Relugolix

Limits on what this shows

• Key negative/null findings: The Ribas et al. model is a permanent genetic knockout, not the reversible pharmacologic suppression relugolix produces, so magnitude comparison is not established; whether a course of relugolix therapy produces a comparable change in humans is untested.
• At-risk subgroups: Not established for relugolix specifically in either formulation; theoretically longer-duration users of either product given more sustained hormone suppression.
• Counter-evidence on record: None found directly contradicting the mechanism.

Regulatory status

Not addressed on either label.

Population evidence

Tian, Lou, and Shi, "From mitochondria to sarcopenia: role of 17β-estradiol and testosterone" (Frontiers in Endocrinology 2023, PMID 37152937), a narrative review, states both hormones "demonstrate protective effects on mitochondrial function" in skeletal muscle, and that declining levels of either correlate with sarcopenia via loss of mitochondrial quality control (proteostasis, biogenesis, dynamics, mitophagy). For the estradiol side specifically, Ribas et al. (Science Translational Medicine 2016, PMID 27075628) used a muscle-specific estrogen receptor-alpha knockout mouse model and found abnormal mitochondrial structure, elevated reactive oxygen species, defective mitochondrial fission, and reduced mitochondrial turnover ("retention of dysfunctional mitochondria"), alongside increased adiposity and glucose intolerance. No relugolix-specific, or even pharmacologic (non-genetic-knockout) hypogonadism/hypoestrogenism, mitochondrial study was located for either formulation.

Mechanism

Named at the class/hormonal level: loss of androgen-receptor or estrogen-receptor-alpha signaling, the direct consequence of Orgovyx's and Myfembree's respective hormone-suppression mechanisms, is linked in these sources to impaired skeletal-muscle mitochondrial structure, biogenesis, and quality control.

Counter-evidence held on record

Shares its evidence base with ATP production below; see the Overlap map. This is mechanistic, class-level plausibility only, not a demonstrated relugolix effect, and does not support any dosing or supplement recommendation.

Limits on what this shows

• Key negative/null findings: Bassey et al. reported "some improvement" in unspecified markers on ADT despite MDA remaining elevated, an inconsistency disclosed here rather than resolved; no source located this session measured oxidative-stress markers in women on Myfembree or any estradiol-suppressing GnRH antagonist.
• At-risk subgroups: Longer ADT duration, per the positive correlation in Bassey et al.; not established specifically for relugolix dose or duration.
• Counter-evidence on record: None found contradicting the direction; the evidence is class-level only (relugolix not confirmed in either cited cohort), which caps this at yellow regardless of study quality.

Regulatory status

Neither the ORGOVYX nor the MYFEMBREE label mentions oxidative-stress markers or antioxidant-status monitoring.

Population evidence

Bassey et al. (JCO Global Oncology 2020, PMID 33001740) directly measured oxidative-stress and antioxidant markers, malondialdehyde (MDA), nitric oxide (NO), total plasma peroxide (TPP), and total antioxidant capacity (TAC), by colorimetric assay in 120 Nigerian prostate cancer patients (treatment-naive and androgen-deprivation-therapy-treated) versus 100 healthy controls. ADT-treated patients showed elevated oxidative markers and lower antioxidant capacity than controls, MDA remained elevated during treatment, and treatment duration correlated positively with oxidative markers. Mechanistic corroboration: Shiota et al. (Journal of Urology 2011, PMID 22177207) found androgen deprivation increased oxidative-stress markers in human prostate tissue and promoted castration-resistant progression via Twist1/YB-1 upregulation, reversible with antioxidant (N-acetylcysteine) treatment in cultured cells and in both castrated and non-castrated mouse xenografts. Neither source's abstract, as retrieved this session, names relugolix among the ADT agents studied, and cohort composition could not be confirmed beyond abstract-level data; treated as Tier C class-level evidence for relugolix specifically, not Tier A.

Mechanism

Named at the class/hormonal level: loss of androgen-receptor signaling is linked to increased reactive-oxygen-species generation and reduced antioxidant defense, demonstrated in human ADT cohorts and prostate-tissue/xenograft models generally, not tested for relugolix specifically or for the Myfembree/estradiol-suppression direction.

Counter-evidence held on record

This is a class-level oxidative-stress signal from androgen deprivation broadly, not a relugolix-specific finding, and it is not an indication for antioxidant supplementation; see Fails verification below, where selenium and vitamin E supplementation for ADT side effects is documented to have backfired in a large randomized trial.

Limits on what this shows

• Key negative/null findings: Serum ferritin, transferrin saturation, and hepcidin were not reported in the label summaries or reconstructed abstracts accessed for this review; only hemoglobin (a functional, not a storage, marker) was quantified.
• At-risk subgroups: Bounded specifically to women with pre-existing heavy-menstrual-bleeding-related anemia taking Myfembree for uterine fibroids. Not established in women taking Myfembree for endometriosis pain without baseline heavy bleeding, and not applicable to Orgovyx.
• Counter-evidence on record: This finding should not be generalized into a claim that relugolix, or GnRH-axis suppression broadly, "protects" iron status; it is specific to a bleeding-disorder population where reducing blood loss is the entire point of treatment. A related and easily confused claim, that hormone-suppressing therapies generally deplete iron, would run in the opposite direction from what this drug's own data show in this labeled indication.

Regulatory status

Labeled clinical-trial result on the MYFEMBREE prescribing information (LIBERTY 1/2), not a separate warning or monitoring requirement; iron supplementation is not itself recommended anywhere on the MYFEMBREE label, only spacing guidance if a patient is separately taking iron (see PK basis above).

Population evidence

Same LIBERTY 1/2 phase 3 RCTs as the Oxygen delivery/utilization entry above (N=388, 382), plus the 52-week completer analysis (N=363) reporting sustained "meaningful improvement" in anemia markers and the LIBERTY randomized-withdrawal study confirming durability through 76 weeks. [7][8][9]

Mechanism

Named and indirect: reduced monthly menstrual blood loss reduces the ongoing iron loss that was driving pre-treatment anemia, allowing iron balance and hemoglobin to recover. This is an outcome of reduced bleeding, not a demonstrated direct effect of relugolix on intestinal iron absorption, hepcidin, transferrin, or ferritin; none of those iron-specific markers were reported in the sources located for this review.

Counter-evidence held on record

This is a beneficial, reverse-direction finding, not a depletion; it does not support a general claim that relugolix protects iron status outside this bounded population, and it is not evidence that iron supplementation is needed or helpful on relugolix. Any anemia identified during relugolix treatment outside the heavy-menstrual-bleeding indication should be worked up on its own merits, not assumed to reflect this pattern.

Limits on what this shows

• Key negative/null findings: Dietary copper was equally deficient in all four groups; the study did not measure serum copper or ceruloplasmin directly, only anemia severity and survival as functional/outcome endpoints, so it does not demonstrate that relugolix changes copper status, only that androgen status modulates outcomes under a fixed deficiency. A separate estrogen-focused source, Mehta and Eikum, "Effect of estrogen on serum and tissue levels of copper and zinc" (Advances in Experimental Medicine and Biology, 1989, PMID 2626984), is titled specifically around estrogen's effect on serum copper, but its abstract could not be independently retrieved this session (no reconstructable abstract available, and the publisher chapter was not opened); it is listed in Sources but not used to support this entry, consistent with this protocol's rule against citing unopened content.
• At-risk subgroups: Not established for relugolix in either formulation; the rat finding is specific to a background dietary copper deficiency, which is not established as prevalent in relugolix-treated patients.
• Counter-evidence on record: None found in the reverse direction. This entry is graded yellow because real, if narrow and outcome-based, Tier C mechanistic evidence exists, not because a depletion or protective serum-copper effect has actually been shown.

Regulatory status

Not addressed on either label.

Population evidence

"Sexual differences in the expression of copper deficiency in rats" (Experimental Biology and Medicine, 1987, PMID 3671356): intact and castrated male rats, and intact and ovariectomized female rats, fed a copper-deficient, fructose-containing diet for 8 weeks. Intact males developed anemia, cardiac hypertrophy, and died from the deficiency; castration reduced anemia severity and delayed mortality but did not prevent it. Female rats did not die regardless of hormone status. No relugolix, GnRH-antagonist, or human study exists; this is Tier C class-level evidence (surgical androgen removal, not this drug specifically).

Mechanism

Named at the class/hormonal level: testosterone appears to worsen physiological vulnerability to an already copper-deficient diet in male rats; removing testosterone, the pharmacologic analog of what Orgovyx produces, is protective in this narrow toxicological sense. The pathway connecting androgen status to copper-deficiency tolerance, versus copper absorption or serum level itself, is not established.

Counter-evidence held on record

This is not evidence that copper supplementation is needed, protective, or harmful during relugolix therapy; it is a narrow 1987 rat toxicology finding about sensitivity to a background dietary deficiency, not a measured effect on relugolix-treated patients' copper status.

Limits on what this shows

• Key negative/null findings: Ishida et al. found overall diversity indices were stable; only specific genera shifted, arguing against a broad dysbiosis and for a narrower, hormone-tracking compositional change.
• At-risk subgroups: Men achieving very low testosterone (<20 ng/dL), expected with any effective ADT including Orgovyx. Not established for the Myfembree/estradiol-suppression side; only rodent ovariectomy-model literature was located there, and individual article pages were not independently opened this session for content beyond title.
• Counter-evidence on record: None found contradicting the direction; multiple independent human studies converge qualitatively, a stronger evidence base than a single study, though still capped at yellow since relugolix itself was not confirmed in any cohort.

Regulatory status

Not addressed on either label.

Population evidence

Ishida et al. (The Prostate 2025, PMID 41389040), a prospective Japanese cohort of men with high-risk localized prostate cancer starting ADT (enrolled March 2021 to August 2022): overall microbial diversity remained stable, but specific genera, Ruminococcus 2 and Eubacterium ruminantium, increased significantly after 3 months of ADT, with men reaching very low testosterone (<20 ng/dL) showing higher Ruminococcus 2 proportions, a dose-response pattern. Kure et al. (Prostate Cancer and Prostatic Diseases 2022, PMID 35418210) and Wang (Prostate Cancer and Prostatic Diseases 2023, PMID 37696986) separately report gut-microbial-profile changes with androgen deprivation therapy, including long-term ADT; a 2023 Chinese-language review (Zhonghua Yi Xue Za Zhi, PMID 36597735) surveys this literature. None of these sources' abstracts, as retrieved this session, name relugolix among the ADT agents used, and cohort drug composition could not be confirmed beyond abstract-level data; treated as Tier C class-level evidence for relugolix specifically.

Mechanism

Named at the class/hormonal level (mechanism G, microbiome disruption): testosterone suppression is linked to dose-dependent shifts in specific gut-bacterial genera across multiple independent human ADT cohorts, though not for relugolix by name.

Counter-evidence held on record

This is a class-level compositional signal from androgen suppression generally, not a relugolix-specific finding, and it is not evidence that probiotic or prebiotic supplementation is needed or beneficial during relugolix therapy; no such intervention has been tested in this population.

Limits on what this shows

• Key negative/null findings: The 28% versus 29% incidence is nearly identical between relugolix and the leuprolide comparator, arguing this is a class-wide consequence of adequate androgen-axis suppression itself, not something distinctive to relugolix's chemistry. Serum ferritin, transferrin saturation, and hepcidin were not reported in the located sources; only hemoglobin (a functional marker) was quantified, and there is no indication this represents iron-deficiency anemia specifically.
• At-risk subgroups: Not separately named beyond the overall trial population; risk would track with degree and duration of testosterone suppression, which for advanced prostate cancer is typically long-term or lifelong, unlike the 24-month duration cap on the Myfembree combination product discussed below.
• Counter-evidence on record: None found contradicting the direction of this finding. See the framing caution: this must not be conflated with, or averaged against, the opposite-direction Myfembree finding below, which occurs in a different drug combination, sex, and population.

Regulatory status

FDA ORGOVYX PI, Section 6.1, Table 2 (HERO trial laboratory abnormalities, ≥15% incidence): "Hemoglobin decreased," 28% all grades / 0.5% Grade 3-4 on relugolix (N=622) versus 29% all grades / 0.7% Grade 3-4 on leuprolide. Fracture is separately listed among adverse reactions requiring dosage interruption in 0.3% of relugolix-treated patients (Section 6.1).

Population evidence

HERO trial: international phase 3 RCT, N=930 (622 relugolix 120 mg once daily, 308 leuprolide depot injection), men with advanced prostate cancer requiring androgen deprivation, 48-week primary endpoint (Shore et al., NEJM 2020). [5] An independent Canadian Agency for Drugs and Technologies in Health (CADTH) clinical review of the same trial separately confirms: "Loss of bone mineral density was reported in similar proportions in both groups." [6]

Mechanism

Named at the general endocrine-physiology level: testosterone supports erythropoiesis via stimulation of erythropoietin production and suppression of hepcidin; castration-level androgen suppression removes that stimulus, producing a mild normocytic anemia. This review located a specific mechanistic paper on this pathway (testosterone/erythropoietin/hepcidin) via search-result titles only, could not open it this session because of the disclosed tooling rate-limiting, and is therefore not cited here as supporting evidence, per this protocol's prohibition on citing unopened sources; the mechanism is stated as established general endocrinology, not tied to a specific citation verified this session.

Counter-evidence held on record

This is castration-associated anemia from reduced erythropoietin drive, not an iron or nutrient deficiency; iron supplementation is not indicated by this mechanism, and unexplained anemia in a patient on Orgovyx should be worked up on its own clinical merits rather than assumed nutritional. Do not average or merge this entry with the opposite-direction Myfembree entry below; they describe different drug products, populations, and mechanisms.

Limits on what this shows

• Key negative/null findings: No hematocrit, reticulocyte, ferritin, transferrin saturation, or arterial-oxygenation data beyond hemoglobin were located in the sources accessed for this review; the finding is specifically a hemoglobin-concentration result. A theoretical countervailing mechanism exists (estrogen normally suppresses hepcidin, favoring iron absorption, so any residual hypoestrogenism from incomplete add-back could theoretically blunt absorption), but the net measured direction in the actual trial population is clearly toward improvement.
• At-risk subgroups: Bounded specifically to women with pre-existing heavy-menstrual-bleeding-related anemia taking Myfembree for uterine fibroids. Not established, and not mechanistically expected, in men on Orgovyx monotherapy, or in women taking Myfembree for endometriosis pain without baseline heavy bleeding.
• Counter-evidence on record: None found contradicting this direction within its bounded population. See the Overlap map: this entry and the Iron entry below rest on the same LIBERTY 1/2 hemoglobin data and should not be counted as two independent confirmations of a single underlying effect.

Regulatory status

FDA MYFEMBREE PI, Section 14.1, labeled trial results, women with baseline hemoglobin low enough to qualify as anemic: Study L1, 44.2% achieved a >2 g/dL hemoglobin rise on MYFEMBREE versus 17.2% on placebo (difference 26.9 percentage points); Study L2, 55.0% versus 5.7% (difference 49.3 percentage points).

Population evidence

LIBERTY 1 and 2: two replicate international phase 3 RCTs, N=388 and 382 total, women with fibroid-related heavy menstrual bleeding, MYFEMBREE versus placebo, 24 weeks (Al-Hendy et al., NEJM 2021). [7] A 52-week completer analysis (N=363) reported that "anemia markers showed meaningful improvement" with sustained benefit (Al-Hendy et al., Obstet Gynecol 2022). [8] The LIBERTY randomized-withdrawal study confirmed durability of bleeding control to 76 weeks with continued treatment (Am J Obstet Gynecol 2023). [9]

Mechanism

Named and indirect: relugolix (via GnRH-receptor antagonism) suppresses the ovarian cyclicity driving heavy uterine bleeding; the estradiol/norethindrone acetate add-back stabilizes the endometrium. Reduced monthly blood loss reduces the ongoing iron loss and hemorrhagic drain on red-cell mass that was driving the pre-treatment anemia, allowing hemoglobin to recover over months of treatment. This is a hematologic outcome of reduced bleeding, not a direct effect of relugolix on erythropoietin, marrow function, or hemoglobin synthesis.

Counter-evidence held on record

This is the resolution of a pre-existing bleeding-related anemia, not evidence that relugolix or Myfembree improves oxygen delivery in general; it must not be extrapolated to athletic performance, altitude tolerance, men, or any population without baseline heavy menstrual bleeding, and it does not apply to Orgovyx.

Limits on what this shows

• Key negative/null findings: No direct ATP or energy-metabolism measurement, in relugolix patients or in either cited source's model, was located. The absence of fatigue as a top-tier labeled adverse reaction on either relugolix label is a mild piece of counter-evidence against a strong clinical energy-deficit signal, though it is not a direct physiological measurement.
• At-risk subgroups: Not established for relugolix specifically.
• Counter-evidence on record: Labeled adverse-reaction data, the absence of prominent fatigue, argues mildly against a clinically meaningful effect, though this does not rule out a subclinical change.

Regulatory status

Not addressed on either label. Fatigue is not listed among the ≥10% adverse reactions on the ORGOVYX label (most common: hot flush 54%, glucose increased 44%, triglycerides increased 35%), nor among MYFEMBREE's most common listed adverse reactions.

Population evidence

Same sources as Mitochondrial burden above. Tian et al. 2023 states mitochondria function as "the primary ATP production source" in skeletal muscle, tying the sarcopenia-associated mitochondrial quality-control decline described there directly to energy output; Ribas et al. 2016 describes muscle estrogen-receptor-alpha-knockout mitochondrial abnormalities (structure, reactive oxygen species, fission, turnover) without directly quantifying ATP synthesis rate.

Mechanism

Identical to Mitochondrial burden, extrapolated to ATP output as the sources' own stated downstream consequence rather than a separately measured endpoint in either source.

Counter-evidence held on record

Shares its evidence base with Mitochondrial burden above; see the Overlap map. No supplement or dosing recommendation follows from this entry.