How Nandrolone Decanoate Affects LH

Nandrolone suppresses the HPG axis through two parallel pathways. First, as a potent androgen, it activates androgen receptors at the hypothalamus and pituitary, suppressing GnRH pulses and LH secretion (the same mechanism as testosterone). Second, nandrolone and its metabolites bind progesterone receptors in the hypothalamus and pituitary, adding a progestogenic layer of suppression that testosterone does not have. This dual mechanism produces deeper LH suppression than testosterone at comparable androgenic doses. Nandrolone decanoate's long half-life (7-12 days) and prolonged metabolite detection (up to 6 months) mean the suppressive signal persists long after the last injection.

LH is typically suppressed to undetectable levels (below 0.5 IU/L) within 1-2 weeks of starting nandrolone decanoate at bodybuilding doses (200-600 mg/week). Due to the long half-life and depot effect, LH remains suppressed for 4-8 weeks after the last injection. Recovery of LH to reference range (1.7-8.6 IU/L) may take 3-6 months or longer, particularly after prolonged use. Nandrolone metabolites (19-norandrosterone, 19-noretiocholanolone) remain detectable in urine for up to 6 months after a single 150 mg dose.

Do not start PCT or draw recovery bloodwork until at least 4-6 weeks after the last nandrolone decanoate injection. The first meaningful LH assessment is at mid-PCT (4-6 weeks into SERM therapy, which itself started 4-6 weeks post-last-pin). If LH remains below 1.5 IU/L at this timepoint, the compound may not have fully cleared or the axis is severely suppressed. Retest at 3 months and 6 months post-last-injection to track the full recovery trajectory.

Nandrolone cycles require more aggressive PCT planning than testosterone-only cycles. Consider using HCG (250-500 IU every other day) during the ester clearance window (weeks 1-4 post-last-pin) to maintain testicular responsiveness before starting SERMs. Also monitor prolactin, as nandrolone's progestogenic activity elevates prolactin, which independently suppresses LH. Elevated prolactin during PCT may require cabergoline. If LH has not recovered by 6 months post-cessation, refer to endocrinology for evaluation of prolonged post-androgen abuse hypogonadism (PPAAH).

Further reading: PCT bloodwork: when to test and how to know you have recovered