STEP 16. Pull your ferritin levels. I don't see many men on the Peak Testosterone Forum pulling their ferritin levels, a measure of our body's iron stores. This differs from measures of plasma iron levels, such as RBC counts, hemoglobin and hematocrit, that are used to diagnose anemia. These measures provide a snapshot of current usable blood iron, whereas ferritin, on the other hand, is the iron actually stored in your tissues.
Ferritin seems a bit dull until you find out how important it is. Most men showing up on this forum have some of a suite of common symptoms, such as fatigue, erectile dysfunction, lowered libido, depression, loss of morning erections, etc. Oddly enough, ferritin can often explain and expose the root cause of many of these symptoms. Ignoring ferritin can be a big mistake for this reason.
Plus, it is a very cheap test: - about $25 from the first two places I checked on my Testosterone Labs page, where you can pull the numbers yourself without a doctor's orders. (Thank God and Mother Nature for medical freedom!) This is important, because the great majority of doctors will not pull ferritin for a physical, so it can be tough to get tested through an insurance-based system. But you can do it yourself and then figure out what to do from there.
MY LAB RESULTS: I am the perfect example of the above. Being a health geek, I actually have all my lab results and, as far as I know, ferritin has only been pulled once by my physicians in 15+ years. And, most significantly, my physician never pulled ferritin when I had severe symptoms as listed above. Rather than relying on a financially overburdened healthcare system, I ordered ferritin a few days ago and found that I had a ferritin level of 131 mcg/l. At this point, I felt I could relax, because, as you'll below, my value is very average and midrange.
Let's go over the 10 Great Reasons For Men to Measure Their Ferritin Levels:
1. Low Values Are Associated with Fatigue. We have had a couple of men on the Peak Testosterone Forum with low ferritin who struggled with fatigue. For example, look at this classic case on where a man described the following after going on TRT with HCG:
"Other things I've seen improve: energy a little higher (I still feel very tired after a long day at work but it's more manageable). I can workout now and not feel completely achy, sore the next day. My depression and anxiety is also more manageable now. It hasn't completely gone away, I still have bad weeks where I'm sad and depressed, but overall my confidence has gained. I don't stress about situations as much." 
Notice that his energy improved on TRT, which is common, but he was still struggling with fatigue. Later in the thread he mentions that "also of note, I got back my recent bloodwork I had done following up on my ferritin levels. After 1 month of supplementing with Ferrous Sulphate 260mg daily, my ferritin level went from 18 to 25 ng/dL." This is low ferritin by most standards and yet it is apparent that he does not know that ferritin itself can cause an issue.
2. Low Ferritin Leads to Low Dopamine. I have not been able to find out the root cause, but many sources say that low ferritin leads to low dopamine, which in turn will lead to increased anxiety and lowered libido and motivation.
3. Low Ferritin Can Result from Overtraining. Overtraining is a significant issue for many men and can temporarily destroy a man's health and hormones. The damage is usually not permanent but can be at times and this is why it is important to monitor yourself. It turns out that ferritin is one of the top ways to evaluate this issue, something I discuss in my page Best Signs of Overtraining.
4. Low Values Are Associated with Hypothyroidism. If your thyroid function isn't where it should be, then this can lower the acid levels in your stomach. This is hard on digestion and the absorption of minerals including iron and ferritin levels can fall. There is also a viscious circle involved here potentially, because low ferritin levels likely slow down the thyroid. This is shown by the fact that some low thyroid patients with low ferritin are improved with iron supplementation. (Don't supplement iron without talking to your doctor or naturopath.) And don't underestimate the power of hypothyroidism to create low testosterone like symptoms: the two conditions have significant overlap.
5. Associated with Alzheimer's Disease and Colon Cancer. Iron, in general, is "inflammatory." As one paper put it: "Iron and its homeostasis are intimately tied to the inflammatory response."  For example, a 2013 UCLA that utilized a specialized MRI technique found high iron levels in the brain are actually the root cause of Alzheimer's. (This still needs to be proved but the evidence is stacking up. They felt strongly that this is actually the source of the issue and that the famed tau and beta proteins associated with Alzheimer's are a byproduct of iron accumulation.  Additional evidence was provided by the fact that an even more recent study found that ferritin levels in spinal fluid also accurately predicted Alzheimer's. 
6. High Ferritin Values Increase Risk of Getting Colon Cancer. According to one study, there was a non-powerful but significant association between ferritin and the development of colon cancer.  For example, the researchers noted that those with high (> 289 mcg/l) had a 50% greater risk of having a polyp than those in the lowest ferritin group.
7. Low Values Associated with Existing Colon Cancer. Although high iron levels could play a role in the development of colon cancer, once colon cancers sets in, ferritin levels will likely fall due to low grade GI bleeding. For example, researchers warned that "to clarify the significance of serum iron and ferritin as indicators of iron loss caused by continuous bleeding, and, thus, to determine their value as markers of colorectal cancer, values for the two were compared in male patients with early and advanced colorectal cancer and age-matched male controls." They verified this relationship by noting that controls had average ferritin levels of 117 mcg/l whereas those with early and late state colon cancer had ferritin levels of 80.5 and 48.8 mcg/l, respectively.  This was further verified in another study that showed if your ferritin was over 100 mcg/l, you had a minimal (7%) chance of having colon cancer.  (It should be pointed out that it was not quite as good at predicting gastric or rectal cancer.)
8. Low Values Are Associated with Restless Leg Syndrome. Restless Leg Syndrome can be miserable and potentially lead to lower testosterone and neurotransmitter levels, since sleep is affected. Research indicates that often the root cause of this issue is low ferritin. 
9. If You Supplement with Vitamin C or Turmeric. Many men megadose with Vitamin C for a variety of reasons, including it's ability to shave the peaks off of your cortisol spikes and increase nitric oxide levels. There are also studies showing it can help in the battle against heart disease. However, Vitamin C can increase absorption of iron, which could potentially cause some men some issues.. This is one of the reasons that some experts say to always take your Vitamin C on an empty stomach. If your ferritin is on the high side, then you want to be very cautious with Vitamin C and diligent not to artificially increase iron absorption.
Turmeric is the opposite from what I have read. Although there are contradictory studies, on this, some work shows that turmeric extract can lower ferritin levels.
10. Hemochromatosis. Some men have a genetic condition that causes them to accumulate iron in their tissues. The SNPSs ("mutations") involved are far from rare and affect approximately one in 200 men of European ancestry. Hemochromatosis can cause a host of medical conditions and issues, and, as I document in my page on Causes of Low Testosterone, will generally lead to significantly decreased testosterone levels if unmonitored and untreated.
1) Annu Rev Nutr, 2010 Aug 21, 30: 105 122, "Iron Homeostasis and the Inflammatory Response"
2) UCLA Newsroom, "UCLA study suggests iron is at core of Alzheimer's disease: findings challenge conventional thinking about possible causes of disorder", by Mark Wheeler, August 20, 2013
3) Nat Commun, 2015 May 19, 6:6760, "Ferritin levels in the cerebrospinal fluid predict Alzheimer's disease outcomes and are regulated by APOE"
4) BMC Gastroenterology, 2012, "Ferritin above 100 mcg/L could rule out colon cancer, but not gastric or rectal cancer in patients with involuntary weight loss"
5) Am J Epidemiol, 1996, 144(1) , "Plasma Ferritin, Iron Intake, and the Risk of Colorectal Polyps"
6) J Gastroenterol, 1994 Feb, 29(1):19-23, "Clinical significance of serum iron and ferritin in patients with colorectal cancer"