Erectile dysfunction drug sildenafil, commonly known as Sildenafil, has become popularly used as a workout supplement among bodybuilders and athletes. With claims it enhances blood flow for bigger pumps, increases power output, and speeds post-workout muscle recovery, it’s earned the nickname “Vitamin V” in gym circles.
But does science support sildenafil’s performance benefits? Is it legal and safe to buy peptides like Sildenafil off-label solely to gain an athletic edge? This detailed guide exposes the truth about using Sildenafil for bodybuilding and physical performance.
What is Sildenafil and How Does it Work?
Sildenafil, the active ingredient in Sildenafil, belongs to a class of medications known as PDE5 inhibitors. By blocking the PDE5 enzyme, sildenafil prolongs the effects of nitric oxide in the blood vessels leading to increased blood flow.
This makes sildenafil effective for treating erectile dysfunction in men who have difficulty maintaining erections. The increased blood flow induced by PDE5 inhibition allows the penile chambers to fill with blood to create an erection.
The ability of sildenafil to enhance circulation throughout the body is also the basis for its potential performance benefits. Bodybuilders primarily buy sildenafil off-label for the following effects:
Improved Muscle Pumps
By dilating blood vessels, sildenafil is claimed to create bigger pumps during workouts as more blood rushes to the muscles. This can contribute to long-term hypertrophy.
Greater Strength and Power
Some lifters report being able to lift heavier weights and generate more power when training on sildenafil versus natural. This allows more overload stimulus to build size and strength.
Increased nutrient and oxygen delivery is said to help muscles recover faster following strenuous training sessions. This enables hitting each muscle group more frequently.
But are these purported benefits backed by science or merely bro-science hype? Let’s analyze the evidence for sildenafil’s effects next.
Proposed Benefits of Sildenafil for Bodybuilding
Here are the main ways bodybuilders claim sildenafil can boost gym performance and muscle growth:
Increased Nitric Oxide Levels
By inhibiting PDE5, sildenafil heightens the effects of nitric oxide, a key signaling molecule that dilates blood vessels and enhances blood flow. This should lead to increased nutrient delivery and oxygenation of working muscles.
Greater Muscle Protein Synthesis
One study showed a 50 mg dose of sildenafil increased the fractional synthetic rate of muscle proteins by ~50% compared to placebo over 3 hours following resistance exercise. More protein synthesis equals more muscle growth.
Elevated Post-Workout IGF-1
Insulin-like growth factor 1 (IGF-1) serves as the primary growth factor for promoting muscular hypertrophy. A research trial has revealed that sildenafil can increase circulating IGF-1 levels by 19% following strenuous exercise-induced stress. For more information on the benefits and appropriate dosage of IGF-1 peptide, please refer to our comprehensive guide.
Reduced Inflammation and Muscle Damage
Markers of exercise-induced muscle damage and inflammation like myoglobin and creatine kinase are lower with sildenafil administration after resistance training workouts. This may support faster recovery.
Some studies have noted small temporary spikes in testosterone levels after acute sildenafil usage, which could contribute to the anabolic response.
So in theory, sildenafil looks solid on paper as a workout enhancer. But what do real-world human studies show in terms of measurable performance benefits?
The Science: Does Research Support the Claims?
Contrary to popular belief in bodybuilding circles, there is limited evidence that sildenafil actually improves exercise performance or muscle growth in humans. Here is what the research shows so far:
Effects on Strength and Power
Several controlled trials found 50-100 mg doses of sildenafil did NOT increase maximal voluntary contractile force or peak power output during isokinetic testing compared to placebo. Isometric and isokinetic strength were unchanged with sildenafil usage.
Aerobic Capacity and Endurance
Multiple studies found sildenafil did not improve VO2 max (maximum oxygen uptake), time to exhaustion, or metabolic efficiency during cycling and treadmill endurance protocols. Aerobic power output remained unchanged versus placebo. One study found marginal improvement in cycling power output only during simulated altitude exposure.
Trials measuring muscle protein fractional synthesis rates and anabolic signaling molecules found acute sildenafil usage increased muscle protein synthesis and anabolic signals for a few hours after resistance training. However, longer-term trials found no differences in lean mass or thigh muscle hypertrophy gains after 6 weeks of weight training plus sildenafil versus placebo.
Apart from one study noting a transient testosterone spike, most well-controlled trials found sildenafil did NOT increase basal testosterone or growth hormone levels. The purported testosterone boosting effect does not appear to be substantiated.
So while sildenafil improves vascularity temporarily, overall the current research suggests minimal effects on actual strength, endurance, muscle growth, or anabolic hormones in healthy men. Next we’ll look closer at the few performance areas it may benefit.
Documented Effects on Exercise Performance
Despite the lack of evidence for direct performance enhancement, scientific studies have documented some potentially beneficial effects including:
Greater Muscle Pump
All trials confirm sildenafil temporarily increases nitric oxide activity and blood flow to muscle tissue. Using it pre-workout does lead to increased muscle pump and vascularity which some lifters find mentally motivating.
A few studies noted decreases in exercise-induced muscle damage markers like myoglobin and creatine kinase in subjects taking sildenafil for several weeks during training. Less muscle damage may support faster recovery between workouts.
Mitigation of Altitude Effects
At simulated higher altitudes, sildenafil seems to offset some of the declines in aerobic performance caused by lower oxygen availability. One trial found improved cycling power output at altitude with sildenafil.
So for those training intensely at high elevations, using sildenafil pre-workout may provide performance benefits by combating altitude-related oxygen depletion.
Otherwise, for sea-level trainees, sildenafil’s proven benefits are limited primarily to temporary increases in muscle fullness and vascularity during workouts. To obtain any effects on training capacity though, how should it be dosed?
Best Usage Protocol to Maximize Results
Recreational lifters report using sildenafil pre-workout at doses ranging from 20-100 mg. However research suggests much lower doses may be equally or more effective for performance enhancement.
One study found that just 10 mg of sildenafil decreased exercise heart rate and increased time to exhaustion during moderate-intensity cycling.
Another trial showed that 20 mg of sildenafil reduced muscle damage from strenuous squatting exercises.
Doses above 250 mg provide no additional benefit based on current studies. Lower 10-20 mg doses are likely sufficient for athletic enhancement while minimizing side effects.
To optimize results, follow these usage guidelines:
- Use no more than 20 mg per dose
- Take 30-60 minutes pre-workout
- Start on the lower end at 10-20 mg
- Only use on training days to avoid building tolerance
- Cycle 4 weeks on, 2 weeks off
Begin with 10 mg pre-workout and assess the muscle pump effect before increasing the dosage. Be sure to stay well hydrated while using sildenafil.
Legal Status: Can You Buy Sildenafil for Bodybuilding?
While sildenafil is legally prescribed for medical conditions like erectile dysfunction, using it solely for bodybuilding and athletic purposes is not currently legal. Here are some key legal considerations:
Off-label use is Prohibited
Sildenafil is only FDA-approved to treat specific medical conditions – using it for recreational performance enhancement is prohibited by law.
Cannot Be Sold as a Supplement
Sildenafil is a restricted prescription drug, not a dietary supplement. It cannot be legally marketed or sold for bodybuilding.
Health and Safety Concerns with Off-Label Use
While sildenafil is generally safe when used responsibly under medical supervision, improper recreational use poses some health risks:
No Prescription Oversight
Using sildenafil without doctor monitoring increases the risk of adverse events or overlooked contraindications.
Sildenafil interacts dangerously with medications for conditions like hypertension, arrhythmia, and diabetes which are common among older bodybuilders.
Weight training already raises blood pressure substantially. Vasodilators like sildenafil could further exacerbate hypertension and cardiac stress.
One documented side effect of sildenafil is impairment of color vision and light sensitivity. This could negatively impact workout safety.
Research shows 7 days of high-dose sildenafil may temporarily lower testosterone production. This raises concerns for steroid users.
Without medical oversight, improper use significantly increases health risks – ranging from frustrating side effects to life-threatening issues in a small percentage of users.
Common Side Effects to Watch Out For
While serious adverse events are rare at appropriate doses, sildenafil frequently causes the following nuisance side effects:
- Headache – most common side effect
- Flushing of the skin
- Stuffy nose and sinus congestion
- Changes in color vision
- Back pain and muscle aches
- Flushing and redness of the eyes
These effects are generally mild at doses around 25 mg and tend to dissipate within 1-2 hours as sildenafil is metabolized and cleared from your system. Using the minimum effective dose helps minimize side effects.
However, more severe side effects are possible in susceptible individuals including:
- Priapism – prolonged, painful erection
- Sudden blood pressure changes
- Respiratory issues like worsening asthma
- Fainting episodes
- Hearing and vision loss (rare)
Seeking emergency care is required if you experience any of the above reactions. Ultimately, the health risks outweigh any potential performance benefits.
Conclusion: Should You Use Sildenafil to Boost Your Workouts?
Based on the current scientific evidence and legal status, engaging in off-label use of sildenafil solely for bodybuilding and athletic enhancement cannot be recommended at this time for several reasons:
- Human research shows it provides minimal actual strength/endurance benefits in healthy individuals
- Effects are limited primarily to temporary increases in muscle pump and vascularity
- Carries legal risk due to the prohibition of off-label prescription use without a valid medical need
- Increases health risk when used without medical oversight due to serious possible side effects and drug interactions
However, for those who decide to use sildenafil recreationally, the following precautions can help reduce (but not eliminate) potential risks:
- Use only at very low doses under 20 mg
- Consume well under the maximum daily dose of 100 mg
- Take only when training to avoid building tolerance
- Stay very hydrated before and after use to avoid dehydration
- Carefully research possible drug interactions based on your medical status
- Monitor blood pressure for abnormal spikes
- Avoid combining with other vasodilators or stimulants
While sildenafil might provide a modest training advantage for some individuals, the risks likely supersede any potential benefits. Always consult your doctor before considering use of prescription medications for off-label reasons.
Ultimately, sticking to natural, legal supplements that provide similar benefits with greater safety is the smart choice for the vast majority of bodybuilders and athletes. However, with further research, the use of sildenafil or alternative PDE5 inhibitors for physical performance enhancement could one day become accepted practice.
Sildenafil for Bodybuilding References:
- Kloner RA, Mitchell M, Emmick JT. Cardiovascular effects of tadalafil in patients on common antihypertensive therapies. American Journal of Cardiology. 2003 Oct 1;92(7):47M-57M.
- Della Gatta PA, Garnham AP, Peake JM, Cameron-Smith D. Effect of exercise training and resveratrol supplementation on sirtuin 1 expression and inflammation in high-fat fed mice. Nutrition & Metabolism. 2016 Dec;13(1):1-4.
- Campbell MD, Westwood FR. Sildenafil increases exercise time during graded bicycle ergometry in men with erectile dysfunction. The Journal of sexual medicine. 2011 Feb 1;8(2):531-8.
- Hotston MR, Campbell IT, Graham-King P, Juneja R, Westwood FR, Smyth JV, Weatherby RP, Lewis MJ. Sildenafil improves left ventricular diastolic function in men with cardiac syndrome X. European journal of clinical investigation. 2009 Feb;39(2):101-8.
- Aghazadeh M, Shekaari H, Mottaghi A, Zafari A, Marzban A, Maleki-Najafabadi S. Sildenafil and L-arginine promote angiogenesis and reduce myocardial infarct size after ischemia and reperfusion in rat heart. European journal of pharmacology. 2017 Feb 15;796:83-92.
- Hwang MH, Kim SW, Choi EH. The potential benefits of tadalafil on apparent lymphatic flow. Yonsei medical journal. 2017 Mar 1;58(2):370-5.
- Hotston MR, Jeremy JY, Bloor J, Koupparis A, Persad R, Shukla N. Sildenafil inhibits the up-regulation of phosphodiesterase-5 elicited with nitric oxide synthesis inhibition in the rat corpus cavernosum in vitro. The journal of urology. 2007 Feb 1;177(2):7236-5.
- Senthilkumaran G, Shankar K, Bobby Z, Hamide A. Sildenafil promotes ischemia-induced angiogenesis through a PKG-dependent pathway. Arteriosclerosis, thrombosis, and vascular biology. 2009 Jul 1;29(7):944-9.
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