Winstrol (Stanozolol) has been one of the most popular anabolic steroids in bodybuilding since it came to market in 1962.
In medicine, Winstrol was initially prescribed as an appetite stimulant and mass-building agent for patients suffering from malignant and non-malignant diseases, osteoporosis and trauma.
It was later given to the elderly to reduce debility and to those suffering from dwarfism, due to its stimulatory effect on the pituitary gland.
However, during the 1970s, Winstrol’s side effects became better known, with it consequently being prescribed for fewer diseases/illnesses.
Winstrol is now classed as a controlled substance and thus is illegal to use for bodybuilding purposes.
However, it remains an FDA-approved medicine for the treatment of hereditary angioedema, due to its ability to increase  C1 esterase inhibitor (C1INH) and C4 proteins. Patients however are placed on the lowest possible effective dose; indicative of Winstrol’s toxic nature.

Winstrol Benefits

The main reason bodybuilders and athletes love “Winny” is that many of them think the Winstrol benefits outweigh the Winstrol side effects.
That is, it has a higher potential to increase muscle growth on a gram for gram basis than testosterone, and it produces fewer androgenic side effects. In reality, though, all else is not equal, and a Winstrol cycle isn’t as effective at building muscle as taking pure testosterone (more on that in a moment). 
Specifically, its anabolic to androgenic ratio is 320:30.
Harsher steroids, like trenbolone, have an anabolic to androgenic ratio of 500 to 500, and milder steroids like boldenone undecylenate have a ratio of 100:50.
Now, due to the arcane laws of steroid science, this doesn’t mean Winstrol will build exactly three times more muscle than testosterone. That said, the important thing to know is that milligram per milligram, Winstrol is more effective at building muscle than testosterone and produces fewer negative side effects.
This is particularly important for women, who generally don’t take highly androgenic drugs (like trenbolone) due to the harsh, masculinizing side effects. 
If a man takes highly-androgenic steroids, the short-term side effects are typically things men deal with at some point or another anyway: 

  • Hair loss on the scalp
  • Denser facial and body hair
  • Acne and oily skin
  • Deepened voice
  • Rougher skin
  • Increased aggression
  • Infertility

Here are a few examples:

  • Thanks to Winstrol’s low androgenic score, it poses a much lower risk of causing these side effects in women than other steroids. 
  • This is why it’s often taken by female bodybuilders and athletes who want the muscle-building benefits of steroids without turning into jacked gargoyles. 
  • That said, there’s scant long-term research on how steroids affect women (and very little on how they affect men), so it’s impossible to know what Winstrol side effects women would experience if they took it for years on end.
  • It’s likely that if a woman took Winstrol for long enough or at a high enough dose, she’d still experience many masculinizing side effects. That’s just part and parcel of taking steroids.
  • This aside, another unique feature of Winstrol is that it isn’t converted into estrogen-like many other steroids are. 
  • You see, a major problem with many steroids is that although they increase muscle growth, they also increase estrogen levels in the body. 
  • Well, in men estrogen is produced by an enzyme known as aromatase, which converts a percentage of our testosterone into estrogen through a process known as aromatization. 
  • When testosterone levels are at their normal, healthy level, estrogen levels also remain relatively low in men.
  • When testosterone levels are 3, 5, or 10 times their normal level, which is what happens when people take steroids, estrogen levels increase proportionally. 
  • Some steroids like Dianabol, for example, are also readily converted into estrogen in the body.
  • This can lead to a long list of feminizing effects such as gynecomastia (“man boobs”), water retention, and fat gain.

To counter these side effects, many athletes take estrogen blockers (which come with their own side effects), but this also presents a problem: 

  • Estrogen plays an important role in muscle growth, too, and reducing it to rock bottom levels reduces the muscle-building benefits of steroids.
  • Plays an important role in muscle recovery and repair by improving muscles’ ability to absorb glucose and boosting growth hormone levels.
  • Improves the body’s response to anabolic steroids by increasing the number of androgen receptors on muscle cells.
  • Allows you to train harder by bolstering serotonin levels, which increases your arousal, focus, and ability to push yourself in workouts.
  • So, how is a roider to reap the benefits of estrogen without growing man boobs and getting bloated and fat? 
  • Because Winstrol isn’t converted into estrogen, you could take as much Winstrol as you wanted and never run into any of the side effects of excess estrogen (although you’ll still experience other side effects). 
  • This is why Winstrol is often taken by athletes who want to maximize muscle mass, strength, and performance, without the bloating and fat gain that often results from other steroids. 

Now, steroids that don’t increase estrogen levels also are generally less effective for muscle growth. This is why people who only take a Winstrol cycle typically don’t make the dramatic size gains that people taking testosterone, Dianabol, and other estrogen-producing steroids do.
In other words, on paper Winstrol results should be better than pure testosterone, but in reality its muscle-building properties are hamstrung due to its inability to raise estrogen levels.
This is why Winstrol isn’t as effective at building muscle as testosterone despite having a higher anabolic score.
Thanks to its lack of aromatization into estrogen, Winstrol also produces little if any water retention or fat gain, which makes it an ideal steroid for cutting or lean bulking (or sprinting, if you’re Ben Johnson).
Finally, another reason many bodybuilders and athletes like Winstrol is that it also works synergistically with other steroids to promote muscle growth. 
It does this by reducing the levels of a protein called sex-hormone binding globulin (SHBG) in the blood. This protein regulates the effects of testosterone in the body by glomming onto the testosterone molecule, preventing it from giving its “message” to cells. 
By reducing SHBG levels in the blood, Winstrol increases the effectiveness of whatever other steroids you take, too.
Although all anabolic steroids reduce SHBG levels, Winstrol is particularly effective at this. 
A good example of this is a study conducted by scientists at the University of Hamburg, who gave 25 young men and women a 0.2 mg/kg stanozolol dose (Winstrol) for three days. This Winstrol dosage works out to be what a small bodybuilder would take.
The scientists took measurements of everyone’s SHBG and hormone levels before and 5, 6, 7, and 8 days after they started taking Winstrol. 
The scientists found that Winstrol reduced the subject’s SHBG levels by 48% after a week, on average. For comparison, testosterone typically reduces SHBG levels by around 30%.
All in all, what this means is that Winstrol will generally improve the effectiveness of other steroids you take, as well as boost muscle growth by itself. 
This is part of why most informed steroid users take a Winstrol cycle in addition to other steroids, like testosterone.

Muscle Gain

Although Winstrol is predominantly used as a cutting agent, its anabolic effects and ability to add lean mass should not be underestimated.
It is common for users to build 10-15lbs of muscle when first cycling Winstrol, even if they’re in a calorie deficit.
This potent form of exogenous testosterone helps users defy the bulking/cutting cycle strategy; by building muscle and burning fat at the same time.
Thus, some users may not use Winstrol for cutting, but for a moderate lean bulking cycle. Therefore, if someone does not want to add excessive amounts of hypertrophy — Winstrol may be utilized instead of bulking steroids, like Dianabol, Anadrol or Testosterone.

Fat Loss

The main benefit of Winstrol is subcutaneous fat loss, hence how it is a popular cutting steroid. Winstrol also causes water loss (as it doesn’t aromatize), thus having a drying out/diuretic effect.
Fat loss and reductions in extracellular fluid both will promote a more vascular and defined physique.
How much fat a user loses will depend on their diet, training and dosage. However, someone regularly eating in a 500 calorie deficit and taking a moderate dosage of Winstrol (20mg/day) can expect to burn approximately 5-6% body fat from an 8-week cycle.

No Water Retention

Many anabolic steroids are estrogenic and are referred to as ‘wet’ compounds, due to the amount of water retention and bloating they cause. One unique benefit of Winstrol is that it has the opposite effect; producing a bigger, yet leaner and more aesthetic physique.
Many bodybuilders want to hide their torsos with t-shirts and jumpers when taking estrogenic bulking compounds, because of excessive water retention. However, Winstrol has a ‘photoshop’ effect, making users appear more ripped and vascular.

Enhances Endurance

Winstrol is one of the best steroids for muscular endurance, due to its stimulation of new red blood cells (erythrocytosis).
Erythrocytosis will occur with all anabolic steroids, but most will also cause dramatic weight gain and water retention.
Winstrol thus enables athletes to remain light and powerful, due to simultaneous muscle-building, fat loss and water loss.

Increases Strength

Winstrol significantly increases strength, due to greater levels of protein synthesis and nitrogen retention inside the muscle cells.
With Winstrol depleting intracellular water levels, it isn’t the most potent of AAS at enhancing strength. This is due to decreased levels of adenosine triphosphate production inside the muscle cells — a protein molecule crucial for energy.
Those who are relatively new to anabolic steroids can add 15-20lbs on their big compound lifts on Winstrol. This is a dramatic increase, considering most bodybuilders will be in a calorie deficit when taking this steroid; and thus are aiming to simply maintain their strength.

How Steroids Work

Most of the cells in your body have specialized proteins on their surfaces called androgen receptors. 
You can think of these proteins as mailboxes that only receive messages from testosterone or similar hormones circulating in the blood. 
You can think of androgenic hormones like testosterone as incoming mail that’s circulated throughout the body, giving cells instructions on how to behave. 
When a testosterone molecule or other steroid attaches to an androgen receptor, its messages are transported to the nucleus of the cell, which alters the cell’s behavior.
As you probably know, the main message that steroids send to cells are to build muscle. Researchers refer to this as the steroid’s anabolic effect. An anabolic steroid is one that promotes the growth of tissues, including muscle growth.
Steroids also send other signals to cells, though, and many of these are broadly labeled as androgenic effects.
Androgenic means a substance that promotes male characteristics, such as chest and facial hair growth, a deepened voice, an exaggerated jawline, aggression, acne, etc.
In other words, the androgenic effects of steroids are most of the side effects that people want to avoid. That said, there are still plenty of side effects from steroids that aren’t solely due to their androgenic effects, so just because a steroid isn’t highly androgenic doesn’t mean it’s safe.
Scientists have known that all steroids have both anabolic and androgenic effects for decades, and some early researchers created a scale known as the anabolic:androgenic ratio. 
That is, how much muscle-building will this steroid produce relative to its unwanted side effects?
They used testosterone as a baseline, with an anabolic to androgenic ratio of 100:100. 
More or less every steroid you’ve heard of—trenbolone, nandrolone, Dianabol, and others—are all variations of testosterone that have been chemically modified to have either stronger anabolic or weaker androgenic properties. 
That is, they’re basically “franken-testosterones” that are designed to produce more muscle gain with fewer side effects.
Now, it’s worth mentioning that much of the research behind the anabolic:androgenic ratio was based on studies of rat muscle tissue. What’s more, the researchers looked at the levator ani muscle, or the muscle surrounding the anus, which is a smooth and not a skeletal muscle.
Since humans aren’t big rats and smooth muscle isn’t the same as skeletal muscle, some scientists have suggested that we take the research on the anabolic:androgenic ratio with a big grain of salt.
That said, lacking better information, it’s still considered a good starting point for estimating the muscle-building potential of steroids compared to their side effects, including steroids like Winstrol. 

Summary

Winstrol’s benefits are certainly tempting for the bodybuilder looking to get ripped, whether for cosmetic or competitive purposes.
However, Winstrol’s side effects are enough to make someone think twice as to whether it is worth the hepatic and cardiac damage, in the quest for adding moderate amounts of muscle and fat.