Yes, you can take testosterone shots if you have Parkinson’s disease. Testosterone therapy is not contraindicated in Parkinson’s patients, and in fact, low testosterone is notably common in men with the condition. Studies estimate that 35 to 50 percent of men with Parkinson’s have low testosterone levels, a rate higher than what normal aging alone would explain. The key is confirming you actually have low testosterone through blood work and then monitoring for side effects, just as any man on testosterone therapy would need.
Why Low Testosterone Is Common in Parkinson’s
Parkinson’s disease and low testosterone overlap more than you might expect. In one study of 68 Parkinson’s patients, 35 percent had low testosterone. A second study screened 50 men with Parkinson’s and found that half qualified as testosterone deficient. These rates are meaningfully higher than what doctors see in age-matched men without the disease, though researchers are still working out exactly why the overlap exists.
Part of the connection may be biological. Testosterone influences the brain’s dopamine signaling system, the same system that deteriorates in Parkinson’s. Testosterone can bind to receptors in the brain region responsible for dopamine production and alter how dopamine is made, transported, and broken down. When testosterone drops, dopamine regulation may suffer further, potentially compounding both the motor and non-motor symptoms of the disease.
What Testosterone Therapy Can and Cannot Do
The honest picture is that testosterone shots address low testosterone symptoms rather than Parkinson’s itself. In a double-blind, placebo-controlled trial called TEST-PD, 30 men with Parkinson’s and probable testosterone deficiency received either testosterone or a placebo for eight weeks. The study found no statistically significant difference between the two groups on standard Parkinson’s motor and non-motor scales, though a few cognitive measures did improve in the testosterone group, including verbal learning and visual memory tasks. The researchers noted that the small sample size, short duration, and a strong placebo effect from injections may have masked real benefits.
Case reports tell a somewhat more encouraging story for non-motor symptoms. In a series published in JAMA Neurology, five men with Parkinson’s and confirmed testosterone deficiency had fatigue, depression, low libido, and reduced energy that didn’t respond to antidepressants or standard Parkinson’s medications. After starting testosterone therapy, all five experienced meaningful improvement in those stubborn symptoms. One patient reported marked improvement in mood, energy, and the ability to feel pleasure within a month. Others saw gains in libido and erectile function.
There is also a published case showing improvement in motor function, specifically handwriting, tremor amplitude, and self-reported motor scores, in a Parkinson’s patient treated with testosterone. But this was a single patient, not a controlled trial, so it’s best understood as a signal worth investigating rather than proof.
The takeaway: if you have Parkinson’s and confirmed low testosterone, therapy is most likely to help with fatigue, low mood, poor energy, reduced libido, and decreased strength. These are symptoms that overlap between the two conditions, and treating the testosterone deficiency can peel away a layer of disability that Parkinson’s medications alone won’t touch.
Safety Profile in Parkinson’s Patients
In the TEST-PD trial, testosterone was generally well tolerated. The most common side effect was mild swelling in the lower legs, which occurred in 40 percent of the testosterone group compared to 20 percent on placebo. Two patients, one in each group, had a rise in PSA (a marker related to prostate health). No serious adverse events were attributed to the testosterone itself.
The broader concern many men have about testosterone and prostate cancer appears to be less worrisome than once thought. Current evidence does not support a link between testosterone replacement and the development of new prostate cancer. Studies of older men with low testosterone who received therapy did not show higher rates of prostate cancer compared to untreated men. What can happen is that PSA levels rise modestly after starting treatment, leading to more biopsies and the detection of cancers that might have gone unnoticed otherwise. For men who have already been successfully treated for prostate cancer with no signs of recurrence, testosterone therapy may still be an option.
Sleep Apnea Risk
This is the side effect most relevant to Parkinson’s patients specifically. Sleep problems are already common in Parkinson’s, and testosterone at higher doses can cause or worsen sleep apnea. Clinical trials have consistently shown that testosterone, particularly at doses of 200 mg or more of injectable testosterone per week, increases the severity of sleep-disordered breathing. If you already have sleep apnea or snore heavily, your doctor will want to evaluate this before starting injections and may recommend a sleep study.
What Monitoring Looks Like
Starting testosterone therapy means committing to a regular monitoring schedule. Here’s what to expect in practical terms:
- Blood testosterone levels are checked three to six months after starting. For injectable testosterone, the blood draw happens midway between injections. Your doctor is aiming for a mid-normal range, and the dose gets adjusted if levels come back too high or too low.
- Hematocrit (a measure of red blood cell concentration) is checked at baseline, again at three to six months, then yearly. Testosterone stimulates red blood cell production, and if this number climbs above 54 percent, therapy is paused until it drops. This is important because thickened blood raises the risk of clotting.
- PSA and prostate exams are recommended before starting treatment and again at three to twelve months for men ages 55 to 69, or younger men at increased risk. A PSA jump of more than 1.4 points within the first year or a level above 4.0 at any time triggers a urology referral.
- Symptom check-ins happen at three to twelve months and then annually to assess whether the therapy is actually helping and whether side effects like leg swelling, mood changes, or urinary symptoms have appeared.
None of this monitoring is unique to Parkinson’s patients. It’s the same protocol used for any man on testosterone therapy, with the added awareness that sleep quality and swelling deserve extra attention given the realities of living with Parkinson’s.
Practical Considerations for Parkinson’s Patients
If you’re already managing Parkinson’s with medications like levodopa, adding testosterone does not appear to create dangerous drug interactions. The TEST-PD participants were taking substantial doses of Parkinson’s medications alongside testosterone without safety issues. That said, the overlap in symptoms between low testosterone and Parkinson’s, particularly fatigue, cognitive fog, and depression, means it can be difficult to tell which condition is causing what. Getting a blood test for free testosterone is the straightforward way to sort this out.
Injectable testosterone is the most studied form in Parkinson’s patients, but gels, patches, and pellets are all options. The choice often comes down to preference and dexterity. If Parkinson’s-related tremor or stiffness makes applying a daily gel difficult, injections every one to two weeks (administered by a healthcare provider or a caregiver) may be more practical. Some men prefer longer-acting formulations that require dosing only every ten weeks.
The symptoms most likely to improve, such as energy, mood, and sexual function, tend to show changes within the first one to three months. If you haven’t noticed any benefit after that window, it’s worth reassessing whether the therapy is worth continuing.