On-Cycle Support Protocol: Every Supplement Mapped to Your Bloodwork

Most on-cycle support advice boils down to "take TUDCA and fish oil." Well-intentioned, but incomplete. Steroid cycles damage multiple organ systems at the same time: liver, lipids, haematology, glucose metabolism, cardiac tissue. A protocol that only covers one or two of these leaves gaps that show up when bloodwork comes back ugly, or worse, that never show up on standard panels at all.

This article takes a different approach. Instead of listing supplements and hoping you figure out which ones you need, every recommendation is mapped directly to the blood marker it protects. You will know exactly what each supplement does, which lab value confirms it is working, and when to escalate from supplement support to pharmaceutical intervention.

How to use this protocol

Every supplement in this guide is assigned an evidence grade:

• Grade A: Supported by randomized controlled trials in relevant populations. Strong mechanistic basis confirmed by clinical outcomes.
• Grade B: Supported by observational studies, animal models, or RCTs in adjacent populations (e.g., heart failure patients, diabetics). Plausible mechanism, limited direct data in AAS users.
• Grade C: Traditional use, in-vitro data, or anecdotal bodybuilding consensus without published human trials. May still be worth including based on safety profile and cost.

The core principle: every supplement should have a blood marker you can check. If you cannot measure whether something is working, you are guessing.

Master supplement-to-marker map

This is your reference table. Each row connects a supplement to the organ system it protects, the specific blood markers you should monitor, and the evidence grade supporting its use.

Liver protection: TUDCA and NAC

Oral steroids attack the liver through two distinct pathways, and most athletes only protect against one.

TUDCA: the cholestasis shield

TUDCA (tauroursodeoxycholic acid) protects against bile flow obstruction, the more dangerous form of liver damage from C17-alpha alkylated steroids. Compounds like Dianabol, Anadrol, and Superdrol inhibit the bile salt export pump (BSEP), trapping toxic bile acids inside hepatocytes.

TUDCA displaces these toxic bile acids competitively. In the largest dose-response trial, Crosignani et al. tested 500, 1000, and 1500 mg/day in patients with primary biliary cirrhosis. All three doses significantly reduced liver enzymes after the first month, with the 1000 and 1500 mg doses showing further improvement over time (Crosignani et al., 1996). Even the 500 mg dose worked for mild elevation.

Dosing protocol:

• Injectable-only cycle (no orals): not required, but 250-500 mg/day is reasonable insurance
• Mild oral (Anavar, Turinabol): 500 mg/day
• Moderate oral (Dianabol, Winstrol): 1000 mg/day
• Harsh oral (Anadrol, Superdrol, Halotestin): 1500 mg/day

Warning about TUDCA and UDCA overlap: TUDCA is the taurine conjugate of UDCA. Taking both simultaneously offers no additional benefit since they compete for the same bile acid receptors. Choose one, not both.

NAC: the oxidative damage shield

N-acetylcysteine works through a completely different mechanism than TUDCA. It replenishes glutathione, the liver's primary antioxidant, protecting against the reactive oxygen species generated by alkylated steroids inside hepatocytes.

The best preventive data comes from Baniasadi et al. (2010), who gave 600 mg NAC twice daily to patients starting hepatotoxic anti-tuberculosis drugs. Hepatotoxicity occurred in 37.5% of controls but 0% of the NAC group (Baniasadi et al., 2010). Sukumaran et al. (2023) found similar liver function improvements with NAC co-administration in TB patients, with significantly better liver enzyme profiles at 4 and 8 weeks compared to placebo (Sukumaran et al., 2023).

The timing myth: NAC is often recommended only during the cycle. But the Baniasadi data used NAC from day one of hepatotoxic drug exposure, not as rescue therapy after enzymes spike. Start NAC before or with your first oral dose, not after bloodwork already shows damage.

Dosing: 600 mg twice daily (1200 mg total). Take on an empty stomach for best absorption.

When to escalate beyond supplements

Supplements have limits. If your ALT exceeds 5x the upper reference limit (roughly >200 U/L) or bilirubin starts climbing (a sign of cholestasis, not just hepatocellular damage), stop the oral compound. No amount of TUDCA or NAC will save you from a Superdrol cycle that causes severe cholestatic hepatitis. In a case series of five previously healthy men who used methasteron (Superdrol), all developed jaundice with bilirubin levels peaking weeks after discontinuation (Shah et al., 2008).

For a deep dive on liver enzyme interpretation, compound hepatotoxicity rankings, and the GGT trick for distinguishing liver damage from muscle damage, see our TUDCA and NAC liver protection guide and liver enzymes on steroids.

Lipid management: the triple stack

Steroid cycles, especially those including oral compounds, can suppress HDL by 50-78% and raise LDL by 36% on average. No single supplement reverses this. But three supplements working through different mechanisms can meaningfully limit the damage.

Why you need to start before the cycle

This is the most underappreciated part of lipid support. Each supplement has a different time-to-effect:

• Omega-3: 4 weeks to measurable triglyceride reduction
• Citrus bergamot: 6 weeks to LDL impact
• Berberine: 8 weeks to significant LDL receptor upregulation

If you start these on day one of your cycle, you are unprotected during the exact window when oral steroids hit your lipids hardest (HTGL activity triples within 72 hours of first oral dose). Start your lipid stack 4-6 weeks before cycle day one.

Omega-3 fatty acids (Grade A)

High-dose fish oil (2-4 g combined EPA+DHA per day) reduces triglycerides by 15-30% and modestly raises HDL. The mechanism is well-established: omega-3s reduce hepatic VLDL synthesis and secretion, the precursor particle for LDL production.

The REDUCE-IT trial showed cardiovascular event reduction with 4 g/day of icosapent ethyl (pure EPA), but even standard fish oil at 2 g EPA+DHA shows consistent triglyceride lowering in meta-analyses.

Dosing: 2-4 g of combined EPA+DHA per day (not total fish oil; read the label). Take with a fat-containing meal for absorption.

Citrus bergamot (Grade B)

Bergamot polyphenols inhibit HMG-CoA reductase, the same enzyme targeted by statins, though with much lower potency. Clinical trials show 15-25% LDL reduction at 500-1000 mg/day of standardized extract.

No RCT has tested bergamot in AAS users specifically. The evidence comes from hyperlipidaemic populations. But the mechanism is sound, the safety profile is excellent, and it complements omega-3 (which works on triglycerides/VLDL) by targeting LDL through a separate pathway.

Dosing: 500 mg twice daily of standardized bergamot polyphenol extract (look for 38% or higher flavonoid content).

Berberine (Grade A for LDL and glucose)

Berberine upregulates LDL receptors on hepatocytes, increasing clearance of LDL particles from circulation. It also activates AMPK, which improves glucose uptake and insulin sensitivity. That makes it a two-for-one supplement for cycles that include compounds affecting glucose metabolism (like MK-677 or growth hormone).

Yin et al. (2008) showed berberine reduced HbA1c from 9.5% to 7.5%, comparable to metformin, in a head-to-head RCT of type 2 diabetics (Yin et al., 2008).

Dosing: 500 mg two to three times daily with meals. Cap use at 90 days continuously, then cycle off for 2-4 weeks. Extended use beyond 90 days shows diminishing returns in clinical data.

Caution: Berberine inhibits CYP3A4 and CYP2D6. If you take pharmaceutical AIs like anastrozole or any prescription medications metabolized by these enzymes, discuss with your physician.

When to escalate: the ApoB checkpoint

If your ApoB exceeds 130 mg/dL despite the triple supplement stack, supplements alone are not enough. This is when the conversation with your doctor about prescription lipid-lowering therapy (statins, ezetimibe) becomes necessary. ApoB is a better predictor of cardiovascular risk than LDL-C because it counts the actual number of atherogenic particles, not just the cholesterol they carry.

For compound-by-compound lipid impact rankings, recovery timelines, and the aromatization factor, see our cholesterol on steroids guide. For a head-to-head ranking of lipid supplements with clinical data, see our cholesterol supplements ranked article.

Haematology management: polycythaemia prevention

Testosterone and most AAS stimulate erythropoietin (EPO) production, increasing red blood cell mass. This is why haematocrit creeps up on cycle. A systematic review and network meta-analysis by Nackeeran et al. (2022) found that intramuscular testosterone cypionate/enanthate increased mean haematocrit by 4.0%, compared to just 1.4% with transdermal patches, a statistically significant difference (Nackeeran et al., 2022).

A haematocrit above 54% increases blood viscosity and thrombotic risk. Most clinicians use this as the threshold for therapeutic phlebotomy.

Naringin (Grade B)

Naringin, the flavonoid responsible for grapefruit's bitter taste, has an unusual property: it appears to normalize red blood cell parameters rather than simply suppress them. Robbins et al. (1988) found a statistically significant normalizing effect on erythrocyte counts (p < 0.01) in subjects consuming naringin-containing grapefruit juice (Robbins et al., 1988).

Jung et al. (2003) confirmed safety at 400 mg/day for 8 weeks with no adverse effects on blood counts or organ function, while also lowering total cholesterol by 14% and LDL by 17% in hypercholesterolaemic subjects (Jung et al., 2003).

Dosing: 500-1000 mg/day of naringin extract. Grapefruit juice is an alternative source but requires 2-3 glasses daily for equivalent dosing, and the sugar content adds up.

Grapefruit interaction warning: Naringin and its metabolite naringenin inhibit CYP3A4, the same enzyme interaction that makes grapefruit juice contraindicated with many medications. If you use prescription aromatase inhibitors, statins, or calcium channel blockers, this interaction can increase drug levels. Discuss with your physician.

Hydration and donation

Beyond supplementation, two practical interventions help manage haematocrit:

Dehydration concentrates blood and inflates haematocrit readings. Make sure you are well-hydrated before blood draws, but do not overhydrate, as this can dilute readings and mask real elevation.

If haematocrit exceeds 54% despite naringin and hydration, removing 450-500 mL of blood through donation or therapeutic phlebotomy is the definitive intervention. Some athletes on long-term TRT or blast-and-cruise schedules need this every 8-12 weeks.

For the full haematology picture on cycle, including haemoglobin, MCV, and differential white cell changes, see our haematology panel for enhanced athletes and TRT haemoglobin and haematocrit guide.

Prolactin control: P5P and the cabergoline escalation ladder

19-nor compounds (Deca, Trenbolone, MENT) can elevate prolactin through direct dopamine receptor interactions. Elevated prolactin causes sexual dysfunction, gynecomastia, and mood disturbances. That combination derails cycles and gets misattributed to estrogen problems.

P5P: the first-line supplement (Grade B)

Pyridoxal-5-phosphate (P5P) is the active form of vitamin B6. The standout study is Zhuo et al. (2021), an RCT of 200 patients that found high-dose B6 (300 mg twice daily) reduced prolactin by 68.1%, outperforming aripiprazole at 37.4% reduction (Zhuo et al., 2021).

Why P5P specifically, and not regular pyridoxine (the common supplement form)? Vrolijk et al. (2017) documented the "B6 paradox": at high doses, pyridoxine actually inhibits pyridoxal-5-phosphate (the active coenzyme) and can cause peripheral neuropathy (Vrolijk et al., 2017). P5P bypasses this conversion problem entirely, delivering the active coenzyme form directly.

Dosing: 50-100 mg/day of P5P. Start at 50 mg and increase if prolactin remains elevated on bloodwork.

When to escalate to cabergoline

If prolactin stays above 25-30 ng/mL despite P5P supplementation, cabergoline is the pharmaceutical escalation. Cabergoline is a potent dopamine D2 receptor agonist that reliably normalizes prolactin, but it is a prescription medication with its own side profile (nausea, orthostatic hypotension, and at high chronic doses, cardiac valve concerns).

The escalation ladder: P5P first for 4-6 weeks, check prolactin levels, then cabergoline only if P5P fails. Most athletes on 19-nor compounds at moderate doses will manage prolactin with P5P alone.

Glucose and insulin sensitivity: the MK-677 and GH problem

MK-677 (ibutamoren) and exogenous growth hormone both impair glucose metabolism through GH-mediated insulin resistance. MK-677 is particularly problematic because it is taken daily for months, creating chronic GH elevation that progressively worsens insulin sensitivity.

The mechanism is straightforward: growth hormone opposes insulin's action on muscle and fat tissue, reducing glucose uptake. Over weeks to months, this shows up as elevated fasting glucose, rising HbA1c, and increased fasting insulin levels.

Berberine for glucose management (Grade A)

Berberine pulls double duty here: it manages both the lipid damage from AAS and the glucose dysregulation from GH secretagogues. Yin et al. (2008) showed berberine reduced HbA1c from 9.5% to 7.5% in diabetics, rivalling metformin (Yin et al., 2008). The AMPK activation pathway is the same one metformin uses, which is why the two show comparable glucose-lowering effects.

Dosing for glucose: 500 mg with each meal (1500 mg total daily) when running MK-677 or GH.

Dihydroberberine is the tolerability upgrade, not an efficacy upgrade. Berberine's problem is that it absorbs badly and wrecks some people's guts at the doses that work. Dihydroberberine is a reduced form that solves the absorption half convincingly: 100 mg produced roughly nine times the peak plasma berberine of a 500 mg berberine dose (Moon et al., 2021). Be careful what you conclude from that. The same trial measured glucose and insulin and found no significant difference between any condition, and it ran five participants over a single day. So the absorption advantage is established and the glycaemic benefit is not. Use it at 100-200 mg twice daily if berberine upsets your stomach, and treat it as a swap rather than an addition.

Chromium picolinate (Grade C)

Chromium enhances insulin receptor signaling, but the clinical evidence is mixed. Studies in non-diabetic populations generally show minimal effect. Only worth considering if fasting glucose is already elevated (>100 mg/dL) and you want an additional low-cost intervention alongside berberine.

Dosing: 200-1000 mcg/day. Do not exceed 1000 mcg.

When to escalate to metformin

If fasting glucose exceeds 110 mg/dL or HbA1c rises above 5.7% despite berberine, talk to your physician about metformin. Many bodybuilders on long-term GH or MK-677 protocols end up on metformin prophylactically, and there is good clinical logic behind it: metformin has a decades-long safety record and directly counters GH-induced insulin resistance.

For the full guide to GH, MK-677, and insulin resistance management, see our GH and insulin resistance article.

Cardiac and mitochondrial protection

This category gets overlooked in on-cycle support discussions, but it should not be. Clenbuterol depletes cardiac taurine reserves within 3 hours of administration (Doheny et al., 1998). High-dose AAS cause left ventricular hypertrophy over time. These are the risks that do not show up on standard bloodwork until the damage is advanced.

CoQ10 (Grade A for cardiac protection)

Coenzyme Q10 supports mitochondrial electron transport and acts as a lipid-soluble antioxidant in cardiac tissue. The Q-SYMBIO trial (n=420) found that CoQ10 at 300 mg/day reduced cardiovascular mortality by 43% in heart failure patients over 2 years (Mortensen et al., 2014).

CoQ10 also matters specifically for anyone on statins: statins inhibit the mevalonate pathway, which produces both cholesterol and CoQ10. If you escalate to statin therapy for lipid management, CoQ10 supplementation becomes close to mandatory.

Dosing: 200-300 mg/day of ubiquinol (the reduced, more bioavailable form). Take with a fat-containing meal.

Taurine (Grade A for blood pressure)

Taurine is the most abundant free amino acid in cardiac tissue. A meta-analysis of taurine supplementation trials found it reduced systolic blood pressure by 4.38 mmHg on average, a clinically meaningful reduction for athletes on compounds that raise blood pressure.

The clenbuterol connection makes taurine non-negotiable for anyone using clen. Doheny et al. (1998) showed that clenbuterol significantly depletes myocardial taurine within 3 hours of a single dose, with levels remaining depressed at 12 hours before recovering at 24 hours (Doheny et al., 1998).

Dosing: 3-6 g/day, split into two doses. 3 g is sufficient for general cardiac support; use 6 g if you are running clenbuterol.

Blood pressure and vascular protection

Blood pressure is the marker this crowd neglects most, and one of the few that does damage quietly for years. It is also directly caused by what you are running: in amateur bodybuilders measured on and off cycle, diastolic pressure and mean arterial pressure both rose significantly during use and normalised 6 to 8 weeks after stopping (Grace et al., 2003). Long-term users show worse: thicker interventricular septum, thicker posterior wall, and a sympathetic shift that correlates with both the pressure rise and the hypertrophy (Barbosa Neto et al., 2018).

Your marker here is a cuff, not a blood tube. Measure it seated, twice, morning and evening, and average the week.

Magnesium (Grade A)

A meta-analysis of 34 trials found oral magnesium at a median 368 mg/day of elemental magnesium lowered systolic pressure by 2.00 mmHg and diastolic by 1.78 mmHg, with 300 mg/day and one month being enough to shift both serum magnesium and pressure (Zhang et al., 2016). That is a small effect on its own. It roughly doubles to 4.18/2.27 mmHg in people with insulin resistance or prediabetes (Dibaba et al., 2017), which is exactly the group running GH, MK-677 or insulin.

Dosing: 300-400 mg/day elemental magnesium. Ignore the form wars. The one human absorption study comparing forms found bisglycinate, the form most heavily marketed for this purpose, produced no significant plasma rise over six hours while oxide and citrate did (Pajuelo et al., 2024). It is a small, single-dose, manufacturer-sponsored study, so treat it as a reason to stop paying a premium rather than proof that glycinate is useless.

Expect: 2 mmHg if your metabolic health is fine, closer to 4 mmHg if it is not, within 4 to 12 weeks.

Vitamin C (Grade B for blood pressure)

Twenty-nine trials at a median 500 mg/day over a median 8 weeks give a pooled 3.84 mmHg systolic and 1.48 mmHg diastolic reduction (Juraschek et al., 2012). That is a better return than magnesium for less money.

What it does not do is worth stating, because it is sold on exactly these claims. A meta-analysis of 18 exercise-specific trials found no effect on cortisol, no effect on muscle soreness, no effect on strength, and no effect on CRP after acute exercise (Righi et al., 2020). Take it for your blood pressure, not your recovery.

Dosing: 500 mg/day. Expect: roughly 4/1.5 mmHg over 8 weeks.

Telmisartan (Grade A, prescription)

This is a real antihypertensive, not a supplement, and it needs a doctor. It earns its place here because of a property most angiotensin receptor blockers do not have: partial PPAR-gamma activation, which improves insulin sensitivity as a side effect of lowering pressure. In non-diabetic hypertensive patients, high-dose telmisartan significantly reduced serum insulin and HOMA-IR over six weeks where a calcium channel blocker did not (Benndorf et al., 2006).

Head to head against losartan over 8 weeks, telmisartan dropped systolic pressure 22.1 mmHg against losartan's 16.5 mmHg, and far fewer patients needed a dose increase (Lee et al., 2004).

For anyone whose pressure is genuinely high on cycle and who is also fighting GH-driven insulin resistance, telmisartan addresses both. We cover the full protocol in how to lower blood pressure on cycle.

Tadalafil and vitamin K2: two honest downgrades

Tadalafil gets recommended for vascular health as much as for its actual purpose. The largest pooled analysis, 63 trials across the PDE5 inhibitor class, found a 2.80 mmHg systolic and 1.80 mmHg diastolic reduction plus a genuine improvement in flow-mediated dilation (Zhang et al., 2025). A stricter meta-analysis correcting for heterogeneity and publication bias concluded the endothelial benefit was "not convincing" (D'Andrea et al., 2019). Take tadalafil if you want tadalafil. Do not take it as a blood pressure drug.

Vitamin K2 is the more interesting cautionary tale. At 180 mcg/day of MK-7 over three years, arterial stiffness improved and the calcification marker dp-ucMGP halved (Knapen et al., 2015). Then a trial gave 720 mcg/day for two years to men with existing aortic valve calcification. The biomarker moved hard, from +45 to -212 pmol/L against placebo. The actual calcium score did not move at all: 275 versus 292 Agatston units (Diederichsen et al., 2022).

That is the cleanest illustration in this whole article of why we anchor supplements to markers and then stay sceptical about the marker. K2 reliably improves a proxy for vascular calcification. Whether it improves vascular calcification is unproven. Take it if you like, at 180 mcg/day, and understand you are buying a biomarker.

Micronutrients: which ones move a marker, and which do not

The pattern across every micronutrient below is the same. They work if you are deficient and they do essentially nothing if you are not. Which means the honest first step is a blood test, not a purchase.

Zinc (Grade C unless you are actually deficient)

This is the one this community gets most wrong. The famous finding is real: when researchers experimentally restricted dietary zinc in healthy young men, total testosterone fell from 39.9 to 10.6 nmol/L, and supplementing marginally deficient elderly men roughly doubled it (Prasad et al., 1996).

Now the part nobody quotes. In healthy exercising men who were already zinc-replete, a high-dose zinc supplement raised serum zinc significantly and moved total and free testosterone by nothing at all (Koehler et al., 2009). Even in men with diagnosed hypogonadism on hCG and FSH, adding 40 mg/day of zinc produced benefit the authors themselves described as "very subtle" (Liu et al., 2017).

If you eat 200 g of protein a day from meat and whey and take a multivitamin, you are not zinc deficient, and zinc will not raise your testosterone. Test serum zinc before you bother.

Dosing if deficient: 30 mg/day elemental. Recheck: serum zinc and testosterone at 3 to 6 months.

Selenium (Grade B, and only for one specific marker)

Selenium is worth taking if your thyroid antibodies are up, and close to pointless otherwise. The Cochrane review of selenomethionine at 200 mcg/day found significant reductions in anti-TPO antibodies, while explicitly noting that whether this translates into fewer symptoms or a lower levothyroxine dose was never established (van Zuuren et al., 2013). A later overview found the antibody drop appears at 3 and 6 months and is not sustained at 12 (Wang et al., 2023).

The T4 to T3 conversion claim is the weak one. A 501-person randomised trial in adults who were not selenium deficient found no effect on thyroid function at all, despite plasma selenium rising as expected (Rayman et al., 2008).

Dosing: 200 mcg/day as selenomethionine specifically, not selenite. Do not exceed 400 mcg/day from all sources. Marker: anti-TPO antibodies, not free T3. Recheck: 3 months, more reliably at 6.

Vitamin D3 (Grade A for deficiency, Grade D for testosterone)

Correct a deficiency because deficiency is bad for you. Do not correct it expecting a testosterone increase.

The trial everyone cites gave 3,332 IU/day for a year to vitamin D deficient men with low-normal testosterone and saw total testosterone rise from 10.7 to 13.4 nmol/L (Pilz et al., 2011). It was a subgroup of a weight loss trial with 31 men on vitamin D, not a purpose-built testosterone study, and it has not held up. A 2024 meta-analysis of 17 trials found a pooled increase in total testosterone so small it is clinically meaningless and no effect on free testosterone, SHBG, FAI, LH, FSH or oestradiol (Abu-Zaid et al., 2024). The most rigorous pooled analysis to date found no clear effect on total testosterone at all, with GRADE certainty rated low to very low (Paez-Allendes et al., 2026).

Dosing: enough to reach sufficiency, above 75 nmol/L. Marker: vitamin D. Not testosterone.

Inflammation: curcumin earns its place

Curcumin is the one supplement in this section with genuinely strong evidence, and the one most likely to be taken in a form that does nothing.

Raw curcumin is functionally unabsorbed. When 2 g was given to healthy volunteers, serum levels were undetectable or near it. Adding 20 mg of piperine raised bioavailability by 2000% (Shoba et al., 1998). If your curcumin does not contain piperine or use a lipidated or micellar carrier, you are swallowing an expensive dye.

Taken properly it works. A synthesis of 103 randomised trials across 7,216 participants rated CRP as one of only four outcomes with high-certainty evidence of benefit (Jafari et al., 2024). The magnitude tracks how inflamed you were to begin with: in rheumatoid arthritis it dropped CRP by 0.93 mg/L (Zhang & Niu, 2025), while in healthy physically active women 500 mg/day for 8 weeks produced a smaller but statistically real reduction (Salehi et al., 2021).

Dosing: 500-1000 mg/day of standardised extract with piperine. Marker: hs-CRP. Expect: a modest reduction over 8 weeks, larger if your baseline CRP is above 3 mg/L. Set expectations at inflammatory support, not hypertrophy.

The two that do not hold up

Every supplement guide is a list of things to buy. This section is the opposite, and it is the most useful part of the article.

DIM is not an aromatase inhibitor

DIM is stacked on cycle by people who want an over-the-counter alternative to anastrozole. It does not do that job, and the evidence is not ambiguous.

No human trial has ever shown DIM lowering total or free serum oestradiol in anyone. Its only measured endocrine effect is a shift in which oestrogen metabolites you excrete in urine, toward the 2-hydroxy pathway. In the original 19-person study that ratio rose 47% but missed statistical significance at P=0.059 (Dalessandri et al., 2004). A larger, better-controlled trial in BRCA1 carriers then failed to replicate even that, at P=0.35 (Nikitina et al., 2015).

Both studies were in women being investigated for breast cancer risk. There is no trial of DIM in men, and none in men on exogenous testosterone.

The mechanistic data points the wrong way entirely. In male rats at comparable doses, DIM reduced sperm quality and increased testicular apoptosis (Aksu et al., 2016), and in human prostate cells it acts as an androgen receptor antagonist (Le et al., 2003). An androgen receptor antagonist is close to the last thing you want in an on-cycle stack.

If your E2 is genuinely high and symptomatic, use a real aromatase inhibitor at the lowest effective dose and monitor it with bloodwork.

NMN raises a cofactor and nothing you can measure

NMN reliably raises blood NAD+. That much is settled across several trials. The question is whether anything downstream follows, and in the populations closest to this audience the answer is currently no.

In healthy older men, 250 mg/day for up to 12 weeks raised NAD+ significantly, produced only nominally significant changes in gait speed and grip strength that the authors themselves flagged as needing replication, and did nothing to body composition (Igarashi et al., 2022). In 48 amateur runners over 6 weeks, some aerobic measures improved while VO2max itself, oxygen pulse and peak power did not differ from baseline in any group (Liao et al., 2021).

One post-hoc analysis found higher NAD+ after supplementation correlated with higher triglycerides and higher ALT and AST (Kuerec et al., 2026). That is an association rather than proof of harm, but it is a strange thing to find in a supplement being sold for longevity, and it is the opposite of what you want on a cycle that is already stressing your liver and lipids.

There is no trial of NMN in bodybuilders, TRT users, or anyone on PEDs. It raises a number in your blood that no standard panel measures, and it has not been shown to move any number that one does.

Protocol builder: match your cycle type

Not every cycle needs the same support stack. Here are four common cycle archetypes with their minimum and recommended support protocols.

Injectable-only cycle (Test + Primo, Test + EQ, etc.)

Injectable-only cycles are the gentlest on bloodwork. HDL will still drop (9-16% with testosterone enanthate alone) but not catastrophically. Haematocrit management becomes the main concern on longer blasts.

Oral-heavy cycle (any cycle with Dbol, Anadrol, Winstrol, Superdrol)

Scale TUDCA dose to oral compound severity. Superdrol and Halotestin warrant the full 1500 mg. Anavar and Turinabol are fine at 500 mg.

19-nor cycle (Deca, Tren, MENT)

Prolactin management is the distinguishing concern here. Start P5P from day one; do not wait for symptoms. Trenbolone in particular hits lipids hard (comparable to oral compounds due to its resistance to aromatization), so the full lipid stack is warranted on tren cycles.

MK-677 or GH protocol

Glucose and insulin sensitivity are the primary concerns. If running MK-677 alongside an AAS cycle, combine this stack with the relevant cycle-type stack above.

For more on MK-677 and other peptide monitoring, see our SARMs and peptides bloodwork guide.

Timing, stacking, and blood test validation

The pre-cycle window

Start lipid supplements 4-6 weeks before cycle day one. Omega-3 needs 4 weeks, bergamot needs 6, and berberine needs up to 8 weeks for full LDL receptor upregulation. Liver support (TUDCA, NAC) can start on cycle day one since their mechanisms are more immediate.

Mid-cycle blood draw (weeks 4-6)

This is your first checkpoint. At minimum, pull:

• Liver panel: ALT, AST, GGT, bilirubin
• Lipid panel: total cholesterol, LDL, HDL, triglycerides, ApoB if available
• Haematology: haematocrit, haemoglobin, RBC
• Hormones: prolactin (if running 19-nors), estradiol
• Metabolic: fasting glucose, HbA1c (if running MK-677 or GH)

Compare results against your pre-cycle baseline. If any marker has moved beyond the expected range for your compounds, adjust supplementation or escalate before the problem compounds.

Post-cycle recovery confirmation

Do not assume markers normalize because you stopped the cycle. Some values (HDL, haematocrit) can take 8-12 weeks to recover. Pull a full panel 6-8 weeks after your last injection to confirm recovery.

For detailed blood test timing recommendations by compound and ester, see our blood test timing on TRT guide.

Minimum viable stack vs. comprehensive stack

If budget or pill fatigue limits you, here are the two tiers.

Minimum viable stack (3 supplements)

1. NAC (1200 mg/day) for liver antioxidant protection
2. Omega-3 (2 g EPA+DHA/day) for lipid baseline protection
3. CoQ10 (200 mg/day) for cardiac mitochondrial support

Total cost: roughly $30-50/month. These three cover the most critical organ systems with Grade A evidence.

Comprehensive stack (7+ supplements)

Add to the minimum: 4. TUDCA (500-1500 mg/day) if running oral steroids 5. Citrus bergamot (1000 mg/day) for additional LDL management 6. Berberine (1000-1500 mg/day) for LDL + glucose (especially with MK-677/GH) 7. P5P (50-100 mg/day) if running 19-nor compounds 8. Taurine (3-6 g/day) if running clenbuterol or compounds that raise blood pressure 9. Naringin (500-1000 mg/day) if haematocrit is trending high

Total cost: roughly $80-150/month. This is the full protocol for athletes running complex stacks with multiple compound classes.

Key takeaways

• Every on-cycle support supplement should map to a specific blood marker you can test. If you cannot measure the effect, you cannot manage it.
• Start lipid supplements (omega-3, bergamot, berberine) 4-6 weeks before cycle day one. They need time to reach effective levels.
• TUDCA and NAC protect against different liver damage pathways (cholestasis vs. oxidative). Use both when running oral steroids, and scale TUDCA dose to compound severity.
• P5P is the first-line supplement for prolactin management on 19-nor compounds. Escalate to cabergoline only if bloodwork confirms P5P is insufficient.
• Berberine pulls double duty: LDL reduction via LDL receptor upregulation and glucose management via AMPK activation. It is the single most versatile supplement on this list.
• ApoB >130 mg/dL despite full lipid stack means supplements are not enough. Discuss pharmaceutical intervention with your physician.
• CoQ10 and taurine are non-negotiable for cardiac protection, especially on clenbuterol (which depletes myocardial taurine within hours) or if escalating to statins (which deplete CoQ10).
• The minimum viable stack (NAC + omega-3 + CoQ10) costs $30-50/month and covers the three most critical organ systems with Grade A evidence.

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