SARMs (selective androgen receptor modulators) occupy a strange space in the performance-enhancing world. They are not AAS, but they are not harmless either. They were developed to separate the anabolic effects of androgens from the androgenic side effects: and in some ways, they succeeded. But the bloodwork profile of SARMs reveals a different risk pattern: less estrogenic, less hematologic impact, but comparable or worse effects on lipids and liver function.
The mechanism behind SARMs explains their bloodwork signature. They bind androgen receptors with high affinity but recruit coactivators differently than testosterone, which is why they are less androgenic in skin and prostate. However, in the liver, they act as full agonists, which is why SHBG drops sharply and why liver enzymes rise. This tissue selectivity is not absolute. At doses above 20 mg/day for Ostarine or 10 mg/day for RAD-140, the selectivity window narrows, and you see more systemic suppression. That is why bloodwork at week 4 is not optional. It tells you whether your dose is still within the selective range or whether you have crossed into a generalized androgen effect that will hammer your HDL and HPTA.
If you are using or considering SARMs, here is exactly what to monitor before, during, and after: and how to interpret the results.
Pre-Cycle: The Complete Baseline
Baseline blood work before any SARM cycle is non-negotiable: even for "mild" compounds like Ostarine. Without a baseline, you cannot distinguish the SARM's effects from your pre-existing values, and you miss the trajectory that tells you whether your body is tolerating the compound.
If your baseline shows any red flag, do not start the cycle. For example, if your ALT is already 45 U/L (upper normal is around 40), a SARM like LGD-4033 can push it to 90 within two weeks. Similarly, if your HDL is already below 40 mg/dL, a 30% suppression will put you in the cardiovascular risk zone. And if your total testosterone is below 300 ng/dL, you are already hypogonadal; adding a SARM will only deepen that hole. In those cases, fix the underlying issue first. Recheck in 4 to 6 weeks. A clean baseline is not just a formality. It is the difference between a controlled experiment and a guessing game.
A baseline that shows LDL above 130 mg/dL or HDL below 40 mg/dL should give you pause. SARMs will only worsen that picture. If your liver enzymes are already above the upper reference limit, choose a less hepatotoxic compound or reconsider. Also, measure free testosterone via equilibrium dialysis if available, not just calculated. Calculated free T assumes normal SHBG, and SARMs will suppress SHBG, making calculated values unreliable. Your baseline free T is your reference point for post-cycle recovery, so accuracy matters. If you are over 35, add a PSA test to rule out subclinical prostate issues before starting.
Your pre-cycle panel should include:
Draw your baseline blood work fasted, in the morning, before any training or caffeine. Testosterone and cortisol are highest in the morning, and lipids are affected by recent food. If you train the day before, that can transiently elevate AST and ALT. So schedule your draw after a rest day. Also, do not take any supplements that affect liver enzymes or lipids for at least 48 hours before the draw. That includes fish oil, which can lower triglycerides, and any pre-workout with stimulants. The goal is a true baseline, not a best-case or worst-case snapshot. Consistency matters more than perfection. Use the same lab and the same time of day for every draw during and after the cycle.
- Hormones: LH, FSH, total testosterone, free testosterone (calculated or direct), SHBG, estradiol
- Liver: AST, ALT, GGT, total bilirubin
- Lipids: Total cholesterol, HDL, LDL, triglycerides, ApoB
- Metabolic: Fasting glucose, HbA1c
- Hematologic: CBC (hemoglobin, hematocrit, RBC count)
Pay special attention to SHBG. SARMs universally suppress SHBG by binding to androgen receptors in the liver, and the degree of SHBG suppression correlates with both efficacy and side effect severity. A pre-cycle SHBG above 30 nmol/L gives you more "room" before the SARM suppresses it to concerning levels.
When SHBG drops, free testosterone rises initially, which is why some users feel a surge in the first two weeks. But that free testosterone is also aromatized to estradiol, and because SHBG normally binds estradiol too, you can see estradiol spike even with total testosterone suppressed. This is why gynecomastia is possible on SARMs, especially with LGD-4033. If your estradiol goes above 50 pg/mL on a SARM cycle, lowering the dose is the safe first step to try yourself. An aromatase inhibitor can also address it, but that's a prescription medication — starting or dosing one is a decision for a licensed medical professional, not something to self-administer. Do not ignore it. High estradiol will blunt your gains, cause water retention, and worsen lipid profiles. Monitor estradiol at week 4, not just testosterone.
Why SHBG Matters for SARMs
Mid-Cycle Monitoring: Three Critical Areas
Once you start a SARM cycle, your blood work at week 4 and week 8 must focus on three areas where SARMs have the most significant impact:
Liver Enzymes (AST, ALT, GGT)
HDL Cholesterol
Total Testosterone
At week 4, check liver enzymes, HDL, and total testosterone. If ALT or AST has tripled from baseline, consider stopping the SARM. If HDL has dropped below 25 mg/dL, add omega-3s (3-4 g/day EPA+DHA) and reassess at week 8. If total testosterone is below 100 ng/dL, plan for PCT: suppression at this level will not self-resolve quickly.
If your total testosterone is below 100 ng/dL at week 4, you are severely suppressed. Do not wait until week 8 to plan PCT. This is where you want a licensed medical professional or a knowledgeable prescriber involved: SERMs like clomiphene, tamoxifen, and enclomiphene are prescription medications, and getting the dose and duration right matters for both effectiveness and side effects. The key is to act early — suppression that lasts longer than 8 weeks increases the risk of Leydig cell desensitization, which can prolong recovery. Also, if your LH is below 1.0 mIU/mL at week 4, that indicates central suppression, and a SERM is more effective than waiting for natural recovery.
SARM vs. AAS: Bloodwork Impact Compared
| Marker | SARMs | AAS |
|---|---|---|
| HDL suppression | 20–50% (comparable to moderate AAS) | 30–70% (dose-dependent) |
| Liver toxicity | Moderate–high (LGD, RAD: ~30% get elevated ALT/AST) | Depends on compound; orals > injectables |
| Testosterone suppression | Significant (LGD, RAD: 60–80%) | Complete (all AAS suppress HPTA) |
| Estrogenic effects | Minimal to none | Varies (aromatizing vs. non-aromatizing) |
| Hematocrit impact | Mild (5–15% increase) | Moderate–high (20–40% or more) |
| SHBG suppression | Universal and pronounced | Varies by compound |
| Creatinine impact | Minimal | Significant (muscle mass + training) |
| PCT typically needed? | Yes for LGD, RAD, S-23. Possibly for Ostarine. | Yes, for any suppressive cycle |
Post-Cycle: HPTA Recovery and Confirmation
Post-cycle blood work for SARMs follows the same principles as AAS, but the timeline may be shorter. Most SARM users recover endogenous testosterone production within 4-8 weeks of stopping, compared to 8-16 weeks for traditional AAS cycles. However, recovery is not guaranteed: especially with longer cycles or higher doses.
Recovery timing depends on the specific SARM and dose. LGD-4033 at 10 mg/day for 8 weeks causes deeper suppression than Ostarine at 20 mg. If you used a SARM with a long half-life like RAD-140 (60 hours), expect a longer recovery. Do not start PCT until you have confirmed suppression with bloodwork at 4 weeks post-cycle. A common mistake is starting a SERM immediately after the SARM clears, before confirming suppression is actually present — that can overstimulate LH and cause estrogen spikes. Instead, wait for LH to drop below 3.0 mIU/mL. If LH is still above 3.0 at 4 weeks, your HPTA is already recovering. Use PCT only when needed, under a licensed medical professional's guidance, and monitor estradiol during PCT to avoid iatrogenic highs.
Post-cycle monitoring timeline:
- 4 weeks post-cycle: Check LH, FSH, total testosterone. LH should be above 3.0 mIU/mL. If still suppressed, continue monitoring.
- 8 weeks post-cycle: Full hormone panel. LH > 4.0, FSH > 4.0, total testosterone > 350 ng/dL suggests adequate recovery.
- 12 weeks post-cycle: Confirmation panel. Total testosterone should be at or near baseline. If still below 300 ng/dL, consider medical evaluation and possible TRT discussion.
SARM Stacking Is Not Smarter
Common SARM Bloodwork Mistakes
Even experienced SARM users make these mistakes. Avoiding them keeps your data clean and your health protected:
Another mistake is testing at different times of day or after a heavy meal. For example, if you draw blood at 7 AM fasted for baseline, then at 3 PM after lunch for week 4, your testosterone will be 20 to 30% lower due to circadian rhythm, and your triglycerides will be elevated. That will make you think the SARM is hitting you harder than it is. Always draw at the same time, fasted, and after a rest day. Also, do not compare values from different labs. Assays vary. If you switch labs, re-establish a baseline. Consistency in testing conditions is as important as the compounds themselves. Without it, you are making decisions on noise, not signal.
- Skipping pre-cycle baselines. Without a baseline, you cannot quantify the SARM's impact. A "normal" ALT at week 4 could be a 3x increase from your personal normal: and you would not know it.
- Ignoring HDL trajectory. A single HDL of 35 mg/dL at week 4 might seem acceptable. But if your baseline was 65, that 46% drop is a signal that the compound is hitting your lipids hard. Track the percentage change, not just the absolute value.
- Assuming no PCT needed for "mild" SARMs. Ostarine at 25 mg/day for 8 weeks can suppress testosterone by 40-50%. While many users recover without PCT, monitoring is essential: and some will need pharmacological support.
- Running cycles longer than 8 weeks. Extended SARM cycles (12+ weeks) produce progressive liver and lipid damage without additional benefit. The risk-reward ratio shifts negatively after week 8.