A 2016 phase 1–2 prospective study orally administered 800 mg per day to 27 patients with telomere diseases. The primary efficacy endpoint was a 20% reduction in the annual rate of telomere attrition measured. Toxic effects formed the primary safety endpoint. The study was halted early, after telomere attrition was reduced in all 12 patients who could be evaluated. 12 of 27 patients achieved the primary efficacy end point, 11 of whom increased telomere length at 24 months. Hematologic responses (secondary efficacy endpoint) occurred in 10 of 12 patients who could be evaluated at 24 months. Elevated liver-enzyme levels and muscle cramps (known adverse effects) of grade 2 or less occurred in 41% and 33% of the patients, respectively. 
Other significant adverse effects of testosterone supplementation include acceleration of pre-existing prostate cancer growth in individuals who have undergone androgen deprivation; increased hematocrit , which can require venipuncture in order to treat; and, exacerbation of sleep apnea .  Adverse effects may also include minor side-effects such as acne and oily skin, as well as, significant hair loss and/or thinning of the hair, which may be prevented with 5-alpha reductase inhibitors ordinarily used for the treatment of benign prostatic hyperplasia , such as finasteride .  Exogenous testosterone may also cause suppression of spermatogenesis , leading to, in some cases, infertility.  It is recommended that physicians screen for prostate cancer with a digital rectal exam and prostate-specific antigen (PSA) level before starting therapy, and monitor PSA and hematocrit levels closely during therapy. 
The exact dosing instructions for nitric oxide supplement is not known. However, most supplements contain an average dose of grams of L-arginine and L-citrulline. We suggest you follow a process known as tolerance mapping to understand just how much nitric acid is required for your body. The process is simple. All you have to do is start with a small dose in Week 1. During the first week, make sure you note down the benefits and side effects that you are feeling. Once your body has adjusted to the lowest dose possible, you can then increase the dosing until you start feeling beneficial effects. Gradually, your body starts adjusting to the supplement and you will hit your optimal dose. However, the temporary recommendations for the supplement that you can take 2000mg-6000mg per day for optimum effects. Please note that overdosing is possible as dose variations can happen due to physiological differences. In case you notice diarrhea, vomiting, weakness, and nausea, stop the supplement immediately and consult your personal physician. Please note that liquids are absorbed much faster than solids and dosages for liquids will be lower than that of solid preparations.