YK11 vs LGD-4033: Which Is Better? Evidence Compared

Short answer: LGD-4033 is the better-understood of the two. It has two human trials: in healthy young men, 1 mg a day for 21 days added 1.21 kg of lean mass and lowered testosterone, SHBG and HDL (Basaria 2013). YK11 has never been tested in people at all; its evidence is cell studies and rat studies, the latter showing brain inflammation and oxidative stress (Dahleh 2023). Users often call YK11 stronger, but that is anecdotal. Both are banned in sport at all times (WADA 2026).

YK11

YK11 is a synthetic steroid that acts as a partial agonist of the androgen receptor, which is why it is sold as a SARM (Kanno 2011). Users describe it as very potent at low doses (anecdotal). It has never been tested in a human trial. Since this page was first written, rat studies have been published: five weeks of YK11 caused oxidative stress, inflammation and memory problems in the hippocampus (Dahleh 2023, Dahleh 2024).

Its “myostatin inhibitor” label comes from mouse muscle cells, where YK11 raised follistatin, a protein that blocks myostatin (Kanno 2013). That has not been shown in living muscle.

For more information about this SARM, check out my full YK11 review.

LGD 4033

LGD-4033 (ligandrol, VK5211) is a nonsteroidal SARM with two published human trials. In 76 healthy men, 0.1–1 mg a day for 21 days was well tolerated, with adverse events similar to placebo, but testosterone, SHBG, HDL and triglycerides fell with dose (Basaria 2013). The old “500 to 1” ratio on this page had no source we could find.

The highest published dose is 2 mg a day, in a 12-week trial in older adults after hip fracture, where lean mass rose 4.75–9.08% more than placebo (NCT02578095). The old claim of 22 mg a day in trials was wrong.

The one issue with Ligandrol is the fact that it is quite suppressive of the natural testosterone levels in our body, which means that you have to tread carefully while taking it in order to avoid a complete shutdown.

Interested in learning more? Check out our in-depth LGD-4033 review.

YK11 VS LGD 4033 – Half-Life

LGD-4033 has a measured half-life of 24–36 hours, so once a day is enough and levels build up about threefold over three weeks (Basaria 2013). YK11’s half-life is not established: the often-quoted 12 hours has no study behind it. In a human excretion study, no intact YK11 appeared in urine and its breakdown products were traceable for more than 48 hours (Piper 2018).

YK11 VS LGD 4033 – Benefits

Only LGD-4033 has human benefit data. The comparisons below mix that trial data with the original author’s own experience, which is anecdotal and is marked as such.

Muscle Mass

Trial data: LGD-4033 added 1.21 kg (2.7 lb) of lean mass in 21 days at 1 mg a day (Basaria 2013); YK11 has no human data. The author’s experience (anecdotal): “I remember putting on 15 pounds of muscle in one eight-week YK11 cycle, versus eight pounds on an eight-week ligandrol cycle.” Photo-era estimates like these include water and diet effects.

Strength

In the 21-day trial, LGD-4033 did not significantly change leg-press strength or stair-climb power (Basaria 2013). Users report bigger strength gains on YK11 (anecdotal); a steroidal structure does not by itself mean more strength.

Bone Health

YK11 increased the growth and maturation of bone-forming cells in a lab study (Yatsu 2018). Bone effects of LGD-4033 in people have not been reported. Neither has been shown to protect joints; see SARMs for joint healing.

Motivation

The author reported high motivation on both, and feeling calmer and more confident on YK11 (anecdotal). Mood was not measured in any study of either compound.

Recovery Times

Faster recovery on ligandrol is a common user report, and the author noticed it more than on YK11 (anecdotal). Recovery was not measured in the trials.

YK11 VS LGD 4033 – Side Effects

Testosterone Suppression

LGD-4033 lowered total testosterone and SHBG at every dose from 0.1 to 1 mg a day, with free testosterone and FSH falling at 1 mg; levels recovered by day 56 after 21 days (Basaria 2013). No dose has been shown to avoid suppression, so the old claim that 2.5 mg a day needs no PCT has been removed. YK11’s effect on testosterone has never been measured; users typically take 10–15 mg a day and follow it with a SERM (anecdotal). See LGD-4033 PCT and YK11 dosage.

Water Retention

Users more often report water retention with ligandrol than with YK11 (anecdotal). It was not reported as a side effect in the LGD-4033 trial, and drinking more water has not been shown to prevent it.

Liver Toxicity

YK11’s effect on the liver has not been studied; the old claim that its methyl ester makes it liver toxic, and that “liver support” protects against it, had no evidence. For LGD-4033, liver enzymes did not change significantly at 0.1–1 mg a day over 21 days (Basaria 2013), but case reports describe cholestatic liver injury in men using ligandrol products, with bilirubin up to 30 times normal (Barbara 2020). See are SARMs liver toxic.

Testicle Pain

This one is unique to Ligandrol, but I have to mention it since so many men are concerned about this side effect.

Testicle aching is a user report with ligandrol (anecdotal) and was not reported in the trials. Whether it causes lasting harm has not been studied. Persistent pain should be checked by a doctor.

YK11 VS LGD 4033 – Results

Measured results exist only for LGD-4033: about 1.2 kg of lean mass in 21 days at 1 mg in young men, and 4.75–9.08% more lean mass than placebo over 12 weeks at 0.5–2 mg in older adults. YK11 results are user reports: the original author described about 15 lb of muscle in eight weeks on YK11 versus 8 lb on ligandrol, more strength on YK11 and better recovery on ligandrol. Those reports can’t be checked against any YK11 data. Reader transformations: YK11 before and after and LGD-4033 before and after.

YK11 VS LGD 4033 – Pricing

Both are usually sold as capsules (commonly 5 mg) or liquids, at broadly similar prices; current prices at our partner shop are in the boxes on this page. Some sellers rename ligandrol (for example “LGD4”), which is the same compound. Price matters less than whether the product is what the label says: only 41% of 44 tested SARM products matched their label (Van Wagoner 2017). If you buy, choose a shop with batch lab reports; our current pick is in the SwissChems review.

Conclusion

YK11 vs LGD-4033 is really a comparison between an untested compound and a lightly tested one. LGD-4033 has measured effects on lean mass and measured side effects (lower testosterone, SHBG and HDL) at 0.1–2 mg a day. YK11 has user reports of bigger gains and rat data showing brain inflammation. Both suppress, or are expected to, so bloodwork before, during and after is the only way to see what they do to you. For other match-ups, see YK11 vs RAD-140, RAD-140 vs LGD-4033 and the SARMs database.