Primoten (Methenolone Enanthate) is an injectable steroid that exhibits moderately strong anabolic properties with very low androgenic properties.

Estrogenic Side Effects 

Primoten (Methenolone Enanthate) is not aromatized by the body, and is not measurably estrogenic. Estrogen linked side effects should not be seen when administering this steroid. 

Primoten (Methenolone Enanthate) can cause side effects like development of gynecomastia, water retention and strong elevations in blood pressure but these are very rare.

Androgenic Side Effects 

Although classified as an anabolic steroid, androgenic side effects are still possible with this substance. This may include bouts of oily skin, acne, and body/facial hair growth. 

Anabolic/androgenic steroids may also aggravate male pattern hair loss. 

Women are warned of the potential virilizing effects of anabolic/androgenic steroids. These may include a deepening of the voice, menstrual irregularities, changes in skin texture, facial hair growth, and clitoral enlargement.

Hepatotoxicity Side Effects 

Primoten (Methenolone Enanthate) does not have hepatotoxic effects and therefore, liver toxicity is unlikely. 

Cardiovascular Side Effects

Anabolic/androgenic steroids can have deleterious effects on serum cholesterol. This includes a tendency to reduce HDL (good) cholesterol values and increase LDL (bad) cholesterol values, which may shift the HDL to LDL balance in a direction that favors greater risk of arteriosclerosis.

The relative impact of an anabolic/androgenic steroid on serum lipids is dependant on the dose, route of administration (oral vs. injectable), type of steroid (aromatizable or non-aromatizable), and level of resistance to hepatic metabolism.

Anabolic/androgenic steroids may also adversely affect blood pressure and triglycerides, reduce endothelial relaxation, and support left ventricular hypertrophy, all potentially increasing the risk of cardiovascular disease and myocardial infarction. 

Primoten (Methenolone Enanthate) is likely to have a stronger negative effect on the hepatic management of cholesterol than testosterone or nandrolone due to its non-aromatizable nature, but a much weaker impact than c-17 alpha alkylated steroids. 

To help reduce cardiovascular strain, it is advised to maintain an active cardiovascular exercise program and minimize the intake of saturated fats, cholesterol, and simple carbohydrates at all times during active steroid administration. Supplementing with fish oils and a natural cholesterol/antioxidant formula is also recommended.

Testosterone Suppression

All anabolic/androgenic steroids are expected to suppress endogenous testosterone production. Testosterone is the primary male androgen, and offers strong negative feedback on endogenous testosterone production.

Testosterone-based drugs will, likewise, have a strong effect on the hypothalamic regulation of natural steroid hormones. Without the intervention of testosterone-stimulating substances, testosterone levels should return to normal within 1-4 months of drug secession. 

Note that prolonged hypogonadotrophic hypogonadism can develop secondary to steroid abuse, necessitating medical intervention.