An important precursor to Testosterone, Luteinizing Hormone (LH) is critical for sperm and testosterone production. It is one of the best predictors of overall testicular function and is a key hormone that useful in the evaluation of male fertility.
What is Luteinizing Hormone?
If you google LH, most of the articles you find will talk about the role of luteinizing hormone in ovulation. For women, a surge of LH is a trigger that causes the ovary to release the egg. If you’ve been trying to conceive, your wife may be monitoring her LH levels as a way to know exactly when her “fertile window” will occur. If she has trouble with ovulation, doctors may prescribe medications that help with ovulation. Many of these drugs help stimulate the body to produce more LH and its cousin hormone FSH (follicle stimulating hormone). If you are not trying to conceive, she may be on hormonal birth control pills. These pills prevent ovulation by blocking FSH and LH.
Less is written about the role in LH in men. While it may seem like a feminine hormone due to its role in ovulation, it is actually one of the manliest hormones in your body. You can think of LH as a tiny drill sergeant that commands the Leydig Cells in the testicle to produce testosterone. When LH is present, the Leydig Cells generate Testosterone, when it is not, they don’t. LH is commander and chief of your Testosterone and critically important for sperm production, muscle building and overall sexual health.
Male hormones have a cyclical nature to them. LH signals the testicle to produce Testosterone. In turn, Testosterone seeps out of the testicle and into the blood stream where it circulates around the body and is put to good use doing manly things like growing chest hair, making muscles big and your voice deep. The brain monitors blood testosterone levels, if they drop too low, it will send a signal to the pituitary gland to send out more LH to kick start testosterone production.
If testosterone is chronically high (as in the case when using steroids or other performance enhancers) the brain will shut down production of LH. When testosterone supplementation is stopped, men can experience a “crash” as T levels plummet but the brain lags in re-starting the machinery to generate LH.
To measure LH levels, men need to get a blood test done. Typically, doctors will order a blood test to measure a panel of hormones which usually includes FSH, LH and Testosterone. They may also add Estrodial and Prolactin which will provide additional information and insight into your hormonal health.
In a normal day, LH and Testosterone levels cycle from high to low. When getting a blood test done to measure hormone levels it is important to note the time of day that the test was performed to better understand the values.
Nearly all hormones are measured in relation to Testosterone level. Testosterone naturally peaks first thing in the morning (partially responsible for morning wood) For this reason, doctors prefer to measure hormones between 8-10am to get a snap shot of your hormone profile when Testosterone level is likely to be highest.
When preparing for a LH test there are a few things to make sure your doctor is aware of:
Current medications: Current or past use of testosterone supplements, anabolic steroids, clomid or other performance enhancers (If you are using something at the gym and aren’t quite sure what it is, you should bring it with you to the appointment).
Normal LH range for adult men: 1 – 10 mIU/mL
Different labs report different reference ranges based on the exact way that they perform the test. From a review of various lab reports, generally the agreed upon range should be somewhere between 1.0 and 2.0 on the low end and between 9.0 and 10.0 on the high end. Values lower than 1.0 or higher than 10.0 typically indicate some sort of problem.
For average men, LH typically falls somewhere between 4-7mIU/mL with drops and surges (about 6) throughout the day. Values below 4 and above 7 may be considered borderline and are useful to look at when compared to other hormone levels, particularly Testosterone and Prolactin.
Low T but Normal LH Levels
Interestingly, things that can temporarily impact testosterone production such as a varicocele, alcohol or obesity do not tend to affect LH very much. In the studies that we have reviewed these types of conditions have shown significant drops in testosterone levels and very little effect in LH. Occasionally, LH may show up a little low, but often it is completely in the normal range.
Therefore, low testosterone levels accompanied with normal LH levels often indicate a reversible cause of Low T and can be very useful in helping to diagnose underlying condition and creating a game plan for treating the underlying cause while managing symptoms of low T.
What causes high LH in Men?
Typically, if LH is high and testosterone is low then some sort of damage is causing the testicle to not function as well and the pituitary gland is trying to compensate by going into overdrive and flooding the balls with extra LH in hopes that it will encourage higher Testosterone production. In cases like this, LH levels are often off the charts high sometimes double or triple the normal values. Common causes for this include:
Borderline High LH levels
Slightly elevated LH levels (8.0 – 10.0 range) can be caused by medications or untreated autoimmune disorders. A number of studies have linked Celiac’s Disease with slightly elevated LH. Men with untreated Celiac’s disease can have moderately high LH levels, that usually return to normal upon starting a gluten-free diet.
What causes low LH in Men?
The most common reason for LH deficiency in men is the use of external androgens (testosterone, anabolic steroids or other performance enhancers). External androgens trick the brain into thinking the body is producing naturally high levels of testosterone which shuts down production of luteinizing hormone and consequently natural testosterone production. This is most exaggerated in men who have used steroids for long periods of time.
The second most common cause of low LH levels is a health issue that directly impacts the function of the pituitary gland itself. Most common causes of pituitary malfunction include:
Genetic conditions: such as Kallman’s Syndrome or Prader-Willi Syndrome
Borderline low LH results
LH levels in the 1.0 – 3.0 range can be caused by a number of things that can temporarily imbalance hormones such as:Overtraining (endurance)Being significantly under or overweightAlcohol consumptionSpikes in insulinMedications or other drugsHigh stressChronic conditions that can imbalance hormones such diabetes, insulin resistance and various auto-immune disorders can cause borderline or low levels of LH.
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