Viagra vs Cialis (sildenafil vs tadalafil) for crazy pumps, increasing testosterone and building muscle. Which is best?

Viagra and Cialis are PDE-5 inhibitors mostly known for treating erectile dysfunction (mostly in older men). Cialis has also been approved for the treatment of lower urinary tract symptoms suggestive of benign prostatic hyperplasia. It can also help lower high blood pressure, by relaxing the smooth muscle around blood vessels.

They potentiate the effects of nitric oxide (NO). NO promotes cGMP production, which induces vasorelaxation. Phosphodiesterase (PDE) enzymes break cGMP down. PDE enzymes become upregulated in pathological conditions, such as erectile dysfunction, muscle wasting, etc.

PDE5 is not only expressed in the penis and skeletal muscle, but also in the testis. Therefore PDE5 inhibitors should be able to help improve blood flow (better pumps and erections), muscle growth and testosterone.

Viagra vs Cialis on testosterone

Both Cialis and Viagra have been shown to increase testosterone by working directly on the testis. However, Viagra increases estrogen, whereas Cialis lowers it.

Higher testosterone can improve blood flow and build more muscle.

#1 Viagra vs Cialis on testosterone and LH

In this study, they gave men either 50mg Viagra or 20mg Cialis. The men took it on demand and the monthly use was 2-12 caps for both groups (R).

Cialis was able to increase total (6.3 vs 4.5nmol/L increase) and free testosterone (28.4 vs 13.1pmol/L) to a great extent than Viagra.

Cialis also decreased LH the most (2.5 vs 1.2IU/l). This indicates that Cialis is likely better than Viagra at improving testicular sensitivity to LH.

As an aside, Cialis was most effective at increasing monthly sexual activity (frequency) whereas Viagra was ineffective.

These results (Cialis on libido) are confirmed by this study as well (R).

#2 Cialis on testosterone and testosterone to estrogen ratio

Over 12 months, 10-20mg Cialis on demand: 

• didn’t alter total or free testosterone levels (411.4 +/- 131.4 to 434.2 +/- 177.1 ng/dL and 47.7 +/- 15.3 to 49.9 +/- 19.1 pmol/L, 
• but it did decrease estradiol (19.9 +/- 9.6 to 16.6 +/- 8.1 ng/dL) and 
• increase the testosterone to estradiol ratio (26.3 +/- 15.3 to 32.6 +/- 17.7, P = 0.05).

Interestingly, the decrease in estradiol was only evident in lean, but not obese men (>27.5 kg/m2) (R). 

#3 Viagra on testosterone and oxidative stress

50mg Viagra once a week for 6 months was able to:

• Increase total serum testosterone (426.4 +/- 174.8 vs. 569.6 +/- 146.1 ng/dL) – 143.2ng/dl increase.
• Increase salivary testosterone levels (56.1 +/- 22.3 vs. 110.0 +/- 48.4 pg/mL) – almost double increase.
• Decrease salivary 8-OHdG levels (2.30 +/- 0.23 vs 0.90 +/- 0.05 ng/mL), a marker of oxidative stress (R).

#4 Viagra on testosterone and other hormones

Men were started on 50mg Viagra and then increased (up to 100mg max) or decreased (25mg minimum) based on symptom resolution (dose optimized protocol) for 6 months (R).

After 6 months, Viagra:

• Increased total testosterone by 3.6 nmol/L (103 ng/dL) and free testosterone by 110 pmol/L (31.7 pg/mL)
• Increased serum DHT by 0.17 nmol/L (4.9 ng/dL) 
• Increased estradiol by 14 pmol/L (3.7 pg/mL) and estrone by 10.7 pmol/L (2.9 pg/mL)
• Suppressed luteinizing hormone (-1.3 units/L)  
• Increased androstenedione by 1.3 nmol/L (38 ng/dL)

#5 Cialis on testosterone and LH

After 3 months, 5mg of daily Cialis (R):

• Increased testosterone from 3.6 ± 0.5 to 5.2 ± 0.3ng/ml (360 to 520ng/dl)
• Decreased LH levels from 5.6 ± 0.6 to 4.6 ± 0.5 

#6 Cialis (5 vs 20mg) on testosterone and testosterone to estradiol ratio

After 2 months, 5mg of daily Cialis was best able to increase the testosterone to estradiol ratio, whereas 20mg of Cialis on demand was ineffective (R). In this study, neither 5 nor 20mg was able to increase testosterone.

In summary, both Viagra and Cialis can increase testosterone, whereas Viagra increases estradiol and Cialis lowers it. This is important since estradiol is an independent risk factor for erectile dysfunction. Article: How estrogen contributes to ED (scroll down to the estrogen section).

Viagra vs Cialis on blood flow and pump

Both Cialis and Viagra are PDE5 inhibitors, which promote vasorelaxation. This allows more blood to rush to the muscles, resulting in more vascularity and greater pumps.

Everyone will respond a little differently to these drugs, so it’s likely worth experimenting with which ones give you the best results.

Viagra vs Cialis on muscle growth and fat loss

PDE5 inhibitors might be able to promote muscle mass growth and fat loss.

This study found that Viagra stimulated muscle protein synthesis (doubled it) to a similar magnitude observed in response to 100–200 mg/week testosterone injection (R). However, a boost in muscle protein synthesis doesn’t equate to muscle gained, so don’t get too excited.

This human study found that 5mg of Cialis daily increased lean mass by about 0.3kg after 2 months, whereas 20mg on demand was ineffective (R). Keep in mind that they didn’t exercise, so the results might have been bigger if they did.

20mg Cialis promotes lipolysis, and these fatty acids can then be burned for energy (R).

NO stimulates glucose uptake and oxidation, as well as fatty acid oxidation in insulin-sensitive tissues. As you can see in the graphs below, glucose decreased with Cialis even while free fatty acids increased (usually an increase in FFAs cause insulin resistance).

There isn’t a lot of research on PDE5 inhibitors and fat loss yet, but these two animal studies found that Cialis significantly lowered visceral and subcutaneous fat mass (R).

The ways Cialis helps with muscle growth are by (R):

• Enhancing insulin secretion and insulin sensitivity
• Improving vascular function and nutrient uptake into muscles
• Increasing myogenin and androgen receptor protein expression in skeletal muscle cells  

The ways Cialis help with fat loss are by:

• Improving blood flow to fat cells
• Promoting lipolysis and fatty acid oxidation
• Improving insulin sensitivity
• Improving fat cell and mitochondrial health (R)
• Promote browning of white adipose tissue (R).

Viagra vs Cialis against muscle fatigue

Both Viagra and Cialis can help with muscle endurance so that you can get more reps.

This study found that after 8 days of using 25mg Viagra, reps to failure significantly improved compared to the placebo group (R).

In the graph below you can see A) Isometric strength (Viagra didn’t improve it), B) Isokinetic strength and C) repetitions to failure after 8 days.

A few ways PDE5 inhibitors (like Viagra) increase reps to failure are by (R):

• Improving excitation‐contraction coupling (prevents calcium accumulation in cells, thus promoting better relaxation) (R).
• Improving myofibrillar function
• Enhancing perfusion (passage of blood into the muscle)
• Increasing muscle glycogen and glucose oxidation, due to enhanced glucose uptake
• Enhancing glucose and fat oxidation (thus better ATP production)
• Enhancing muscle oxygenation (R).

Mice deficient in skeletal muscle NO production have increased skeletal muscle fatigability and reduced force production and even fibrosis (R, R). A deficiency in NO can even lead to fibrosis and PDE5 inhibitors can prevent this.

Possible risks of Viagra and Cialis

• Possible increase in oxidative stress with exercise
  • Taking 20mg of Cialis before exercise, resulted in a significant increase in muscle damage without affecting plasma antioxidant status (R). This was only an acute study, but it could have been because they were able to train harder, which resulted in more damage.
  • Taking 20mg of Cialis for 2 weeks decreased antioxidant capacity at resting conditions, therefore making subjects more susceptible to the oxidative stress induced by an exhaustive bout of exercise (R). Again, the study was only short term and they used a relatively large dose (20mg vs 5-10mg). It could be that the peeps would adapt after 4 or so weeks. 
  • It might be best to take Cialis with an anti-oxidant such as tart cherry to prevent excess oxidative stress caused by Cialis or Viagra.
• Headaches
• Nasal congestion
• Flushing
• Indigestion
• Low blood pressure (if taken with other high blood pressure meds)
• Muscle and back pain
• More concerning or serious side effects (although rare):
  • Vision changes (blurred vision, vision with a blue tinge and increased sensitivity to light)
  • Hearing problems (loss of hearing or tinnitus).
  • Prolonged erections (priapism)

When to take them

Cialis works within 30min, has a 17.5 hour half-life and lasts up to 36-48 hours. Cialis reaches its peak levels in the body around the 2-hour mark

Viagra (if taken on an empty stomach) works without 12min, peaks around 30min, lasts about 4 hours and is out of your system in 12 hours.

So both can be taken 1-2 hours before your workout. There is really no need to pick one of the other due to the faster onset of effect. It’s best to wait 30 min after taking your pre-workout, so if you take Viagra or Cialis at the same time, you should be ready to go regardless of which one you took.

Summary

Both Viagra and Cialis can help improve your pumps, increase testosterone and help build muscle and lose fat.

Cialis decreases estradiol whereas Viagra increases it. If you’re someone with high estrogen or someone that aromatase quickly, then Cialis is likely the better option.

But at the end of the day, it might be best to experiment with both to see to which one you respond the best.

Start with a low dose to minimize symptoms. Perhaps 5mg Cialis or 25mg Viagra, then increase to 10mg Cialis or 50mg Viagra. No need to go higher than that.

To supercharge the blood flow effects of PDE5 inhibitors, take citrulline (or a pre-workout supplement) with it. Citrulline will boost nitric oxide levels and cGMP and the PDE5 inhibitors will prevent cGMP breakdown.

The forbidden pre-workout is to take your PDE5 inhibitor with caffeine or strong coffee.

It can also be taken with anabolic steroids (such as Anavar), which have been said to result in great pumps.

In summary, 100-200mg caffeine, 5g citrulline malate and 10mg Cialis.