Primobolan (Methenolone) Side Effects
Primobolan is widely recognized as one of the few anabolic steroids that is considered to be very 'mild' in the sense that not only does it carry no risk of estrogenic side effects at all doses, but it also has a very weak androgenic strength rating, meaning that it is far less likely to cause androgenic side effects than most other anabolic steroids.
This is why Primobolan is often compared and contrasted with its close sibling Anavar.
Both are anabolic steroids medically used to treat women and children with little risk of side effects, and are considered very 'mild' when it comes to potential side effects.
However, this is where the similarities end, as Primobolan is a milder anabolic steroid when compared to most other anabolic steroids in existence (and when compared to Anavar), as well as having a weaker affinity for various side effects.
Estrogenic side effects
Primobolan is a DHT derivative anabolic steroid and therefore does not exhibit any interaction with the aromatase enzyme at any dose,[1] so there are no estrogenic side effects with Primobolan.
Estrogen related side effects such as water retention, hypertension (increased blood pressure due to water retention), and gynecomastia do not occur with primobolan alone.
Androgenic side effects
Although Primobolan has a very low androgenic strength rating compared to testosterone, Primobolan can still produce androgenic side effects, especially in individuals who are more sensitive to this category of Primobolan side effects.
All anabolic steroids exhibit varying degrees of androgenic effects, some to a lesser extent than others.
Primobolan is one of those anabolic steroids that tends to have much less androgenic activity than other anabolic steroids, but the risk of androgenic side effects when using primobolan should not be completely dismissed.
Androgenic side effects include increased sebum secretion (oily skin), increased acne breakouts (associated with increased sebum secretion), increased body and facial hair growth, and an increased risk of developing male pattern baldness (MPB) (in individuals with the genetic traits necessary to develop MPB).
Primobolan side effects that fall under the realm of androgenic side effects also include masculinizing effects in female users.
Feminizing effects in women may include male secondary sex characteristics (growth of voice, body, and facial hair), clitoral enlargement, and menstrual irregularities.
Primobolan will not exacerbate these symptoms, especially if the female dosage is kept appropriate and cycles are kept short and moderate.
One of the unique benefits of Primobolan (and all DHT derivatives in particular) is the fact that it does not interact with 5-alpha reductase (the enzyme that converts testosterone into the much more masculine dihydrotestosterone), so there is no risk of Primobolan being converted into a more potent androgenic hormone in the process.
Therefore, it is safe to assume that the androgenic strength associated with Primobolan will remain constant and consistent throughout the duration of use.
HPTA and Endogenous Testosterone Production Side Effects
When used in the doses required for athletic performance and physique enhancement, all anabolic steroids inhibit or completely shut down the hypothalamic-pituitary-testicular axis (HPTA) and endogenous natural testosterone production through a negative feedback loop.
Primobolan side effects are no exception to this rule for all anabolic steroids.
Primobolan in particular is often touted as a “mild” anabolic steroid with “mild” testosterone suppression side effects.
This is a myth that is demonstrably false as evidenced by clinical data and must be corrected.
Primobolan has been shown to very mildly suppress HPTA when administered at medically prescribed doses (around 20-25mg per day).
However, this is not the case when considering bodybuilding doses and the doses required to improve physique and athletic performance.
For example, in one study, subjects were orally administered 30 to 45 mg of primobolan per day, and more than half of the subjects showed a 15 to 65% suppression of endogenous testosterone production [2].
The doses administered to these subjects are actually doses that are still considered fairly low (30-45mg per day) for athletic performance and physique enhancement purposes.
Considering that bodybuilding and performance enhancing doses of Primobolan typically start in the 100mg range, Primobolan has been shown to be a very potent suppressor of endogenous testosterone production.
While Primobolan's level of suppression is lower than most anabolic steroids, it is still a very potent compound and many people should be aware of this fact.
At the end of every cycle, it is very important that each individual participate in a proper and well-planned post cycle therapy (PCT) program that includes the use of testosterone stimulating compounds (Nolvadex and/or HCG) for 4-6 weeks immediately following the end of the cycle in order to fully restore the body's endogenous production of testosterone and related hormones.
Without a proper PCT program, users are at risk for lifelong impairment or discontinuation of HPTA, which will require medical intervention.
Hepatotoxic side effects
Injectable primobolan (methenolone enanthate) and oral primobolan (methenolone acetate) do not have the typical C17 alpha alkylation common to almost all oral anabolic steroids, so primobolan does not have any measurable hepatotoxic effects on the body.
Oral primobolan has not demonstrated any concerning changes in liver enzyme levels[3].
Notably, primobolan itself is resistant to hepatic metabolism and degradation, and only one case of death due to hepatotoxicity and liver failure has been documented in a single elderly male who was prescribed primobolan to treat anemia [4].
Thus, although high doses of oral primobolan can be used in practice, oral primobolan still has some degree of resistance to metabolism and breakdown in the liver, so the risk of hepatotoxicity of primobolan should not be completely dismissed, especially as the doses of oral formulations are increased to higher and higher amounts.
Injectable primobolan (methenolone enanthate) does not have a liver toxicity issue as its route of administration bypasses the first pass through the liver.
Cardiovascular side effects
Primobolan side effects include cardiovascular tension and negative cholesterol changes, which are common to all anabolic steroids.
These include a decrease in HDL (good cholesterol) and an increase in LDL (bad cholesterol).
As a result of these changes, the risk of atherosclerosis increases, and the degree to which these changes are exacerbated is generally dose dependent (higher doses increase the negative changes and risk).
Other factors that influence these negative cholesterol changes include duration of use and route of administration.
In terms of route of administration, oral anabolic steroids are known to have the worst negative effects on cholesterol compared to injectable anabolic steroids.
It is for this reason that oral anabolic steroids have a negative reputation for having a much more severe negative effect on cholesterol compared to injectable anabolic steroids.
This is because the liver is essentially the body's cholesterol processing and production center, and increased hepatotoxicity from oral anabolic steroid use is associated with negative cholesterol changes.
While taking anabolic steroids, it is essential to pay proper attention to a clean diet and consume a variety of healthy cholesterol-promoting foods such as omega-3 fatty acids and fish oil (at least 2-4 grams per day).
Primobolan References
[1] Progress. Intern. Congress Hormonal Steroids, Milan, 1962. Excerpta Med. Intern. Congress Ser No. 51, p. 209. excerpt. Med. Discover., Amsterdam, 1962.
[2] A comparative study of the effects of methenolone acetate and mesterolone on the pituitary gland and male gonads. Trenkner R, Senge T, Hienz H et al. Arzneimittelforschung. 1970 20(4):545-7.
[3] Failure of non-17-alkylated anabolic steroids to produce abnormal liver function tests. J Clin Endocrinol Metab. 1964 Dec;24:1334-6.
[4] Fatal outcome in a patient with severe aplastic anemia after treatment with methenolone acetate. Ann Hematol. 1993 Jul;67(1):41-3. Tsukamoto N, Uchiyama T, Takeuchi T, Sato S, Naruse T, Nakazato Y.
