a key player in the endocrine system – particularly when it comes to testosterone production, fertility, and the hormonal feedback loop that governs reproductive health in both men and women. Produced by the anterior pituitary gland, LH stimulates the Leydig cells in the testes to produce testosterone. Without LH, natural testosterone synthesis grinds to a halt.
For women, LH plays a central role in the menstrual cycle, triggering ovulation and supporting the production of progesterone.
How LH Works in the Body
In men, LH acts like the “on switch” for testosterone. Here’s how the loop works:
If testosterone levels drop (e.g. due to castration, suppression, or chemical intervention), the body usually increases LH secretion to compensate.
LH Suppression and SARMs: What’s the Connection?
SARMs (Selective Androgen Receptor Modulators) are often touted as a “safer” alternative to anabolic steroids. They work by binding to androgen receptors in muscle and bone tissue – promoting growth while theoretically sparing other organs. However, SARMs still activate negative feedback loops in the endocrine system.
Here’s what typically happens:
Low LH = Low Testosterone = Risk of Hypogonadism
A sustained drop in LH can lead to hypogonadotropic hypogonadism, where the testicles no longer receive enough stimulation to produce testosterone. Symptoms may include:
While SARMs are selective, they are not invisible to the endocrine system.
Can LH Be Restored After SARMs?
Yes – but it depends on the individual, the SARM used, dosage, and duration. In most cases, LH rebounds naturally over several weeks once the SARM is discontinued. However, in more pronounced suppression cases, a PCT protocol using Clomiphene or Enclomiphene may be advised to stimulate LH production.
Key Takeaways
Victoria Atkinson, DPhil · Freelance
Freelance science journalist
Victoria Atkinson is a freelance science journalist based in York. Victoria specialises in chemistry and its interface with the natural and human-made worlds, and has written for Chemical and Engineering News, Live Science, Physics World and Technology Networks. Victoria was formerly a science content developer at the University of Oxford and a member of the Chemistry World editorial team, and was nominated for the Association of British Science Writers Newcomer of the Year award in 2023.
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