19-nor anabolic steroids are testosterone-derived compounds modified by the removal of the 19th carbon atom, a change that significantly alters their metabolism and receptor activity. This modification gives them a distinct hormonal profile, including reduced DHT and estrogen conversion and strong anabolic potential.
This article reviews their key properties, how they differ from testosterone, and current trends in their use.
What are 19-nor anabolic steroids
19-nor anabolic steroids are a subgroup of anabolic-androgenic compounds derived from testosterone. Their name comes from a small structural modification: the removal of the carbon atom at the 19th position of the steroid backbone. Despite being a subtle change, it significantly alters how these compounds bind to receptors and how they behave in the body.
The most well-known 19-nor derivatives are nandrolone and trenbolone. These compounds are recognized for their strong anabolic activity, high nitrogen retention, and pronounced effects on muscle recovery.
Compared with testosterone, 19-nor anabolic steroids:
- produce a steadier, more sustained anabolic response;
- show a lower tendency to convert into estrogen through aromatization.
Because of their modified structure, 19-nor steroids interact differently with several hormonal pathways, including those influencing prolactin levels.
Where 19-nor steroids are used in bodybuilding
In bodybuilding, 19-nor anabolic steroids are primarily used for phases that require sustained anabolic activity with relatively low androgenic load. Compounds such as nandrolone and trenbolone are valued for their ability to enhance nitrogen retention, increase protein synthesis and support recovery under high training volume.
Because they produce fewer DHT-related effects, many athletes use them during mass-gaining cycles or in long off-season blocks where joint comfort, recovery quality and steady muscle growth are priorities. Their application typically includes:
- off-season mass-building phases;
- strength-focused training blocks;
- cycles requiring improved recovery and reduced joint discomfort;
- regimens aiming for steady, lean muscle gain without high estrogenic or DHT-driven effects.
How are 19-nor anabolic steroids different from testosterone
The primary difference lies in their structure: 19-nor anabolic steroids lack the carbon atom at the 19th position, which changes how they interact with androgen receptors and how they are metabolized. This modification generally leads to stronger anabolic activity relative to their androgenic effects, giving many 19-nor compounds a more ‘muscle-focused’ profile compared with testosterone.
Another key difference is their behavior in estrogen-related pathways. Testosterone readily aromatizes into estradiol, while most 19-nor derivatives show a much lower tendency to undergo aromatization. As a result, they typically produce fewer estrogen-related effects but can influence prolactin levels instead, creating a distinct hormonal footprint.
19-nor compounds also tend to provide a more stable and prolonged anabolic effect due to their pharmacokinetics. Many of them release more slowly and maintain steadier blood concentrations, which contributes to consistent performance outcomes and a different side-effect profile compared with traditional testosterone-based regimens.
DHT and Its Relevance to 19-nor Anabolic Steroids
19-nor anabolic steroids exhibit minimal conversion to DHT, which represents a significant pharmacological advantage of this class.
DHT (dihydrotestosterone) is a highly active metabolite of testosterone formed via 5α-reduction. It binds to androgen receptors with greater affinity than testosterone, producing pronounced effects in androgen-responsive tissues such as the skin, hair follicles, sebaceous glands and the prostate. Consequently, DHT is responsible for many characteristic androgenic reactions, including increased sebum production, acne, hair loss, irritability and elevated prostate stimulation.
Because 19-nor compounds do not undergo meaningful conversion to DHT, the risk of these DHT-mediated side effects is substantially lower. This structural and metabolic distinction contributes to a comparatively milder androgenic profile, particularly in terms of dermatological and prostate-related effects, when contrasted with testosterone-based anabolic agents.
Safety Profiles of 19-nor Steroids and Testosterone
The safety profiles of 19-nor anabolic steroids and testosterone differ primarily due to their distinct metabolic pathways. Testosterone converts into both estradiol via aromatization and dihydrotestosterone (DHT) via 5α-reduction. These pathways contribute to a characteristic spectrum of side effects, including estrogen-related water retention or gynecomastia, as well as DHT-mediated issues such as:
- acne;
- increased sebum production;
- hair loss;
- prostate stimulation.
In contrast, 19-nor steroids show minimal conversion to DHT and generally a lower rate of aromatization. This reduces the likelihood of DHT-driven and estrogen-dependent adverse effects. However, 19-nor compounds can influence prolactin regulation, which introduces a different set of potential risks, including altered libido, erectile dysfunction or gynecomastia of prolactin origin. Thus, their ‘safer’ profile applies only to specific side-effect categories, not universally.
| Parameter | Testosterone | 19-nor Anabolic Steroids |
| Conversion to DHT | High 5α-reduction → significant DHT production | Minimal → negligible DHT formation |
| DHT-mediated effects (acne, sebum, hair loss, prostate stimulation) | Common due to active DHT formation | Substantially reduced |
| Aromatization to estrogen | Moderate to high → estradiol formation | Lower aromatization rate |
| Estrogen-related effects (water retention, gynecomastia) | More likely | Reduced, but not absent |
| Impact on prolactin | Typically neutral | Possible elevation due to progestogenic activity |
| Endocrine “footprint” | Predictable, dual conversion pathways (DHT + estradiol) | Distinct profile with limited DHT involvement and potential prolactin modulation |
| Typical side-effect pattern | Mixed androgenic + estrogenic | Lower androgenic/estrogenic, but possible prolactin-related |
| Overall risk distribution | Concentrated in DHT and estradiol pathways | Shifted toward prolactin-related mechanisms |
How does 19-nor Steroids affect prolactin
Prolactin becomes a concern when its levels rise above the normal physiological range. Elevated prolactin can interfere with the hypothalamic–pituitary–gonadal axis, reducing dopamine activity and suppressing the production of sex hormones. This often leads to decreased libido, impaired erectile function and reduced overall hormonal balance.
High prolactin can also contribute to additional symptoms, such as:
- mood changes or fatigue;
- decreased testosterone levels;
- prolactin-related gynecomastia;
- impaired fertility.
Market trends and demand for 19-nor compounds
In the performance-enhancement market, demand for 19-nor anabolic steroids remains consistently strong due to their pronounced anabolic action and comparatively milder DHT-related profile. Athletes increasingly prefer compounds with predictable pharmacokinetics and lower androgenic burden, making 19-nor derivatives a stable segment of interest.
Common 19-nor compounds include:
- Nandrolone Decanoate (Deca-Durabolin);
- Nandrolone Phenylpropionate (NPP);
- Trenbolone Acetate;
- Trenbolone Enanthate and others.
Demand is further supported by the rising use of long training cycles, where steady anabolic activity, improved recovery and reduced DHT-driven side effects are considered advantageous compared with highly androgenic agents.
Conclusion
19-nor steroids offer a unique balance of high anabolic activity with lower DHT- and estrogen-related effects, while introducing their own prolactin-linked considerations. These characteristics shape their growing use in bodybuilding and long training cycles. Understanding their mechanism of action helps clarify how they compare to testosterone and why demand for this class continues to rise